Cultivable Endophytic Bacteria in Seeds of Dongxiang Wild Rice and Their Role in Plant-Growth Promotion

Abstract

Dongxiang wild rice (Oryza rufipogon Griff.) germplasm is a precious resource for the improvement of agronomic traits in rice. Rice seeds also harbor a diverse endophytic bacterial community, and their interactions with their hosts and each other can influence plant growth and adaptability. Here, we investigated the community composition of cultivable endophytic bacteria obtained from the surface-sterilized seeds of Dongxiang wild rice and screened them for plant growth-promoting traits. Phylogenetic analysis of 16S rRNA gene sequences indicated that the 47 isolates were affiliated with five classes and 13 discrete genera, and Bacillus and Microbacterium predominated. Evaluations of plant growth promoting (PGP) traits showed that 45 endophytic bacteria isolates produced between 3.37 and 90.11 μg mL−1 of Indole-3-acetic acid (IAA), with the highest yield of 90.11 μg mL−1 (Fse28). Further, 37 of the isolates were able to solubilize mineral phosphate, while 28 other isolates had the ability of N2-fixation, 17 isolates possessed 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity with the highest yield of 20.72 μmol mg−1 protein h−1 (Fse35), and 17 isolates were also able to produce siderophores. The two strains Fse28 and Fse35 had multiple PGP traits that significantly improved the agronomic traits (root length, shoot length, dry matter, and chlorophyll content) of cultivated rice seedlings. Our results illustrate the rich diversity of seed endophytic bacteria in Dongxiang wild rice and their potential for developing novel efficient bioinoculants to enhance soil fertility and favor seedling growth.

A bacterial formulation based on two exopolysaccharide-producing rhizobacteria from Dongxiang wild rice (Oryza rufipogon Griff.) confers drought tolerance in cultivated rice Dongdao-4 (Oryza sativa L.)

“…A previous report looked at siderophores and their relationship to drought resistance, and found that the strain producing the highest level of siderophores is associated with excellent drought resistance of host plants (Ashry et al 2022). Some siderophore-producing bacteria have been found in DXWR, with Bacillus being one of the main genera (Sultana et al 2021;Zhang et al 2021), which is in harmony with our ndings in DXWR with strain N1g.…”

“…as well the potential of DXWR-associated bacteria to promote plant growth, among which is the genus Bacillus spp. (Zhang et al 2021) and Enterobacter spp. (Ahmed et al 2021).…”

Analysis of Endophytic Bacterial Diversity in Seeds of Different Genotypes of Cotton and the Suppression of Verticillium Wilt Pathogen Infection by a Synthetic Microbial Community

“…3A, B). Recent studies have reported the enrichment of potentially bene cial endophytic bacteria, such as Paenibacillus and Bacillus [71,72], in some plant seeds. These microbes may preferentially colonize seeds, thus, providing a barrier against pathogens.…”

Endophytic bacteria enhance the growth and salt tolerance of rice under saline conditions

“…Among methods that have been applied to reduce the effect of salination on crop yield, the one using plant growth-promoting bacteria is emerging as an alternative method that could alleviate biotic and abiotic stresses in plants (Vaishnav et al, 2019). There were several studies have been carried out to explore the endophytic bacterial community colonizing the internal tissues of healthy rice plants (Chu et al, 2021;Zhang et al, 2021). An example is endophytic bacteria, strain Fse28, obtained from the surface-sterilized seeds of Dongxiang wild rice presented a significant improvement in the rice seed germination (86 %) compared with the control (70 %) after 5 days of germination (Zhang et al, 2021).…”

“…There were several studies that demonstrated the plant growthpromoting functions of endophytic bacteria isolated from wild rice and trade rice (Chu et al, 2021). For example, the endophytic bacteria isolated from wild rice such as Bacillus, Microbacterium, Pantoea ananatis D1, Herbaspirillum, Ideonella, Enterobacter, and Azospirillum were able to produce IAA, which showed roles in promoting plant growth (Lu et al, 2021;Zhang et al, 2021). These results suggest that endophytic bacteria could be developed into biofertilizers used in organic cultivation to promote the growth and development of plants in normal as well as saline conditions.…”