Dissection of leucine-rich repeat receptor-like protein kinases: insight into resistance to Fusarium wilt in tung tree

The tung tree is a woody oil plant native to China and widely distributed in the subtropics. The three main species commonly known as Vernicia are V. fordii, V. montana, and V. cordata. The growth and development of V. fordii are affected by a large number of plant pathogens, such as Fusarium wilt caused by Fusarium sp. In contrast, V. montana shows significant resistance to Fusarium wilt. The leucine-rich repeat receptor-like protein kinase (LRR-RLK) is the largest class of receptor-like kinases associated with plant resistance to Fusarium wilt. Here, we identified 239 VmLRR-RLKs in V. montana, and found that there were characteristic domains of resistance to Fusarium wilt in them. Phylogenetic analysis suggested that the VmLRR-RLKs are divided into 14 subfamilies, indicating that homologous genes in the same group may have similar functions. Chromosomal localization analysis showed that VmLRR-RLKs were unevenly distributed on chromosomes, and segment duplications were the main reason for the expansion of VmLRR-RLK family members. The transcriptome data showed that six orthologous pairs were up-regulated in V. montana in response to Fusarium wilt, while the corresponding orthologous genes showed low or no expression in V. fordii in resistance Fusarium wilt, further indicating the important role of LRR-RLKs in V. montana’s resistance to infection by Fusarium spp. Our study provides important reference genes for the future use of molecular breeding to improve oil yield and control of Fusarium wilt in tung tree.