Beneficial Microorganisms as a Sustainable Alternative for Mitigating Biotic Stresses in Crops

Abstract

Nowadays, population growth, the global temperature increase, and the appearance of emerging diseases in important crops generate uncertainty regarding world food security. The use of agrochemicals has been the “go-to” solution for the control of phytopathogenic microorganisms, such as Magnaporte oryzae, causing blast disease in rice and other cereals; Botrytis cinerea, causing gray mold in over 500 plant species; and Puccinia spp., causing rust in cereals. However, their excessive use has harmed human health, as well as ecosystems (contaminating water, and contributing to soil degradation); besides, phytopathogens can develop resistance to them. The inoculation of plant growth-promoting microorganisms (PGPMs) to crops is a sustainable strategy for increasing the yield and quality of crops and mitigating biotic stresses. Likewise, PGPMs, such as Pseudomonas, Bacillus, and Trichoderma, can trigger a series of signals and reactions in the plant that lead to the induction of systemic resistance, a mechanism by which plants react to microorganism stimulation by activating their defense system, resulting in protection against future pathogen attack. These plant defense mechanisms help to mitigate biotic stresses that threaten global food security. Thus, the study of these mechanisms at molecular, transcriptomic, and metabolomic levels is indispensable to elucidate how stresses affect globally important crops.

Bacillus cabrialesii: Five Years of Research on a Novel Species of Biological Control and Plant Growth-Promoting Bacteria

“…On the other hand, it is known that PGPM and BCA can trigger the systemic resistance of plants, priming them before the arrival of pathogens [37,38]. The plant defense system related to the interaction with PGPM and BCA is complex and is mainly activated by microorganism-associated molecular patterns (MAMPs), which can be protein fragments essential for microorganisms, such as flagellins in bacteria or β-glucans in fungi, or metabolites produced by the microorganism [5]. In this sense, the induction of systemic resistance in wheat plants by the metabolites produced by B. cabrialesii subsp.…”

“…For example, climate change can interfere with plant physiology (transpiration, respiration, photosynthesis, and growth rates). Thus, the plants enter into a state of stress leading to a significant loss in crop yield; it is stated that biotic and abiotic stresses cause approximately 50-82% losses of crop productivity [4][5][6]. In addition, these consequences of climate change can lead to the emergence of strong, more infective pests and diseases, causing between 20 and 40% losses in agricultural production [2,4].…”

“…In this context, the development of innovative agricultural practices is needed to satisfy the sustainability of global food demand. Beneficial microorganisms, especially plant growth-promoting microorganisms (PGPM), play an essential role in maintaining functional and healthy agroecosystems [5,10]. These PGPM can enhance the acquisition of nutrients by plants, mitigate plant stress, and provide protection against pests and diseases through different mechanisms, improving crop yield and quality [4].…”

The Mitigation of Phytopathogens in Wheat under Current and Future Climate Change Scenarios: Next-Generation Microbial Inoculants

“…For example: Paenibacillus xylanexedens, Bacillus spp., Azotobacter spp., Streptomyces spp., Ochrobacttrum intermedium, Paenibacillus lentimorbus, Trichoderma spp., Pseudomonas spp., Pythium oligandrum, Bacillus velezensis, Bacillusamyloliquefaciens, Priestia sp. TSO9 [87][88][89][138][139][140]. Nevertheless, only a few species are registered as commercial biofungicides for their use in the control of wheat diseases.…”

Heavy Metal Stress Management through Phytoremediation to Mitigate Climate Change Impacts: An Overview

“…Abiotic stress is imposed on plants by either physical or chemical factors of the environment [3], while biotic stress exposed to the plants are biological entities like weeds, pathogens, insects, pests, etc. [4,5]. Despite all other stresses, heavy metal stress is of great importance and has notable adverse effects on plant growth and productivity [6].…”