Molecular mechanisms underlying drought stress and acclimation responses in C76-16 Leaf (Arachis hypogaea L.)

Peanut is the third most important oilseed and legume crop in the world known for its high protein content. It is an excellent food source to overcome malnutrition in developing and under developed countries. More than 80% of the world peanut production is from arid and semi-arid regions where water is a limiting factor. Plants adapt to these stress conditions by undergoing various physiological, morphological, and molecular changes. To develop peanut drought tolerant lines, understanding drought stress and acclimation responses is very important. In this study, real field conditions were mimicked in a greenhouse experiment using C76-16, a national drought tolerant peanut check variety. A 108 bp paired end RNA-Seq was performed on 24 leaf samples from three time points. Gene expression analysis between acclimated and control, non-acclimated and control at second dry down resulted in 6916 and 8937 differentially expressed contigs. Downstream analysis using Mercator and MapMan revealed that there are no significant changes between the acclimated and the non-acclimated plants during drought stress in C76-16 genotype. In addition, drought tolerance responses in C76-16 are mainly regulated by transcription factors that act as positive and negative regulators of drought stress tolerance. The drought stress specific transcription factors identified in this study are MYB44, bHLH122, NF-YA5, MYB20, MYB60, NLP7, which are involved in regulating stomatal movements. DREB, HSF-A2 and bHLH112 were also identified which play an important role in drought tolerance. In addition, accumulation of stress related molecules such as proline, glycine betaine, H+-ATPase, aquaporins, and LEA proteins were found to play a prominent role in drought tolerance. Ubiquitination related proteins such as XERICO helps in ABA homeostasis which is important in conferring drought tolerance. Overall, this study provides an overview of drought tolerant mechanisms in the leaves of C76-16 which can contribute in breeding drought tolerant peanut genotypes.

Embargo status: Restricted until 09/2022. To request the author grant access, click on the PDF link to the left.