化感水稻内生真菌的分离鉴定及其发酵产物的生物学效应研究

以化感水稻品种‘PI312777’‘6173’和‘6180’为研究对象,从水稻根、茎和叶中分离获得70株内生真菌,采用形态学观察和rDNA-ITS区序列分析,对内生真菌进行分类鉴定。进一步以化感水稻‘PI312777’分离得到的粘红酵母和塔宾曲霉为试验菌株,通过不同稀释倍数的真菌发酵液对非化感水稻进行MS半固体培养基育苗试验,研究化感水稻内生真菌发酵产物对非化感水稻萌发率、株高等形态指标及苯丙氨酸解氨酶（PAL）、过氧化氢酶（CAT）和过氧化物酶（POD）活性的影响。结果表明,从供试化感水稻品种中共分离得到17种内生真菌,经rDNA-ITS系统发育树分析鉴定为10个属,这些内生真菌主要分布在曲霉属（Aspergillus）（29.63%）、青霉属（Penicillium）（16.67%）和镰刀菌属（Fusarium）（12.96%）。不同稀释浓度塔宾曲霉发酵液对水稻幼苗生长均有促生作用,其中50倍稀释浓度处理可显著提高水稻幼苗的株高、根长及POD酶活性。粘红酵母菌发酵液5倍稀释浓度可显著提高水稻幼苗的PAL酶活性并对水稻幼苗有促生作用。稗稻共生条件下,塔宾曲霉和粘红酵母发酵稀释液对水稻均有促生效应。本研究可为化感水稻内生真菌进一步应用于水稻生产实践提供有益指导。

Isolation and Identification of Endophytic Fungi from Allelopathic Rice and Analysis of Biological Effects of Their Fermentation Products

Using allelopathic rice ‘PI312777’ ‘6173’ and ‘6180’ as the materials, 70 endophytic fungi were isolated from the roots, stems and leaves, and were further classified and identified by morphologic observation and rDNA ITS sequence analysis. To study the effects of fungal fermentation products on the morphological indexes such as germination rate, stem height and phenylalanine ammonia lyase, catalase and peroxidase changes, Rhodotorula mucilaginosa and Aspergillus tabiensis isolated from allelopathy rice ‘PI312777’ were used as the experimental strains and their fermentation broth of different concentrations were used to carry out MS semi-solid medium seedling experiment on non-allelopathy rice. The results showed that 17 isolates of endophytic fungi and 10 genera were identified through rDNA-ITS sequence analysis. Aspergillus, Penicillium and Fusarium were the dominant species in allelopathic rice with the relative isolate frequency 29.63%, 16.67% and 12.96%, respectively. Different concentrations of A. tabiensis fermentation broth all promoted the growth of rice seedlings, among which the 50 times diluted concentration treatment significantly improved plant height, root length and POD activity of rice seedlings compared with the control treatment. High concentration of R. mucilaginosa fungus fermentation broth improved PAL activity of rice. Under the symbiotic condition of barnyard grass and rice, A. stabiensis and R. mucilaginosa both had promoting effects on the growth of non-allelopathic rice. The finding of this study could provide useful guidance for the further application of allelopathic endophytes in rice production.