重楼中一株产纤维素酶内生真菌的分离及鉴定

从重楼根茎中分离、鉴定具有产纤维素酶活性的内生真菌。采用表面消毒法从重楼块茎中分离内生真菌;用纤维素酶活性CMC平板检测分离菌株的产纤维素酶活性;对高产菌株进行形态学观察和分子生物学测序鉴定;探究影响纤维素酶活力的因素;利用平板法检测该株菌产其他胞外水解酶的活性。从3个来源的重楼中分离出41株内生真菌,通过平板检测发现AS-5、AS-7、AS-9和AS-18菌株能产生纤维素酶,其中AS-9菌株活性最强;通过形态学观察和ITS、LSU序列分析将AS-9菌株鉴定为Setophoma terrestris;该菌在pH值为7.0和温度为28℃时表现出最大纤维素酶活性,紫外线照射对产纤维素酶活性无明显作用;检测发现AS-9菌株同时具有产酪蛋白酶、脂肪酶、天冬酰胺酶、谷氨酰胺酶和脲酶活性。首次在重楼中发现内生真菌Setophoma terrestris,且具有较好的产纤维素酶能力,值得深入研究。

Isolation and Identification of a Cellulase-producing Endophytic Fungus in Paris polyphylla var.yunnanensis

This paper aims to isolate and identify an endophytic fungus with cellulase activity in Paris polyphylla var.yunnanensis.Surface disinfection method was applied to isolate the endophytic fungi from P.polyphylla var.yunnanensis rhizome.CMC plate assay was used to detect the cellulase activity of the isolated strains.Morphological features and sequence characters based techniques were applied to identify the strains producing high-yield cellulase.The factors affecting the cellulase activity were also explored.Finally,plate activity screen method was used to test the activity of other extracellular hydrolases production.A total of 41 fungal endophytes were isolated from 3 origins of P.polyphylla var.yunnanensis.Among the 41 isolates,strains named as AS-5,AS-7,AS-9 and AS-18 were found to be able to produce cellulase,and strain AS-9 showed the strongest cellulase production activity.AS-9 was identified as Setophoma terrestris based on the morphological observations and ITS,LSU sequences analysis.AS-9 presented maximal cellulase activity at pH7.0 and 28℃.UV exposure did not have a significant effect on cellulase production of AS9.Meanwhile,S.terrestris AS-9 also demonstrated the activities of producing caseinase,lipase,asparaginase,glutaminase and urease production.To the best of our knowledge,S.terrestris AS-9 is first detected as an endophytic fungus in P.polyphylla var.yunnanensis and shows a better cellulase production capacity.It is worth for further study.