Transcriptomics of drought stress acclimation response in peanut (Arachis hypogaea L.)

Date

2015-05

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Abstract

Peanut (Arachis hypogaea L.) is the second most important legume in the world and provides inexpensive but significant source of protein and edible oils.However, more than half of the peanut production area falls under arid and semi-arid regions, where peanuts are frequently subjected to drought stresses for different duration and intensities. In the United States, peanut is produced widely in the Texas High Plains region but the declining levels of water in the Ogallala aquifer has limited the available irrigation capacity to these regions. In a typical center-pivot irrigation system, plants undergo repeated cycles of water-deficit and recovery. Hence, there is a need to cultivate stress-tolerant peanut varieties that can adapt to these altering water-deficit cycles. In order to do so, first the acclimation response has to be well studied. In this study, a relatively tolerant peanut genotype from the US mini core collection was subjected to water-deficit stress acclimation. RNA-Seq was performed on root tissues using 108 bp paired end sequencing on an Illumina HiSeq2500 sequencer. Pairwise comparisons between different time points identified 13,655 differentially expressed genes(DEGs).Functional annotation of DEGs revealed that acclimation was controlled by several interacting pathways like calcium and G-protein coupled receptor mediated signaling, regulation by WRKY and R2R3-MYB transcription factors, proline accumulation, and activity of oxygen scavengers. The phytohormone ABA acted as a central mediator in generating this root-to-shoot stress response. Interestingly, we found that methionine accumulation is important for drought-stress acclimation in peanut. Some of these genes could be utilized by peanut breeders to improve water-deficit stress acclimation in field conditions.


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Keywords

Transcriptomics, Peanut, Drought

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