Decoding the mojo of plant-growth-promoting microbiomes
Introduction
The Food and Agriculture Organization of the United Nations (FAO) has recently estimated the world's population to reach 10 billion by 2050 [1]. The potential consequences of this may affect the food prices, as the population is expected to grow by 34% over the next three decades. On the other hand, agriculture production is not expected to rise at this pace. Henceforth, there is a dire need to increase agricultural productivity to balance the socio-economic disturbances that may arise due to the population boom [2]. Moreover, the high population explosion is recorded in the developing countries with less per capita income like India, Pakistan, Bangladesh, and China, while in the developed countries, the rise in population is steady but sluggish (U.S, countries of Europe and Japan). Since developed countries consume more protein and meat, it would be essential to produce twice as much food [3]. The possible solution to satisfy increasing agricultural demands will be the use of transgenic crops, improved fertilizers, increasing soil fertility, minimizing disease and seed infections [4]. Many of the mentioned solutions have inherent limitations that are difficult to overcome. Transgenic crops in various countries are banned due to ethical concerns. Likewise, all artificial inventions can deliver positive and negative effects. Biotic and abiotic factors are a major concern that decline global agronomic productivity. Reducing fertile land availability and human population expansion are the two crucial intimidation for agronomic sustainability [5].
The fundamental cause for a major decline in crop yield globally is environmental stress. Abiotic stress like high winds, drought, extreme temperatures, soil salinity, solidification, pH, and acid rain affect the yield and tillage of agronomic plants. Soil salinity and soil solidification are the most devastating environmental stress, which causes major reductions in agriculture land area, plant yield, and panegyric [6]. It is estimated that 50% of arable land will be salinized due to abiotic cause by 2050 [5].
Plants can overcome abundant environmental compression and hostile conditions. They react to these adverse situations through many morphological, biochemical, and molecular mechanisms and interaction among their respective signalling pathways [7]. Phyto-pathogens, pests, parasites, fungi, bacteria, nematodes, and viruses are the pathogens primarily responsible for the plant diseases [8]. In arable land, the constant exposure of the plants to biotic stress leads to changes in plants anabolic and catabolic processes, which eventually results in yield loss and physiological disruption. In such a scenario, a sustainable and effective biotechnological technique that induces interaction between plant root exudates and soil microflora is needed to increase crop productivity and enhance soil health [9]. Epiphytes, endocellular and exocellular microorganisms colonize plants in their natural environment. Microorganisms of the rhizosphere and rhizoplane, especially beneficial bacteria, and fungi, may boost plant response in a stressful environment and improve productivity [10]. Ambient environments, soil characteristics, and microbial composition may have an effect on the rhizospheric microbiota [11].
The plant microbiome refers to the diverse range of beneficial microorganisms associated with plants [12]. In this context, plants can be viewed as superorganisms that rely on their microbiome for specific functions and traits. However, we have limited knowledge about plant-associated microbiome and their effect on crop productivity, growth, health and disease [13]. Plants can exploit the rhizospheric microbiome according to their benefit by selectively inducing microorganisms with the traits that aid development and survival [14]. Whether plants produced secondary metabolites as exudates to ‘cry for help’ or are not ‘just crying’ remains to be addressed [15].
Section snippets
Microbiome
Soil fertility, plant health, growth, production, carbon sequestration, and phytoremediation are all aided by the microbiome colonizing the soil and the plant's surface [16]. Numerous experimental studies suggested that the plant and genotypes of the same crop reports minimal variation in plant microbiome [17]. Interaction among plant-soil microbiome is complex. Recent studies have focused on the pathogenicity of microbial agents like biofertilizer and bioaugmentor, as well as how they use and
Plant growth promotion by microbiome
Abundant microorganisms present in the soil environment. The preliminary focus is given to the rhizospheric microorganisms. The rhizosphere is derived from the Greek word “rhiza”, meaning root. The word rhizosphere is coined by Hiltner. The rhizosphere is the region that connects the plant root, tiny hair, root surrounding soil area, and numerous microbial communities. It is a zone of intensive microbial development following nutrient concentrations in which important macro-micronutrients and
Genetic base of plant-growth-promoting traits
Numbers of Plant-Growth-Promoting rhizobacteria and fungi showing plant helpful properties, genome interpretation showed several genes contributing to plant beneficial functions including nitrogen fixation, phosphate solubilization, siderophore production phytohormones production and induced systemic resistance. According to Ref. [91] analyzed and identified the effect of 23 genes involved in direct and indirect PGPR mechanisms, based on genome sequence identification of 304 different group of
Commercialization of PGPR and PGPF
Preparation of bioformulation should be cautious with microbes because certain variables such as, ageing, price, use, ease in purchase, marketing, compatibility for agronomic use are responsible for damaging their potential. In addition to this, toxigenicity, pathogenicity, allergic nature, sustainability in any environmental condition and gene transfer process should be taken into consideration. Interestingly, the use of rhizobacteria to produce bacterial bioformulation is dependent on the
Conclusion and future prospective
Plant microbiome and their interaction are exceptionally diverse and there are numerous factors that impart its effect on plant health. Scientific evidence emphasizes the significance of the rhizospheric microbiota, such as plant growth-promoting bacteria and fungi, which is beneficial for plant development and yield. According to our knowledge, if we apply bio-formulation and biofertilizer in good proportion, it may help to reduce the loss in crop production and enable pest-free crops with no
Author's contributions
RM and DG contribute to the conception and design of the manuscript. RM and KM compiled the literature and wrote the manuscript. DG and MS reviewed the manuscript.
Funding
We are also thankful for UGC-BSR Research Start-Up-Grant No. F.30-521/2020(BSR) for providing funding.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We acknowledge the support provided by Department of Microbiology and Biotechnology, School of Sciences, Gujarat University, DST- FIST sponsored department for providing necessary facilities and research support.
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2023, Chemical Engineering JournalCitation Excerpt :In the batch reactors, the dominant phyla in the control set were Proteobacteria and Bacteroidetes (Fig. 6a). The plant growth-promoting rhizospheric (PGPR) microbial community consists of four major phyla: Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes [47]; therefore, the abundance of these phyla indicates that the microbial community is mainly composed of PGPRs, which play a dual role in plant growth promotion and bioremediation [48]. An increase in the abundance of Proteobacteria and Firmicutes was observed with increasing concentrations of BPS (Fig. 6a).