Gene networks involved in cold stress response in chickpea Cicer arietinum L anthers

Abstract

Cold stress (CS) coinciding with the onset of the flowering in chickpea poses a newlinemajor threat for realizing high productivity in northern hill regions of India. CS induces newlinepollen sterility in chickpea leading to flower abortion and consequently low productivity. newlineSome genotypes of chickpea, though agronomically inferior, tolerate cold and produce newlineviable pollen leading to seed set even under cold stress. Changes in carbohydrate content newlinein contrasting genotypes of chickpea were observed in the present study under CS newlinewherein, the genotype ICC 16349 (cold tolerant) maintained normal carbohydrate pool newlinewhereas genotype GPF2 (cold susceptible) failed to do so. Not only carbohydrate content newlinebut enzymes of the carbohydrate pathway e.g. invertase, sucrose synthase, alpha and beta newlineamylase showed greater activity in cold tolerant genotype. Under recovery period, the newlinelevels of carbohydrates as well as carbohydrate metabolism enzymes shifted towards newlinenormal with a few modifications. The expression of carbohydrate metabolism genes that newlineis UDP glucose pyro phosphorylase like, ADP glucose pyro phosphorylase, Beta newlineamylase3 and Beta amylase1 changed significantly under cold stress in the cold tolerant newlineas well as cold susceptible genotypes. The expression level of Isoamylase3 and newlineIsoamlyase3x2 was higher in leaves of cold susceptible genotype GPF2. Starch newlinedegradation was lower in ICC 16349 (cold tolerant) as compared to GPF2 (cold newlinesusceptible) as evident from expression of genes; Beta amylase3 and Beta amylase1 and newlineglucan water kinase. The expression of starch synthase increased in theICC16349.The newlineexpression of ABA metabolism genes was higher in GPF2 and the expression of GA newlinebiosynthesis genes Gibberellin20oxidase1 and Gibberellin20 oxidase3 reduced in the newlineanthers of ICC 16349 and GPF2 with the exception of Gibberellin20oxidase1 that newlineenhanced in GPF2. A combination of 5and#956;M Sucrose and 5and#956;M GA was the best treatment newlinefor mitigation of cold under pot as well as field conditions as it showed marked increase newlinein chlorophyll content, relative leaf water content, cellular respiration and reduction in newlineelectrolyte leakage in both the genotypes. The study has implications in the development newlineof cold tolerant chickpea varieties and devise other appropriate strategies for mitigation newlineof cold, thereby resulting in increased productivity of chickpea. newline