尖孢镰刀菌古巴专化型胱硫醚γ-合成酶的功能分析  

Functional analysis of cystathionine gamma-synthase in Fusarium oxysporum f.sp.cubense

作　　者：刘礼广 丁兆建 李梦涵 吴春花 谢欣捷 彭军[2] 张欣 LIU Liguang;DING Zhaojian;LI Menghan;WU Chunhua;XIE Xinjie;PENG Jun;ZHANG Xin(College of Science,Qiongtai Normal University,Haikou 571127,Hainan,China;Environment and Plant Protection Institute,Chinese Academy of Tropical Agricultural Sciences,Haikou 571101,Hainan,China;Tropical Biodiversity and Bioresource Utilization Laboratory,Qiongtai Normal University,Haikou 571127,Hainan,China)

机构地区：[1]琼台师范学院理学院,海南海口571127 [2]中国热带农业科学院环境与植物保护研究所,海南海口571101 [3]琼台师范学院热带生物多样性与资源利用实验室,海南海口571127

出　　处：《菌物学报》2023年第7期1575-1587,共13页Mycosystema

基　　金：国家自然科学基金(32260655,31801690);海南省自然科学基金高层次人才项目(2019RC249);海南省高等学校科学研究资助项目(Hnky2022-50);财政部和农业农村部国家现代农业产业技术体系资助项目(CARS-31);大学生创新创业训练计划(S202113811002)。

摘　　要：甲硫氨酸在真菌、细菌和植物的生物学过程中起着重要作用。禾谷镰刀菌Fusarium graminearum的FgMETB基因编码一个胱硫醚γ-合成酶,是甲硫氨酸合成所必需的。本研究利用同源重组的方法,在尖孢镰刀菌古巴专化型4号生理小种Fusariumoxysporumf.sp.cubenserace4(Foc4)获得了FgMETB同源基因FoMETB的敲除突变体菌株;与野生型菌株相比,突变体菌株ΔFoMETB在以SO_(4)^(2-)为唯一硫源的基本培养基(minimal medium)上不能生长。1 mmol/L甲硫氨酸的添加恢复了突变体菌株ΔFoMETB的生长,但半胱氨酸的添加不能恢复该缺失突变体的生长,说明FoMETB的敲除阻遏了Foc4半胱氨酸转化甲硫氨酸的通路。此外,ΔFoMETB的气生菌丝和菌丝干重明显减少、分枝增多、产孢量显著降低、疏水性缺失和对巴西蕉组培苗的致病性显著减弱。由此表明,FoMETB参与调控尖孢镰刀菌古巴专化型的生理特性和致病性,甲硫氨酸合成途径的关键合酶FoMETB有望成为新的抗真菌药物靶标。Methionine plays a crucial role in various biological processes in fungi,bacteria and plants.FgMETB encodes a cystathionine gamma-synthase,which is essential for methionine biosynthesis in Fusarium graminearum.In this study,the deletion mutant strains of FoMETB,a homologue of F.graminearum FgMETB,in Fusarium oxysporum f.sp.cubense race 4(Foc4)were obtained by using homologous recombination technology.The FoMETB deletion mutant strains were unable to grow on minimal medium containing SO_(4)^(2−)as the sole sulphur source.Supplementation of 1 mmol/L methionine,but not 1 mmol/L cysteine,rescued the defect of mycelial growth of FoMETB deletion mutant.These results indicated that the enzyme encoded by FoMETB is involved in conversion of cysteine into methionine.In addition,the FoMETB deletion mutant strains showed significant reduction in aerial hypha growth,conidiation,dry weight of mycelium and virulence attacking banana plantlets.This study indicated that FoMETB plays a critical role in regulation of various biological processes in Foc4.This key synthase FoMETB in methionine synthesis is desirable as a new potential antifungal drug target.

关 键 词：尖孢镰刀菌古巴专化型 甲硫氨酸合成 致病性 

分 类 号：S436.68[农业科学—农业昆虫与害虫防治]