果胶酶激发子对黄瓜叶片病程相关蛋白及细胞壁物质的影响

Effect of Treatment with Pectinases Extract on Pathogenesis-Related Proteins and Cell Wall Substances in Cucumber Leaves

以草酸青霉菌(Penicillium oxalicum)的固态发酵产物———果胶酶粗提液喷雾诱导黄瓜,研究了该激发子对黄瓜细胞内几丁质酶和-β1,3-葡聚糖酶2种病程相关蛋白(PR s蛋白)以及细胞壁物质的影响.结果表明,经激发子处理后,黄瓜叶片中几丁质酶和-β1,3-葡聚糖酶活性诱导升高,木质素及富含羟脯氨酸糖蛋白(HRGP)含量也诱导增强;同时,在激发子处理后接种黑星病菌的黄瓜中,上述2种PR s蛋白及细胞壁物质被大量诱导合成.其中,两种PR s蛋白均在接种后d 4达到最高值,分别为22.72 U/mg(pro)和268.16 U/mg(pro);木质素和HRGP含量在接种后d 3后达最高,分别比对照高196.12%和272.98%.表明果胶酶激发子在接种前期对黄瓜几丁质酶、-β1,3-葡聚糖酶、木质素及HRGP的诱导产生是导致病情降低的内在机制.

Pectinases extract from the fermentation product of Penicillium oxalicum was tested for its ability to induce an increase of pathogenesis-related proteins （PRs） and cell wall substances in cucumber leaves. After treatment with pectinases extract, chitinase and β-1,3-glucanase activities increased, the content of lignin and hydroxyproline-rich glycoprotein （HRGP） enhanced. In another experiment, cucumber leaves treated with pectinases extract and inoculated with Cladosporium cucumerinum were assayed for these defense-related substances. The contents of chitinase, β-1, 3-glucanase, lignin and HRGP increased significantly and remained at a higher level throughout the experiment in pectinases extract-treated and pathogen-inoculated leaves, and they were significantly higher than those in untreated and inoculated leaves in the period after inoculation and before disease occurrence. The activities of chitinase and β-1,3-glucanase reached the highest level after the pathogen was inoculated for 4 d, and they were 22.72 U/mg protein and 268.16 U/mg protein, respectively. The contents of lignin and HRGP peaked after the inoculation for 3 d, and they were 196.12% and 272.98% higher than control. The results suggested that the increased levels of chitinase, β-1, 3-glucanase, lignin and HRGP in cucumber leaves after treatment with pectinases extract played an important role in the induced resistance to C Fig 4, Ref 16