Abiotic Salt Stress in Crop Species

Molecular markers provide a rapid approach to breeding for desired traits. To use them, it is necessary to
determine the linkage between quantitative trait loci (QTL) and such markers. This study was conducted to investigate the
genetic basis of salinity responses in Egyptian bread wheat (Triticum aestivum L.). In this context, a doubled haploid (DH)
population (SGDH) of 139 individuals was produced from the cross between two Egyptian breeding cultivars
(Sakha 93, salt tolerant) and (Gemmeza 7, salt susceptible). The DH population was tested under saline hydroponics
culture and various plant responses were measured. A molecular genetic map of the SGDH population covering 3645.3
cM, was constructed using Restriction Fragment Length Polymorphism (RFLP), Microsatellite or Simple Sequence
Repeats (SSR), and Amplified Fragment Length Polymorphism (AFLP) markers. In total, 325 loci along the 21 wheat
chromosomes were mapped. The B genome showed the highest number of mapped markers followed by the A and the D
genomes respectively. Interval and composite interval mapping (using QTL cartographer) were used to identify the
genomic regions controlling traits related to salt tolerance with a threshold of LOD 3. Analysis of QTLs has revealed the
approximate location of the significant markers associated with 12 traits related to salt tolerance traits across the A, B and
D genomes. Fifty five significant QTL were detected on 15 of the 21 chromosomes mapped in this study, for some of these
more than one QTL was identified. In many cases QTL were mapped very close to each other, indicating possible gene
clustering or pleiotropy. For some traits, the total percentage of phenotypic variation explained by all QTL exceeded
50-60% but on average it was in the region of 15%. Chromosomes of homologues groups 2 and 5 exerted the biggest effect
on most phenotypic traits, especially chromosomes 2B and 5B. The results indicated that there is considerable potential for
improving salt tolerance of hexaploid wheat by using marker-assisted selection.

One of the major issues facing humankind is global food security. A changing climate, coupled with a heightened consumer awareness of how food is produced and legislative changes governing the usage of agrichemicals for improving plant health and yield, means that alternative, more integrated and sustainable approaches are needed for crop management practices. To this end, there is increasing recognition of the value of the role of microbial inoculants in agriculture. The focus of this review is to understand how plant-growth-promoting bacteria and arbuscular mycorrhizal fungi can play a part in improving crop yield by promoting the health status of the plant through the sequestration of various nutrients and in the control of plant diseases.

A study was conducted to assess and map the  fertility status of salt affected soils in central rift valley of Ethiopia  Amibara Irrigation Project  area,  based on selected  soil  physico-chemical properties.  Based on  the information obtained from reconnaissance survey and  topographic
map of the study area, two hundred sampling  spot areas  were identified  and a total  of four hundred soil sample s were  collected  from two soil depth  using systematic sampling technique .  Then,  salinity  and sodicity  parameters for all soils were  analyzed.  Based on analytical  results,  the study  area was  classified  into 6 mapping  units:  non-saline non-sodic and saline soil  in  Vertisols;  whereas in Fluvisols, non-saline non-sodic, saline, saline-sodic and sodic soils  were indetified.  Triplicate soil samples from  6 mapping  units with 2 depths, a total of  36 soil samples were used for assessment of soil fertility status  and  mapping.  The results of the study revealed that the soil texture (silt and clay), BD, PD, TP, FC, PWP, AWHC and all  selected  soils chemical properties studied were significantly affected (P ≤ 0.05 and/or P ≤ 0.01) by salt affected soil except sand and C:N ratio were non-significant in Fluvisols.  In Vertisols, clay, BD, PD, TP, PWP, TN, C:N  ratio, Mg, K, CEC and PBS non-significantly affected salt affected soil  but the rest    parameters were  significantly  affected.  Furthermore, BD, TP, OM, TN, Av.P  and exchangeable  Na  were  significantly (P  <  0.05) affected by soil
depth in both soil types. The soils in the study area were loose soils with the BD of 1.46 to 1.48 g cm-3 in the Vertisols and 1.34 to 1.62 g cm-3
in the Fluvisols.  Highest values of  soil fertility indicating parameters such as TP (43.84 and 47.85 %), OM (1.75 and 1.59 %), TN (0.078 and
0.083%), Av.  P (44.50 and 34.80 mg kg-1), CEC (50.12 and 49.12  cmol kg-1), Fe (8.19 and 6.72 mg kg-1) and Zn (0.84 and 0.89 mg kg-1) in the Vertisols and Fluvisols,  respectively were recorded in non-saline non-sodic soil.  These properties  showed decreasing pattern  from non-saline non-sodic soil to other salt affected soil classes. This could be attributed to its relatively highest OM and lowest salt contents soil. In the case of Vertisols, OM and CEC values decline from non-saline non-sodic soil to saline soil with 12.0 % and 4.96 %,  respectively.  In  Fluvisols: OM values decline from non-saline non-sodic soil to saline-sodic soil with 54.08 %, whereas the  CEC values  decline  from non-saline non-sodic soil to  sodic soil  by  20.11 %.Furthermore, considering the soil depths, higher mean values of TN (0.085 and 0.067%), exchangeable Ca (37.97  and 32.42  cmol kg-1),  PBS  (90.30  and  94.71 %)  and Mo (0.084  and 0.138  mg kg-1) were  recorded in  the Vertisols and Fluvisols  respectively,  in  the  surface (0-20 cm) soil layer than in the subsurface (20-40  cm) depths.  In general, an intensive mechanized
irrigated farm along with inefficient irrigation practice  and management induced salinity and sodicity  to the  soil.  In addition  to this, low inputs  of organic matter  and insufficient use of inorganic  fertilizers had contributed for the  deterioration of  soil fertility indicating parameters.  Therefore, reducing the intensity of mechanized irrigated farm, use of  well agricultural water management practices and integrated management of inorganic and organic fertilizers could replenish the degraded soil fertility for sustainable  for crop production in the study area.

In arid and semi-arid regions, the genus Atriplex has agronomic and ecological interest. Indeed, in addition to their good forage quality, they ensure fixation and soil enrichment. Halophytic plants are able to tolerate saline environments. They often show a diversity of structural and physiological adaptations that include salt bladders, salt glands or hairs and multiple rows of hypodermis (probable with accumulation and storage role). Related to higher salinity of soil, the halophytes react also by some adaptive, anatomical features. In order to elucidate the anatomical variability level, roots, stems and Leaves of one species of Atriplex were used: Atriplex halimus L. The results show anatomical differences that can be linked to her degrees of adaptation to external conditions.

The advent of agricultural biotechnology offers new approaches for the genetic improvement of date palm
(Phoenix dactylifera L.), an important economic fruit crop in arid regions. In vitro studies were conducted to
recover date palm plants exhibiting enhanced tolerance to salinity and drought stress, two major agricultural
problems in arid areas. The response of date palm callus cultures to salt stress was investigated by exposing cell
suspension and callus cultures to varying concentrations of sodium chloride (NaCl). The reaction of callus to
the duration of exposure to NaCl, potassium chloride (KCl) and calcium chloride (CaCl2) was evaluated.
Similarly, drought tolerance was assessed in response to varying concentrations of polyethylene glycol (PEG-
8000). Significant differences were reported in various parameters measured including callus growth, somatic
embryogenesis, proline content and ion distribution. Calli with enhanced tolerance to these selection agents
were obtained; however, plant regeneration from these cell lines was not realized. Although the available data
provide an insight of the behavior of date palm callus in the presence of salt and drought stress, further research
work is required to refine the selection procedures and plant regeneration from the selected tolerant cell lines.

Response of photosynthetic apparatus in some sunflower cultivars, i.e., S.28111, Hysun-33, Hysun-39, and SF0049, to salt, drought, and combined stresses were studied. The combined stress caused severe damage to photosynthetic apparatus as compared to single stress. The maximum quantum yield of PSII, phenomenological fluxes, plastoquinone pool size, performance indexes, and driving force of absorption were greatly affected by the combined stress. Among the cultivars, the combined stress produced synergistic effect (greater damage) in Hysun-33 and cross-tolerance (lesser damage) in S.28111. Similarly, concerning the ion imbalance, S.28111 and SF0049 showed lower Na + and Cl-concentrations with lesser electrolyte leakage as compared to Hysun-33 and Hysun-39 under salt and combined stress. Results revealed that the disturbance in photosynthetic performance could be easily determined using JIP test by measuring chlorophyll a fluorescence. This information can be useful for the screening of oilseed crop plants having better photosynthetic performance under salinized and desertified conditions. Additional key words: electron transport rate; malondialdehyde; nonphotochemical quenching; OJIP transient. Abbreviations: ABS/RC-apparent antenna size of active PSII RC; Area-area over the fluorescence curve between F0 and Fm; DFABS-driving force on absorption basis; DI0/RC-effective dissipation of energy in active RC; ET0/RC-electron transport per active reaction center; F0-minimum fluorescence; F0/Fv-efficiency of water-splitting complex; F0/Fm-quantum yield baseline; Fm-maximum fluorescence; Fm/F0-electron transport rate through PSII; Fv/F0-size and number of active reaction centers of photosynthetic apparatus; Fv/Fm-maximum quantum yield of PSII; J-linear electron transport rate; MDA-malondialdehyde; NPQ-nonphotochemical quenching; PIABS-performance index on absorption basis; PICS-performance index on cross-section basis; PItot-total performance index; qN-nonphotochemical quenching coefficient; qP-photochemical quenching; RC/ABS-density of reaction centers on chlorophyll basis; RC/CSm-amount of active reaction centers per excited cross section; TR0/DI0-ratio of trapping and dissipation fluxes; TR0/RC-maximal trapping rate of absorbed photons in RC; δR0 or RE0/ET0-probability that an electron is transported from reduced PQ to electron acceptor side of PSI; ΔVIP-amplitude of the relative variable fluorescence of the I-toP rise ; ΦPSII-efficiency of PSII or quantum yield of PSII; ϕR0-quantum yield for reduction of the end electron acceptors at the PSI acceptor side (RE); ψ0-yield of electron transport per trapped excitation or probability with which a PSII trapped electron is transferred from reduced QA to QB.

Malnutrition is one of the major problems in the poor people of Bangladesh. There are some reports that additional nitrogen (over than recommended does) application to wheat plants result in more protein content in wheat grain. To justify these phenomena, the experiment was conducted in consecutive two years (2015-16 and 2016-17) at two locations (Gazipur and Dinajpur) during rabi season (November to March each year). There were used six nitro-gen (N) treatments, such as 0, 100, 125, T3; 150, 175 and 200 kg N ha-1. In the study, wheat cultivated at Dinajpur location exhibited more spikes m-2, spike length, spikelets spike-1, grains spike-1, 1000-grain weight and higher grain yield in both years than Gazipur location. Considering combined N levels over the locations, the highest grain protein (14 %) as well as grain yield (5.00 t ha-1) was estimated when 200 kg N ha-1 was applied. In economics point of view, 200 kg N ha-1 application also gave the maximum (BCR, 1.21) followed by 175 kg N ha-1 (1.20) and 150 kg N ha-1 1.20). Whereas, the maximum MBCR was found in 100 kg N ha-1 (15.63). There-fore, to minimize malnutrition severity among the children as well as adult people in the developing countries like Bangladesh, 175 or 200 kg N ha-1 may be applied in wheat to increase percentage protein in wheat grain.

Globally salinity is considered as one of the most
serious problems of agriculture and allied sectors,
especially in arid and semiarid regions. Increased soil
salinity may be the main factor in making arable land
unfavorable for a wide range of crop species (Epstein
et al., 1980). The factors that lead to increased salinity
are the usage of saline water for irrigation and application
of fertilizer (Epstein et al., 1980). Saline soils are
characterized with high levels of sodium and chloride
content and thus exert severe abiotic stress on the
growth and development of plants by inducing
changes in most physiological and biochemical processes.
Multiple factors are involved in the alleviation
of salinity stress but phytohormones are thought to be
among the most essential endogenous substances
involved in the underlying mechanisms of tolerance or
susceptibility of various plant species (Velitchkova and
Fedina, 1998).

The effect of salt stress on antioxidative activity was studied in two species of halophytes Atriplex: halimus and canescens. The plants were exposed to 100, 300 and 600 mM l ‐1 NaCl for 30 days. The parameter of oxidative stress induced by salt, malondialdehyde (MDA) and the activity of peroxidase (POD) are determined. The results show that in terms of lipid peroxidation, the two species are very little or not affected by the salt for all concentrations applied. This reflects a better protection of cell membranes against oxidative damaging effects of salt. However, in terms of peroxidase activity, variability of responses is observed. This variability is a function of the salt concentration, the organ and species. RESUME: L'effet du stress salin sur l'activité antioxydative est étudié chez deux espèces halophiles d'Atriplex halimus L. endémique des régions méditerranéennes et canescens (Pursh) Nutt endémiques des régions américaines. Les plantes sont exposées à 100, 300 et 600 mM l ‐1 NaCl pendant 30 jours. Le paramètre du stress oxydatif induit par le sel, malondialdéhyde (MDA) et l'activité de la peroxydase (POD) sont déterminés. Les résultats obtenus montrent qu'en terme de peroxydation lipidique, les deux espèces étudiées sont très peu ou pas affectées par le sel sous tous les traitements. Ceci présume l'action protectrice des membranes cellulaires contre les effets oxydatifs provoqués par salinité. Cependant, en terme d'activité peroxydase, une variabilité de réponses est observée. Cette variabilité est fonction de la concentration saline appliquée, de l'organe et de l'espèce.

The interactive effects of saline water (2000, 4000 and 6000 mg/l) and foliar application of 400 mg/l of ascorbic acid (Asc) or α – tocopherol (α-Toco) on three flax cultivars (Sakha 3, Giza 8 and Ariane) were conducted during two successive seasons (2011 and 2012). The results showed that, total soluble carbohydrates, free amino acids, proline contents were significantly increased with increasing salinity levels in all three tested cultivars except free amino acid content of Giza 8 which showed a non significant decrease. While, nucleic acids (DNA and RNA) showed significant decreases compared with the corresponding controls. Moreover, applications of vitamins (Asc or α-Toco) as foliar spraying increased all mentioned contents compared to the corresponding salinity levels. On the other hand, lipid peroxidation, and activity levels of polyphenol oxidase (PPO), peroxidase (POX) and catalase (CAT) enzymes showed progressive significant increases with increasing salinity levels of all tested three cultivars, while the behaviour of superoxide dismutase (SOD) activity showed an opposite response as compared with the control in Sakha 3 and Giza 8. Treatments with Asc or α-Toco induced significant reduction in lipid peroxidation and activities of PPO and POX of all three tested cultivars. Meanwhile, SOD increased in all three cultivars, and CAT activities increased only in Sakha 3 cultivar under salt stress as compared with reference controls. Some modifications are observed in protein patterns hence some proteins were disappeared, while certain other proteins were selectively increased and synthesis of a new set of proteins were induced, some of these responses were observed under treatments and salinity, while others were induced by either treatments or salinity.

Modulation of salt stress effects on the growth, physio-chemical attributes and yields of Phaseolus vulgaris L. plants by the combined application of salicylic acid and Moringa oleifera leaf extract Moringa oleifera leaf extract Salt stress Growth and productivity Physio-chemical attributes a b s t r a c t Two field experiments were aimed to study the effects of salicylic acid (SA; 1 mM) and Moringa oleifera leaf extract (MLE; 1 extract: 30 tap water), used singly or in combination on the growth, physio-chemical attributes and yields of common bean (Phaseolus vulgaris L.) plants grown on a saline soil (EC = 6.23 – 6.28 dS m −1). The SA or MLE application, used as seed soaking or foliar spray, improved growth characteristics (i.e., shoot length, number and area of leaves per plant, and plant dry weight) and physio-chemical attributes (i.e., RWC% and MSI%, concentrations of total chlorophylls, total carotenoids, total soluble sugars, free proline and ascorbic acid, contents of N, P, K and Ca, and ratios of K/Na and Ca/Na) in bean plants. In addition, green pod and dry seed yields were improved when compared with the controls (tap water seed soaking or foliar spray). Combined treatments of SA and MLE (i.e., seed soaking in SA + foliar spray with SA, seed soaking in SA + foliar spray with MLE, seed soaking in MLE + foliar spray with SA, and seed soaking in MLE + foliar spray with MLE) significantly increased all abovementioned parameters compared to the control (seed soaking in tap water + foliar spray with tap water). In contrast, there were significant reductions in leaf EL% and Na% under these combined treatments. The combined seed soaking in SA + foliar spray with MLE treatment was found to be highly effective at improving the growth and yields of bean plants by alleviating the inhibitory effects of soil salinity stress.

This study compared the effects of salt stress on the growth, photosynthesis, proline content and ion accumulation in seedlings of cultivated soybean ZH13 and wild soybean BB52. The results showed that salt stress markedly reduced the growth of two varieties, but BB52 grew better than ZH13 at the same salt stress. Then we speculated the reason was that it owned better abilities to maintain photosynthesis efficiency, osmotic adjustment and ion homeostasis. With increasing salinity, the higher Pn, CE and chlorophyll content in BB52 facilitated its better growth. Besides, the higher accumulation of proline under salt stress ensured its less decreases of ψw and RWC. And above all, BB52 not only absorbed much less Na+ and Cl- and accumulated them in roots to restrict their transportation to the above-ground parts, but also assimilated more K+. Therefore, BB52 was able to maintain a higher K+/Na+ ratio, especially in leaves that is very important for salt tolerance. In conclusion, ZH13 and BB52 exhibited a certain tolerance through many kinds of physiological regulations such as photosynthetic modulation, osmotic adjustment and ion homeostasis, but BB52 seemed to have a higher salt tolerance.

Öz Sulama suyunun SAR değeri suyun kalite sınıfının belirlenmesinde birincil parametredir. Bu nedenle SAR değeri dikkate alınmadan sodyum tuzu ile yapılan çalışmalarda elde edilen sonuçlar tuz zararı olmayıp sodyum zararını temsil etmektedir. Mısır bitkisinin sulama suyu tuzluluğunu hangi seviyeye kadar tolere edilebileceğini tespit etmek amacıyla SAR değeri 1'in altında ayarlanarak farklı tuz konsantrasyonuna sahip sulama suları ile çimlendirme ve saksı denemeleri yapılmıştır. Çimlendirme denemesi sonucunda sulama suyu tuzluluk seviyesindeki artışa paralel olarak kök uzunluğu, fide kuru ağırlığı ve çimlenme oranı azalmıştır. Kök uzunluğu sulama suyu tuzluluğunun 3 dS m-1 ECi seviyesinde olumsuz etkilenmeye başlarken fide kuru ağırlığı ve çimlenme oranı 5 dS m-1 ECi seviyesinde etkilenmeye başlamıştır. Saksı denemesinde sulama suyu tuzluluk seviyesindeki artışa paralel olarak bitki boyu ve bitki kuru ağırlığı değerleri azalmış olup 8 dS m-1 ECi seviyesinde olumsuz etkilenmiştir. Anahtar kelimler: Mısır, sulama suyu tuzluluğu, çimlenme, SAR Abstract The SAR value of irrigation water is the primary parameter in determining the quality class of the water. For this reason, the results obtained in studies with sodium salt without taking into account the SAR value are not salt losses and represent sodium losses. In order to determine to what level the maize plant's irrigation water salinity can be tolerated, germination and pot experiments were carried out using irrigation waters with different salt concentrations so that the SAR value is less than 1. As a result of germination trial, parallel to the increase in irrigation water salinity, root length, seedling dry weight, and germination rate decreased. The root length started to be affected negatively at 3 dS m-1 ECi level of irrigation water salinity, seedling dry weight and germination rate started to be affected at 5 dS m-1 ECi level. In the pot experiment, parallel to the increase in irrigation water salinity, plant height and plant dry weight values decreased and were negatively affected at 8 dS m-1 ECi level.

The diverse ways that extreme climate events are expressed at the local level have represented a challenge for the development of transgenic "climate-ready" (resilient to environmental stress) seeds. Based on the Argentinean "HB4" technology, this paper analyzes how ignorance and a sunflower gene are mobilized to overcome this difficulty in soy and wheat. HB4 seeds can be understood as myopic: the technology does not obstruct the capacity of soy and wheat plants to sense droughts, but it prevents their natural reaction, which would be to put a halt on crop production and redirect their energy toward survival. Plants thus become "short-sighted" to droughts. Informed by ignorance studies and by the immunological concept of tolerance, this paper analyzes HB4 myopia as a type of non-human ignorance: an asset that allows plant breeders to achieve varied plant responses to droughts and to encode their capitalist values (that prioritize production over survival) into plants' DNA. Moreover, ignorance becomes a molecular commodity that can be selected, transferred between organisms, and traded in markets. HB4's prioritization of production resonates with other technologies of climate adaptation and mitigation that do not promote structural changes to the capitalist system.

Salinity is a devastating problem of arid and semi-arid climatic regions with uneven salt accumulation which hinders growth and development of crops. The deleterious effects of salinity mainly depend on level and source of salinity. We hypothesized that types of sodium salt (NaCl and Na2SO4) might cause variable toxicity in maize (Zea mays L.) plants. The objective of the present study was to compare the effect of different types of sodium salt (NaCl and Na2SO4), each at EC 5 and 10 dS m-1 on growth, physiology and nutrient contents of maize plant grown in earthen pots under wire house conditions. Results revealed toxic effects of salt stress on seed germination, root and shoot growth and biomass. Maize physiology in terms of sub-stomatal CO2 index, chlorophyll and relative water contents, photosynthetic and tran-spiration rate also reduced under salt stress. Among the types of salt and levels of salinity, NaCl applied at the rate of 10 dS m-1 caused the highest reduction in seed germination, growth and physiology due to high accumulation of Na and Cl ions whereas low in K ion in maize plant tissues. Based on the findings, we do conclude that NaCl applied at the rate of 10 dS m-1 has more negative impact on maize growth and nutrient acquisition than Na2SO4 at same level of salinity.

Dwindling high quality water resources and growing population are forcing growers to irrigate crops with water of high salinity. It is well recognized that salinity negatively affects plant physiology and biochemistry, and represents one of the most serious threats to crop production and food security. Meanwhile, engineered nanoparticles (ENPs) are increasingly detected in irrigation water and agricultural soils due to the rapid advancement of nanotechnology. Previous research has demonstrated that ENPs such as cerium oxide nanoparticles (CeO2-NPs) exert significant impact on plant growth and production. However, almost all previous studies were conducted in well controlled environment. Knowledge on how ENPs affect plant development in a stressed condition is almost empty. The goal of the present study was to understand the physiological and biochemical changes in Brassica napus L. (canola) cv. &#39;Dwarf Essex&#39; under synergistic salt stress and CeO2-NPs effects. Two salinity le...

To investigate the effect of soaking with chitosan and proline levels under salinity stress on seedlings characters of wheat, a laboratory experiment was carried out at Central Laboratories in Central Administration for Seed Testing and Certification, Ministry of Agriculture, Egypt, during January 2019. The experiment was conducted in factorial experiment in randomized complete block design (RCBD) with four replications. The first factor included four levels of soaking with chitosan (0.00, 0.25, 0.50 and 0.75%). The second factor integrated with five levels of soaking with proline (0, 1, 5, 9 and 13mM). The third factor incorporated with four levels of salinity i.e. 0, 4, 8 and 12dSm-1 of NaCl. The results indicated that soaking in chitosan at 0.75% recorded highest values of seedlings characters, followed by soaking in chitosan at 0.50%. The highest values of seedlings characters were produced from soaking in highest level of proline (13mM), followed soaking in proline at 9mM. The highest values of seedlings characters were obtained from the control treatment (without salinity stress), followed by salinity stress at the level of 4dSm-1 of NaCl and then salinity stress at the level of 8dSm-1 of NaCl. It could be concluded that for maximizing seedlings characters of bread wheat Shandaweel 1 cultivar under salinity stress, it could be recommended to soaking with the mixture of chitosan at the rate of 0.75 or 0.50% and proline at the rates of 13 or 9mM for 6 h.

Finger millet (Eleusine coracana L.) is a hardy cereal known for its superior level of tolerance against
drought, salinity, diseases and its nutritional properties. In this study, attempts were made to unravel the physiological and molecular basis of salinity tolerance in two contrasting finger millet genotypes viz., CO 12 and Trichy 1. Physiological studies revealed that the tolerant genotype Trichy-1 had lower Na+ to K+ ratio in leaves and shoots, higher growth rate (osmotic tolerance) and ability to accumulate higher amount of total soluble sugar in leaves under salinity stress. We sequenced the salinity responsive leaf transcriptome of contrasting finger millet genotypes using Ion Proton platform and generated 27.91 million reads. Mapping and annotation of finger millet transcripts against rice gene models led to the identification of salinity responsive genes and genotype specific responses. Several functional groups of genes like transporters, transcription factors, genes involved in cell signaling, osmotic homeostasis and biosynthesis of compatible solutes were found to be highly up-regulated in the tolerant Trichy 1. Salinity stress inhibited photosynthetic capacity and photosynthesis related genes in the susceptible genotype CO 12. Several genes involved in cell growth and differentiation were found to be
up-regulated in both the genotypes but more specifically in tolerant genotype. Genes involved in flavonoid biosynthesis were found to be down-regulated specifcally in the salinity tolerant Trichy 1. This study provides a genome-wide transcriptional analysis of two fnger millet genotypes differing in their level of salinity tolerance during a gradually progressing salinity stress under greenhouse conditions.

Molecular markers provide a rapid approach to breeding for desired traits. To use them, it is necessary to determine the linkage between quantitative trait loci (QTL) and such markers. This study was conducted to investigate the genetic basis of salinity responses in Egyptian bread wheat (Triticum aestivum L.). In this context, a doubled haploid (DH) population (SGDH) of 139 individuals was produced from the cross between two Egyptian breeding cultivars (Sakha 93, salt tolerant) and (Gemmeza 7, salt susceptible). The DH population was tested under saline hydroponics culture and various plant responses were measured. A molecular genetic map of the SGDH population covering 3645.3 cM, was constructed using Restriction Fragment Length Polymorphism (RFLP), Microsatellite or Simple Sequence Repeats (SSR), and Amplified Fragment Length Polymorphism (AFLP) markers. In total, 325 loci along the 21 wheat chromosomes were mapped. The B genome showed the highest number of mapped markers followe...

Potato (Solanum tuberosum L.) tubers are an excellent staple food due to its high nutritional value. When the tuber reaches physiological competence, sprouting proceeds accompanied by changes at mRNA and protein levels. Potato tubers become a source of carbon and energy until sprouts are capable of independent growth. Transcript profiling of sprouts grown under continuous light or dark conditions was performed using the TIGR 10K EST Solanaceae microarray. The profiles analyzed show a core of highly expressed transcripts that are associated to the reactivation of growth. Under light conditions, the photosynthetic machinery was fully activated ; the highest up-regulation was observed for the Rubisco activase (RCA), the glyceraldehyde-3-phosphate dehydroge-nase (GAPDH), and the Photosystem II 22 kDa protein (CP22) genes, among others. On the other hand, sprouts exposed to continuous darkness elongate longer, and after extended darkness, synthesis of chloroplast components was repressed , the expression of proteases was reduced while genes encoding cysteine protease inhibitors (CPIs) and metallocarboxypeptidase inhibitors (MPIs) were strongly induced. Northern blot and RT-PCR analysis confirmed that MPI levels correlated with the length of the dark period; however , CPI expression was strong only after longer periods of darkness, suggesting a feedback loop (regulation mechanism) in response to dark-induced senescence. Prevention of cyste-ine protease activity in etiolated sprouts exposed to extended darkness could delay senescence until they emerge to light.

Food security (a pressing issue for all nations) faces a threat due to population growth, land availability for growing crops, a changing climate (leading to increases in both abiotic and biotic stresses), heightened consumer awareness of the risks related to the use of agrichemicals, and also the reliance on depleting fossil fuel reserves for their production. Legislative changes in Europe mean that fewer agrichemicals will be available in the future for the control of crop pests and pathogens. The need for the implementation of a more sustainable
agricultural system globally, incorporating an integrated approach to disease management, has never been more urgent. To that end, the Valorizing Andean Microbial Diversity (VALORAM) project (http://valoram.ucc.ie), funded under FP7, examined the role of microbial
communities in crop production and protection to improve the sustainability, food security, environmental protection, and productivity for rural Andean farmers. During this work, microbial volatile organic compounds (mVOCs) of 27 rhizobacterial isolates were identified using gas chromatography/mass spectrometry (GC/MS), and their antifungal
activity against Rhizoctonia solani was determined in vitro and compared to the activity of a selection of pure volatile compounds. Five of these isolates, Pseudomonas palleroniana R43631, Bacillus sp. R47065, R47131, Paenibacillus sp. B3a R49541, and Bacillus simplex M3-4 R49538 trialled in the field in their respective countries of origin, i.e., Bolivia, Peru, and Ecuador, showed significant increase in the yield of potato. The strategy followed in the VALORAM project may offer a template for the future isolation and determination of putative biocontrol and plant growth-promoting agents, useful as part of a low-input integrated pest management system.

Various environmental stresses limit the plant growth and productivity. Earlier we reported the stress inducible dehydrin gene, OsDhn1, in rice. In this study we generated OsDhn1-overexpression transgenic rice plants (OsDhn1-OXs) to understand the dehydrin function. OsDhn1-OXs showed an enhanced drought and salt stress tolerance as judged by chlorophyll fluorescence (Fv/Fm), fresh and dry weight, water and chlorophyll content, and survival ratio. Furthermore, OsDhn1-OXs showed significantly increased tolerance to methyl viologen (MV)-induced oxidative stress. Under salt and drought stress condition, OsDhn1-OXs maintained relatively low level of H2O2 as compared to wild type plants. Taken together, it is suggested that OsDhn1 plays an important role in the stress tolerance via scavenging reactive oxygen species (ROS).

Plant exposure to salinity is rapidly followed by a decrease in growth rate. Most of the physiologists interpreted this phenomenon as a direct consequence of metabolic perturbations induced by NaCI. This mechanistic approach has been briefly analysed in this review, together with many observations which contradict it, such as: (i) the lack of correlation between metabolic perturbations and decrease in growth foJ/owing exposure to salinity; (ii) the large difference between sensitivity to salinity of the whole plant and its cells in culture; (iii) the alleviation of growth inhibition by salinity, by phytohormonal treatments; (iv) the ability of plants to adapt to high levels of salinity within a few weeks. A "whole plant approach" of the growth reduction by a saline environment is presented in the light of recent experimental data. It is argued that, for plants exposed to a sublethal level of salinity, the primary cause for reduction in growth rate is not the direct inhibiting effect of Na+ or cr ions on metabolic processes. The decrease in growth rate is rather due to a change in hormonal balance of the plant, which originates from a modulation of hormone production by the root, the organ sensing the soil environment. Therefore, metabolic perturbations, considered in the mechanistic approach as the cause for growth reduction, are consequent to hormonal changes induced by the presence of NaCI. These considerations allow the reconciliation of many of the contradicting results which were accumulated in the literature during the search for a hypothetiC "limiting factor" of growth in saline environment. It also provides an explanation for the ability of plants to adapt to lethal levels of salinity within a few weeks. Improvemerlt of salinity tolerance, in crop plants, was conditioned by the identification of the main toxic effect of NaCI on plant metabolism, and by selection of plants which overcome it. As a consequence of this new approach, radical changes are foreseeable in future research in improvement of salinity tolerance in crop plants.

This review article was prepared based on our recent publications on cold-responsive plant calcium signaling released in Japanese, after a major revision updating the topics. Plants respond to various environmental stimuli such as acute changes in temperature, by activating each component in the signaling cascade such as Ca2+ channels, required for adaptations to changing environments. In this study, the effects of naturally existing rare earth elements) added as chloride salts, on Ca2+ influx through ion channels, induced by two different temperature stresses, namely cold and heat shocks were tested using suspension-cultured transgenic tobacco cell line (BY-2) expressing aequorin, a Ca2+-sensitive luminescent protein in its cytosol. Action of Al3+ , a putative TPC1-type channel inhibitor was also examined. Based on the results obtained, the nature of temperature-sensitive Ca2+ influx was discussed.

Aim of the study: To evaluate the morpho-physiological changes of Acacia auriculiformis in response to seawater induced salin-ity stress along with its tolerance limit. Area of study: Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Material and methods: Three saline treatments (4, 8, 12 dS m –1) were applied to six-month aged Acacia auriculiformis seedlings from January 2014 to June 2014 and the tap water was used as control treatment. To observe salinity effects, the following parameters were measured by using various established techniques: plant height and leaf number, plant biomass, shoot and root distribution as well as shoot and root density, water uptake capacity (WUC), water saturation deficit (WSD) and water retention capacity (WRC), exudation rate, and cell membrane stability. Main results: Diluted seawater caused a notable reduction in shoot and root distribution in addition to shoot and root density, though plant height, leaf number and plant bioma...

A field experiment was carried out at South of El-Husainia plain (salt affected soil), El-Sharkia Gov., Egypt, during two successive winter seasons of 2013/2014 and 2014/2015 to study the effects of anhydrous ammonia (AA); either applied individually or in combination with urea, at a rate of 90 kg N fed-1 , as compared to urea only on some soil microorganisms populations and their total activity (expressed as dehydrogenase activity) through two soil depths (0-10 and 10-20 cm) at different time periods, i.e., 7, 15, 21, 30, 60 and 90 days after sowing. Some physiological properties and productivity of wheat (Triticum aestivum L. cv) cv. Sakha-93 were also a matter of concern in this research and were investigated. Results showed that all microbial populations under assessment, i.e., bacteria, actinomycetes, fungi, algae, cyanobateria and nitrifiers, decreased sharply (>10 2-fold(with the sole application of AA, particularly during the early days after injection (7 and 15 days). Such an effect was more obvious in the lower soil depth (injection zone) than in the upper one. Conversely, significant increases in all microbial populations were recorded with urea fertilization at the corresponding time periods. It is worthy to mention that microbial populations and activities in the saline soil fertilized with AA began to recover and flourish by the 21 st day after sowing at rates exceeding significantly those recorded for urea treatment, over the rest of the experimental periods, and the arrangement could be as follows: AA > AA + urea > urea. Generally, all microbial populations and their activity had a compatible trend, in response to N sources (AA and urea) during two growing seasons. Results also showed that applying AA fertilizer as N source increased significantly chlorophyll a & b, carotenoids content, protein content, leaf area index, crop growth rate and net assimilation rate of wheat plants by percentages of 15.6, 30.9, 58.0, 11.7, 8.3, 9.2 and 1.7, respectively, in comparison with urea at 1 st growing season. Consequently, wheat yield components were significantly higher in soils fertilized with AA fertilizer than that received urea fertilizers by 17.0% for 1000 grain weight, 13.9 % for biological yield and 14.8% for grain yield at the 1 st season. The highest values of both N-uptake, i.e., 54.43 and 53.38 kg fed-1 and N use efficiency (NUE), i.e., 30.49 and 29.91 kg kg-1 , for grain yield in 1 st and 2 nd seasons, respectively, were attained for AA fertilizer followed by the combined treatment (urea + AA), while, urea fertilizer exhibited the least performance.

Biotic and abiotic stresses impose a major threat to agriculture. Increase crop productivity need to develop stress tolerant plants. Tomato (Lycopersicon esculentum Mill.) is a model plant for studying the mechanisms of plant salt tolerance. Plants may be exposed to different salt levels at various stages of development; seed germination represents a major bottleneck in the species life cycle. In this context, seeds of eight varieties of tomato were tested under different levels of NaCl. Two approaches were adopted in this investigation: (a) Morphometric variability measurement, (b) biochemical changes of protein profile and iso-enzyme esterase activity. For the morphometric variability, two quantitative components were measured, vigor seed and length of seedling, for each parameter tolerance index (IT = treated / control) was evaluated. Statistical analysis was carried by software STATISTICA (version6. France). One-way ANOVA analysis indicates a significant difference between treatments and between varieties by depending on the increasing salt level for both components, differences between means were determined. Following the biometric analysis two genotypes were selected to complete biochemical analysis under stress conditions, MCH (salt-tolerant) and MRMD (moderately-tolerant). SDS-PAGE electrophoresis was used to determinate the effect of NaCl on protein expression and Native-PAGE electrophoresis to study isozymatic activity of esterase (EC 1.11.2). Results showed that salt-tolerant genotype increase of presently consecutive expression proteins; in contrast high levels of NaCl induce denaturation of proteins isoforms in sensitive genotype. Another interesting finding about antioxidant esterase activities; an important elevate expressed of esterase isoforms was founded in the salt-tolerant than the sensitive one. High levels of salt stress inhibited completely some of them in both genotypes.

Because rare earth elements (REEs) are not present at high concentrations in the normal environments surrounding living organisms, the biological roles of REEs had not been intensively tested to date. In this article, the ongoing studies on the biology and biochemistry of REEs applied to growing plants and plant cells are reviewed.

Current agricultural production methods, for example the improper use of chemical fertilizers and pesticides, create many health and environmental problems. Use of plant growth-promoting bacteria (PGPB) for agricultural benefits is increasing worldwide and also appears to be a trend for the future. There is possibility to develop microbial inoculants for use in agricultural biotechnology, based on these beneficial plant–microbe interactions. For this study, ten bacterial strains were isolated from Yongin forest soil for which in vitro plant-growth promoting trait screenings, such as indole acetic acid (IAA) production, a phosphate solubilization test, and a siderophore production test were used to select two PGPB candidates. Arabidopsis thaliana plants were inoculated with Paenibacillus yonginensis DCY84T and Micrococcus yunnanensis PGPB7. Salt stress, drought stress and heavy metal (aluminum) stress challenges indicated that P. yonginensis DCY84T-inoculated plants were more resistant than control plants. AtRSA1, AtVQ9 and AtWRKY8 were used as the salinity responsive genes. The AtERD15, AtRAB18, and AtLT178 were selected to check A. thaliana responses to drought stress. Aluminum stress response was checked using AtAIP, AtALS3 and AtALMT1. The qRT-PCR results indicated that P. yonginensis DCY84T can promote plant tolerance against salt, drought, and aluminum stress. P. yonginensis DCY84T also showed positive results during in vitro compatibility testing and virulence assay against X. oryzae pv. oryzae Philippine race 6 (PXO99). Better germination rates and growth parameters were also recorded for the P. yonginensis DCY84T Chuchung cultivar rice seed which was grown on coastal soil collected from Suncheon. Based on these results, P. yonginensis DCY84T can be used as a promising PGPB isolate for crop improvement.

A stable salt-tolerant potato cell line, able to grow on media containing 60–450 mM NaCl (i.e. low to high salinity) was selected. Callus grown on 120 or 150 mM NaCl showed higher fresh weights than the rest of the treatments. Replacing NaCl by KCl or Na2SO4 showed that reductions in fresh weight were mainly due to the presence of Na+ ions. When PEG 6000 was added to the medium instead of salt, the salt tolerant cell lines were unable to overcome the PEG-induced water stress. Whole plants, regenerated from salt tolerant callus, exhibited salt stress tolerance as evidenced by their higher fresh and dry weights when watered with 90 mM NaCl, and they also produced more tubers per plant under salt stress. Salt-tolerant plants differed phenotypically from control plants both in terms of leaf shape, tuber flesh and skin colour, which was reddish. In addition, DNA fingerprinting by RAPDs, with 70 different primers, confirmed that the salt tolerant regenerants also differed genotypically from the control, salt sensitive Kennebec potato plants from which they had been selected.

Salinity is a major abiotic stress that can adversely affect plant growth, yield, other physiological parameters, and soil health. Salinity stress on biomass production of salt-sensitive crops, like snap bean (Phaseolus vulgaris), is a serious problem, and specifically in South Florida, USA, where saline soils can be found in major agricultural lands. Research studies focused on the 'snap bean-Rhizobium-arbuscular mycorrhizal fungi (AMF)' relationship under salinity stress are limited, and fewer studies have evaluated how this tripartite symbiosis affects glomalin production (GRSP), a glycoprotein released by AMF. A shade house experiment was conducted to elucidate the effects of three microbial inoculations (IC = inoculation control; IT1 = AMF and IT2 = AMF + Rhizobium) on three salinity treatments (SC = salinity control 0.6 dS m −1 , S1 = 1.0 dS m −1 , and S2 = 2.0 dS m −1) on snap bean growth and yield. Our results indicate that S2 reduced 20% bean biomass production, 11% plant height, 13% root weight, and 23% AMF root colonization. However, microbial inoculations increased 26% bean yield over different salinity treatments. Maximum salinity stress (S2) increased 6% and 18% GRSP production than S1 and SC, respectively, indicating the relative advantage of abiotic stress on AMF's role in soil. Dual inoculation (IT2) demonstrated a beneficial role on all physiological parameters, biomass production, and GRSP synthesis compared to single inoculation (IT1) treatment with all three salinity levels.

Ozone (O3)‑induced cell death in two suspension‑cultured cell lines of tobacco (Nicotiana tabacum L.) derived from Bel‑W3 (hyper‑sensitive to O3) and Bel‑B (highly tolerant to O3) varieties were studied. By exposing the newly prepared cell lines to the pulse of ozonized air, we could reproduce the conditions demonstrating the difference in O3 sensitivity as observed in their original plants, depending on the exposure time. Since O3‑induced acute cell death was observed in the dark, the requirement for photochemical reactions could be eliminated. Addition of several ROS scavengers and chelators inhibited the cell death induced by O3, indicating that singlet oxygen (1O2), hydrogen peroxide (H2O2), hydroxyl radical and redox‑active metals such as Fe2+ play central roles in O3‑induced acute damages to the cells. As expected, we observed the generation of 1O2 and H2O2 in the O3‑treated cells using chemiluminescent probes. On the other hand, an NADPH oxidase inhibitor, superoxide dismutase (SOD), and some SOD mimics showed no inhibitory effect. Thiols added as antioxidants unexpectedly behaved as prooxidants drastically enhancing the O3‑induced cell death. It is noteworthy that some ROS scavengers effectively rescued the cells from dying even treated after the pulse of O3 exposure, confirming the post‑ozone progress of ROS‑dependent cell death mechanism. Since one of the key differences between Bel‑B and Bel‑W3 was suggested to be the capacity for ROS detoxification by catalase, the endogenous catalase activities were compared in vivo in two cell lines. As expected, catalase activity in Bel‑B cells was ca. 7‑fold greater than that in Bel‑W3 cells. Interestingly, Ca2+ chelators added prior to (not after) the pulse of O3 effectively inhibited the induction of cell death. In addition, increases in cytosolic Ca2+ concentration sensitive to Ca2+ chelators, ion channel blockers, and ROS scavengers were observed in the transgenic Bel‑W3 cells expressing aequorin, suggesting the action of Ca2+ as a secondary messenger initiating the oxidative cell death. The O3 ‑induced calcium response in Bel‑W3 cells was much greater than Bel‑B cells. Based on the results, possible pathways for O3 ‑dependent generation of the lethal level of ROS and corresponding signaling mechanism for induction of cell death were discussed.