摘要

红豆根内生链霉菌的特性、拮抗活性及对红豆组培苗生长的促进作用

作者(年代):P.F. Kouomou Djuidje

可可是世界上最重要的六大块根作物之一。它具有很高的营养价值，是一种重要的经济作物。摘要由稻瘟病(Pythium myriotylum)引起的椰子树根腐病(CRRD)虽然很重要，但它仍然是世界上大多数椰子树种植区的主要生产制约因素。本研究的重点是从喀麦隆山附近采集的椰子树根中分离、评价和鉴定其内生放线菌，以了解其潜在的拮抗真菌的活性和促进植物生长的能力。根据其形态特征，从健康白椰根中分离出7组不同的放线菌。约60%的分离株被分配到PERM2组。在PDA上双重培养的抑菌活性允许选择PERM1、PERM2、PERM4和PERM5作为活性菌株(对P. myriotylum抑制率超过50%)。随后通过表型和分子鉴定鉴定了这4个分离株，鉴定了细胞外水解酶的产生、植物生长促进(PGP)性状，并评估了它们在组织培养上的效果。经鉴定，这些拮抗内生菌株均属于链霉菌属。16S rRNA基因的测序和与GenBank数据库中检索到的序列的比对表明，PERM2和PERM4分别与samsunensis和brunneogriseus链霉菌很接近，但单独聚在一个不同的亚分支中。 The comparison of some physiological and biochemical properties of PERM2 and PERM4 with the most closely related Streptomyces species showed that these strains differs phenotypically. PERM2 and PERM4 might represent new species. The selected actinobacteria exhibited several properties often associated with plant growth promoting traits. All selected Streptomyces were able to produce siderophores, phytohormone (IAA), ACC deaminase and solubilize phosphate. The isolate PERM2, with maximum IAA (20.30 ?g/ml) produced, increased significantly root length (14.26 � 0.5 cm) compare to positive control (6.87 � 0.3 cm). Moreover, PERM2 increased significantly fresh weight of roots (1.903 � 0.06 g) compare to negative control (0.371 � 0.06 g). Otherwise, PERM2 also increased number of secondary roots significantly compare to negative control. These results suggest the possibility of using endophytic Streptomyces strains especially isolate PERM2 in formulation of potential bio fungicides and biofertilizers.