马铃薯干腐病病原镰孢菌体内产细胞壁降解酶特性研究

干腐病是马铃薯窖储期的主要病害,病原菌往往通过薯块表面的机械擦伤入侵块茎并破坏块茎的薄壁细胞而进行侵染,其中病菌的进一步扩展需要降解寄主细胞壁,因此,针对干腐病病原镰孢菌产酶特性的研究具有重要意义。以接骨木镰孢菌（Fusarium sambucinum）、燕麦镰孢菌（Fusarium avenaceum）、拟丝孢镰孢菌（Fusarium trichothecioides）、黄色镰孢菌（Fusarium culmorum）、拟枝孢镰孢菌（Fusarium sporotriodides）为试验菌种,以克新1号为寄主材料,对5种镰孢菌体内产细胞壁降解酶特性及温度对这些致病菌的产酶特性的影响进行了研究。结果表明,当5种镰孢菌接种在马铃薯薯块上后,均可以产生羧甲基纤维素酶（Cx）、β-葡萄糖苷酶、多聚半乳糖醛酸酶（PG）、果胶甲基半乳糖醛酸酶（PMG）,其中Cx的活性在侵染后期最高,PMG在侵染前期较高,且Cx活性低于PMG。在温度对镰孢菌活体内产细胞壁降解酶的影响试验中发现,相对于不接菌对照,Cx、PMG的活性在25℃时较高,β-葡萄糖苷酶在20℃下活性较高,PG在20℃和25℃的活性都较高。以上结果说明：镰孢菌侵染马铃薯时会产生大量的细胞壁降解酶,Cx活性在侵染后期较高,PMG活性在侵染前期较高,且低温不利于真菌细胞壁降解酶的产生。

Characteristics of Cell Wall Degradation Enzyme Produced by Main Pathogenic Fusarium spp. in Potato Dry Rot

Dry rot is the main disease during the storage period of potato pits. Pathogens often invade the tubers through the mechanical abrasion of potato tuber and destroyed the parenchyma cells of the tuber to infect and spread. Therefore, it is of great significance to study the enzyme production characteristics of Fusarium. In this experiment, the characteristics of enzyme production by cell wall degrading enzymes in 5 Fusarium species and the effect of temperature on enzyme production characteristics were investigated by using Kexin 1 as the host material, test strains were Fusarium. sambucinum, F. avenaceum, F. trichothecioides, F. culmorum, and F. sporotriodides. The results showed that after inoculation of 5 species of Fusarium on potato tubers, amount of carboxymethyl cellulose (Cx), β-glucosidase, polygalacturonase (PG) and Methylgalacturonase (PMG) in all 5 treatments were all higher than that in control. The activity of cellulase was the highest in the late stage of infection, and the activity of pectinase was higher in the early stage of infection, and the cellulase activity was lower than that of pectinase. In an experiment on the effect of temperature on cell wall degrading enzymes produced by Fusarium in vivo, comparison with the control, the enzyme activities of Cx, PMG were higher at 25℃, the activity of β-glucosidase enzyme was higher at 20℃, the activity of PG was higher at both 20℃ and 25℃. The above results showed that Fusarium produced large amounts of cell wall degrading enzymes when infecting potato, cellulase activity was higher in the late stage of infection, pectinase activity was higher in the early stage of infection, and low temperature was not conducive to the production of fungal cell wall degrading enzymes.