AoOTAbZIP介导渗透压调控赭曲霉fc-1生长和产毒的影响  

AoOTAbZIP mediates osmotic pressure regulation of growth and toxin production by Aspergillus ochraceus fc-1

作　　者：马艳玲 黎铭轩 邓颖瑶 庄木园 刘阳 MA Yanling;LI Mingxuan;DENG Yingyao;ZHUANG Muyuan;LIU Yang(School of Food Science and Engineering,Foshan University,Foshan 528225,China;National Technical Center(Foshan)for Quality Control of Famous and Special Agricultural Products(CAQS—GAP—KZZX043),Foshan 528225,China;Guangdong Key Laboratory of Food Intelligent Manufacturing,Foshan 528225,China)

机构地区：[1]佛山大学食品科学与工程学院,广东佛山528225 [2]全国名特优新农产品质量控制技术中心(CAQS-GAP-KZZX043),广东佛山528225 [3]广东省食品智能制造重点实验室,广东佛山528225

出　　处：《佛山科学技术学院学报（自然科学版）》2024年第6期15-23,共9页Journal of Foshan University(Natural Science Edition)

基　　金：广东省基础与应用基础研究基金(2022A1515010037);国家重点研发计划资助项目(2022YFE0139500)。

摘　　要：赭曲霉毒素是一种引起世界广泛关注的霉菌毒素,其中赭曲霉毒素A(OTA)是由不同曲霉菌和青霉菌产生的一种低分子量、剧毒的次级代谢产物。为研究NaCl诱导渗透胁迫下bZIP基因的功能作用,构建了ΔbZIP突变体,探究了赭曲霉中AoOTAbZIP基因介导渗透压胁迫对OTA的合成调控作用,旨在比较野生型菌株和突变型菌株在不同渗透胁迫条件下的真菌生长和OTA产量。在中等渗透压条件下(20 g/LNaCl)的培养基中,与对照组相比(0 g/LNaCl),野生型与突变株的生长受到促进作用(野生型增长了20%,突变型增长了20%),野生型的产毒量也增加7倍了,未检测到突变株产毒;在高渗透压条件下(100 g/L NaCl)的培养基中,与对照组相比(0 g/L NaCl),野生型与突变株的生长受到明显的抑制作用(野生型减少了65%,突变株减少了60%),野生型的产毒量有所减少(减少约34%),未检测到突变株产毒;结果表明bZIP的缺失导致突变株生长对渗透压的耐受性增强,并消除了OTA的产生。与野生型相比,△AoOTAbZIP菌株中OTA合成基因otaA、otaB、otaC和otaD基因表达量极低,说明AoOTAbZIP基因通过调控OTA合成基因表达参与OTA的合成。在致病性实验中,发现野生型与△AoOTAbZIP突变型菌株对葡萄的侵染无显著差异,表明AoOTAbZIP基因的缺失对赭曲霉的致病性无明显影响。Ochratoxin is a mycotoxin of worldwide concern,of which Ochratoxin A(OTA)is a low molecular weight,highly toxic and secondary metabolite produced by different Aspergillus and Penicillium species.In order to investigate the functional role of bZIP gene under NaCl-induced osmotic stress,aΔbZIP mutant was constructed to investigate the role of AoOTAbZIP gene in Aspergillus ochraceus in mediating the regulation of OTA synthesis by osmotic stress,with the aim of comparing the fungal growth and OTA production of the wild-type and the mutant strains under different osmotic stress conditions.In a moderate osmotic stress(20 g/L NaCl)medium,growth of the wild-type and mutant strains was promoted(20%growth of the wild-type and 20%growth of the mutant)compared to the control(0 g/L NaCl),and the amount of virulence produced by the wild-type was increased 7-fold,while no virulence production was detected in the mutant strain.In a medium with high osmotic stress(100 g/L NaCl),there was a significant inhibitory effect on the growth of the wild-type and mutant strain(65%reduction in the wild-type and 60%reduction in the mutant strain),a reduction in the production of poison in the wild-type(about 34%reduction),and no production of poison by the mutant strain was detected,as compared to the control(0 g/L NaCl);These results indicated that the deletion of bZIP gene enhanced the mutant strain’s tolerance to osmotic stress and eliminated OTA production.The expression of the OTA synthesis genes otaA,otaB,otaC,and otaD was extremely low in the△AoOTAbZIP strain compared to the wild type,suggesting that the AoOTAbZIP genes are involved in the synthesis of OTA through the regulation of OTA synthesis gene expression.In pathogenicity experiments,no significant difference was found between the wild-type and△AoOTAbZIP mutant strains on grapevine,suggesting that deletion of the AoOTAbZIP gene has no significant effect on the pathogenicity of A.ochraceus.

关 键 词：赭曲霉 OTA合成 渗透压 bZIP转录因子 

分 类 号：TS201.6[轻工技术与工程—食品科学]