Hidden in plain sight: Systematic investigation of Leucine-rich repeat containing genes unveil the their regulatory network in response to Fusarium wilt in tung tree.

Leucine-rich repeat-containing genes (LRRs) have been reported to play important roles in responses to diseases. However, we poorly understood the response of LRRs to Fusarium wilt infection in tung tree (Vernicia fordii), which is an important economic tree. Here, 437 LRR-containing proteins containing nine types of LRR domains were identified in V. fordii genome. Phylogenetic analysis suggested that nine types of LRR domains could not be divided into separate classes, implying that these LRR domains had a common origin. Totally, 27 LRRs were related to possible resistance to Fusarium wilt after 2, 8, and 13 days post-inoculation. We further found that Vf06G1605 was up-regulate under Fusarium wilt infection after these three time points, Vf10G1602 and Vf02G1413 were up-regulated at 8, and 13 dpi, while Vf07G2320 was down-regulated at these three time points. The WGCNA and promoter elements suggested that WRKY possibly regulate the responses of LRRs to Fusarium wilt infection. This study highlighted the phylogeny and function of LRRs in V. fordii and provided a systematic analysis of these genes in the V. fordii genome. Our results presented here might clearly illustrate physiological mechanisms of resistance to Fusarium wilt infection and the target of marker-assisted breeding in V. fordii.