柑橘采后病原菌意大利青霉creA基因的克隆及表达分析

Cloning and expression analysis of creA from Penicillium italicum, a postharvest pathogen of citrus fruits

为初步分析柑橘采后病原菌意大利青霉(Penicillium italicum)碳代谢调控因子CreA的功能,克隆到意大利青霉的creA基因。PicreA基因全长1236bp,无内含子,PiCreA蛋白由411个氨基酸组成,含有2个转录因子典型的锌指结构域。系统进化分析表明,PiCreA蛋白与扩展青霉(Penicillium expansum)亲缘性最高。采用荧光定量PCR方法,观察到PicreA基因面对不同碳源诱导具有不同的表达响应。对于单糖一般在短时间内诱导得到较高表达,随着时间延长,抑制碳源葡萄糖诱导PicreA呈现先下降再上升的趋势,推测发生了PicreA的自我抑制;而在去抑制碳源木糖环境中,PicreA的表达量略有下降并逐渐保持相当高的水平。对于非糖类的去抑制碳源乙醇,PicreA基本维持稳定的较高表达状态。PicreA基因在整个意大利青霉侵染柑橘过程中稳定表达。

In order to analyze the function of CreA,a carbon metabolism regulator of Penicillium italicum ,which is a postharvest pathogen of citrus fruits,the PicreA gene was successfully cloned.The gene has 1 236 bp cDNA length without intron,which encodes 411 amino acids and contains two typicalzinc finger domains of transcription factors.Phylogenetic tree analysis showed that the PiCreA protein had the highest homology with Penicillium expansum .Transcriptional analysis of PicreA revealed a complex express profile in response to different carbon sources.For monosaccharide,higher expression was induced in a short period of time.With the prolongation of time,in the case of repressing carbon source such as glucose, PicreA expression showed a gradual decline and then increased.It was presumed that self-inhibition of PicreA occurred.In term of the depressing carbon source like xylose, PicreA expression level lightly decreased and gradually remained fairly high.For non-monosaccharide carbon source such as ethanol,high level of PicreA expression was maintained.The PicreA gene is stably expressed throughout the infection process of Penicillium italicum on citrus fruits.