Browsing by Author "Sreenivasulu, Nese"

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Comparative transcriptome analysis of contrasting foxtail millet cultivars in response to short-term salinity stress
(Elsevier, 2011) Puranik, Swati; Jha, Sarita; Srivastava, Prem S.; Sreenivasulu, Nese; Prasad, Manoj
Soil salinity represents a major abiotic stress that adversely affects crop growth and productivity. In this study, 21-day-old seedlings of two foxtail millet (Setaria italica) cultivars differing in salt tolerance were found to also differ in lipid peroxidation, ion balance and activity of antioxidative enzymes (glutathione reductase and catalase) under short-term salinity stress (250 mM NaCl for 1-48 h). With the aim of better understanding the molecular mechanisms underlying plant responses to short-term salinity stress, two suppression subtractive hybridization cDNA libraries (forward and reverse) were constructed of these cultivars. A total of 249 non-redundant ESTs was identified by random EST sequencing and grouped into 11 functional categories. Macroarray analysis of these clones showed that 159 (63.9%) were differentially expressed (≥ 2-fold) in response to salinity stress, with 115 (72.3%) up and 44 (27.7%) down-regulated. A data search of transcriptional profiling under salinity stress in other species revealed that 81 (51%) of the 159 differentially expressed transcripts found in foxtail millet have not been reported in previous studies. Hence, these new transcripts may represent untapped gene sources allowing specific responses to short-term salt-stress in an orphan crop known to possess a natural adaptation capacity to abiotic stress. Quantitative real-time PCR of 21 highly up-regulated (≥2.5-fold) transcripts showed temporal variation in expression in both cultivars under salinity. Among them, several transcription factors and signalling genes were preferentially expressed in the tolerant cultivar. These results suggest that the tolerant cultivar possesses more effective signal-perception mechanisms for metabolic adjustments in plants under harsh saline conditions. Our findings provide evidence that the unknown genes identified in this study, in addition to several known genes, may play important roles in stress tolerance mechanisms present in foxtail millet.
Differential antioxidative responses to dehydration-induced oxidative stress in core set of foxtail millet cultivars [Setaria italica (L.)]
(Springer Science, 2011) Lata, Charu; Jha, Sarita; Dixit, Vivek; Sreenivasulu, Nese; Prasad, Manoj
Foxtail millet (Setaria italica L.) known as a relatively drought-tolerant crop across the world is grown in arid and semi-arid regions. To the best of our knowledge, no systematic study on drought tolerance screening of foxtail millet germplasm being a drought-tolerant crop has been reported so far. To explore genetic diversity of drought-induced oxidative stress tolerance in foxtail millet, we employed lipid peroxidation measure to assess membrane integrity under stress as biochemical marker to screen 107 cultivars and classified the genotypes as highly tolerant, tolerant, sensitive, and highly sensitive. From this comprehensive screening, four cultivars showing differential response to dehydration tolerance were selected to understand the physiological and biochemical basis of tolerance mechanisms. The dehydration-tolerant cultivars (IC-403579 and Prasad) showed considerably lower levels of lipid peroxidation and electrolyte leakage as compared with dehydration-sensitive cultivars (IC-480117 and Lepakshi), indicating better cell membrane integrity in tolerant cultivars. Correspondingly, tolerant genotypes maintained higher activity of catalase (EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), and glutathione reductase (GR; EC 1.6.4.2) across different time-course period of polyethylene glycol (PEG) treatments in comparison to sensitive ones. The above biochemical results were further validated through quantitative real-time PCR analysis of APX and GR, whose transcripts were substantially induced by PEG treatments in tolerant cultivars. These results suggest that tolerant cultivars possess wider array of antioxidant machinery with efficient ascorbate-glutathione pathway to cope with drought-induced oxidative stress.
Potential of underutilized crops to introduce the nutritional diversity and achieve zero hunger
(Springer Nature Publishing AG, 2022) Singh, Roshan Kumar; Sreenivasulu, Nese; Prasad, Manoj
Several crops with enormous nutritional values were once largely consumed by mankind. However, due to selective domestication, most of them had become marginally cultivated in a confined region. It is an estimate from various studies on the evaluation of mankind that about 80,000 plant species have been directly used by humans for food, fodder, fibre, medicine, and industrial purposes. Among these, more than 25,000 are edible and about 7000 have either been domesticated or collected from the wild for food at one time or another (Muthamilarasan et al. 2019). At present, merely 30 species are being cultivated for food, among which 6 crops including rice, wheat, maize, potato, soybean, and sugarcane share more than 75% of total plant-derived energy intake. Green revolution in Asia occurred due to the introduction of high-yielding rice and wheat varieties with excess soil nitrogen application has uplifted the undernourished incidences from one in three people being hungry during 1960 to roughly one out of ten in the present date. However, the advent of green revolution has negatively impacted crop diversity in developing countries. Narrowing down of crop diversification together with consumption of highly processed food and sedentary life resulted in double-burden nutritional challenges with nearly 2 billion people still suffering from malnutrition and additional 1.9 billion people suffering from obesity and non-communicable diseases due to higher caloric intake (Sreenivasulu and Fernie 2022; Tiozon et al. 2021). Switching to crops with higher caloric yields has ended the cultivation of super-nutrient crops and general awareness of broader climatic adaptation of several native species to be grown in marginal environments.