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Article|01 Nov 2021|OPEN
D6 protein kinase in root xylem benefiting resistance to Fusarium reveals infection and defense mechanisms in tung trees
Qiyan Zhang1,2, Liwen Wu1,2, Hengfu Yin1,2, Zilong Xu1,2, Yunxiao Zhao1,2, Ming Gao1,2, Hong Wu2, Yicun Chen 2,1, & Yangdong Wang2,1,
1State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China
2Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400 Zhejiang Province, China

Horticulture Research 8,
Article number: 240 (2021)
doi: 10.1038/hortres.2021.240
Views: 17

Received: 10 Mar 2020
Revised: 04 Jun 2021
Accepted: 13 Jun 2021
Published online: 01 Nov 2021

Abstract

Fusarium oxysporum, a global soil-borne pathogen, causes severe disease in various cultivated plants. The mechanism underlying infection and resistance remains largely elusive. Vernicia fordii, known as the tung tree, suffers from disease caused by F. oxysporum f. sp. fordiis (Fof-1), while its sister species V. montana displays high resistance to Fof-1. To investigate the process of infection and resistance ability, we demonstrated that Fof-1 can penetrate the epidermis of root hairs and then centripetally invade the cortex and phloem in both species. Furthermore, Fof-1 spread upwards through the root xylem in susceptible V. fordii trees, whereas it failed to infect the root xylem in resistant V. montana trees. We found that D6 PROTEIN KINASE LIKE 2 (VmD6PKL2) was specifically expressed in the lateral root xylem and was induced after Fof-1 infection in resistant trees. Transgenic analysis in Arabidopsis and tomato revealed that VmD6PKL2 significantly enhanced resistance in both species, whereas the d6pkl2 mutant displayed reduced resistance against Fof-1. Additionally, VmD6PKL2 was identified to interact directly with synaptotagmin (VmSYT3), which is specifically expressed in the root xylem and mediates the negative regulation responding to Fof-1. Our data suggested that VmD6PKL2 could act as a resistance gene against Fof-1 through suppression of VmSYT3-mediated negative regulation in the lateral root xylem of the resistant species. These findings provide novel insight into Fusarium wilt resistance in plants.