Rhizospheric Communication through Mobile Genetic Element Transfers for the Regulation of Microbe–Plant Interactions

Abstract

The transfer of mobile genetic elements (MGEs) has been known as a strategy adopted by organisms for survival and adaptation to the environment. The rhizosphere, where microbes and plants coexist, is a hotspot of MGE transfers. In this review, we discuss the classic mechanisms as well as novel mechanisms of MGE transfers in the rhizosphere. Both intra-kingdom and cross-kingdom MGE transfers will be addressed. MGE transfers could be ancient events which drove evolution or recurrent events which regulate adaptations. Recent findings on MGE transfers between plant and its interacting microbes suggest gene regulations brought forth by such transfers for symbiosis or defense mechanisms. In the natural environment, factors such as temperature and soil composition constantly influence the interactions among different parties in the rhizosphere. In this review, we will also address the effects of various environmental factors on MGE transfers in the rhizosphere. Besides environmental factors, plant root exudates also play a role in the regulation of MGE transfer among microbes in the rhizosphere. The potential use of microbes and plants for bioremediation will be discussed.

Nutrition vs association: plant defenses are altered by arbuscular mycorrhizal fungi association not by nutritional provisioning alone

“…Alternatively, AMF could be directly altering induced defenses by regulating plant gene expression or, possibly, through horizontally transferred genes [27]. Both have been studied in different species, including wheat [28], rice [29], tomato [30], and common beans [31] with relative gene expression of developmental and defensive genes increasing by orders of magnitude in wheat and tomato and horizontal gene transfer often associated with improved resistance against biotic or abiotic stressors [32,33].…”

Drought influences the fungal community structure, diversity, and functionality inhabiting the grapevine xylem and enhances the abundance ofPhaeomoniella chlamydospora

“…Various beneficial and pathogenic microorganisms, including bacteria, fungi, and oomycetes, coexist in the rhizosphere alongside plants. In response to each other’s presence and the ever-changing environment, there is a complex web of communication among all parties involved (Venturi and Keel 2016; Ku et al 2021). Consequently, our study delved into the co-occurrence networks within the xylem microbiome of plants under water deficit and non-stressed conditions, aiming to assess the impact of water deficit on fungal dynamics within the xylem microbiome.…”

Beneficial Soil Microbiomes and Their Potential Role in Plant Growth and Soil Fertility

“…Up to 20% of the bacterial genome is disseminated during horizontal gene transfer events [84]. The rhizosphere is considered to be one of the hotspots of microbial gene transfer whereas the microbiome is a rich reservoir of genetic functionality [85,86].…”

“…The pSym plasmid found in Rhizobium sp., in addition to nodulation and atmospheric nitrogen fixation genes, is involved in phytohormone synthesis and transport of root exudate compounds. This conjugative plasmid is commonly transferred to the soil or rhizosphere community, mainly after sensing certain plant compounds such as flavonoids [86,87]. An approximately 150 kb plasmid was observed in an endophytic plant growth-promoting Enterobacter sp.…”