Genome-wide identification and analysis of wheat LRR-RLK family genes following Chinese wheat mosaic virus infection

Background: As the largest plant receptor-like protein kinase (RLK) superfamily, the 21 leucine-rich repeat receptor-like kinases (LRR-RLKs) family are involved in plant 22 growth, development, and stress responses. However, the functions of LRR-RLKs in 23 wheat immunity remain unknown.

Results: In the current study, 929 LRR-RLKs were identified in Triticum aestivum 25 genome database using the BLAST and hidden Markov models (HMM) approach and 26 divided into 14 clades. Chromosomal localization and synteny analysis revealed that 27 TaLRR-RLKs were randomly distributed on all chromosomes with 921 collinear 28 events. Through the cis-acting elements analysis, we observed that TaLRR-RLKs 29 participated in hormone response, light response, development, metabolism, and 30 response to environmental stress. The transcript level of 14 random selected 31 TaLRR-RLKs from each subfamily was regulated by plant hormone treatment and 32 Chinese wheat mosaic virus (CWMV) infection. The function of TaLRR-RLKs in 33 wheat resistance to CWMV infection was further investigated by virus-induced gene 34 silencing assay. Additionally, the accumulation of MeJA response genes, as well as 35 CWMV RNA were not changed in the TaLRR-RLK silencing plants under MeJA 36 treatment.

Conclusions: Our results demonstrated that TaLRR-RLKs play an important role in 38 wheat resistance to viral infection via hormone signals and lay the groundwork for the 39 functional study of TaLRR-RLKs in wheat.