Ravi Rajwanshi

Rice being a staple cereal is extremely susceptible towards abiotic stresses. Drought and salinity are two vital factors limiting rice cultivation in Eastern Indo-Gangetic Plains (EIGP). Present study has intended to evaluate the consequences of salinity stress on selected drought tolerant rice genotypes at the most susceptible seedling stage with an aim to identify the potential multi-stress (drought and salt) tolerant rice genotype of this region. Genotypic variation was obvious in all traits related to drought and salt susceptibility. IR84895-B-127-CRA-5-1-1, one of the rice genotypes studied, exhibited exceptional drought and salinity tolerance. IR83373-B-B-25-3-B-B-25-3 also displayed enhanced drought and salt tolerance following IR84895-B-127-CRA-5-1-1. Variations were perceptible in different factors involving photosynthetic performance, proline content, lipid peroxidation, K(+)/Na(+) ratio. Accumulation of reactive oxygen species (ROS) disintegrated cellular and sub-cellular...

ABSTRACT The amount of land available for crop production is decreasing steadily due to urban growth and land degradation. This decrease in the amount of arable land available for crop production and increase in human population will have major implications for food security over the next 2-3 decades. A vast tract of agricultural land in India is presently non-arable due to excessive salinity and an effort to generate salt-tolerant crop plants is a prime target for ensuring increased productivity. The Indian mustard (Brassica juncea) belongs to the Cruciferae family. There are nearly 40 different varieties of this yellow flowering plant that botanists classify into the genus Brassica. The most common are, Brassica nigra, Brassica juncea and Brassica hirta. Brassica juncea is one of the major oilseed crops of India, the oil content varying between 28.6% and 45.7%. Its seed residue is used as cattle feed and in fertilizers (Reed, 1976). It is a high biomass crop and also helpful in phytoremediation of heavy metals in the polluted soils (Ebbs and Kochian, 1998; Lin et al, 2004). Glucosinolates found in Brassica sp. are of interest due to the potential use of their degradation products such as fumigants, isothiocyanates and nitriles which have been demonstrated to control fungi, bacteria and nematodes (Mojtahedi et al, 1991). In Ayurveda, the Indian medicine, as well as Yunani, mustard oil are extensively used (Krishnamurthy, 1993). Mustard seeds are useful in the treatment of skin diseases because of its high sulphur content. Mustard green is a rich source of vitamins of the category A, C and E. Mustard green is also known to be very helpful for digestion, and helps to speed up metabolism. Mustard seeds are rich in selenium and magnesium which help in protecting the various coordinating functions of the brain that become incoherent as a result of aging process. Mustard seeds are a very good source of omega-3 fatty acids as well as calcium, dietary fiber, iron, manganese, niacin, phosphorus, protein and zinc. They are also known to provide relief from asthma, bronchitis, cardiovascular disorders and are recommended to diabetic patients. Mustard prevents the growth of cancer cells and also helps in increasing blood circulation. Brassica juncea being such an important oil seed crop which is subjected to salinity stress in the areas where it is grown and it is being an irrigated crop, the productivity is affected. Therefore, Glyoxalase system was chosen for the crop improvement to achieve enhanced salt stress tolerance and hence genetic manipulation were carried out by the candidate gene i.e. glyoxalase I and glyoxalase II. The Glyoxalase system was discovered in the early 20th century (Dakin and Dudly, 1913). Its exact role in metabolism is not clear, although, its wide distribution and ubiquitous nature does suggest that it fulfills a function of some fundamental importance. Szent-Gyorgyi et al (1966) proposed a theory on the possible role of glyoxalase system. According to this theory, methylglyoxal known as retine, is cytotoxic and arrests cell division, while Glyoxalase I designated as promine detoxifies it and initiates cell proliferation. The ubiquitous Glyoxalase pathway is a two-step enzyme catalyzed reaction. Glyoxalase I (EC 4.4.1.5, lactoylglutathione lyase) catalyses the isomerization of the hemithioacetal to S-D-lactoylglutathione which is formed by a non-enzymatic reaction between GSH and methylglyoxal whereas Glyoxalase II (EC 3.1.2.6, hydroxacylglutathione hydrolase) catalyses the hydrosis of S-2-hydroxyacylglutathione derivatives to GSH and D-lactate (Jagt, 1988; Uotila et al, 1989; Thornalley et al, 1990). In higher plants, the Glyoxalase I activity was found to be correlated with the mitotic index in Pisum sativum and Datura callus cultures (Ramaswamy et al, 1983; 1984). Ramaswamy et al (1984) and Sethi et al (1988) observed an inverse correlation between Glyoxalase I activity and cell differentiation in plants, a concept which was supported by Kalia et al (1999) who showed reduction in cell division by isoascorbate, an inhibitor of Glyoxalase I in tobacco. Unlike the Glyoxalase I, the Glyoxalase II is the less studied component of glyoxalase system. Glyoxalase II activity has been reported in various prokaryotes and eukaryotes viz. in human, calf, rat, mouse, rabit, chicken, frog, snake, fish, Saccharomyces cerevisiae and H. markii, Neisseria meningitidis, Trypanosoma, Plasmodium falciperum and Leishmania brazilensis, and wide range of helminthes, cestodes, digeneans, nematodes and C. albicance. In plants, Glyoxalase II has been purified from a variety of sources in plants like, Zea mays, spinach and Aloe vera and detailed characterization of the genes coding for cytoplasmic and mitochondrial Glyoxalase II have been carried out in Arabidopsis thaliana (Maiti et al, 1997; Ridderstrom & Mannervik 1997; Marasinghe et al, 2005), Zea mays (Norton et al, 1989) and Brassica juncea (Saxena et al,…

Global issues are leading to concerns over food security. These include climate change, urbanization, increase in population subsequently leading to greater energy and water demand. Futuristic approach for crop improvement involves gene pyramiding for agronomic traits that empower the plants to withstand multiple stresses. In an earlier study from the laboratory, the efficacy of overexpressing γ-tocopherol methyl transferase (γ-TMT) gene from the vitamin E biosynthetic pathway has been shown to result in six-fold increase of the most biologically active form, the α-tocopherol in Brassica juncea which resulted in alleviation of salt, heavy metal and osmoticum induced stress by the transgenic plants. The glyoxalase I (gly I) gene from the glyoxalase pathway has also been earlier shown by us to impart tolerance against multiple abioitc stresses by detoxification of the cytotoxic compound methylglyoxal in Brassica juncea. Recently, both the transgenes were pyramided in Brassica juncea l...

The amount of land available for crop production is decreasing steadily due to urban growth and land degradation. This decrease in the amount of arable land available for crop production and increase in human population will have major implications for food security over the next 2-3 decades. According to survey done by FAO in 2010, more than one billion people around the world are undernourished and one in six people suffer from severe hunger in developing countries. A vast tract of agricultural land in India is presently non-arable due to excessive salinity and an effort to generate salt-tolerant crop plants is a prime target for ensuring increased productivity. The Glyoxalase system was discovered in the early 20th century. Its exact role in metabolism is not clear, although, its wide distribution and ubiquitous nature does suggest that it fulfills a function of some fundamental importance. The ubiquitous Glyoxalase pathway is a two-step enzyme catalyzed reaction. Glyoxalase I ca...

ABSTRACT The amount of land available for crop production is decreasing steadily due to urban growth and land degradation. This decrease in the amount of arable land available for crop production and increase in human population will have major implications for food security over the next 2-3 decades. A vast tract of agricultural land in India is presently non-arable due to excessive salinity and an effort to generate salt-tolerant crop plants is a prime target for ensuring increased productivity. The Indian mustard (Brassica juncea) belongs to the Cruciferae family. There are nearly 40 different varieties of this yellow flowering plant that botanists classify into the genus Brassica. The most common are, Brassica nigra, Brassica juncea and Brassica hirta. Brassica juncea is one of the major oilseed crops of India, the oil content varying between 28.6% and 45.7%. Its seed residue is used as cattle feed and in fertilizers (Reed, 1976). It is a high biomass crop and also helpful in phytoremediation of heavy metals in the polluted soils (Ebbs and Kochian, 1998; Lin et al, 2004). Glucosinolates found in Brassica sp. are of interest due to the potential use of their degradation products such as fumigants, isothiocyanates and nitriles which have been demonstrated to control fungi, bacteria and nematodes (Mojtahedi et al, 1991). In Ayurveda, the Indian medicine, as well as Yunani, mustard oil are extensively used (Krishnamurthy, 1993). Mustard seeds are useful in the treatment of skin diseases because of its high sulphur content. Mustard green is a rich source of vitamins of the category A, C and E. Mustard green is also known to be very helpful for digestion, and helps to speed up metabolism. Mustard seeds are rich in selenium and magnesium which help in protecting the various coordinating functions of the brain that become incoherent as a result of aging process. Mustard seeds are a very good source of omega-3 fatty acids as well as calcium, dietary fiber, iron, manganese, niacin, phosphorus, protein and zinc. They are also known to provide relief from asthma, bronchitis, cardiovascular disorders and are recommended to diabetic patients. Mustard prevents the growth of cancer cells and also helps in increasing blood circulation. Brassica juncea being such an important oil seed crop which is subjected to salinity stress in the areas where it is grown and it is being an irrigated crop, the productivity is affected. Therefore, Glyoxalase system was chosen for the crop improvement to achieve enhanced salt stress tolerance and hence genetic manipulation were carried out by the candidate gene i.e. glyoxalase I and glyoxalase II. The Glyoxalase system was discovered in the early 20th century (Dakin and Dudly, 1913). Its exact role in metabolism is not clear, although, its wide distribution and ubiquitous nature does suggest that it fulfills a function of some fundamental importance. Szent-Gyorgyi et al (1966) proposed a theory on the possible role of glyoxalase system. According to this theory, methylglyoxal known as retine, is cytotoxic and arrests cell division, while Glyoxalase I designated as promine detoxifies it and initiates cell proliferation. The ubiquitous Glyoxalase pathway is a two-step enzyme catalyzed reaction. Glyoxalase I (EC 4.4.1.5, lactoylglutathione lyase) catalyses the isomerization of the hemithioacetal to S-D-lactoylglutathione which is formed by a non-enzymatic reaction between GSH and methylglyoxal whereas Glyoxalase II (EC 3.1.2.6, hydroxacylglutathione hydrolase) catalyses the hydrosis of S-2-hydroxyacylglutathione derivatives to GSH and D-lactate (Jagt, 1988; Uotila et al, 1989; Thornalley et al, 1990). In higher plants, the Glyoxalase I activity was found to be correlated with the mitotic index in Pisum sativum and Datura callus cultures (Ramaswamy et al, 1983; 1984). Ramaswamy et al (1984) and Sethi et al (1988) observed an inverse correlation between Glyoxalase I activity and cell differentiation in plants, a concept which was supported by Kalia et al (1999) who showed reduction in cell division by isoascorbate, an inhibitor of Glyoxalase I in tobacco. Unlike the Glyoxalase I, the Glyoxalase II is the less studied component of glyoxalase system. Glyoxalase II activity has been reported in various prokaryotes and eukaryotes viz. in human, calf, rat, mouse, rabit, chicken, frog, snake, fish, Saccharomyces cerevisiae and H. markii, Neisseria meningitidis, Trypanosoma, Plasmodium falciperum and Leishmania brazilensis, and wide range of helminthes, cestodes, digeneans, nematodes and C. albicance. In plants, Glyoxalase II has been purified from a variety of sources in plants like, Zea mays, spinach and Aloe vera and detailed characterization of the genes coding for cytoplasmic and mitochondrial Glyoxalase II have been carried out in Arabidopsis thaliana (Maiti et al, 1997; Ridderstrom & Mannervik 1997; Marasinghe et al, 2005), Zea mays (Norton et al, 1989) and Brassica juncea (Saxena et al,…

Fruit ripening process is associated with change in carotenoid profile and accumulation of lycopene in tomato (Solanum lycopersicum L.). In this study, we quantified the β-carotene and lycopene content at green, breaker and red-ripe stages of fruit ripening in eight tomato genotypes by using high-performance liquid chromatography. Among the genotypes, lycopene content was found highest in Pusa Rohini and lowest in VRT-32-1. To gain further insight into the regulation of lycopene biosynthesis and accumulation during fruit ripening, expression analysis of nine carotenoid pathway-related genes was carried out in the fruits of high lycopene genotype—Pusa Rohini. We found that expression of phytoene synthase and β-carotene hydroxylase-1 was four and thirty-fold higher, respectively, at breaker stage as compared to red-ripe stage of fruit ripening. Changes in the expression level of these genes were associated with a 40% increase in lycopene content at red-ripe stage as compared with brea...