前期研究表明，在玉米大斑病菌中存在9个漆酶样多铜氧化酶，其中漆酶基因StLAC2敲除导致黑色素含量降低，不能产生分生孢子，直接影响侵染能力。为进一步研究漆酶基因家族基因在生物学功能上的差异，本文利用同源重组技术创制StLAC6基因敲除突变体并对其对玉米大斑病菌生长发育、致病、杀菌剂抗性等方面的作用进行研究。结果表明通过同源重组技术成功创制了2株StLAC6基因敲除突变体，分析发现StLAC6基因缺失后对玉米大斑病菌的生长、菌丝形态和侵染能力没有显著影响，而且突变体细胞壁及细胞膜功能均正常。进一步对其超微结构进行分析发现，StLAC6基因敲除突变体菌丝中的过氧化物酶体形态异常，影响了菌丝内脂滴合成，同时敲除突变体中的酚类化合物和黑色素的合成增加。通过比较野生型和突变体的EC50值，发现StLAC6敲除导致病菌对嘧菌环胺、三环唑、吡唑醚菌酯等多种常见杀菌剂的敏感性增加，表明漆酶参与了玉米大斑病菌对杀菌剂的抗性。为了明确漆酶基因家族成员的关系，对StLAC6敲除突变体中其他漆酶基因的表达进行分析，发现StLAC1等多个玉米大斑病菌漆酶基因的表达水平发生了显着变化，说明漆酶基因家族成员间存在功能互补。本文为研究植物病原真菌中漆酶基因家族的功能和相互关系提供了新的见解。

Laccases, as a kind of multicopper oxidase, play an important role in pigment synthesis and growth in fungi and are involved in their interactions with host plants.  In Setosphaeria turcica, 9 laccase-like multicopper oxidases have been identified, and StLAC2 is involved in the synthesis of the melanin that accumulates in the cell wall.  The function of another major laccase gene, StLAC6, was studied here.  The knockout of StLAC6 had no effect on the growth, morphology or invasion ability of S. turcica, but the morphology and function of peroxisomes of knockout mutants were abnormal.  The knockout of the StLAC6 gene resulted in increased contents of phenolic compounds and melanin and the sensitivity to fungicides increased compared with wild type strains.  In the mutants of StLAC6, there is a significant change of the expression levels of other laccase genes.  This study provides a new insight into laccase functions and the relationship of the laccase gene family in plant pathogenic fungi.