Comparative physiological and transcriptomic analyses reveal key regulatory networks and potential hub genes controlling peanut chilling tolerance.

ABSTRACT

The unclear molecular mechanism by which peanuts adapt to chilling stress limits progress in molecular breeding for peanut chilling tolerance. Here, the physiological and transcriptional differences between two genotypes with contrasting tolerance under chilling stress were compared. The inhibition of photosynthesis mainly caused by stomatal factors was a common response of peanut seedlings to chilling stress. Chilling-tolerant genotypes could inhibit the accumulation of ROS to adapt to chilling stress, and enhanced activities of CAT and APX were major causes of lower H2O2 content. The results of a conjoint analysis of physiological indices and the RNA-Seq database by WGCNA indicated that the genes in key modules were significantly enriched in pathways related to the oxidation-reduction process. Hub genes encoding RLK, CAT, MYC4, AOS, GST, PP2C, UPL5 and ZFP8 were likely to positively regulate peanut chilling tolerance, but hub genes encoding PAO, NAC2 and NAC72 were likely to negatively regulate peanut chilling tolerance.