Kelch repeat protein Clakel2p and calcium signaling control appressorium development in Colletotrichum lagenarium
Kelch repeat protein Clakel2p and calcium signaling control appressorium development in Colletotrichum lagenarium
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DOI：
10.1128/ec.00227-07
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发表时间：
2008-01-01
期刊：
影响因子：
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通讯作者：
Kubo, Yasuyuki
中科院分区：
文献类型：
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作者：
Sakaguchi, Ayumu;Miyaji, Toshihiko;Kubo, Yasuyuki
Kelch重复蛋白是基本细胞功能的重要介质，存在于多种生物体中。然而，这些蛋白在丝状真菌中的作用尚未被表征。我们分离到了一株裂糖菌（Schizosaccharomyces pombe tea1）同源物——炭黑菌（Colletotrichum lagenarium ClaKEL2）的kelch重复编码基因。对clakel2突变体的分析表明，clakel2是附着胞正常形态发生所必需的细胞极性的建立所必需的，并且存在一个植物信号特异性的附着胞发育绕过clakel2功能的旁路途径。Clakel2p定位于生长的菌丝和芽管的极化区，其定位受到微管组装阻断剂的干扰。clakel2突变体形成了异常的附着胞，并且这些附着胞在渗透菌丝发育到纤维素膜（真菌感染的人工模式底物）方面存在缺陷。令人惊讶的是，clakel2突变体在寄主植物上形成了正常的附着胞，并保持了渗透能力。clakel2突变体在人工基质上恢复了正常的附着胞形成，当细胞在CaCl(2)存在下孵育或从黄瓜子叶渗出物中孵育时。此外，钙通道调节剂抑制正常附着胞形成的恢复。这些结果表明，可能存在一个独立于ClaKEL2转导附着胞发育的植物源信号的旁路通路，并且钙信号参与了这一转导
Kelch repeat proteins are important mediators of fundamental cellular functions and are found in diverse organisms. However, the roles of these proteins in filamentous fungi have not been characterized. We isolated a kelch repeat-encoding gene of Colletotrichum lagenarium ClaKEL2, a Schizosaccharomyces pombe tea1 homologue. Analysis of the clakel2 mutant indicated that ClaKEL2 was required for the establishment of cellular polarity essential for proper morphogenesis of appressoria and that there is a plant signal-specific bypass pathway for appressorium development which circumvents ClaKEL2 function. Clakel2p was localized in the polarized region of growing hyphae and germ tubes, and the localization was disturbed by a microtubule assembly blocker. The clakel2 mutants formed abnormal appressoria, and those appressoria were defective in penetration hypha development into cellulose membranes, an artificial model substrate for fungal infection. Surprisingly, the clakel2 mutants formed normal appressoria on the host plant and retained penetration ability. Normal appressorium formation on the artificial substrate by the clakel2 mutants was restored when cells were incubated in the presence of CaCl(2) or exudates from cucumber cotyledon. Furthermore, calcium channel modulators inhibited restoration of normal appressorium formation. These results suggest that there could be a bypass pathway that transduces a plant-derived signal for appressorium development independent of ClaKEL2 and that a calcium signal is involved in this transduction