Zhu Yuan, Mahaney James, Jellison Jody, Cao Jinzhen, Gressler Julia, Hoffmeister Dirk, Goodell Barry
MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Beijing, China.
Department of Sustainable Biomaterials, Virginia Tech, Blacksburg, VA, USA.
J Ind Microbiol Biotechnol. 2017 Mar;44(3):329-338. doi: 10.1007/s10295-016-1889-5. Epub 2016 Dec 29.
This study aims to clarify the role of variegatic acid (VA) in fungal attack by Serpula lacrymans, and also the generation and scavenging of reactive oxygen species (ROS) by the fungus. VA promotes a mediated Fenton reaction to generated ROS after oxalate solubilizes oxidized forms of iron. The fungal extracellular matrix (ECM) β-glucan scavenged ROS, and we propose this as a mechanism to protect the fungal hyphae while ROS generation is promoted to deconstruct the lignocellulose cell wall. A relatively high pH (4.4) also favored Fe(III) transfer from oxalate to VA as opposed to a lower pH (2.2) conditions, suggesting a pH-dependent Fe(III) transfer to VA employed by S. lacrymans. This permits ROS generation within the higher pH of the cell wall, while limiting ROS production near the fungal hyphae, while β-glucan from the fungal ECM scavenges ROS in the more acidic environments surrounding the fungal hyphae.
本研究旨在阐明变色酸（VA）在干腐菌侵害过程中的作用，以及该真菌对活性氧（ROS）的产生和清除情况。在草酸盐溶解铁的氧化形式后，VA促进介导的芬顿反应以产生活性氧。真菌细胞外基质（ECM）中的β-葡聚糖清除活性氧，我们认为这是一种在促进活性氧生成以解构木质纤维素细胞壁的同时保护真菌菌丝的机制。与较低pH（2.2）条件相比，相对较高的pH（4.4）也有利于铁（III）从草酸盐转移至VA，这表明干腐菌存在pH依赖的铁（III）向VA的转移。这使得在细胞壁较高的pH环境中产生活性氧，同时限制在真菌菌丝附近产生活性氧，而来自真菌ECM的β-葡聚糖在真菌菌丝周围更酸性的环境中清除活性氧。
