大花黄牡丹内生菌的分离鉴定及其抗菌活性菌株的筛选

采用研磨法从健康大花黄牡丹的根、茎、叶柄、叶和种子中进行菌种分离,依据其形态、培养特征及其他生物学特性对菌株进行初步鉴定；采用平板对峙法对分离的内生菌进行拮抗试验研究,并对强活性菌株进行16S rD-NA序列鉴定,以明确大花黄牡丹内生菌的种类,筛选对农作物病害有抑制作用的菌株.结果表明:(1)获得内生真菌188株,鉴定为10个属,以短蠕孢属(50％)、青霉孢属(18.6％)和曲霉孢属(12.3％)为优势种群.获得内生放线菌145株,以链霉菌属(98.6％)为优势种群.表明大花黄牡丹内生菌在数量和种类上存在极丰富的多样性,同时在不同组织存在一定的差异性.(2)抑菌试验结果显示,21.6％真菌对指示菌有抑菌作用,抑菌圈直径最大为10mm；27.8％放线菌对指示菌有抑菌作用,其中菌株PND31的抑菌活性较强,抑菌谱较广.(3)16S rDNA序列鉴定显示,菌株PND31与链霉菌属聚在一起,初步归为链霉菌属一个种.

Isolation and Dentification of Endophyte from Paeonia ludlowii and Screening of Their Antimicrobial Activities

In order to select endophytes strains on the inhibition of plant disease,we isolated strains from healthy root,stem and petiole,leaf and seed of Paeonia ludlowii by grinding method.Morphological characteristics,culture and biological characteristics were used for identifying strains preliminary;Flat-panel confrontation method was used for studying antagonistic effect of strains and 16S rDNA sequence was used for identifying strains with strong activity.The results show that:(1)188 endophytic fungi strains were isolated and identified as 10 genera,Brachyosporium(50%),Penicillium(18.6%) and Aspergillus(12.3%) as the dominant population.145 endophytic actinomycetes strains were isolated,Streptomyces(98.6%) as the dominant population.The numbers and types of endophyte were extremely rich in P.ludlowii,at the same time there were certain differences in the different organizations.(2)Antibacterial test results showed that 21.6% fungi indicated antimicrobial effect,diameters of bacteriostatic circle up to 10 mm;27.8% actinomycetes indicated antimicrobial effect.The strain PND31 had the strongest antifungal activity and broad antimicrobial spectrum.(3)16S rDNA sequence showed that strains of Streptomyces and PND31 were got together,PND31 was initially classified as a species of the Streptomyces.