Bioprospecting Plant-Growth-Promoting Endophytic Bacteria Isolated from Moso Bamboo (Phyllostachys edulis) Shoots

Abstract

Endophytic bacteria improve plant health and are sometimes necessary to fight against adverse conditions. Bamboo shoots can be eaten as a vegetable and grow into culm wood. However, few studies have focused on the colonization characteristics of endophytic bacteria in Moso bamboo shoots at different tissue sites and different growth developmental phases. Endophytic bacteria were isolated from the top, the base, and the root of Moso bamboo shoots during three different growth and development stages (winter shoot period underground (S1), spring shoot period at 50 cm aboveground (S2), and fast growth shoot period at 200 cm aboveground (S3)), and the highest content of isolable endophytes were in roots in the S3 stage. A total of 253 different endophytic bacteria strains were totally isolated and then evaluated in term of their PGP (plant growth promoting) traits such as inorganic phosphorus solubilization, organic phosphorus solubilization, hormone production, siderophore production, ACC deaminase, and biological nitrogen fixation. Among those newly isolated strains, Pseudomonas rhodesiae RD7-4 had the strongest phosphorus solubilizing ability, Burkholderia pyrrocinia BD24-2 had the strongest nitrogen fixing ability, and Pseudomonas edaphica TD33-1 had the strongest IAA production ability. Inoculation with all three strains significantly increased the content of soluble starch in Arabidopsis, and B. pyrrocinia BD24-2 significantly increased the fresh weight and promoted the growth of the root system. Furthermore, in pot experiments, B. pyrrocinia BD24-2 significantly increased the biomass, root length, and leaf area. Our study contributes to understanding the endophytes in Moso bamboo shoots, and indicates that the strain BD24-2 can be potentially acted as a plant growth promoter.