Methylobacterium Species Promoting Rice and Barley Growth and Interaction Specificity Revealed with Whole-Cell Matrix-Assisted Laser Desorption / Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF/MS) Analysis

Abstract

Methylobacterium species frequently inhabit plant surfaces and are able to utilize the methanol emitted from plants as carbon and energy sources. As some of the Methylobacterium species are known to promote plant growth, significant attention has been paid to the mechanism of growth promotion and the specificity of plant–microbe interactions. By screening our Methylobacterium isolate collection for the high growth promotion effect in vitro, we selected some candidates for field and pot growth tests for rice and barley, respectively. We found that inoculation resulted in better ripening of rice seeds, and increased the size of barley grains but not the total yield. In addition, using whole-cell matrix-assister laser desorption/ionization- time-of-flight mass spectrometry (MALDI-TOF/MS) analysis, we identified and classified Methylobacterium isolates from Methylobacterium-inoculated rice plants. The inoculated species could not be recovered from the rice plants, and in some cases, the Methylobacterium community structure was affected by the inoculation, but not with predomination of the inoculated species. The isolates from non-inoculated barley of various cultivars grown in the same field fell into just two species. These results suggest that there is a strong selection pressure at the species level of Methylobacterium residing on a given plant species, and that selection of appropriate species that can persist on the plant is important to achieve growth promotion.

High-throughput sequencing-based analysis of the composition and diversity of endophytic bacterial community in seeds of upland rice

“…At the same time, research shows that secondary metabolites produced by some species of Microbacterium have a significant inhibitory effect on some pathogenic bacteria of the host plant (Lopes et al 2015;Mannaa et al 2017;Savi et al 2018). Researchers often isolate Methylobacterium from plants such as rice, barley, and legumes (Liu et al2019;Chen et al 2019;Tani et al 2015;Andrews and Andrews 2017).…”

Bacterial Population in Intestines of Litopenaeus vannamei Fed Different Probiotics or Probiotic Supernatant

“…Paracoccus species were significantly reduced in group N compared with the control, which may confirm indirectly that NRW-2 competes more strongly with Paracoccus than HC-2, indicating that NRW-2 and Paracoccus share the same or similar adhesive sites in the shrimp intestine. Polymorphum gilvum and Methylobacterium species are also reported to have oil-degrading and cypermethrin-degrading capacities [7,27], respectively, and Methylobacterium species have been shown to promote the growth of rice and barley [32], so these species may also exert probiotic effects in L. vannamei. In all the treatment groups, only the HC-2 bacteria-free supernatant significantly increased the richness of Actinobacteria and Fibrobacteres compared with the control group, although this varied in the individuals of group S, and contributed to the reduction of some other species, such as Maribius salinus, Haloferula phyci, Phaeobacter gallaeciensis, and Octadecabacter sp.…”

Hansschlegelia quercus sp. nov., a novel methylotrophic bacterium isolated from oak buds

“…(natural products of plant metabolism) as carbon and energy sources and supply various bioactive compounds to the plants (phytohormones, vitamins, etc.) [30][31][32].…”