Department of Plant Pathology, University of Minnesota, St.Paul, MN, USA.
Mol Plant Microbe Interact. 2012 Nov;25(11):1408-18. doi: 10.1094/MPMI-04-12-0081-R.
The gene Tri12 encodes a predicted major facilitator superfamily protein suggested to play a role in export of trichothecene mycotoxins produced by Fusarium spp. It is unclear, however, how the Tri12 protein (Tri12p) may influence trichothecene sensitivity and virulence of the wheat pathogen Fusarium graminearum. In this study, we establish a role for Tri12 in toxin accumulation and sensitivity as well as in pathogenicity toward wheat. Tri12 deletion mutants (tri12) are reduced in virulence and result in decreased trichothecene accumulation when inoculated on wheat compared with the wild-type strain or an ectopic mutant. Reduced radial growth of tri12 mutants on trichothecene biosynthesis induction medium was observed relative to the wild type and the ectopic strains. Diminished trichothecene accumulation was observed in liquid medium cultures inoculated with tri12 mutants. Wild-type fungal cells grown under conditions that induce trichothecene biosynthesis develop distinct subapical swelling and form large vacuoles. A strain expressing Tri12p linked to green fluorescent protein shows localization of the protein consistent with the plasma membrane. Our results indicate Tri12 plays a role in self-protection and influences toxin production and virulence of the fungus in planta.
基因 Tri12 编码一种预测的主要易化剂超家族蛋白，据推测该蛋白在赤霉菌属产生的单端孢霉烯族毒素的外排中发挥作用。然而，Tri12 蛋白（Tri12p）如何影响小麦病原体禾谷镰刀菌的毒素敏感性和毒力尚不清楚。在这项研究中，我们确定了 Tri12 在毒素积累和敏感性以及对小麦的致病性中的作用。与野生型菌株或异位突变体相比，Tri12 缺失突变体（tri12）在接种小麦时毒力降低，导致毒素积累减少。与野生型和异位菌株相比，tri12 突变体在诱导单端孢霉烯生物合成的培养基上的径向生长减少。在接种 tri12 突变体的液体培养基培养物中观察到毒素积累减少。在诱导单端孢霉烯生物合成的条件下生长的野生型真菌细胞会出现明显的亚顶膨大和形成大液泡。与绿色荧光蛋白连接表达 Tri12p 的菌株显示该蛋白与质膜的定位一致。我们的结果表明 Tri12 在自我保护中发挥作用，并影响真菌在植物体内的毒素产生和毒力。
