Morpho-physiological responses and expression analysis of MYB94 transcription factor gene in four groundnut cultivars under drought and salinity stress

Abstract

Aim: The present study aimed to evaluate the impact of salinity stress on morpho-physiological parameters and relative expression of the MYB94 transcription factor gene among four widely cultivated groundnut cultivars. Methodology: A comparative analysis of morpho-physiological parameters was studied in four groundnut cultivars (Kadiri-Amaravati, Kadiri-Lepakshi, Kadiri-6, and Kadiri-9) subjected to different concentrations of NaCl prepared in half-strength Arnon’s nutrient growth medium. The relative expression analysis of a stress responsive transcription factor gene, MYB94 was studied in four groundnut cultivars subjected to drought and NaCl stress by qRT PCR. Results: NaCl stress resulted in a significant increase in proline content, MDA content in cultivar Kadiri-9 compared to other cultivar studied. On the contrary, plant growth, shoot dry weight, root dry weight, leaf relative water content, cell membrane injury decreased to lesser extent in cultivar Kadiri-9 than Kadiri-Amaravati, Kadiri-Lepakshi, Kadiri-6 under salinity stress. qRT-PCR based relative expression analysis of the MYB94 gene revealed a significant increase of transcript expression levels in cultivar Kadiri-9 compared to other three cultivars under both drought and salinity stress. Interpretation: Groundnut cultivar Kadiri-9 showed better tolerance to NaCl stress as evidenced from enhanced proline content, better relative water content and lesser extent of membrane damage when compared with other groundnut cultivars under given NaCl stress treatments. In addition, relative expression of MYB94 gene was significantly higher due to NaCl stress as compared to drought stress conditions in cultivar Kadiri-9 suggested that the MYB94 could be involved in salt stress tolerance. Key words: Groundnut, MYB94 transcription factor, qRT-PCR, Salinity stress