Genome-wide Identification, Evolutionary and Expression Analyses of CrRLK1L Gene Family in Peanut (Arachis hypogaea L.)

CrRLK1L is subfamily of the receptor-like kinase family, which unique to plants and play an important role in regulation of plant growth and development and response to stress. Information about the number, location, structure, molecular phylogeny and expression of CrRLK1L genes in peanut were limited. In this study, 89 CrRLK1L genes were identified in the peanut genome, and further divided into ten groups according to phylogenetic analysis. CrRLK1L genes were dispersive and unevenly distributed on 20 chromosomes. Structure analysis revealed that AhCrRLK1LVIIIs and AhCrRLK1LIXs exhibit 7 to 16 introns, but all the AhCrRLK1LIIs, AhCrRLK1LVs, AhCrRLK1LVIs and the majority of the AhCrRLK1LIVs and AhCrRLK1LXs contained no intron. Synteny analysis showed that segmental duplications played a critical role in AhCrRLK1Ls expansion, and many AhCrRLK1Ls duplications occurred after the divergence of peanut and Arabidopsis/soybean from their last common ancestor. Gene transcription analyses revealed that five of the AhCrRLK1LIIs specifically expressed in flowers. All AhCrRLK1LVIIs and three AhCrRLK1LIIIs, might participate in regulation of pollen tube growth. AhCrRLK1LVs presented high transcription levels in different organisms, and induced by biotic and abiotic stresses, indicated its importance during plant growth, development and stress responses. In addition, fifteen genes in species specific clades and eleven CrRLK1LIVs were differently expressed after drought stress. And thirty-six AhCrRLK1Ls were induced by aluminum (Al) stress in Al tolerant peanut cultivar. Those result provide a foundation for further exploring the function of AhCrRLK1Ls in regulation growth and response to biotic and abiotic stress in peanuts.