An ABC Transporter and a Cytochrome P450 of Nectria haematococca MPVI Are Virulence Factors on Pea and Are the Major Tolerance Mechanisms to the Phytoalexin Pisatin
An ABC Transporter and a Cytochrome P450 of Nectria haematococca MPVI Are Virulence Factors on Pea and Are the Major Tolerance Mechanisms to the Phytoalexin Pisatin
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DOI：
10.1094/mpmi-09-10-0198
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发表时间：
2011-03-01
影响因子：
3.5
通讯作者：
VanEtten, Hans D.
中科院分区：
文献类型：
--
作者：
Coleman, Jeffrey J.;White, Gerard J.;VanEtten, Hans D.
植物真菌病原菌血球菌（Nectria haematococca MPVI）产生一种细胞色素P450，负责解毒植物抗菌素pisatin，该植物抗菌素是由其寄主豌豆作为防御机制产生的。在这项研究中，我们证明这种真菌也产生一种特异性的atp结合盒（ABC）转运体NhABC1，增强其对pisatin的耐受性。此外，尽管这两种机制都有助于对pisatin的耐受性，并作为宿主特异性毒力因子，但这两种基因的突变使真菌对pisatin更加敏感，对豌豆基本上没有致病作用。NhABC1在离体处理和豌豆侵染过程中被快速诱导。此外，NhABC1能够对马铃薯产生的植物抗菌素石英素产生耐受性。NhABC1似乎与马铃薯病原菌白斑赤霉素的GpABC1同源，并且与来自稻瘟病菌的MoABC1一起存在于一个系统发育相关的进化枝中，该进化枝富含参与毒力的ABC转运蛋白。我们提出NhABC1和细胞色素P450可能以顺序的方式起作用，其中NhABC1从鱼素外排中消耗的能量释放对细胞色素P450的抑制，最终通过两种机制实现鱼素耐受。这些结果表明，一个成功的病原体已经进化出多种机制来克服这些植物抗微生物化合物。
The fungal plant pathogen Nectria haematococca MPVI produces a cytochrome P450 that is responsible for detoxifying the phytoalexin pisatin, produced as a defense mechanism by its host, garden pea. In this study, we demonstrate that this fungus also produces a specific ATP-binding cassette (ABC) transporter, NhABC1, that enhances its tolerance to pisatin. In addition, although both mechanisms individually contribute to the tolerance of pisatin and act as host-specific virulence factors, mutations in both genes render the fungus even more sensitive to pisatin and essentially nonpathogenic on pea. NhABC1 is rapidly induced after treatment with pisatin in vitro and during infection of pea plants. Furthermore, NhABC1 was able to confer tolerance to the phytoalexin rishitin, produced by potato. NhABC1 appears to be orthologous to GpABC1 of the potato pathogen Gibberella pulicaris and, along with MoABC1 from Magnaporthe oryzae, resides in a phylogenetically related clade enriched with ABC transorters involved in virulence. We propose that NhABC1 and the cytochrome P450 may function in a sequential manner in which the energy expense from pisatin efflux by NhABC1 releases the repression of the cytochrome P450, ultimately allowing pisatin tolerance by two mechanisms. These results demonstrate that a successful pathogen has evolved multiple mechanisms to overcome these plant antimicrobial compounds.