茄科尖孢镰刀菌3个专化型细胞壁降解酶的比较

Comparison of cell wall degrading enzymes from three different Fusarium oxysporum formae speciales of Solanaceae

对茄科作物致病尖孢镰刀菌番茄专化型(Fusarium oxysporum f. sp. lycopersici,FOL)、茄子专化型(F.oxysproum f. sp. melongenae,FOM)和辣椒专化型(F.oxysporum f. sp. capsicum,FOC)细胞壁降解酶多聚半乳糖醛酸酶(PG)、果胶甲基半乳糖醛酸酶(PMG)、多聚半乳糖醛酸反式消除酶(PGTE)、果胶甲基反式消除酶(PMTE)及纤维素酶(Cx)进行比较。对3个专化型分别在寄主植物体内细胞壁降解酶活性测定表明:发病茄子和番茄体内酶活性从高到低依次为PG、PMG、PGTE、Cx 和PMTE,发病辣椒体内酶活性从高到低依次为PG、PGTE、PMG、PMTE 和Cx。体外诱导试验发现,FOC所产生的PG活性比FOM和FOL高,而FOM所产生的PGTE比FOC和FOL高,3个专化型的PMG、PMTE和Cx活性没有显著差异。通过PG同工酶薄层等电聚焦电泳分析,FOL、FOM和FOC分别产生5、5、3个PG同工酶,各有1条特异的PG同工酶条带。推测此3个专化型PG同工酶的差异可能和病原菌的致病作用和寄主专化性差异有关。

We compared the cell wall degrading enzymes, including polygalacturonase （ PG ） , pectin methyl- galacturonase （ PMG ）, polygalacturonic acid transeliminase （ PGTE ） , pectin methyl transeliminase （ PMTE ） and cellulose （ Cx ）, from three different Fusarium oxysporum formae speciales of Solanaceae as F. oxysporum f. sp. lycopersici （ FOL ）, F. oxysproum f. sp. melongenae （ FOM ）, and F. oxysporum f. sp. capsicum （ FOC ） . We found that the higher to lower enzyme activity order were PG, PMG, PGTE, Cx and PMTE in inoculated eggplant or tomato in planta, while an order of PG, PGTE, PMG, PMTE and Cx in inoculated capsicum. We also found that PG activity of FOC was higher than that of FOM or FOL in vitro. There was no significant difference in the activity of PMG, PMTE and Cx in these three fungal in vitro. Analysis of PG isoenzymes by IEF-PAGE showed that FOL, FOM and FOC could secrete a total of 13 PGs, with 5, 5, and 3 PG isoenzymes, respectively. Each fungus had a specific PG band. These results will provide useful information for managing Fusarium wilt and insights into pathogenic factors for phytopathology.