Physiological, biochemical and molecular responses of finger millet (Eleusine coracana) genotypes exposed to short-term drought stress induced by PEG-6000
Kasinathan Rakkammal, Theivanayagam Maharajan, R.N. Shriram, P.S. Jeevan Ram, Stanislaus Antony Ceasar, Manikandan Ramesh
Abstract
Drought is a dangerous abiotic stress affecting major cereals' growth, development, and yield, including finger millet . This study examined the physiological responses of 10-finger millet genotypes under various concentrations of drought. Drought reduced the physiological traits of ten-finger millet genotypes by >50%. The tolerant (IC 87469) and susceptible (IC 49940) genotypes were selected based on the physiological traits for further biochemical and molecular analyses. Contents of chlorophyll pigments ( a, b, and a + b ) were significantly higher (>70%) in IC 87469 compared to IC 49940. Activities of antioxidant enzymes were also significantly higher in IC 87469 genotype than in IC 49940. The proline content increased by >65% in the leaf and root tissues of IC 87469 compared to IC 49940. More than four classical drought-responsive genes (CDRG) were expressed in both tolerant and susceptible finger millet genotypes of leaf and root tissues under drought conditions. However, expression levels of four ( EcCAT1, EcSOD, EcPSCS, and EcGR ) and two ( EcP5CS and EcGR ) genes were significantly higher in leaf and root tissues, respectively, in IC 87469 genotype compared to IC 49940. This is the first study to identify and analyze the CDRG from the genome sequence of finger millet. This study may form the foundation for future biotechnological approaches to characterize the genes and improve the drought tolerance in finger millet. • Drought stress affected the growth, biochemical, and molecular responses in finger millet genotypes. • Drought tolerant genotype produced a better performance for physiological, biochemical, and molecular changes. • More CDRG were expressed in the drought-tolerant genotype compared to drought susceptible genotype under drought stress. • Antioxidant enzyme activities were also higher in the drought-tolerant genotype than in the susceptible one.