Browsing by Author "Padhiar, Deeksha"

Now showing 1 - 5 of 5

Assessing cold stress resilience in wild chickpea accessions using physiological, biochemical, and reproductive traits
(Springer Nature, 2025) Kaur, Sarbjeet; Padhiar, Deeksha; Singh, Mohar; Parida, Swarup K.; Jha, Uday C.; Sharma, Kamal Dev; Prasad, P. V. Vara; Siddique, Kadambot H. M.; Nayyar, Harsh
Domesticated chickpea (Cicer arietinum L.) exhibits high sensitivity to temperatures below 20/10 °C during its reproductive phase resulting in substantial loss of flowers, pods and crop yields. With the aim to add new sources of cold tolerance and elucidate mechanism of cold-tolerance in wild species of chickpea, the present study evaluated 36 wild accessions of three Cicer species (Cicer judaicum, Cicer pinnatifidum, Cicer reticulatum) at the reproductive stage for yield, and reproductive, physiological and biochemical traits under cold stress (15/7 °C) for two consecutive years. Cluster analysis based on yield-related traits such as pod number, seed weight, and total seed count categorized these accessions as cold-tolerant and cold-sensitive. Six C. judaicum accessions (ILWC 256, ICC 13852, ILWC 263, ILWC 20, ILWC 223, and ILWC 30) were tolerant to cold whereas the remaining ones were cold-sensitive. Under cold stress, cold-tolerant accessions exhibited lower impairment of physiological processes as compared to the cold-sensitive accessions e.g. lower tissue damage and electrolyte leakage, and higher chlorophyll content, carotenoid content, chlorophyll fluorescence, and leaf water content, thereby resulting in higher photosynthetic efficiency and carbohydrate accumulation in cold-tolerant accessions. At the biochemical level, the tolerant accessions demonstrated significantly higher amounts of cryoprotectants and enhanced activities of enzymatic and non-enzymatic antioxidants resulting in substantially lower levels of reactive oxygen species. Cold-tolerant accessions also accumulated more proline and trehalose compared to their sensitive counterparts. Slight disruptions in physiological processes, low oxidative stress and accumulation of cryoprotectants under cold stress were associated with higher pollen viability, pollen germination, pollen load, ovule receptivity, pod set, number of pods and seed yield in cold-tolerant accessions while opposite was true for cold-sensitive accessions. The wild chickpea accessions exhibiting high seed yield under cold stress are promising candidates for breeding programs aimed at cold tolerance.
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.
Differential resilience of chickpea's reproductive organs to cold stress across developmental stages: insights into antioxidant strategies for enhanced fertility
(Frontiers Media S.A., 2025) Padhiar, Deeksha; Kaur, Sarbjeet; Jha, Uday Chand; Prasad, P. V. Vara; Sharma, Kamal Dev; Kumar, Sanjeev; Parida, Swarup Kumar; Siddique, Kadambot H M; Nayyar, Harsh
Chickpea is highly sensitive to cold stress during its reproductive stages, leading to significant reductions in potential pod formation due to decreased reproductive success. This study aimed to investigate the specific responses of anthers and ovules to cold stress, explore the role of oxidative stress and antioxidant mechanisms, and understand the relationship between oxidative stress and reproductive function to enhance our understanding of chickpea responses to cold stress. Chickpea seeds of contrasting genotypes—cold-tolerant (ICC 17258, ICC 16349) and cold-sensitive (ICC 15567, GPF 2)—were sown outdoors in early November under optimal conditions (25.5/15.4°C mean day/night temperatures). At 50 days after sowing, plants were subjected to 13/7°C cold stress (12 h light/dark in walk-in growth chambers. Cold stress significantly increased membrane damage and reduced cellular viability in anthers and ovules, particularly in cold-sensitive (CS) genotypes. Oxidative damage was more pronounced in anthers, particularly at anthesis (stage 2), as indicated by elevated malondialdehyde and hydrogen peroxide levels. Cold-tolerant (CT) genotypes exhibited increased antioxidant activity under stress, especially at pre-anthesis (stage 1), followed by declines at later stage, although responses varied by genotype. Anthers exhibited higher overall antioxidants activity than ovules, while ovules demonstrated notably high catalase activity. Among the antioxidants studied, ascorbate peroxidase and glutathione reductase were most prominent in the CT genotype, along with higher levels of ascorbate (AsA) and glutathione (GSH), highlighting the critical role of the AsA–GSH cycle in conferring cold tolerance to chickpea. Exogenous supplementation with 1 mM ascorbate (AsA) and glutathione (GSH) significantly stimulated pollen germination in cold-stressed plants under in vitro conditions, with a greater effect observed in CS genotypes. Furthermore, antioxidant activity strongly correlated with key reproductive traits such as pollen germination and ovule viability. This study revealed that the anthers and ovules exhibited distinct responses to cold stress, with significant genotypic differences across key reproductive stages. These insights provide a deeper understanding of cold tolerance mechanisms in chickpea and provide vital clues for breeding strategies to enhance resilience and reproductive success under cold stress.
Genotypic variability and trait associations for cold stress tolerance in cultivated chickpea (Cicer arietinum L.) during the reproductive stage
(PLOS, 2026) Padhiar, Deeksha; Kaur, Sarbjeet; Parida, Swarup K.; Jha, Uday C; Shama, Kamal Dev; Prasad, Pagadala Venkat Vara; Siddique, Kadambot H M; Nayyar, Harsh
Chickpea (Cicer arietinum L.), a major winter legume in northern South Asia and Australia, frequently encounters low temperatures (0–15 °C) during reproduction, causing substantial yield losses. The present study involved screening two independent sets of 100 genotypes over consecutive winters to identify sources of reproductive-stage cold tolerance and to elucidate the underlying mechanisms. Following outdoor establishment, plants were exposed to controlled cold stress (15/7 °C day/night) during flowering and pod development (15 d) in walk-in growth chambers. Ten representative cold-tolerant (CT) and ten cold-sensitive (CS) genotypes were selected each year based on integrated performance across yield, physiological, biochemical, and reproductive traits for a detailed mechanistic analysis. Cold-sensitive genotypes exhibited severe dysfunction, characterized by high electrolyte leakage (50−59% above CT) and malondialdehyde (39−51% above CT), indicating membrane damage. Reduced chlorophyll content (21−23%), photosystem II efficiency (23−29%), and stomatal conductance (40−43%) impaired photosynthesis. Inadequate cryoprotectants (reduced by 25−58%) and antioxidants (reduced by 38−55%) caused oxidative damage. Reproductive collapse followed, with pollen viability and germination declining by 24−46%, stigma receptivity and ovule viability decreasing by 41−68%, and seed yields falling by 85−95%. Cold-tolerant genotypes-maintained homeostasis through integrated protection in terms of superior membrane stability, enhanced compatible solutes, and elevated antioxidant activities, which sustained photosynthesis and reproductive success, achieving better yields under cold stress. Principal component analysis revealed cold tolerance as an integrated system (PC1:72.6–81.3% variance), clearly separating the CT from the CS genotypes. Membrane stability, photosynthetic efficiency, and pollen viability emerged as diagnostic traits (r = 0.85–0.91 with yield, p < 0.001; heritability 70−99%). Tolerance operated independently of maturity (R² = 0.10–0.18), enabling donor identification across maturity classes. Twenty cold-tolerant genotypes were identified, spanning the early, medium, and late maturity groups, respectively. These findings establish a mechanistic understanding of reproductive-stage cold tolerance, provide vital selection markers, and identify genetic resources for breeding cold-resilient chickpea cultivars.
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.