Isolation and allelic characterization of finger millet (Eleusine coracana L.) small heat shock protein EcHSP17.8 for stress tolerance

Abstract

Finger millet (Eleusine coracana L.) commonly known as ragi is an orphan cereal crop having significant climatesmart stress adaptation system. Apart from various abiotic stresses worldwide, heat stress is the major limiting constraint for crop yield and the loss of crop yield due to heat stress is increasing every year. Hence, to generate better heat tolerant crop plants there is a need to mine superior alleles. In this regard, efforts were made to isolate and characterize role of small heat shock protein gene HSP17.8 from finger millet. Here, we obtained an EST of having Hsp20 domain based on the expression analysis under heat stress and identified complete gene using homology-based analysis. The obtained gene was named as EcHSP17.8 based on its molecular weight. The complete Open Reading Frame (ORF) of EcHSP17.8 is of 489 bp with peptide length of 162 aa. Expression analysis of this gene in finger millet revealed its maximum expression in roots tissue. This gene was found to be induced by heat (42oC), desiccation, NaCl (250 mM), mannitol (200 mM) and oxidative stress; however maximum upregulation was observed under heat stress up to 40 folds. Expression analysis of this gene in 16 finger millet genotypes under heat stress revealed its maximum expression after 2h which remained upregulated up to 4h showing it as early responsive gene under heat stress. As this gene is well characterized for stress tolerance in other crops, the alleles of HSP17.8 from crop like finger millet can be used as better candidate for generating heat tolerant crop plants.