禾本科植物内生真菌研究20：基于NRPS5基因的我国东部早熟禾亚科植物内生真菌系统发育学分析

【背景】冷季型禾草-Epichloae真菌内生共生体在我国广泛存在,Epichloae内生真菌具有遗传多样性。【目的】选取来自江苏、山东和安徽等6省共8地的早熟禾亚科植物中的21个Epichlo?sp.菌株,检测菌株的NRPS5基因;分析不同宿主内Epichlo?属内生真菌NRPS5基因多样性。【方法】提取Epichlo?spp.菌株DNA,利用特异性引物对菌株中NRPS5基因进行PCR检测和序列分析,并基于NRPS5基因构建最大简约法系统发育树。【结果】NRPS5基因可能广泛分布于我国东部冷季型禾本科植物Epichloae内生真菌中。在同种内生真菌和同一宿主(除鹅观草)中的不同种内生真菌中NRPS5基因相对保守,但不同宿主的内生真菌其碱基序列差异大,与宿主植物采集地点、采集时间和子座的有无均无相关性,NRPS5基因的差异主要与宿主植物有关。这说明NRPS5基因序列比较保守,推测属于NRPS蛋白的功能核心区。【结论】NRPS5基因序列相对保守,可作为真菌遗传多样性分析的一种辅助手段。

Grass endophyte researches 20: Genetic phylogeny analysis of endophytes inhabited in gramineous plants in east China based on NRPS5

Background] Epichloae endophyte-cool season grasses associations spread widely in China, there is genetic diversity in endophyte. Objective] we collected plants from 8 cities of 6 provinces throughout China and hundreds of strains were obtained. NRPS5 genes of 21 Epichlo? spp. strains obtained from endophyte-grass associations were detected. Genetic diversity of NRPS5 genes in Epichlo? spp. was analyzed. Methods] Fungal genomic DNA was extracted. NRPS5 genes were detected by specific DNA primers by PCR, and PCR products were then sequenced and analyzed. Phylogenetic tree based on maximum-parsimony of NRPS5 gene was constructed. Results] NRPS5 genes may be distributed widely in Epichloae inhabited in the cool season grasses of eastern China. There was a small number of bases difference in same Epichlo? spp. or different Epichlo? spp. from same host except Roegneria spp., and there was a large number of bases difference of different host plants. There was no correlation between the locations of the host plant, the time of collection and the formation of stromata, and the differences in the NRPS5 gene fragment were mainly related to the host plants. These results indicated that NRPS5 fragment sequence is conservative, should locate in the function core of the NRPS proteins. Conclusion] NRPS5 gene is relatively conserved, and could be an aiding method to evaluate genetic diversity of Epichlo? spp. endophytes.