Evolution of LysM-RLK Gene Family in Wild and Cultivated Peanut Species

Abstract

In legumes, a LysM-RLK perception of rhizobial lipo-chitooligosaccharides (LCOs) known as Nod factors (NFs), triggers a signaling pathway related to the onset of symbiosis development. On the other hand, activation of LysM-RLKs upon recognition of chitin-derived short-chitooligosaccharides initiates defense responses. In this work, we identified the members of the LysM-RLK family in cultivated (Arachis hypogaea L.) and wild (A. duranensis and A. ipaensis) peanut genomes, and reconstructed the evolutionary history of the family. Phylogenetic analyses allowed the building of a framework to reinterpret the functional data reported on peanut LysM-RLKs. In addition, the potential involvement of two identified proteins in NF perception and immunity was assessed by gene expression analyses. Results indicated that peanut LysM-RLK is a highly diverse family. Digital expression analyses indicated that some A. hypogaea LysM-RLK receptors were upregulated during the early and late stages of symbiosis. In addition, expression profiles of selected LysM-RLKs proteins suggest participation in the receptor network mediating NF and/or chitosan perception. The analyses of LysM-RLK in the non-model legume peanut can contribute to gaining insight into the molecular basis of legume–microbe interactions and to the understanding of the evolutionary history of this gene family within the Fabaceae.

Keywords

• LysM-RLK
• wild and cultivated peanut
• Nod factors
• chitosan
• symbiosis
• defense