Trends in Harnessing Plant Endophytic Microbiome for Heavy Metal Mitigation in Plants: A Perspective

Abstract

Plant microbiomes represent dynamic entities, influenced by the environmental stimuli and stresses in the surrounding conditions. Studies have suggested the benefits of commensal microbes in improving the overall fitness of plants, besides beneficial effects on plant adaptability and survival in challenging environmental conditions. The concept of ‘Defense biome’ has been proposed to include the plant-associated microbes that increase in response to plant stress and which need to be further explored for their role in plant fitness. Plant-associated endophytes are the emerging candidates, playing a pivotal role in plant growth, adaptability to challenging environmental conditions, and productivity, as well as showing tolerance to biotic and abiotic stresses. In this article, efforts have been made to discuss and understand the implications of stress-induced changes in plant endophytic microbiome, providing key insights into the effects of heavy metals on plant endophytic dynamics and how these beneficial microbes provide a prospective solution in the tolerance and mitigation of heavy metal in contaminated sites.

Plant-Microbe Interactions under the Extreme Habitats and Their Potential Applications

“…Endophytes constitute bacterial or fungal microorganisms, inhabiting inter/intracellular spaces within plant tissues, and present in almost all plant species. Since plants restrict the growth of endophytes, endophytes evolve mechanisms for adaptation to the environment [ 69 , 70 ], including the production of metabolites for plant growth and development [ 9 , 10 , 11 ]. Endophytes have been isolated from different plant parts namely meristem, leaves [ 71 ], seeds [ 72 ], roots [ 38 ], and stem, among other tissues.…”

“…The plant and the microbial counterpart impact each other, microbes confer tolerance to plants and improve fitness against environmental stresses while in turn, plants can modulate microbial dynamics, enhancing positive interactions [ 9 ]. In addition, the associated microbial communities influence plant response to fluctuating climatic conditions: some key interactions that alter plants’ phenotypic plasticity comprise nitrogen fixation symbiosis, PGPRs, mycorrhizal associations, and fungal endophytes, among others promote plant adaptability and defense response in challenging conditions [ 8 , 76 ].…”

“…), antibiotics, and anti-freezing substances of industrial importance [ 141 ]. The microbes contribute to plant growth by several mechanisms either by mineral solubilization (K, Zn, P), nitrogen fixation, siderophores production, phytohormone production, or by conferring tolerance to plant pathogens [ 9 ].…”

“…Moreover, these microbes may thrive in extreme conditions such as hypersalinity (2–5 M NaCl, designated as halophiles), high and low temperatures (60–115 °C—known as thermophiles), (−2–20 °C—designated as psychrophiles) and diverse pH range (<4 acidophiles and >9 alkaliphiles), respectively [ 8 ]. The beneficial microbes associated with plants are classified as rhizospheric, epiphytic, or endophytic and demonstrate multi-faceted attributes from ecological and biotechnological perspectives [ 9 , 10 ].…”

Glutamic-N,N-Diacetic Acid as an Innovative Chelating Agent in Microfertilizer Development: Biodegradability, Lettuce Growth Promotion, and Impact on Endospheric Bacterial Communities

“…The physiological intricacies of plantmicrobiome interactions underscore the importance of understanding the complex structure of microbial communities associated with plants [12]. Endophytic microbiomes, a pivotal component influencing plant health, engage in mutualistic relationships with plants, directly impacting the production of phytohormones, antibiotics, and mineral nutrient absorption, thereby fostering plant growth and development [13].…”