Viefhues Anne, Schlathoelter Ina, Simon Adeline, Viaud Muriel, Tudzynski Paul
Institut fuer Biologie und Biotechnologie der Pflanzen, Westfaelische Wilhelms Universitaet Muenster, Muenster, Germany.
UMR BIOGER, INRA, Thiverval-Grignon, France.
Eukaryot Cell. 2015 Jul;14(7):636-51. doi: 10.1128/EC.00043-15. Epub 2015 May 1.
Important for the lifestyle and survival of every organism is the ability to respond to changing environmental conditions. The necrotrophic plant pathogen Botrytis cinerea triggers an oxidative burst in the course of plant infection and therefore needs efficient signal transduction to cope with this stress. The factors involved in this process and their precise roles are still not well known. Here, we show that the transcription factor Bap1 and the response regulator (RR) B. cinerea Skn7 (BcSkn7) are two key players in the oxidative stress response (OSR) of B. cinerea; both have a major influence on the regulation of classical OSR genes. A yeast-one-hybrid (Y1H) approach proved direct binding to the promoters of gsh1 and grx1 by Bap1 and of glr1 by BcSkn7. While the function of Bap1 is restricted to the regulation of oxidative stress, analyses of Δbcskn7 mutants revealed functions beyond the OSR. Involvement of BcSkn7 in development and virulence could be demonstrated, indicated by reduced vegetative growth, impaired formation of reproductive structures, and reduced infection cushion-mediated penetration of the host by the mutants. Furthermore, Δbcskn7 mutants were highly sensitive to oxidative, osmotic, and cell wall stress. Analyses of Δbap1 bcskn7 double mutants indicated that loss of BcSkn7 uncovers an underlying phenotype of Bap1. In contrast to Saccharomyces cerevisiae, the ortholog of the glutathione peroxidase Gpx3p is not required for nuclear translocation of Bap1. The presented results contribute to the understanding of the OSR in B. cinerea and prove that it differs substantially from that of yeast, demonstrating the complexity and versatility of components involved in signaling pathways.
对每个生物体的生活方式和生存至关重要的是对不断变化的环境条件做出反应的能力。坏死营养型植物病原菌灰葡萄孢在植物感染过程中引发氧化爆发，因此需要有效的信号转导来应对这种压力。参与这一过程的因素及其确切作用仍不清楚。在这里，我们表明转录因子Bap1和应答调节因子（RR）灰葡萄孢Skn7（BcSkn7）是灰葡萄孢氧化应激反应（OSR）中的两个关键参与者；两者对经典OSR基因的调控都有重大影响。酵母单杂交（Y1H）方法证明Bap1直接结合gsh1和grx1的启动子，BcSkn7直接结合glr1的启动子。虽然Bap1的功能仅限于氧化应激的调节，但对Δbcskn7突变体的分析揭示了其在OSR之外的功能。可以证明BcSkn7参与发育和毒力，突变体的营养生长减少、生殖结构形成受损以及感染垫介导的宿主穿透减少表明了这一点。此外，Δbcskn7突变体对氧化、渗透和细胞壁应激高度敏感。对Δbap1 bcskn7双突变体的分析表明，BcSkn7的缺失揭示了Bap1的潜在表型。与酿酒酵母不同，谷胱甘肽过氧化物酶Gpx3p的直系同源物对于Bap1的核转位不是必需的。所呈现的结果有助于理解灰葡萄孢中的OSR，并证明它与酵母的OSR有很大不同，展示了信号通路中所涉及成分的复杂性和多功能性。
