Benefits to Plant Health and Productivity From Enhancing Plant Microbial Symbionts

Abstract

Plants exist in close association with uncountable numbers of microorganisms around, on, and within them. Some of these endophytically colonize plant roots. The colonization of roots by certain symbiotic strains of plant-associated bacteria and fungi results in these plants performing better than plants whose roots are colonized by only the wild populations of microbes. We consider here crop plants whose roots are inhabited by introduced organisms, referring to them as Enhanced Plant Holobionts (EPHs). EPHs frequently exhibit resistance to specific plant diseases and pests (biotic stresses); resistance to abiotic stresses such as drought, cold, salinity, and flooding; enhanced nutrient acquisition and nutrient use efficiency; increased photosynthetic capability; and enhanced ability to maintain efficient internal cellular functioning. The microbes described here generate effects in part through their production of Symbiont-Associated Molecular Patterns (SAMPs) that interact with receptors in plant cell membranes. Such interaction results in the transduction of systemic signals that cause plant-wide changes in the plants’ gene expression and physiology. EPH effects arise not only from plant-microbe interactions, but also from microbe-microbe interactions like competition, mycoparasitism, and antibiotic production. When root and shoot growth are enhanced as a consequence of these root endophytes, this increases the yield from EPH plants. An additional benefit from growing larger root systems and having greater photosynthetic capability is greater sequestration of atmospheric CO2. This is transferred to roots where sequestered C, through exudation or root decomposition, becomes part of the total soil carbon, which reduces global warming potential in the atmosphere. Forming EPHs requires selection and introduction of appropriate strains of microorganisms, with EPH performance affected also by the delivery and management practices.

Associations of Pantoea with Rice Plants: As Friends or Foes?

“…This highly diverse group of microbes positively influences plant growth and productivity through increasing overall fitness. This may be achieved by conferring abiotic and biotic stress tolerance, enhancing growth, and decreasing water consumption, or fitness may also be increased by enhancing physiological and genetic characteristics [5,6].…”

The Contrivance of Plant Growth Promoting Microbes to Mitigate Climate Change Impact in Agriculture

“…There are a number of articles, some of which have also been discussed in this article, illustrating the benefits of PGPB in boosting plant growth and development under abiotic stress [ 5 , 54 , 67 , 216 ]. The beneficial role of PGPB has already been confirmed by successful experiments in laboratories and under controlled conditions.…”

“…In the natural environment, bacteria may occur freely in bulk soil from where they can be transferred to the rhizosphere, or internal parts of plants as endophytes [ 2 , 3 ]. The phytomicrobiome is a whole, well-structured community of all microorganisms in a given plant, associated with the host [ 2 , 3 , 4 , 5 ]. The rhizosphere, a thin film of soil around the roots, is the primary location of ion uptake for plants, simultaneously depositing nutrients and signaling molecules into this zone [ 6 , 7 ].…”

“…This phenomenon is expected to worsen in the future, and there is a clear need to address this situation. There is a large body of data in the literature on the effects of mitigation of abiotic stress by selected bacteria [ 5 , 21 , 22 , 23 , 24 , 25 ]. In the present review, an attempt is made to study the effects of using beneficial microorganisms, especially bacteria, on plant growth under major abiotic stresses (salinity and drought).…”

Harnessing Trichoderma in Agriculture for Productivity and Sustainability

“…Agroecology has been a prominent way of redesigning food systems to achieve greener agriculture approaches with higher sustainability [12,13]. One important agroecological approach for maximizing root and rhizosphere efficiency is the application of beneficial microbes, including Trichoderma [14,15]. This strategy can lead to improved crop productivity and better nutrient use efficiency while providing a friendlier option for human health and the environment [16,17].…”