Multiple plant surface signals are sensed by different mechanisms in the rice blast fungus for appressorium formation.
Multiple plant surface signals are sensed by different mechanisms in the rice blast fungus for appressorium formation.
复制标题
通过大米爆炸真菌中的不同机制，可以感觉到多个植物表面信号以形成appressorium。
DOI：
10.1371/journal.ppat.1001261
复制
发表时间：
2011-01-20
期刊：
影响因子：
6.7
通讯作者：
Xu JR
中科院分区：
文献类型：
--
作者：
Liu W;Zhou X;Li G;Li L;Kong L;Wang C;Zhang H;Xu JR
表面识别和渗透是叶病原体最关键的植物感染过程之一。在 Magnaporthe oryzae 中，Pmk1 MAP 激酶调节附着胞的形成和渗透。已知其直系同源物也是其他植物病原真菌中各种植物感染过程所必需的。尽管这一重要途径的许多上游组件已被表征，但表面信号的上游传感器尚未得到很好的表征。 Pmk1 与酵母中的 Kss1 是直系同源的，在 Msb2 和 Sho1 的下游发挥丝状生长的作用。由于 Pmk1 和 Kss1 途径的保守性以及 pmk1 突变体中 MoMSB2 表达的减少，在本研究中，我们对 MoMSB2 和 MoSHO1 基因进行了功能表征。 Momsb2 突变体的附着胞形成和毒力显着降低，而 Mosho1 突变体仅略有降低。 Mosho1 Momsb2 双突变体很少在人工疏水表面上形成附着细胞，Pmk1 磷酸化水平降低，并且对角质单体无反应。然而，它仍然形成附壁并在水稻叶片上造成罕见的、有限的病变。在人工亲水表面上，叶表面蜡和伯醇（但不是石蜡和烷烃）刺激 Mosho1 Momsb2 突变体中附着胞的形成，但在 Momsb2 突变体中更有效。此外，显性活性MST7等位基因的表达部分抑制了Momsb2突变体的缺陷。这些结果表明，除了表面疏水性和角质单体之外，伯醇（草中表皮叶蜡的主要成分）也被米霉识别为附着胞形成的信号。我们的数据还表明，MoMsb2 和 MoSho1 在识别 Pmk1 激活和附着细胞形成的各种表面信号方面可能具有重叠功能。虽然 MoMsb2 对于感知表面疏水性和角质单体至关重要，但 MoSho1 在识别稻叶蜡方面可能发挥更重要的作用。稻瘟病菌是水稻的主要病原体，也是研究真菌与植物相互作用的模型。与许多其他真菌病原体一样，它可以识别稻叶表面存在的物理和化学信号，并形成高度专业化的感染结构，称为附着胞。已知涉及蛋白激酶基因 PMK1 的保守信号转导途径可调节该病原体的附着胞形成和植物渗透。然而，目前尚不清楚参与识别各种植物表面信号的传感器基因。在这项研究中，我们对两个假定的传感器基因 MoMSB2 和 MoSHO1 进行了功能表征。遗传和生化分析表明，这两个基因在识别水稻叶表面存在的不同物理和化学信号以激活 Pmk1 途径和附着胞形成方面具有重叠功能。我们发现伯醇是草叶蜡的主要成分，可以被稻瘟病菌识别为化学信号。虽然 MoMSB2 对于感知稻叶角质分子的疏水性和前体至关重要，但 MoSHO1 在识别蜡成分方面似乎比 MoMSB2 更重要。
Surface recognition and penetration are among the most critical plant infection processes in foliar pathogens. In Magnaporthe oryzae, the Pmk1 MAP kinase regulates appressorium formation and penetration. Its orthologs also are known to be required for various plant infection processes in other phytopathogenic fungi. Although a number of upstream components of this important pathway have been characterized, the upstream sensors for surface signals have not been well characterized. Pmk1 is orthologous to Kss1 in yeast that functions downstream from Msb2 and Sho1 for filamentous growth. Because of the conserved nature of the Pmk1 and Kss1 pathways and reduced expression of MoMSB2 in the pmk1 mutant, in this study we functionally characterized the MoMSB2 and MoSHO1 genes. Whereas the Momsb2 mutant was significantly reduced in appressorium formation and virulence, the Mosho1 mutant was only slightly reduced. The Mosho1 Momsb2 double mutant rarely formed appressoria on artificial hydrophobic surfaces, had a reduced Pmk1 phosphorylation level, and was nonresponsive to cutin monomers. However, it still formed appressoria and caused rare, restricted lesions on rice leaves. On artificial hydrophilic surfaces, leaf surface waxes and primary alcohols-but not paraffin waxes and alkanes- stimulated appressorium formation in the Mosho1 Momsb2 mutant, but more efficiently in the Momsb2 mutant. Furthermore, expression of a dominant active MST7 allele partially suppressed the defects of the Momsb2 mutant. These results indicate that, besides surface hydrophobicity and cutin monomers, primary alcohols, a major component of epicuticular leaf waxes in grasses, are recognized by M. oryzae as signals for appressorium formation. Our data also suggest that MoMsb2 and MoSho1 may have overlapping functions in recognizing various surface signals for Pmk1 activation and appressorium formation. While MoMsb2 is critical for sensing surface hydrophobicity and cutin monomers, MoSho1 may play a more important role in recognizing rice leaf waxes. The rice blast fungus is a major pathogen of rice and a model for studying fungal-plant interactions. Like many other fungal pathogens, it can recognize physical and chemical signals present on the rice leaf surface and form a highly specialized infection structure known as appressorium. A well conserved signal transduction pathway involving the protein kinase gene PMK1 is known to regulate appressorium formation and plant penetration in this pathogen. However, it is not clear about the sensor genes that are involved in recognizing various plant surface signals. In this study we functionally characterize two putative sensor genes called MoMSB2 and MoSHO1. Genetic and biochemical analyses indicated that these two genes have overlapping functions in recognizing different physical and chemical signals present on the rice leaf surface for the activation of the Pmk1 pathway and appressorium formation. We found that primary alcohols, a major component of leaf waxes in grasses, can be recognized by the rice blast fungus as chemical cues. While MoMSB2 is critical for sensing hydrophobicity and precursors of cutin molecules of rice leaves, MoSHO1 appears to be more important than MoMSB2 for recognizing wax components.
登录
查看更多内容
影响因子：
3.5
作者：
Kamakura, T;Yamaguchi, S;Yamaguchi, I
通讯作者：
Yamaguchi, I
影响因子：
11.6
作者：
Lanver, Daniel;Mendoza-Mendoza, Artemio;Kahmann, Regine
通讯作者：
Kahmann, Regine
影响因子：
11.6
作者：
Ding, Sheng-Li;Liu, Wende;Xu, Jin-Rong
通讯作者：
Xu, Jin-Rong
影响因子：
11.4
作者：
Liu, Hao;Suresh, Angayarkanni;Naqvi, Naweed I.
通讯作者：
Naqvi, Naweed I.
影响因子：
56.9
作者：
Madhani, HD;Fink, GR
通讯作者：
Fink, GR