Scheffer Jan, Ziv Carmit, Yarden Oded, Tudzynski Paul
Institut für Botanik, Westf. Wilhelms-Universität, Schlossgarten 3, D-48149 Münster, Germany.
Fungal Genet Biol. 2005 Feb;42(2):107-18. doi: 10.1016/j.fgb.2004.10.005. Epub 2004 Nov 25.
Claviceps purpurea, the ergot fungus, is a common grass pathogen attacking exclusively young ovaries. Its pathogenic development involves an early phase of directed growth (with strictly suppressed branching) towards the floral vascular tissue. Since Ser/Thr protein kinases of the NDR family have been shown to be involved in polar growth and branching in fungi, we have analyzed a C. purpurea homologue of the Neurospora crassa cot-1 gene, cpcot1. It encodes a functional homologue of COT1 since it can fully complement the N. crassa cot-1 mutant phenotype. Delta cpcot1 mutants are significantly impaired in vegetative growth properties: they are characterized by hyperbranching, reduced growth rate, and decreased conidiation. Infection studies on rye plants and isolated ovaries show that the delta cpcot1 mutants are apathogenic; microscopical analyses indicate a very early block, probably in penetration. Thus CPCOT1 is not only involved in polarity and branching and hence oriented growth in the host tissue as expected, but it is essential for the initiation of infection.
麦角菌（Claviceps purpurea）是一种常见的禾本科病原菌，专门侵袭幼嫩子房。其致病发育过程包括一个早期的定向生长阶段（严格抑制分支），朝着花的维管组织生长。由于已证明NDR家族的丝氨酸/苏氨酸蛋白激酶参与真菌的极性生长和分支，我们分析了粗糙脉孢菌（Neurospora crassa）cot-1基因的一个麦角菌同源物cpcot1。它编码COT1的功能同源物，因为它可以完全互补粗糙脉孢菌cot-1突变体表型。缺失cpcot1的突变体在营养生长特性方面有显著缺陷：它们的特征是过度分支、生长速率降低和分生孢子形成减少。对黑麦植株和离体子房的感染研究表明，缺失cpcot1的突变体无致病性；显微镜分析表明，可能在穿透阶段就出现了非常早期的阻断。因此，CPCOT1不仅如预期的那样参与极性和分支以及在宿主组织中的定向生长，而且对于感染的起始至关重要。
