常见瓜类植物的内生真菌多样性

Diversity of endophytic fungi in common cucurbit plants

为认识和掌握常见瓜类植物内生真菌多样性及其变化规律,对从4个地点采集的9种70株健康瓜类植物进行了内生真菌的分离,共获得534个菌株,总体分离率为20.9%。结合形态学和ITS序列分析,鉴定了分属于55个属的455个菌株,有8个属的真菌属于优势类群,相对多度最高的3个属依次为Colletotrichum、Fusarium和Rhizopycnis。Colletotrichum主要存在于植株地上部,Fusarium主要存在于根部和下部茎,Rhizopycnis主要存在于根部,表现出明显的部位差异。河南原阳不同瓜类植物样品中主要内生真菌类群的相对多度和内生真菌的多样性存在明显差异,蛇瓜中Colletotrichum的相对多度达44.7%,显著高于丝瓜中Colletotrichum的相对多度8.0%;黄瓜中Fusarium的相对多度达32.4%,远高于在其他瓜类植物中的相对多度,而在南瓜中Fusarium的相对多度最低,仅为3.0%。江苏无锡和河南原阳的丝瓜植株样品中内生真菌的类群组成有很大不同,表明植株生长的地理环境可能对内生真菌的组成和多样性具有显著影响。

To learn the diversity of endophytic fungi and its variation in common cucurbit plants, 70 asymptomatic cucurbit plants belonging to 9 species were collected from four localities and a total of 534 fungal isolates were obtained by using tissue culture method. The average isolating frequency was 20.9%. Based on morphological characteristics and rDNA ITS sequences, 55 funga genera were identified from 455 isolates, among them eight genera were dominant. The three genera with the highest relative abundance were orderly Colletotrichum, Fusarium and Rhizopycnis. Colletotrichum were mainly distributed in overground parts of plants, while Fusarium in roots and lower stems, and Rhizopycnis in roots, showing obvious positional difference of coloniza- tion. Significant differences existed in relative abundance of main endophytic fungal genera and diversity of the endophytic fung among different kinds of the cucurbit plants growing in Yuanyang, Henan. The relative abundance of Colletotrichum in snake gourd reached 44.7%, higher markedly than that in luffa （8.0%）. The relative abundance of Fusarium in cucumber reached 32.4%, far higher than that in other cucurbits, and that in pumpkin was the lowest, only 3.0%. The floristic composition of the endo- phytic fungi in luffa growing in Wuxi of Jiangsu and in Yuanyang of Henan was obviously different, indicating that geographica condition might have a significant influence on diversity of endophytic fungi in cucurbit plants