College of Agronomy, Gansu Agriculture University, Lanzhou, China; Gansu Engeering Laboratory of Application Mycology, Hexi University, Zhangye, China.
Gansu Provincial Key Lab of Aridland Crop Science/Gansu Key Lab of Crop Improvement & Germplasm Enhancement, Lanzhou, China; College of Life Sciences and Technology, Gansu Agricultural University, Lanzhou, China.
Gene. 2019 May 15;696:95-104. doi: 10.1016/j.gene.2019.02.032. Epub 2019 Feb 16.
The high-osmolarity glycerol (HOG) signaling pathway regulates the adaptation of fungi to environmental stressors. The mitogen-activated protein kinase kinase (MAPKK) PBS2 of Saccharomyces cerevisiae serves as a scaffold protein in the HOG pathway. We characterized the pgpbs gene of Pyrenophora graminea, which encodes a MAPKK that is 56% orthologous to PBS2 of S. cerevisiae. A cloning technique based on homology was applied to amplify the pgpbs gene. Specific silent mutations then were generated in pgpbs. We evaluated the potential roles of PGPBS in the osmotic response, vegetative differentiation, cell wall integrity, drug resistance, and pathogenicity. Our findings indicated that the pgpbs coding region comprises 2075 base pairs and encodes a protein of 676 amino acids. Mutants deficient in pgpbs expression had significant reductions in vegetative growth and were sensitive to calcofluor white (CFW), an inhibitor of cell wall synthesis. Mutants also lost pathogenicity and were sensitive to an osmotic stress-inducing medium containing NaCl and sorbitol. Moreover, mutants had increased resistance to the dicarboximide fungicide iprodione and the triazole fungicide tebuconazole. These findings suggest that pgpbs is involved in the osmotic and ionic stress responses, vegetative differentiation, cell wall integrity, virulence, and tolerance to iprodione and tebuconazole. We expect that our findings will help elucidate the pathogenesis of barley leaf stripe and will inform strategies for breeding resistance to this disease.
高渗甘油（HOG）信号通路调节真菌对环境胁迫的适应。酿酒酵母的丝裂原活化蛋白激酶激酶（MAPKK）PBS2 作为 HOG 通路中的支架蛋白。我们对禾谷镰刀菌的 pgpbs 基因进行了特征描述，该基因编码的 MAPKK 与酿酒酵母的 PBS2 有 56%的同源性。我们应用基于同源性的克隆技术来扩增 pgpbs 基因。然后在 pgpbs 中产生特定的沉默突变。我们评估了 PGPBS 在渗透响应、营养生长分化、细胞壁完整性、抗药性和致病性方面的潜在作用。研究结果表明，pgpbs 编码区包含 2075 个碱基对，编码 676 个氨基酸的蛋白质。pgpbs 表达缺陷的突变体在营养生长方面显著减少，并且对细胞壁合成抑制剂 Calcofluor White（CFW）敏感。突变体也失去了致病性，并且对含有 NaCl 和山梨糖醇的诱导渗透胁迫的培养基敏感。此外，突变体对二羧酰亚胺类杀菌剂异菌脲和三唑类杀菌剂戊唑醇的抗性增加。这些发现表明 pgpbs 参与渗透和离子胁迫反应、营养生长分化、细胞壁完整性、毒性以及对异菌脲和戊唑醇的耐受性。我们期望我们的研究结果将有助于阐明大麦叶斑病的发病机制，并为培育对该病的抗性提供策略。
