Phytopathology. 2002 Jan;92(1):75-80. doi: 10.1094/PHYTO.2002.92.1.75.
ABSTRACT Partial DNA fragments of Botrytis cinerea field isolates encoding the putative osmosensor histidine kinase gene (BcOS1) were cloned by polymerase chain reaction amplification and the predicted amino acid sequences were compared between dicarboximide-sensitive and resistant field isolates. The predicted BcOS1p is highly homologous to osmosensor histidine kinase OS1p from Neurospora crassa including the N-terminal six tandem repeats of approximately 90 amino acids. Four dicarboximide-resistant isolates of B. cinerea (Bc-19, Bc-45, Bc-682, and Bc-RKR) contained a single base pair mutation in their BcOS1 gene that resulted in an amino acid substitution in the predicted protein. In these resistant isolates, codon 86 of the second repeat, which encodes an isoleucine residue in sensitive strains, was converted to a codon for serine. The mutation of Botrytis field resistant isolates was located on the second unit of tandem amino acid repeats of BcOS1p, whereas the point mutations of the fifth repeat of OS1p confer resistance to both dicarboximides and phenylpyrroles and also osmotic sensitivity in Neurospora crassa. These results suggest that an amino acid substitution within the second repeat of BcOS1p is responsible for phenotypes of field resistant isolates (resistant to dicarboximides but sensitive to phenylpyrroles, and normal osmotic sensitivity) in B. cinerea.
摘要 通过聚合酶链反应扩增，克隆了灰葡萄孢田间分离株中编码假定渗透压传感器组氨酸激酶基因（BcOS1）的部分 DNA 片段，并比较了二羧酰亚胺敏感和抗性田间分离株之间的预测氨基酸序列。预测的 BcOS1p 与粗糙脉孢菌的渗透压传感器组氨酸激酶 OS1p 高度同源，包括 N 端约 90 个氨基酸的 6 个串联重复。灰葡萄孢的 4 个二羧酰亚胺抗性分离株（Bc-19、Bc-45、Bc-682 和 Bc-RKR）在其 BcOS1 基因中发生了单个碱基对突变，导致预测蛋白中的氨基酸取代。在这些抗性分离株中，第二个重复的密码子 86 编码敏感菌株中的异亮氨酸，被转换为编码丝氨酸的密码子。田间抗性分离株的突变位于 BcOS1p 串联氨基酸重复的第二个单元，而 OS1p 的第五个重复的点突变既赋予了对二羧酰亚胺和苯并吡咯的抗性，又赋予了粗糙脉孢菌的渗透压敏感性。这些结果表明，BcOS1p 第二个重复内的氨基酸取代是灰葡萄孢田间抗性分离株（对二羧酰亚胺有抗性但对苯并吡咯敏感，且对渗透压敏感）表型的原因。
