Zhang Qiyan, Wu Liwen, Yin Hengfu, Xu Zilong, Zhao Yunxiao, Gao Ming, Wu Hong, Chen Yicun, Wang Yangdong
State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China.
Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, Zhejiang Province, China.
Hortic Res. 2021 Nov 1;8(1):240. doi: 10.1038/s41438-021-00656-2.
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.
尖孢镰刀菌是一种全球范围内的土传病原菌，可在多种栽培植物中引发严重病害。其感染和抗性的潜在机制在很大程度上仍不明确。油桐，又称桐树，易受尖孢镰刀菌蓖麻专化型（Fof-1）引起的病害影响，而其近缘物种木油桐对Fof-1表现出高抗性。为了研究感染过程和抗性能力，我们证明Fof-1能够穿透根毛表皮，然后向心侵入两个物种的皮层和韧皮部。此外，Fof-1在感病的油桐树中通过根木质部向上扩散，而在抗病的木油桐树中未能感染根木质部。我们发现D6类蛋白激酶2（VmD6PKL2）在侧根木质部中特异性表达，并在抗病树木受到Fof-1感染后被诱导。在拟南芥和番茄中的转基因分析表明，VmD6PKL2显著增强了两个物种的抗性，而d6pkl2突变体对Fof-1的抗性降低。此外，已确定VmD6PKL2与突触结合蛋白（VmSYT3）直接相互作用，VmSYT3在根木质部中特异性表达，并介导对Fof-1的负调控反应。我们的数据表明，VmD6PKL2可能通过抑制抗病物种侧根木质部中VmSYT3介导的负调控，作为对抗Fof-1的抗性基因。这些发现为植物抗枯萎病提供了新的见解。
