Plant growth-promoting rhizobacteria (PGPR) located in rhizobacteria soil are beneficial to plant growth and development. A PGPR strain AMCC100017 of Brevibacillus laterosporus synthesizes the plant hormone IAA in a tryptophan-dependent manner. In this study, the AMCC100017 strain was used to treat Malus robusta, an excellent natural rootstock for apple production, and assess its ability to promote growth. The fresh weight, dry weight, plant height, and lateral root growth of M. robusta were significantly increased with treatment. The presence of the AMCC100017 strain increased IAA content in M. robusta and promoted root secretion of tryptophan. Colonization of the strain in the roots al-lowed continuous synthesis of IAA and promoted plant growth. In addition, the photosynthetic efficiency in leaves increased after microbial treatment, and the utilization of nitrogen, zinc, iron, copper and magnesium in leaves was increased, which was conducive to photosynthesis. Interestingly, the activities of CAT and SOD, as well as the contents of ROS in plants colonized by AMCC100017 were increased compared to control plants, but the activities of POD and MDA contents were decreased. AMCC100017 strain affected the antioxidant capacity and stress resistance of plants. AMCC100017 strain increased the content of soluble protein and soluble sugar in plants, improved plant metabolic activity and stress resistance. Therefore, AMCC100017 not only increased IAA content and photosynthetic efficiency to promote M. robusta growth, but also affected plant through multiple metabolic pathways.

Xiaona Wang;Jiucheng Zhang;Xiaofei Wang;Jianping An;Chunxiang You;Bo Zhou;Yujin Hao

State Key Laboratory of Crop Biology,College of Horticulture Science and Engineering,Shandong Agricultural University,Tai'an,Shandong271018,China;Department of Microbiology,College of Life Sciences,Shandong Agricultural University,Tai'an,Shandong 271018,China;National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources,Tai'an,Shandong 271018,China

园艺学报（英文版）

[1]Xiaona Wang;Jiucheng Zhang;Xiaofei Wang;Jianping An;Chunxiang You;Bo Zhou;Yujin Hao-.The Growth-Promoting Mechanism of Brevibacillus laterosporus AMCC100017 on Apple Rootstock Malus robusta)[J].园艺学报（英文版）,2022(01):22-34

AMCC100017,Rootstock,rootstock

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