The role of G protein alpha subunits in the infection process of the gray mold fungus Botrytis cinerea
The role of G protein alpha subunits in the infection process of the gray mold fungus Botrytis cinerea
复制标题
DOI：
10.1094/mpmi.2001.14.11.1293
复制
发表时间：
2001-11-01
影响因子：
3.5
通讯作者：
Tudzynski, B
中科院分区：
文献类型：
--
作者：
Gronover, CS;Kasulke, D;Tudzynski, B
为了确定灰霉菌灰霉病菌灰霉菌（Botrytis cinerea）参与宿主感染的信号转导途径，我们采用异源杂交和聚合酶链反应（PCR）方法分离了编码异源三聚体gtp结合蛋白cc亚基的bcg1和bcg2基因。这两个基因在其他真菌中都有同源物：bcg1是G α (i)类的成员，而bcg2与稻瘟病菌的magC基因和粗神经孢子菌的gna-2基因相似。反转录(RT)-PCR实验清楚地表明，这两个基因在侵染大豆叶片的早期阶段就表达了。对两个基因进行基因替换实验。Bcg1零突变体与野生型菌株菌落形态不同，不分泌细胞外蛋白酶，对豆类和番茄的致病性明显降低。在bcg1突变体中，分生孢子的萌发和植物组织的渗透不受干扰，但感染过程在形成原发性病变后停止。相比之下，bcg2突变体在无菌培养中表现为野生型集落形态，致病性仅略有降低。bcg1突变体与野生型基因拷贝的互补导致了两种寄主植物的菌落形态、蛋白酶分泌和致病性的完全恢复。外源性环AMP恢复了bcg1突变体的野生型生长模式，但没有恢复蛋白酶分泌，提示bcg1在不同的信号通路中发挥重要作用。
To identify signal transduction pathways of the gray mold fungus Botrytis cinerea involved in host infection, we used heterologous hybridization and a polymerase chain reaction (PCR)-based approach to isolate two genes (bcg1 and bcg2) encoding cc subunits of heterotrimeric GTP-binding proteins. Both genes have homologues in other fungi: bcg1 is a member of the G alpha (i) class, whereas bcg2 has similarities to the magC gene of Magnaporthe grisea and the gna-2 gene of Neurospora crassa. Reverse-transcription (RT)-PCR experiments showed clearly that both genes are expressed at very early stages in infected bean leaves. Gene replacement experiments were performed for both genes. bcg1 null mutants differ in colony morphology from the wild-type strain, do not secrete extracellular proteases, and show clearly reduced pathogenicity on bean and tomato. Conidia germination and penetration of plant tissue is not disturbed in bcg1 mutants, but the infection process stops after formation of primary lesions. In contrast, bcg2 mutants show wild-type colony morphology in axenic culture and are only slightly reduced in pathogenicity. Complementation of bcg1 mutants with the wild-type gene copy led to the full recovery of colony morphology, protease secretion, and pathogenicity on both host plants. Application of exogenous cyclic AMP restored the wild-type growth pattern of bcg1 mutants, but not the protease secretion, implicating an essential role of BCG1 in different signaling pathways.