Sánchez-Arreguin José Alejandro, Ortiz-Castellanos M Lucila, Robledo-Briones Angélica Mariana, León-Ramírez Claudia Geraldine, Martínez-Soto Domingo, Ruiz-Herrera José
Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Departamento de Ingeniería Genética, Unidad Irapuato, Km 9.6, Libramiento Norte, Carretera Irapuato-León, Irapuato 36821, Guanajuato, Mexico.
Tecnológico Nacional de México, Instituto Tecnológico Superior de Los Reyes, Los Reyes 60300, Mich, Mexico.
J Fungi (Basel). 2022 Aug 2;8(8):813. doi: 10.3390/jof8080813.
Smut fungi comprise a large group of biotrophic phytopathogens infecting important crops, such as wheat and corn. is a plant pathogenic fungus responsible for common smut in maize and teocintle. Through our analysis of the transcriptome of the yeast-to-mycelium dimorphic transition at acid pH, we determined the number of genes encoding chitin deacetylases of the fungus, and observed that the gene encoding one of them (UMAG_11922; ) was the only one up-regulated. The mutation of this gene and the analysis of the mutants revealed that they contained reduced amounts of chitosan, were severely affected in their virulence, and showed aberrant mycelial morphology when grown at acid pH. When the gene was reinserted into the mutants by the use of an autonomous replication plasmid, virulence and chitosan levels were recovered in the retro mutant strains, indicating that the gene was involved in these features. These data revealed that chitosan plays a crucial role in the structure and morphogenesis of the cell wall during mycelial development of the fungus, and that in its absence, the cell wall becomes altered and is unable to support the stress imposed by the defense mechanism mounted on by the plant host during the infection process.
黑粉菌是一类寄生于植物的病原菌，可感染小麦和玉米等重要农作物。玉米丝轴黑粉菌是一种植物病原真菌，可引发玉米和大刍草的普通黑粉病。通过对该真菌在酸性pH条件下从酵母形态向菌丝形态双态转变的转录组进行分析，我们确定了该真菌中编码几丁质脱乙酰酶的基因数量，并观察到其中一个基因（UMAG_11922）的编码基因是唯一上调的基因。对该基因进行突变并对突变体进行分析后发现，它们的壳聚糖含量降低，毒力受到严重影响，并且在酸性pH条件下生长时菌丝形态异常。当通过自主复制质粒将该基因重新插入突变体中时，回复突变菌株的毒力和壳聚糖水平得以恢复，这表明该基因与这些特征有关。这些数据表明，壳聚糖在该真菌菌丝发育过程中对细胞壁的结构和形态发生起着关键作用，并且在缺乏壳聚糖的情况下，细胞壁会发生改变，无法承受植物宿主在感染过程中启动的防御机制所施加的压力。
