脐孢木霉菌中tri基因簇的克隆及tri基因在不同产素水平下的表达分析

Cloning of tri Cluster and Analysis of tri Genes Expressions under Different Trichodermin-producing Conditions in Trichoderma brevicompactum

木霉素(trichodermin)是单端孢霉烯类化合物的一种,其对多种植物病原真菌具有较强的抑制作用。为分析脐孢木霉菌Trichoderma brevicompactum tri基因簇中各基因与木霉素合成的关系,本研究首先克隆得到了脐孢木霉菌0248的tri基因簇,其全长24793 bp且含有7个开放阅读框。利用实时荧光定量PCR分析基因簇中各基因在产木霉素能力不同的培养基中表达,结果表明,高产素培养基中tri基因表达量在培养40 h时较高,随后的时间里表达量大幅降低。在低产或不产素培养基中,tri基因在培养40 h时表达量远低于其在高产素的培养基中基因表达量,在52 h时表达量有所提高,但在随后的时间里呈下降趋势,即tri基因簇表达量与木霉素的产量呈正相关。该研究为进一步阐明木霉素合成途径中相关基因的功能和提高脐孢木霉菌0248的生物防治效果奠定了基础。

Trichodermin is one of trichothecenes compounds, which has strongly antifungal activity on many kinds of plant pathogenic fungi. To preliminary clarify the function of tri cluster on trichodermin biosynthesis by Trichoderma brevicompactum 0248, the full length of tri cluster（24793 bp） was cloned. Sequence analysis of this cluster identified seven orthologs of T. brevicompactum tri genes. The influence of three carbon sources on the trichodermin production as well as the expression levels of tri genes in T. brevicompactum were also investigated. The result showed that the expression levels of tri genes under high trichodermin-producing condition by T. brevicompactum were much higher than that of trichodermin-nonproducing or low trichodermin-producing condition after 40 h incubation. The high expressions of tri genes in the glucose medium resulted in the accumulation of trichodermin after 40 h incubation. The expression level of tri gene was positively correlated with the yield of trichodermin. It provided a basis for further study the functional of tri genes in T. brevicompactum.