Endophytic Bacteria: Hidden Protective Associates of Plants against Biotic and Abiotic Stresses

Abstract

An endophyte is a microorganism, usually bacterium or fungus, which lives within the internal tissue of a host plant, causing no apparent harm. Some characteristics of an endophyte include ability to promote plant growth and to confer plant tolerance to biotic and abiotic stresses. Endophytic bacteria spread across many phyla including the Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. Endophytic bacteria are recruited by hosts and they get attached to the surface and eventually find their way into the internal tissues where they spread to the intercellular spaces of host plants. These bacteria have been isolated and characterized from different plants. Currently, culture-independent methods such as sequencing of the 16S rRNA gene or metalogenomics are used for identification and characterization of endophytes. The mechanisms by which the endophyte-induced plant protection is brought about can be through direct and/or indirect methods. The direct strategy antagonizes phytopathogens by the production of chemical substances while the indirect mechanisms improve resistance of hosts to pathogens. Global gene expression studies on some common endophytic bacteria implicated these direct and indirect strategies of bacterial-induced protection. More research should be geared towards how the economic importance of endophytic bacteria could be utilized to enhance global food security.

The Expression of Selected Drought Responsive Genes of Maize Is Influenced by Endophytic Bacterial Inoculation

“…Generally, some of the rhizosphereic and phyllospheric bacteria eventually infect the plant, colonize the internal tissue become endophytic. Some of these endophytes find their route towards seeds and establish their as seed endophytes that may be transmitted vertically to the daughter plant after germination (Okungbowa et al, 2019). Plants secrete chemo-attractants through root exudates, which facilitating plant-microbe cross talk thus influencing endophytic colonization (Kawasaki et al, 2016).…”

Wheat quality: A review on chemical composition, nutritional attributes, grain anatomy, types, classification, and function of seed storage proteins in bread making quality

“…Tools in tissue culture techniques, like micropropagation, gametic embryogenesis (103, 109), somatic embryogenesis, cell suspension, and protoplast fusion facilitate the fast, large scale-cloning of highvalue plants to produce pure lines (109). Apart from plant breeding technologies, some abiotic factors can be reversed through environmental management practices and developing microbe linkage to plants to biologically control pathogens (110,111). Diethyl aminoethyl hexanoate application is found to increase plant tolerance to abiotic stress, such as cold (112) and salt stress, (113) whereas applying proline amino acid during plant adaptation increases tolerance to salinity stress (114).…”

Current challenges in plant breeding to achieve zero hunger and overcome biotic and abiotic stresses induced by the global climate changes: A review

“…Not all abiotic factors can be reversed by plant breeding technologies. Some abiotic factors can be reduced by applying modern cultivation technologies like environmental management practices and link microbes to plants is it possible to promote biocontrol against pathogens [41,42]. Also, the application of applying diethyl aminoethyl hexanoate, will increase plant resistance to abiotic stress, like cold [43,44] and salinity resistance [45].…”

“…Another way to increase resistance is by using microbial biotechnology to enhance plant nutrition and/or promote biocontrol against pathogens [41,42], applying diethyl aminoethyl hexanoate to achieve resistance to abiotic stress [43][44][45], and use the prolineto increase salt tolerance [46] and low water condition [47].…”