Assessment of relative expression of some genes involved in cold tolerance in chickpea (Cicer arietimun L.)

In this experiment, the effect of cold stress on cell damage index (H2O2) and photosynthetic enzyme activity of phosphoenolpyruvate carboxylase (PEPC) and relative expression of small Rubisco and large Rubisco subunit genes and the chlorophyll a/b binding protein gene were studied in two chickpea (Cicer arietimun L.) genotypes differing in cold sensitivity (tolerant Sel96th11439 and sensitive ILC533) during cold stress (4˚C). Under cold stress, H2O2 was significantly lower in the tolerant genotype compared to the sensitive one (by 40.8%). Results showed that PEPC activity increased in both genotypes particularly in tolerant genotype (by 69%). However, on the sixth day of cold stress, PEPC activity in tolerant genotype was 16.9% more than sensitive genotype. In tolerant genotype, the expression of small and large Rubisco subunit genes on the first day of cold stress showed significant increase (by 80.3% and 70.6%, respectively) compared to control conditions, while on the sixth day of cold stress, the expression of these genes significantly declined (93.5% and 38.2%, respectively) compared to control conditions. In sensitive genotype, the expression of studied genes significantly declined compared to control conditions. The relative expression of chlorophyll a/b binding protein gene has shown almost the same trend compared to small and large subunit, with the difference that in tolerant genotype, on the sixth day of cold stress was equaled to control plants. These results are probably referred further homeostasis of cell through metabolic activities and photosynthesis for acclimatization the plant to cold stress. The reduction of cell damage index (H2O2) in tolerant genotypes on the sixth day of cold stress compared to sensitive genotype confirms this issue. Therefore, changes in metabolism involved in photosynthesis can be an indicator for assessing the degree of cold tolerance in chickpea.