Publications of NIPGR Scientists

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Author: search.filters.author.Kumar, SanjeevSubject: search.filters.subject.stress

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    Nitric oxide-mediated modulation of reproductive resilience under cold stress in chickpea
    (Frontiers Media S.A., 2025) Kaur, Sarbjeet; Padhiar, Deeksha; Jha, Uday Chand; Kumar, Sanjeev; Sharma, Kamal Dev; Parida, Swarup Kumar; Siddique, Kadambot H. M.; Prasad, P. V. Vara; Nayyar, Harsh
    Chickpeas are particularly sensitive to cold stress during the reproductive phase, which can significantly impair pod set and yield. This study examined the role of sodium nitroprusside (SNP), a nitric oxide (NO) donor, in mitigating cold-induced reproductive damage in cold-tolerant (CT) and cold-sensitive (CS) chickpea genotypes. After 100 days of outdoor growth, plants were subjected to cold stress (15/8°C day/night; 12 h photoperiod) for 21 days in walk-in growth chambers during the reproductive stage of development. Control plants were maintained at 25/15°C day/night temperature. SNP treatment (1 mM) was applied exogenously each time, first two days prior to stress onset and then at seven-day intervals (three applications total). Cold stress significantly lowered endogenous NO levels in leaves, anthers, and ovules, particularly in CS genotypes, thereby leading to reduced pollen viability and germination. SNP treatment restored NO and improved reproductive performance, with stronger responses in the CS than the CT genotype. For instance, pollen germination increased by 57.9% in CS versus 17.6% in CT, and pollen viability increased by 28.0% and 13.1%, respectively. Enhanced anther function resulted in a 157.2% increase in pod set and 62.0% higher seed yield in CS. SNP also improved physiological traits, including a 43.9% increase in cellular viability, 18.6% in stomatal conductance, and 41.9% in chlorophyll content in CS genotypes. Cryoprotectants (proline, trehalose, and sucrose) accumulated in anthers, reinforcing cold resilience, while oxidative stress was simultaneously alleviated through reduced malondialdehyde, hydrogen peroxide, and electrolyte leakage, together with the upregulation of both enzymatic (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx), and glutathione reductase (GR)) and non-enzymatic (ascorbic acid (ASC) and reduced glutathione (GSH)) components. Notably, CS genotypes showed more pronounced improvements from SNP application than CT genotypes, particularly in terms of reproductive success and yield-related traits. These findings highlight the potential of NO donors, such as SNP, to enhance cold tolerance in chickpeas, with promising implications for safeguarding productivity under low-temperature stress, especially in sensitive cultivars.
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    Deciphering the dynamics of enzymes associated with the synthesis of cryoprotectants during cold acclimation in contrasting chickpea genotypes
    (Springer Nature Publishing AG, 2025) Padhiar, Deeksha; Kaur, Sarbjeet; Rani, Anju; Jha, Uday Chand; Prasad, P. V. Vara; Sharma, Kamal Dev; Kumar, Sanjeev; Parida, Swarup K.; Siddique, Kadambot H. M.; Nayyar, Harsh
    Chickpea, a vital legume crop, is highly susceptible to cold stress, especially during its reproductive phase, resulting in significant flower and pod abortions and reduced seed yield. Our previous study demonstrated that cold acclimation is effective in enhancing cold tolerance but benefits only cold-tolerant (CT) genotypes, while cold-sensitive (CS) genotypes remain unaffected. In this extended study aimed at probing the detailed mechanisms of this differential response, we further examined the expression profiles of enzymes involved in the synthesis and breakdown of osmolytes (pyrroline-5-carboxylate synthase, proline dehydrogenase (PDH), betaine aldehyde dehydrogenase) and sugars (sucrose synthase, acid invertase, trehalose-6-phosphate synthase, trehalose-6-phosphate phosphatase, and trehalase activity), along with the expression of various antioxidants (superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase) in both CT and CS genotypes. Seeds of two contrasting chickpea genotypes, cold-tolerant ICC 17258 and cold-sensitive ICC 15567, were planted in pots during the first week of November in an outdoor field environment. After 40 days, the plants were transferred to walk-in growth chambers for cold acclimation at specific temperatures. Initially, the plants were exposed the plants to 25/18℃ (pre-acclimation stage; PAS) for 2 days, followed by a 21-day cold acclimation period with progressively decreasing temperatures over seven days for each cold acclimation stage (CAS): CAS1 (21/13℃), CAS2 (18/10℃), and CAS3 (15/8℃). Subsequently, the plants were subjected to cold stress at 13/7℃ for 15 days and then exposed to 30/23℃ (12 h day/night) until maturity. Our findings demonstrated that the expression of various enzymes involved in the synthesis of osmolytes and sugars in leaves, anthers, and ovules was significantly upregulated during the cold acclimation process in the CT chickpea genotypes but not in the CS genotypes. This enhanced metabolic activity, coupled with elevated levels of enzymatic antioxidants during the acclimation process, contributed to improved leaf water status, photosynthetic efficiency, and ultimately, superior reproductive performance (pollen germination, pollen viability, stigma receptivity, and ovule viability) under cold stress conditions compared to CS genotypes. The enhanced cold tolerance observed in the CT genotypes is likely attributable to their genetic predisposition and efficient stress defense mechanisms facilitated by the upregulated expression of cold-responsive enzymes.