Identification of two mutations that cause defects in the ligninolytic system through an efficient forward genetics in the white-rot agaricomycete Pleurotus ostreatus
Identification of two mutations that cause defects in the ligninolytic system through an efficient forward genetics in the white-rot agaricomycete Pleurotus ostreatus
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DOI：
10.1111/1462-2920.13595
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发表时间：
2017-01-01
影响因子：
5.1
通讯作者：
Honda, Yoichi
中科院分区：
文献类型：
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作者：
Nakazawa, Takehito;Izuno, Ayako;Honda, Yoichi
白腐真菌在全球碳循环中发挥着重要作用，因为它们是自然界中几乎完全生物降解木材木质素的物种。木质素过氧化物酶（LiPs）、锰过氧化物酶（MNP）和多功能过氧化物酶（VP）被认为是木质素降解系统中的关键参与者。然而，除了LiPs，MNP和VP之外，只有很少的其他因子参与木质素分解系统已经使用分子遗传学进行了研究，这意味着存在未鉴定的元件。通过将经典遗传技术与下一代测序技术相结合，他们成功地展示了一种有效的正向遗传学方法，以识别导致白腐真菌Pleopostreatus木质素分解系统缺陷的突变。在这项研究中，他们确定了两个基因-chd 1和wtr 1-突变，其中导致Mn 2+依赖的过氧化物酶活性几乎完全丧失。chd 1基因编码一个假定的染色质修饰剂，和wtr 1编码一个蘑菇特异性蛋白质与一个假定的DNA结合结构域。chd 1 -1突变和wtr 1的靶向破坏阻碍了糙皮侧耳生物降解木材木质素的能力。对上述突变和破坏对某些MNP/VP基因表达的影响的检查表明，糙皮侧耳中木质素分解系统的基础是复杂的机制。
White-rot fungi play an important role in the global carbon cycle because they are the species that almost exclusively biodegrade wood lignin in nature. Lignin peroxidases (LiPs), manganese peroxidases (MnPs) and versatile peroxidases (VPs) are considered key players in the ligninolytic system. Apart from LiPs, MnPs and VPs, however, only few other factors involved in the ligninolytic system have been investigated using molecular genetics, implying the existence of unidentified elements. By combining classical genetic techniques with next-generation sequencing technology, they successfully showed an efficient forward genetics approach to identify mutations causing defects in the ligninolytic system of the white-rot fungus Pleurotus ostreatus. In this study, they identified two genes - chd1 and wtr1 - mutations in which cause an almost complete loss of Mn2+-dependent peroxidase activity. The chd1 gene encodes a putative chromatin modifier, and wtr1 encodes an agaricomycete-specific protein with a putative DNA-binding domain. The chd1-1 mutation and targeted disruption of wtr1 hamper the ability of P. ostreatus to biodegrade wood lignin. Examination of the effects of the aforementioned mutation and disruption on the expression of certain MnP/VP genes suggests that a complex mechanism underlies the ligninolytic system in P. ostreatus.