楸树组培苗内生菌分离鉴定与功能特性解析

Isolation and Identification of Endophytic Bacteria in Catalpa bungei Tissue Culture Seedling and Its Functional Characteristic Analysis

研究旨在挖掘楸树组培苗内生菌资源,开发具有应用潜力的农业微生物菌群,从而促进组培苗快速生长和繁殖。利用选择性培养基对楸树组培苗内生菌进行分离鉴定。采用Ashby固体培养基初筛,测定液体培养基中有效氮浓度,评价内生菌固氮效果;通过Nbrip固体培养基初筛,测定液体培养基中可溶性磷浓度,评价内生菌解磷效果;测定内生菌对植物病原菌链格孢菌和葱柄锈菌的抑制效果。自楸树组培苗中分离获得24株内生菌,经形态和16S rRNA序列鉴定均为根瘤菌属的Rhizobium zeae。菌株NF6的固氮能力最强,其培养基中有效氮浓度达111.97 mg/L;菌株NF11的解磷效果最好,其培养基中可溶性磷浓度达1007.95 mg/L;多数内生菌对供试病原菌均有抑制效果,分别有6株和2株内生菌对链格孢菌和葱柄锈菌的抑制率超过20%。本研究获得了植物促生和生防效果的菌株资源,可为组培苗内生菌的潜在应用提供理论依据。

This study aimed to explore the endophytic bacterial resources of Catalpa bungei tissue culture seedlings,to develop agricultural microorganisms with application potential,promoting the rapid growth and propagation of tissue culture seedlings.The endophytic bacteria were isolated and identified from C.bungei tissue culture seedlings by selective medium in this paper.The nitrogen content in the culture solution was determined to evaluate the nitrogen fixing effect after preliminary screening with Ashby solid medium,and the phosphorus solubilization effect was evaluated using phosphorus content in the culture solution after preliminary screening with Nbrip solid medium,then the inhibitory effect of endophytic bacteria was measured with Alternaria alternate and Fomitopsis semiolaccatus as test objects.24 strains of endophytic bacteria were isolated from the seedling of C.bungei,and they were identified as Rhizobium zeae by morphological and 16S rRNA sequence analysis.The results indicated that the nitrogen fixing capacity of strain NF6 was best as its nitrogen concentration in the Ashby liquid medium reached 111.97 mg/L,and strain NF11 had the best phosphorus solubilization effect due to the phosphorus concentration in Nbrip culture medium reached 1007.95 mg/L.Furthermore,most of the endophytic R.zeae had inhibitory effects on the tested pathogens,and more than 20%of inhibitory rates against A.alternate and F.semiolaccatus respectively had obtained for the 6 and 2 strains of endophytic R.zeae.In this study,the resources of endophytic bacteria with the potentials of promoting growth and resistance to pathogens were obtained,which provided theoretical basis for the potential application of endophytic bacteria in tissue culture seedlings.