Seasonality affects the community of endophytic fungi in coconut (Cocos nucifera) crop leaves

ABSTRACT The diversity of endophytic fungi in healthy coconut palm leaves (Cocos nucifera) was assessed by analyzing fungal isolates from three coconut cultivars (yellow dwarf, green dwarf, and a hybrid cultivar PB121) used agriculturally in Brazil. The influence of season (rainy or dry) on the endophytic fungal community was also analyzed. Overall, 318 fungal isolates were obtained from 972 coconut leaf fragments. The rDNA ITS region was sequenced from representative species of the isolated endophytic fungi and the most common species identified were Nigrospora oryzae, Pestalotiopsis sp., and Zasmidium musae. The alpha diversity of the endophytic fungi was also calculated. Nonmetric multidimensional scaling (NMDS) ordination and permutational analysis of variance (PERMANOVA) revealed significant seasonal effects on the composition of the endophyte community. However, practically no influence was observed on the fungal communities for the different cultivars of coconut.

摘要 本研究以巴西农业生产中应用的三个椰子栽培品种（黄矮椰、绿矮椰及杂交品种PB121）的健康椰子叶片（椰子属Cocos nucifera）为材料，通过分析其中的真菌分离物，探究健康椰子叶片内生真菌的多样性；同时分析了季节（雨季或旱季）对内生真菌群落的影响。本研究共从972份椰子叶片片段中分离获得318株真菌分离物。对分离得到的内生真菌代表物种的核糖体DNA ITS区（rDNA ITS region）进行测序，鉴定出的最常见物种为稻黑孢菌（Nigrospora oryzae）、拟盘多毛孢属（Pestalotiopsis sp.）以及芭蕉纹孢菌（Zasmidium musae）。此外还计算了内生真菌的α多样性。非度量多维尺度分析（Nonmetric Multidimensional Scaling, NMDS）与置换多元方差分析（Permutational Multivariate Analysis of Variance, PERMANOVA）结果显示，季节对内生真菌群落组成具有显著影响，但不同椰子栽培品种对真菌群落几乎无影响。