Diversity of endophytic fungi in common cucurbit plants

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 percent . Based on morphological characteristics and rDNA ITS sequences, 55 fungal 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 colonization. Significant differences existed in relative abundance of main endophytic fungal genera and diversity of the endophytic fungi among different kinds of the cucurbit plants growing in Yuanyang, Henan. The relative abundance of Colletotrichum in snake gourd reached 44.7 percent , higher markedly than that in luffa (8.0 percent ). The relative abundance of Fusarium in cucumber reached 32.4 percent , far higher than that in other cucurbits, and that in pumpkin was the lowest, only 3.0 percent . The floristic composition of the endophytic fungi in luffa growing in Wuxi of Jiangsu and in Yuanyang of Henan was obviously different, indicating that geographical condition might have a significant influence on diversity of endophytic fungi in cucurbit plants.