《植物生理学报》 2016, 52(3): 269-276
摘 要：为了明确花生叶腐病菌分泌的细胞壁降解酶种类和致病作用以及花生品种木聚糖酶抑制剂基因与抗叶腐病的关系, 本研究进行了花生品种对叶腐病的抗性鉴定, 测定了离体条件下和活体内病菌分泌的细胞壁降解酶活性与变化, 扩增了3种花生木聚糖酶抑制剂基因。结果表明: 花生叶腐病菌能产生果胶酶、纤维素酶、木聚糖酶、漆酶等细胞壁降解酶, 无论活体外培养还是接种植株体内都表现为果胶酶活性最高, 其次是漆酶和木聚糖酶, 活性最弱的是纤维素酶; 果胶酶中多聚半乳糖醛酸酶(PG)和果胶甲基半乳糖醛酸酶(PMG)活性强, 而果胶甲基反式消除酶(PMTE)的活性较弱, 甚至在离体条件下没有测到活性, 说明病菌产生的几种细胞壁降解酶活性有较大差异; 其次, 叶腐病菌分泌的细胞壁降解酶在花生不同抗性品种中的活性和变化也不同, 感病品种中测得的细胞壁降解酶活性一般都比抗病品种高, 随接种时间增长的活性变化曲线也比抗病品种增加的速度快。另外, 在花生品种中检测到3种木聚糖酶抑制剂基因XIP、TAXI和TLXI, 但品种间分布不均衡, 其中TAXI基因与花生叶腐病抗性关系密切。
关键词：花生叶腐病菌; 细胞壁降解酶; 致病性; 木聚糖酶抑制剂基因
Corresponding author: WANG Qi-Ran; E-mail: firstname.lastname@example.org
Abstract:In order to define the types and pathogenicity of cell wall degrading enzymes secreted by peanut leaf rot fungus (Rhizoctonia solani), the relationship between peanut resistance to leaf rot and the xylanase inhibitor genes were analyzed, and the cell wall degrading enzyme activities in vivo and in vivo were determined. The results indicated that, cell wall degrading enzymes including pectinase, cellulase, xylanase and laccase could be secreted by R. solani. Among them, whether in vivo or in vitro, pectinase activity was the highest, followed by xylanase and laccase activity, and cellulase activity was the lowest; for pectinase, polygalacturonase (PG) or polymethylgalacturonase (PMG) activity was the highest, however, pectin methyltranseliminase (PMTE) activity was the lowest, and even it had no activity in vitro. The cell wall degrading enzyme activities in disease tissues also showed differences. Both the cell wall degrading enzyme activities and the enzyme activity increasing speed were higher in peanut susceptible varieties than in the resistant varieties. In addition, three kinds of xylanase inhibitor genes XIP, TAXI and TLXI were detected in peanut varieties, but they unevenly distributed in different varieties, and only the TAXI gene was closely related to resistance against peanut leaf rot.
Key words: Rhizoctonia solani; cell wall degrading enzymes; pathogenicity; xylanase inhibitor genes
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