四绺孢球腔菌科真菌地理分布及其生态学功能

根据ITS、LSU、rpb2、tef1和tub2多基因系统发育分析,将云南禾本科植物格孢腔菌目的7株内生真菌鉴定归属于格孢腔菌目Pleosporales四绺孢球腔菌科Tetraplosphaeriaceae的四绺孢属Tetraploa和假四绺孢属Pseudotetraploa以及该目下的一个未定属genera incertae sedis。羧甲基纤维素钠培养基和愈创木酚培养基筛选发现四绺孢球腔菌科的2个菌株具有较强的纤维素酶和漆酶活性,而这个未定属的菌株仅具有较弱的纤维素酶活性、无漆酶活性,表明格孢腔菌目的2个内生真菌类群的纤维素和木质素降解能力不同。多重对应分析发现四绺孢球腔菌科真菌的属与寄主、分离来源和地理位置有关联,其中四绺孢属和假四绺孢属可在活的健康植物作为内生真菌存活,并在植物凋落物和土壤中分离得到,推测四绺孢属和假四绺孢属两属为内生和腐生双生态位真菌。因此,进一步深入探究四绺孢球腔菌科内生真菌参与的禾本科植物凋落物的分解将深化我们对禾本科植物内生真菌多样性和生态学功能的认识。

Geographic distribution and ecological functions of Tetraplosphaeriaceae

Based on the multigenetic phylogenetic analysis of ITS, LSU, rpb2, tef1 and tub2, seven endophytic fungi of Pleosporales in plants of Poaceae in Yunnan Province were identified as Tetraploa and Pseudotetraploa of Tetraplosphaeriaceae and a taxonomically uncertain genus of Pleosporales. Two endophytes of Tetraploa and Pseudotetraploa were found to have stronger activities of cellulase and laccase, while the isolates of genera incertae sedis displayed comparatively weak cellulase activities and without laccase activity on sodium carboxymethyl cellulose medium and guaiacol medium, indicating that the activities of cellulose and lignin degradation abilities were different between taxa. Multiple correspondence analysis showed that the colonization of genera of Tetraplosphaeriaceae were correlated with host, isolated source and geographical location. Tetraploa and Pseudotetraploa can survive as endophytes in living healthy plants, and they also can be isolated from litter and soil. It is suggested that Tetraploa and Pseudotetraploa are endophytic and saprophytic dual-niche fungi. Further investigation of Tetraplosphaeriaceae participating in decomposition of grass plant litter is necessary for enriching our understanding of the diversity and ecological function of endophytic fungi in plants of Poaceae.