玉米大斑病菌HT_毒素对玉米细胞CAT酶活性的影响

Effect of Ht-toxin Produced Setospharia Turcica on Cat Enzyme Activity of Corn Leaves

HT_ 毒素可抑制玉米叶片细胞CAT 酶活性。粗毒素( 含组分Ⅳ) 处理后,供试2 个玉米自交系叶片细胞的CAT 酶活性虽都受到抑制,但毒素处理6 h 时自交系Oh43Ht1 受抑制极其明显;而此时用毒素组分I和标准毒素I处理后Oh43 的相对酶活性又明显低于Oh43Ht1 。即HT_ 毒素对不同Ht 基因玉米叶片细胞CAT 酶活性的抑制作用表现了一定的寄主选择活性。试验发现,标准毒素补加H2O2 后,Oh43 的CAT 酶活性在12 h 内急剧上升(12 h 达最大值:11-056 8 mg/g·FW·min) ,之后又迅速下降;相反,Oh43Ht1 的CAT 酶活性却急剧下降(12 h 达最小值:1-700 0 mg/g·FW·min) ,之后活性上升,可见毒素处理早期,H2O2 可刺激Oh43 玉米细胞CAT 酶的活性,却抑制Oh43Ht1 玉米细胞CAT 酶的活性。此外,玉米幼茎细胞受HT_ 毒素胁迫后,各处理的CAT 酶活性基本类似,即活性早期下降,后期上升。

Activity of CAT enzyme was inhibited after HT_toxin treatment.The activity of CAT enzyme in Oh43 corn leaves was highly inhibited by several HT_toxin preparations used such as crude HT_toxin,component I of HT_toxin ,standard HT_toxin,and its activity would rise while HT_toxin added H 2O 2 which showed they might have detoxification effect.The activity of CAT enzyme in Oh43Htl corn leaves was also inhibited by HT_toxin,but the degree of inhibition depended on HT_toxin preparations used:crude HT_toxin had stronger inhibition and component I standard HT_toxin only had slightly inhibition, and the inhibition would increase while H 2O 2 were added.