Citrus tristeza virus (CTV) is found worldwide wherever citrus is cultivated, causing Citrus tristeza disease resulting in significant yield losses and sometimes the death of the plant. Transgenic citrus plants encoding CTV gene sequences... more
Citrus tristeza virus (CTV) is found worldwide wherever citrus is cultivated, causing Citrus tristeza disease resulting in significant yield losses and sometimes the death of the plant. Transgenic citrus plants encoding CTV gene sequences have shown to exhibit pathogen-derived resistance to CTV. Exogenous application of double-stranded RNA (dsRNA) is an established strategy for plant virus control, making this method an attractive alternative to transgenic RNA interference (RNAi). The dsRNA molecules targeting the CP, p20, and p23 genes of CTV G8 strain were synthesized in vitro and topically applied onto the leaves of sweet orange (Citrus sinensis) infected with CTV strain G8. The exogenous application of all the dsRNAs reduced CTV titer at 10 days post application (dpa) as revealed by quantitative RT-PCR assay done at four different time points. These results provide a proof-of-concept for a non-transgenic approach of controlling CTV, a closterovirus, in a perennial fruit crop suc...
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Soybean [Glycine max (L.) Merrill] is high value oilseed crop grown throughout the world as well as in few soybean growing pockets in India. The hot and humid weather conditions during the soybean cropping season favours the attack by... more
Soybean [Glycine max (L.) Merrill] is high value oilseed crop grown throughout the world as well as in few soybean growing pockets in India. The hot and humid weather conditions during the soybean cropping season favours the attack by various fungal, bacterial and viral diseases, thereby lowering the crop productivity. Rhizoctonia aerial blight or web blight disease, caused by Rhizoctonia solani is considered one of the most economically important disease of soybean in India. It causes yields losses ranging from 35-60% which might reach a devastating level of 80% under favourable environmental conditions. In India, the disease has been reported from most of the soybean growing states of Uttrakhand, Rajasthan, Sikkim, Haryana, Punjab, Uttar Pradesh, Bihar, Madhya Pradesh, Chhattisgarh and Assam. Epidemiological studies prove to be very important in managing the disease as the disease severity highly depends on the weather variables prevailing in the growing season. The present review...
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King chilli crop of Assam, India infected with Chilliveinal mottle virus (ChiVMV) belongs togenus potyvirus of the family potyviridae suffered from necrosis of leaves, leaf puckering, filiform leavesand eventually plant death. King chilli... more
King chilli crop of Assam, India infected with Chilliveinal mottle virus (ChiVMV) belongs togenus potyvirus of the family potyviridae suffered from necrosis of leaves, leaf puckering, filiform leavesand eventually plant death. King chilli crop particularly suffers from decline complex due to high incidenceof viral diseases. Prominent distribution of Chilliveinal mottle virus (ChiVMV) in King chilli growingregion of Jorhat and Golaghat districts of Assam state were considered to study the prevalence andassociation with symptoms associated. Molecular indexing of samples from 30 chilli plantation orchards ofJorhat and Golaghat districts using reverse transcription (RT)-PCR targeting the coat protein (CP) region ofChiVMV genome revealed a high incidence and wide prevalence of the virus. Out of a total of 96 chillisamples collected from different orchards of Jorhat and Golaghat districts, 41 chilli samples (42.70%) werepositive for ChiVMV. From Golaghat out of 34 samples 14 were found po...
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Majority of the leaf spot diseases on soybean crop is caused by different pathogenic fungi. Under favourable conditions and severe infection, it may result in heavy defoliation. It decreases the production efficiency of the crop by... more
Majority of the leaf spot diseases on soybean crop is caused by different pathogenic fungi. Under favourable conditions and severe infection, it may result in heavy defoliation. It decreases the production efficiency of the crop by reducing the surface area available on leaves for photosynthesis. With less photosynthetic activity, the yield may be reduced significantly. Thus, making it a production constraint by reducing the economic viability of the infected soybean crop. Cercospora leaf spot, Target leaf spot, Alternaria leaf spot, Brown Spot, Phyllosticta leaf spot are the major leaf spots caused due to fungus in the soybean crop worldwide. In this review, we are discussing about economic importance, symptomatology, causal organism, disease cycle, epidemiology and integrated management of leaf spots caused due to fungal infection in the soybean crop.
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Soybean is valued globally for its relatively high-quality oil and protein, which comprise approximately 20 and 40% of the soybean, respectively (Clemente and Cahoon 2009). Due to high protein content, soybean is known as ―poor man‘s... more
Soybean is valued globally for its relatively high-quality oil and protein, which comprise approximately 20 and 40% of the soybean, respectively (Clemente and Cahoon 2009). Due to high protein content, soybean is known as ―poor man‘s meat‖. Seeds of soybean also contain about 33% carbohydrates, up to 16.6% of which are soluble sugars (Hou et al., 2009). Among the grain legumes, it has the greatest potential of producing the cheapest source of food protein (Rao and Reddy, 2010). A frequent soybean protein consumption lowers the cholesterol levels and also reduces the risk of coronary heart disease (FDA, 1999; Henkel, 2000). Moreover, it improves the glucose tolerance in some diabetic patients (Messina, 1999). International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 11 (2020) Journal homepage: http://www.ijcmas.com
Field surveys were carried out in 8 citrus growing districts of Assam (Tinsukia, Lakhimpur, Jorhat, Kokrajhar, North Cachar Hills, Karbi Anglong, Golaghat and Kamrup). Altogether 411 samples were collected from three different citrus... more
Field surveys were carried out in 8 citrus growing districts of Assam (Tinsukia, Lakhimpur, Jorhat, Kokrajhar, North Cachar Hills, Karbi Anglong, Golaghat and Kamrup). Altogether 411 samples were collected from three different citrus species, viz ., Assam lemon ( Citrus limon ), Gul nemu ( Citrus jambhiri ) and Khasi mandarin ( Citrus reticulata ). Typical symptoms of CTV (Citrus tristeza virus), namely, leaf yellowing and vein clearing were prominent. Incidence of CTV was more in matured and older plants. Survey results indicated prevalence of the vector Toxoptera citricida and Toxoptera aurantii in this region. The samples were tested for the presence of CTV by double antibody sandwich-enzyme linked immuno-sorbent assay (DAS-ELISA). The results showed 261 trees infected with CTV indicating 63.50 per cent diseases incidence in Assam. Results revealed presence of CTV in all the surveyed districts of Assam showing a high incidence of 78.04 per cent CTV infection in Karbi Anglong dis...
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Among different production constraints in soybean cultivation, the most serious being is diseases. In Assam and other North Eastern states, collar rot caused by Sclerotium rolfsii Sacc. has been found to be a major disease causing plant... more
Among different production constraints in soybean cultivation, the most serious being is diseases. In Assam and other North Eastern states, collar rot caused by Sclerotium rolfsii Sacc. has been found to be a major disease causing plant death and low productivity as rainfall has played a significant role in the establishment of progression of collar rot in soybean. Therefore, the study was undertaken to evaluate the bioefficacy of some commonly available plant extracts against Sclerotium rolfsii Sacc. The aqueous plant extracts of commonly available six plant species were evaluated in vitro by poisoned food technique against their inhibitory effect on the mycelial growth of Sclerotium rolfsii Sacc. Allium sativum was found to be most effective with growth inhibition of 89.77% followed by Chromolaena odorata (86.00%), Allamanda cathertica (83.66%), Laurus nobilis (72.11%), Ageratum conyzoides (54.88%) and Aegle marmelos (50.66%).
Cucumber mosaic virus (CMV) causes great losses in Bhut Jolokia pepper ( Jacq.) plantations in Assam, India. To investigate possible means to induce plant resistance against this virus, the crude extract of bacterially-expressed... more
Cucumber mosaic virus (CMV) causes great losses in Bhut Jolokia pepper ( Jacq.) plantations in Assam, India. To investigate possible means to induce plant resistance against this virus, the crude extract of bacterially-expressed double-stranded (ds) RNA, derived from CMV-2b gene (dsRNA_CMV-2b), was exogenously applied along with CMV-G strain onto Bhut Jolokia plants. In this 'RNA-vaccination' bioassay, disease incidence, assessed by testing the plants at 21 days post inoculation by DAS-ELISA, ranged from 0 to 29% in case of dsRNA-treated plants, and from 55 to 92% when only CMV was applied. CMV-infected pepper plants became severely stunted, having dull light green foliage with leathery appearance, whereas plants receiving dsRNA_CMV-2b exhibited milder symptoms or remained healthy. The results obtained suggest that this non-transgenic approach has a considerable effect in protecting pepper against CMV.
Infection of Citrus tristeza virus (CTV) in Assam was detected by double antibody sandwich-enzyme-linked immuno-sorbent assay (DAS-ELISA). Field surveys were carried out in 8 citrus growing districts of Assam (Tinsukia, Lakhimpur, Jorhat,... more
Infection of Citrus tristeza virus (CTV) in Assam was detected by double antibody sandwich-enzyme-linked immuno-sorbent assay (DAS-ELISA). Field surveys were carried out in 8 citrus growing districts of Assam (Tinsukia, Lakhimpur, Jorhat, Kokrajhar, North Cachar Hills, Karbi Anglong, Golaghat and Kamrup). Altogether, 411 samples were collected from three different citrus species, viz., Assam lemon (Citrus limon), Gul nemu (Citrus jambhiri) and Khasi mandarin (Citrus reticulata) to test against CTV. Results of ..............