Using plant growth-promoting microorganisms (PGPMs) to improve plant development under in vitro culture conditions

Abstract

Plant in vitro culture techniques are highly useful to obtain significant amounts of true-to-type and disease-free plant materials. One of these techniques is clonal micropropagation which consists on the establishment of shoot tip cultures, shoot multiplication, in vitro rooting and acclimatization to ex vitro conditions. However, in some cases, the existence of recalcitrant genotypes, with a compromised multiplication and rooting ability, or the difficulties to overcome the overgrowth of endophytic contaminations might seriously limit its efficiency. In this sense, the establishment of beneficial interactions between plants and plant growth-promoting microorganisms (PGPMs) under in vitro culture conditions might represent a valuable approach to efficiently solve those restrictions. During the last years, significant evidence reporting the use of beneficial microorganisms to improve the yield of in vitro multiplication or rooting as well as their acclimatization to greenhouse or soil conditions have been provided. Most of these positive effects are strongly linked to the ability of these microorganisms to provide in vitro plants with nutrients such as nitrogen or phosphorous, to produce plant growth regulators, to control the growth of pathogens or to mitigate stress conditions. The culture of A. thaliana under aseptic conditions has provided high-quality knowledge on the root development signalling pathways, involving hormones, triggered in the presence of PGPMs. Overall, the present article offers a brief overview of the use of microorganisms to improve in vitro plant performance during the in vitro micropropagation stages, as well as the main mechanisms of plant growth promotion associated to these microorganisms. Main conclusion:The use of beneficial microorganisms improves the performance of in vitro cultured plants through the improvement of plant nutrition, the biological control of microbial pathogens or the production of phytohormones that promote plant growth and development.

Effect of Plant Preservative MixtureTM on Endophytic Bacteria Eradication from In Vitro-Grown Apple Shoots

“…In addition to the antifungal traits, they also found that B. megaterium had strong tolerance to abiotic stress both in vitro and in planta [ 82 ]. Several studies have shown that endophytes are common in tissue culture and demonstrated their beneficial effects as plant growth-promoting agents [ 13 , 23 , 26 , 27 , 28 , 83 , 84 , 85 , 86 ]. Interestingly, working on apple plants grown in vitro, Tamošiūnė et al [ 87 ] noted contrasting effects of bacterization with endophytic bacteria strains of Bacillus and Pseudomonas spp.…”

“…The most frequently found genera of bacterial endophytes are Pantoea , Curtobacterium , Bacillus, Corynebacterium, Mycobacterium , Rhodopseudomonas , Pseudomonas , and Microbacterium [ 23 , 24 , 25 ]. Although usually treated as contaminants, there are examples in which endophytic bacteria appear to have a beneficial effect when introduced within tissue culture systems, increasing multiplication and rooting rates as well as improving the effectiveness of in vitro micropropagation [ 13 , 23 , 26 , 27 , 28 ].…”

Rhizobacteria Increase the Adaptation Potential of Potato Microclones under Aeroponic Conditions

“…Despite the fact that A. baldaniorum Sp245 is not a native species for potato and has been isolated from wheat [ 19 ], the plant-growth-promoting activity of Azosprillum , including this strain, is well known for various plant species, including potato [ 4 , 46 ]. O. cytisi IPA7.2 was isolated from the roots of the potato cultivar Nevsky [ 5 ], and from the experimental data it can be seen that in vitro there are a greater number of cells of this strain in plants.…”

The potential of biostimulants on soil microbial community: a review

“…Some studies have revealed the introduction of a high content of ABA in crop plants planted under stress conditions (Ayaz et al, 2022). On the contrary, some studies have shown improvement in ABA concentration of crop plants planted under stress conditions and propagated with PGPRs and AMFs (Cantabella et al, 2022;Paravar et al, 2023). Under stress conditions, the tomato plants inoculated with the ABA biosynthetic gene 9-cis-epoxy carotenoid dioxygenase (SlNCED) in AMF stress conditions showed that ABA control can be controlled by the forms of stress.…”

“…The efficacy of a biostimulant made up of both bacteria assisting plants and AMFs was observed in various plants, contributing to their growth characteristics. Improvement is obtained in the plant via microbial multiplication, and the production of abundant crops follows as a result of PGPR and AMF introduction, unlike uninoculated plants or plants introduced with only a PGPR or AMF strain alone (Cantabella et al, 2022). Moreover, the research investigating wheat plants by showed an absolute improvement of particular gluten protein fractions included in dough intensity and its elastic nature.…”