思茅松毛虫肠道真菌分离鉴定及水解酶活性初步研究

Isolation and identification of intestinal fungi in the larvae of Dendrolimu kikuchii Matsumura and their hydrolase activity

肠道微生物在昆虫的食物消化、免疫防御中发挥重要作用,但目前对昆虫肠道真菌了解不多。本研究以重要林业害虫—思茅松毛虫Dendrolimu kikuchii Matsumura为材料,分离鉴定其幼虫中的肠道真菌。采用传统微生物分离纯培养的方法从思茅松毛虫4龄幼虫肠道样品中分离肠道真菌,运用ITS序列分析鉴定,并对其产酶活性初步研究。经同源序列比对分析,思茅松毛虫4龄幼虫肠道中共分离得到12株真菌,分别属于德巴利酵母属Debaryomyces sp.,拟盘多毛孢属Pestalotiopsis sp.,青霉属Penicillium sp.,弯担菌属Curvibasidium sp.。产酶活性研究表明8株菌产纤维素酶,9株菌产淀粉酶,7株菌产脂肪酶,2株菌产蛋白酶。DKF-8产淀粉酶能力最高,酶活力是60.907 U/mL。DKF-10产纤维素酶能力最高,酶活力是14.276 U/g,菌株DKF-6产蛋白酶活力是5.561 U/mL,菌株DKF-8产蛋白酶酶活力是2.918 U/mL。思茅松毛虫4龄幼虫肠道真菌物种丰富度较低。本实验为未来深入研究思茅松毛虫肠道微生物功能提供了菌株材料。

Intestinal microorganisms play an important role in insect food digestion and immune defense, but little is known about intestinal fungi. In this study, Dendrolimu kikuchii Matsumura, an important forestry pest was used to isolate and identify intestinal fungi from its larvae. The intestinal fungi of the 4 instar larvae of D. kikuchii were isolated by pure culture and identified by ITS sequence analysis. Then their enzyme activity was preliminarily studied. After homologous sequence alignment analysis, 12 strains of fungi were isolated from the intestinal tract of the 4 instar larvae of D. kikuchii . The isloated fungi were Debaryomyces sp ., Pestalotiopsis sp ., Penicillium sp . and Curvibasidium sp . Among them, results showed that 8 strains produced cellulase, 9 strains produced amylase, 7 strains produced lipase, and 2 strains produced protease. DKF-8 ha the highest amylase producing ability and the enzyme activity was 60.907 U/mL . The cellulase activity of DKF-10 was 14.276 U/g, The protease activity of DKF-6 was 5.561 U/mL and DKF-8 was 2.918 U/mL. The species diversity of intestinal fungi of 4 instar larvae of D. kikuchii was relatively deficient. This work provides potential available strains for functional studies of the gut fungi in D. kikuchii .