锁阳及其寄主白刺内生真菌的生态分布及遗传关系

首次研究了寄生植物锁阳及其寄主白刺内生真菌的分布特征及遗传关系.采用组织块法分离天然白刺、寄生体中锁阳和白刺的内生真菌,利用ITS-rDNA分子序列并结合形态学方法鉴定菌种,研究内生真菌的分离率、定殖率、分离频率、多样性指数、均匀度指数及相似性系数等的差异,以及寄生关系中内生真菌的多样性、遗传关系及分布特征等.结果表明: 本次获得的49株内生真菌隶属于18个分类单元,95.9%为子囊菌,4.1%为担子菌;内生真菌总分离率为15.3%,总定殖率为25.0%;天然白刺中内生真菌Shannon多样性指数最大,为2.13;锁阳花序与锁阳茎的内生真菌相似性系数最大,为0.50;镰孢菌属为白刺的优势菌属,青霉属为锁阳的优势菌属.锁阳与白刺寄生体中真菌类群的差异性分布表明寄生关系对内生真菌群落存在一定影响.

Ecological distribution and genetic relation of endophytic fungi in Cynomorium songaricum and its host Nitraria tangutorum

This is the first report of the distribution and genetic relationships of endophytic fungi from the parasitic plant Cynomorium songaricum and its host Nitraria tangutorum. Endophytic fungi from the root of natural N. tangutorum, parasitic plant C. songaricum and its host N. tangutorum were isolated by tissue culture, and they were identified by morphology combined with molecular barcoding based on ITS-rDNA sequence. The isolation rates, colonization rates, isolation frequency, diversity index, evenness index, similarity coefficient and genetic relationships among fungal taxa were estimated by phylogenetic analysis, and differences in fungal endophyte distribution were investigated. The results showed that a total of 49 isolates were obtained belonging to 18 different taxa. 95.9% of these taxa were in Ascomycota, and the remaining was in Basidiomycota (4.1%). The isolation rate and colonization rate of endophytic fungi were 15.3% and 25.0%, respectively. The Shannon biodiversity index was the highest in the root of natural N. tangutorum at 2.13. The simila-rity coefficient was highest between the stem of C. songaricum and the flower of C. songaricum at0.50. Fusarium was the dominant genus in N. tangutorum, while Penicillium was the primary genus in C. songaricum. The differential distribution of fungal taxa between N. tangutorum and C. songaricum suggested that the parasitic relationship influences the endophytic fungal community.