Potentials, Utilization, and Bioengineering of Plant Growth-Promoting Methylobacterium for Sustainable Agriculture

Abstract

Plant growth-promoting bacteria (PGPB) have great potential to provide economical and sustainable solutions to current agricultural challenges. The Methylobacteria which are frequently present in the phyllosphere can promote plant growth and development. The Methylobacterium genus is composed mostly of pink-pigmented facultative methylotrophic bacteria, utilizing organic one-carbon compounds as the sole carbon and energy source for growth. Methylobacterium spp. have been isolated from diverse environments, especially from the surface of plants, because they can oxidize and assimilate methanol released by plant leaves as a byproduct of pectin formation during cell wall synthesis. Members of the Methylobacterium genus are good candidates as PGPB due to their positive impact on plant health and growth; they provide nutrients to plants, modulate phytohormone levels, and protect plants against pathogens. In this paper, interactions between Methylobacterium spp. and plants and how the bacteria promote crop growth is reviewed. Moreover, the following examples of how to engineer microbiomes of plants using plant-growth-promoting Methylobacterium are discussed in the present review: introducing external Methylobacterium spp. to plants, introducing functional genes or clusters to resident Methylobacterium spp. of crops, and enhancing the abilities of Methylobacterium spp. to promote plant growth by random mutation, acclimation, and engineering.

Underneath the Purple Stain

“…Methylobacterium spp. has, however, appeared in similar studies [10], and the newly attributed genus Methylorubrum, to which some of the species of Methylobacterium have migrated [31,32], deserves further attention. The vast majority of species in both these genera are pink-pigmented, and the pigment is of carotenoid origin [32].…”

“…has, however, appeared in similar studies [10], and the newly attributed genus Methylorubrum, to which some of the species of Methylobacterium have migrated [31,32], deserves further attention. The vast majority of species in both these genera are pink-pigmented, and the pigment is of carotenoid origin [32]. Some of them are inhibited by the presence of NaCl when above 2%, which may mean that these would only thrive in areas where the salt concentration was lower, probably the more superficial ones.…”

Biochar Amendment in Combination with Endophytic Bacteria Stimulates Photosynthetic Activity and Antioxidant Enzymes to Improve Soybean Yield Under Drought Stress

“…Our results are in conformity with the report of Mahajan et al (2005) who showed that the plants treated with microbes had lower antioxidant enzyme levels than plants without microbes, indicating an increased reactive oxygen species scavenging potential of microbes under dry circumstances. Previously, the positive impact of biochar (Zhang et al 2021) and microbial inoculation (Batool et al 2021) on antioxidant enzyme activities under water deficit conditions has been reported. Reduction in water stress by microbes can be due to their close association with the roots of plants thus making the favorable conditions for plant roots for up taking maximum moisture from soil so that plant maintains its ROS equilibrium for better growth and development.…”

Auxin production in the green alga Chlamydomonas involves an extracellular L-amino acid oxidase and supports algal-bacterial mutualism with methylobacteria

“…In prior work, we found that the model alga Chlamydomonas reinhardtii (Salomé and Merchant, 2019), and plant growth-promoting bacteria (PGPB) in the genus Methylobacterium (Zhang et al, 2021) can form a mutualism based on a carbon (C) and nitrogen (N) nutrient exchange (Calatrava et al, 2018). This beneficial interaction between Chlamydomonas and Methylobacterium can be harnessed to improve wastewater bioremediation, biomass generation and hydrogen production (Torres et al, 2022).…”