Characterization and Expression Analysis of WRKY Transcription Factors in Groundnut (Arachis hypogaea L.)

Abstract

Groundnut (Arachis hypogaea L.), is an important subsistence oil yielding crop of the semi-arid tropics and often exposed to several environmental cues (high temperature, drought & heavy metal). The WRKY transcription factor (TF) is one of the master regulator, and play vital role in stress responses. However, far less information is available on functional characterization and tolerance mechanism of stress responsive WRKY genes in groundnut till date. In this study, a comprehensive phylogenetic, protein features, gene structure and motif analysis of WRKY TF gene family was carried out. We conducted expression profiling of 10 WRKY genes under high temperature, drought and heavy metal (CdCl2) in various tissues. Majority of the AhWRKY (Arachis hypogaea WRKY) proteins were clustered and share close relationship with Arabidopsis and Glycine max. RT- qPCR analysis of AhWRKY genes revealed differential expression either in their transcript abundance or in their expression patterns in response to at least one abiotic stress. In particular, AhWRKY41 expression level was found to be maximum in all the stress conditions. On the other hand, AhWRKY20 and AhWRKY22 were down regulated. The obtained data demonstrate that AhWRKY41 may act as a positive regulator in drought/ high temperature/ heavy metal and would exhibit stress tolerance mechanism by activation of stress-associated gene expression.