Pham Trang A T, Kyriacou Bianca A, Schwerdt Julian G, Shirley Neil J, Xing Xiaohui, Bulone Vincent, Little Alan
ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia.
Adelaide Glycomics, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia.
Cell Surf. 2019 Aug 14;5:100029. doi: 10.1016/j.tcsw.2019.100029. eCollection 2019 Dec.
Infection of barley with the powdery mildew causal agent, f. sp. (), can lead to devastating damage to barley crops. The recent emergence of fungicide resistance imposes a need to develop new antifungal strategies. The enzymes involved in cell wall biosynthesis are ideal targets for the development of fungicides. However, in order to narrow down any target proteins involved in cell wall formation, a greater understanding of the cell wall structure and composition is required. Here, we present a detailed carbohydrate analysis of the conidial cell wall, a full annotation of Carbohydrate Active enZymes (CAZy) in the genome, and a comprehensive expression profile of the genes involved in cell wall metabolism. Glycosidic linkage analysis has revealed that the cell wall polysaccharide fraction of conidia predominantly consists of glucosyl residues (63.1%) and has a greater proportion of galactopyranosyl residues compared to other species (8.5%). Trace amounts of xylosyl residues were also detected, which is unusual in ascomycetes. Transcripts of the genes involved in cell wall metabolism show high expression of chitin deacetylases, which assist fungi in evading the host defence system by deacetylating chitin to chitosan. The data presented suggest that the cell wall components of the conidia and the corresponding obligate biotrophic CAZy gene profile play a key role in the infection process.
大麦被白粉病病原菌禾布氏白粉菌（Blumeria graminis f. sp. hordei）侵染会对大麦作物造成毁灭性损害。近期杀菌剂抗性的出现使得开发新的抗真菌策略成为必要。参与细胞壁生物合成的酶是开发杀菌剂的理想靶点。然而，为了缩小参与细胞壁形成的任何靶蛋白范围，需要更深入地了解细胞壁的结构和组成。在此，我们展示了分生孢子细胞壁的详细碳水化合物分析、该病原菌基因组中碳水化合物活性酶（CAZy）的完整注释以及参与细胞壁代谢的基因的全面表达谱。糖苷键分析表明，分生孢子的细胞壁多糖部分主要由葡萄糖残基（63.1%）组成，与其他物种相比，吡喃半乳糖残基的比例更高（8.5%）。还检测到痕量的木糖残基，这在子囊菌中并不常见。参与细胞壁代谢的基因转录本显示几丁质脱乙酰酶高表达，其通过将几丁质脱乙酰化为壳聚糖来帮助真菌逃避宿主防御系统。所呈现的数据表明，分生孢子的细胞壁成分以及相应的专性活体营养型CAZy基因谱在感染过程中起关键作用。
