Extracellular superoxide dismutase VdSOD5 is required for virulence in Verticillium dahliae
Extracellular superoxide dismutase VdSOD5 is required for virulence in Verticillium dahliae
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DOI：
10.1016/s2095-3119(20)63353-6
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发表时间：
2021-06-01
影响因子：
4.8
通讯作者：
Xiao-feng, Dai
中科院分区：
文献类型：
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作者：
Li, Tian;Cai-min, Huang;Xiao-feng, Dai
植物产生活性氧（ROS）来防御病原体。为了抵抗这种攻击，某些病原体表达超氧化物歧化酶（SOD）以产生宿主来源的ROS。然而，超氧化物歧化酶在重要的维管病原菌大丽轮枝菌中的作用尚不清楚。我们的前期研究表明，棉花组织培养能显著诱导棉花黄萎病菌胞外SOD（VdSOD 5）的表达，表明VdSOD 5可能在寄主-病原菌互作和致病力中发挥重要作用。在这里，我们表明，VdSOD 5编码的超氧化物歧化酶的辅因子铜结合位点和功能信号肽，可以进行蛋白质分泌转化酶突变的酵母菌株。VdSOD 5基因的突变（Δ VdSOD 5）没有改变大丽轮枝菌的正常营养生长和产孢，但降低了大丽轮枝菌对感病寄主棉花的毒力。进一步的研究表明，VdSOD 5基因的转录在侵染初期显著上调，VdSOD 5基因的功能丧失使大丽轮枝菌培养滤液和真菌组织SOD活性分别下降74%和28%。与野生型菌株Vd 991相比，Delta VdSOD 5对细胞内ROS产生剂甲萘醌显示出相同的敏感性。此外，氮蓝四唑（NBT）染色表明，VdSOD 5的功能在解毒的超氧化物产生的寄主根在感染。这些结果表明，大丽轮枝菌的VdSOD 5是一种重要的毒力因子，分泌到细胞外以对抗宿主来源的ROS。
Plants produce reactive oxygen species (ROS) to defend pathogens. To counteract this attack, certain pathogens express superoxide dismutases (SODs) to scavenge host-derived ROS. However, the roles of SODs in Verticillium dahliae, an important vascular pathogen, are not clear. Our previous study has shown that a putative extracellular SOD (VdSOD5) of V. dahliae is significantly induced by culturing in cotton tissues, suggesting that VdSOD5 may play an important role in host-pathogen interactions and virulence. Here, we showed that VdSOD5 encoded a superoxide dismutase with a cofactor copper-binding site and a functional signal peptide that can conduct protein secretion in an invertase-mutated yeast strain. The mutations in VdSOD5 (Delta VdSOD5) did not change the normal vegetative growth and conidial production but reduced the virulence of V. dahliae on susceptible host cotton. Further studies showed that the transcription of VdSOD5 was significantly up-regulated during the early stage of infection, and the loss-of-function of VdSOD5 decreased culture filtrate and fungal tissue SOD activities of V. dahliae by 74 and 28%, respectively. Compared to the wild-type strain Vd991, the Delta VdSOD5 showed the same sensitivity to the intracellular ROS generator menadione. Furthermore, nitroblue tetrazolium (NBT) staining demonstrated that VdSOD5 functioned in the detoxification of superoxides generated by host roots during infection. These results suggest that VdSOD5 of V. dahliae is an important virulence factor, secreted out of cells to combat host-derived ROS.