Protection of Pepper Plants from Drought by Microbacterium sp. 3J1 by Modulation of the Plant's Glutamine and α-ketoglutarate Content: A Comparative Metabolomics Approach

Abstract

Drought tolerance of plants such as tomato or pepper can be improved by their inoculation with rhizobacteria such as Microbacterium sp. 3J1. This interaction depends on the production of trehalose by the microorganisms that in turn modulate the phyto-hormone profile of the plant. In this work we describe the characterization of metabolic changes during the interaction of pepper plants with Microbacterium sp. 3J1 and of the microorganism alone over a period of drought. Our main findings include the observation that the plant responds to the presence of the microorganism by changing the C and N metabolism based on its glutamine and α-ketoglutarate content, these changes contribute to major changes in the concentration of molecules involved in the balance of the osmotic pressure. These include sugars and amino-acids; the concentration of antioxidant molecules, of metabolites involved in the production of phytohormones like ethylene, and of substrates used for lignin production such as ferulic and sinapic acids. Most of the altered metabolites of the plant when inoculated with Microbacterium sp. 3J1 in response to drought coincided with the profile of altered metabolites in the microorganism alone when subjected to drought, pointing to a response by which the plant relies on the microbe for the production of such metabolites. To our knowledge this is the first comparative study of the microbe colonized-plant and microbe alone metabolomes under drought stress.

Microbial Endophytes that Live within the Seeds of Two Tomato Hybrids Cultivated in Argentina

“…In this work, we also found that Micrococcus and Microbacterium, E4 and SE31 respectively, promoted the root and shoot growth of tomato plants. Vílchez et al [58] showed that in pepper plants Microbacterium sp. promoted an increase in sugar biosynthesis that probably provided the plants with a more efficient osmotic adjustment, relieving in this way the effect of stress on the host plants.…”

“…Also, Microbacterium sp. protects plants against drought stress while living within them [58]. The plant growth promotion and protection effects of Bacillus and Paenibacillus are the result of several complex and interrelated processes that involve direct and indirect mechanisms such as nitrogen fixation, phosphate solubilization, siderophore and phytohormone production and the control of plant diseases [59][60][61].…”

Microbial Endophytes That Live within Seeds of Two Tomato Hybrid Cultivated in Argentina

“…In this work, we also found that Micrococcus and Microbacterium, E4 and SE31 respectively, promoted root and shoot growth of tomato plants. Vílchez et al [58] showed that in pepper plants Microbacterium sp. promoted an increase in sugar biosynthesis that provided plants with a more efficient osmotic adjustment relieving in this way plants from the effect of stress on the host plants.…”

“…Also Microbacterium sp. protects plants against drought stress while living within plants [58]. The plant growth promotion and protection effect of Bacillus and Paenibacillus is the result of several complex and interrelated processes that involve direct and indirect mechanisms such as nitrogen fixation, phosphate solubilization, siderophore production, phytohormone production and control of plant diseases [59][60][61].…”

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“…9 patentes, gracias a las cuales queda protegido también el uso de estos microorganismos anhidrobiontes para la defensa contra la sequía de cultivos de plantas como el pimiento (Vílchez et al, 2016a). Entre estos xeroprotectores, hay ácidos nucleicos y moléculas que modifican el metabolismo de la planta (Vílchez et al, 2018). Además, el grupo se ha convertido en un referente en ensayos de bioseguridad para determinar el grado de virulencia de los microorganismos que se vayan a liberar al medio ambiente (Vílchez et al, 2016b).…”