Root Morphogenesis of Arabidopsis thaliana Tuned by Plant Growth-Promoting Streptomyces Isolated From Root-Associated Soil of Artemisia annua

Wenbo Fu; Yanshuo Pan; Yuhua Shi; Jieyin Chen; Daozhi Gong; Yuzhong Li; Guangfei Hao; Dongfei Han

doi:10.3389/fpls.2021.802737

Root Morphogenesis of Arabidopsis thaliana Tuned by Plant Growth-Promoting Streptomyces Isolated From Root-Associated Soil of Artemisia annua

Front Plant Sci. 2022 Jan 10:12:802737. doi: 10.3389/fpls.2021.802737. eCollection 2021.

Authors

Wenbo Fu^{1

2}, Yanshuo Pan^{2

3}, Yuhua Shi⁴, Jieyin Chen⁵, Daozhi Gong², Yuzhong Li², Guangfei Hao¹, Dongfei Han²

Affiliations

¹ School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China.
² Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China.
³ College of Natural Resources and Environment, Northwest Agriculture and Forestry University, Yangling, China.
⁴ Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Material Medica, China Academy of Chinese Medical Sciences, Beijing, China.
⁵ State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.

Abstract

In this study, the capacity to tune root morphogenesis by a plant growth-promoting rhizobacterium, Streptomyces lincolnensis L4, was investigated from various aspects including microbial physiology, root development, and root endophytic microbial community. Strain L4 was isolated from the root-associated soil of 7-year plantation of Artemisia annua. Aiming at revealing the promotion mechanism of Streptomyces on root growth and development, this study first evaluated the growth promotion characters of S. lincolnensis L4, followed by investigation in the effect of L4 inoculation on root morphology, endophytic microbiota of root system, and expression of genes involved in root development in Arabidopsis thaliana. Streptomyces lincolnensis L4 is able to hydrolyze organic and inorganic phosphorus, fix nitrogen, and produce IAA, ACC deaminase, and siderophore, which shaped specific structure of endophytic bacterial community with dominant Streptomyces in roots and promoted the development of roots. From the observation of root development characteristics, root length, root diameter, and the number of root hairs were increased by inoculation of strain L4, which were verified by the differential expression of root development-related genes in A. thaliana. Genomic traits of S. lincolnensis L4 which further revealed its capacity for plant growth promotion in which genes involved in phosphorus solubilization, ACC deamination, iron transportation, and IAA production were identified. This root growth-promoting strain has the potential to develop green method for regulating plant development. These findings provide us ecological knowledge of microenvironment around root system and a new approach for regulating root development.

Keywords: PGPR; Streptomyces lincolnensis; endophytic microbes; indole-3-acetic acid (IAA); root morphogenesis.