Endophytic Paenibacillus polymyxa LMG27872 inhibits Meloidogyne incognita parasitism, promoting tomato growth through a dose-dependent effect

Abstract

The root-knot nematode, Meloidogyne incognita, is a major pest in tomato production. Paenibacillus polymyxa, which is primarily found in soil and colonizing roots, is considered a successful biocontrol organism against many pathogens. To evaluate the biocontrol capacity of P. polymyxa LMG27872 against M. incognita in tomato, experiments were conducted both in vitro and in vivo. A dose-response effect [30, 50, and 100% (108 CFU/mL)] of bacterial suspensions (BSs) on growth and tomato susceptibility to M. incognita with soil drenching as a mode of application was first evaluated. The results show that the biological efficacy of P. polymyxa LMG27872 against M. incognita parasitism in tomato was dose-dependent. A significantly reduced number of galls, egg-laying females (ELF), and second-stage juveniles (J2) were observed in BS-treated plants, in a dose-dependent manner. The effect of P. polymyxa on tomato growth was also dose-dependent. A high dose of BSs had a negative effect on growth; however, this negative effect was not observed when the BS-treated plants were challenged with M. incognita, indicating tolerance or a defense priming mechanism. In subsequent in vivo experiments, the direct effect of BSs was evaluated on J2 mortality and egg hatching of M. incognita. The effect of BS on J2 mortality was observed from 12 to 24 h, whereby M. incognita J2 was significantly inhibited by the BS treatment. The effect of P. polymyxa on M. incognita egg hatching was also dependent on the BS dose. The results show a potential of P. polymyxa LMG27872 to protect plants from nematode parasitism and its implementation in integrated nematode management suitable for organic productions.

Impacting of Root-Knot Nematodes on Tomato: Current Status and Potential Horizons for Its Managing

“…in tomato [57] and plant growth-promoting rhizobacteria (PGPR) as well [58]. One of the most important PGPR is strain LMG27872 of Paenibacillus polymyxa that increasing the percentage of J2 mortality and reducing number of galls and egg hatching of M. incognita in tomato [59]. Similarly, the same effect detected by two bacterial isolates ZHA296 and ZHA178 of Paenibacillus castaneae [60].…”

Evaluation of Tunisian wheat endophytes as plant growth promoting bacteria and biological control agents against Fusarium culmorum

“…Interestingly, all these species have been reported as plant growth-promoting agents for wheat and/or other plant species, such as fenugreek (Achromobacter sp. ), lily (B. halotolerans), chickpea (B. subtilis), bean (Enterobacter hormaechei), grapevine (Paenibacillus peoriae), tomato (Paenibacillus polymyxa), pepper (Pseudomonas Frederiksbergensis), and alfalfa (Variovorax paradoxus) [65][66][67][68][69][70][71][72].…”

An updated view of bacterial endophytes as antimicrobial agents against plant and human pathogens

“… Rice, tomato Reduce salinity stress, produce IAA and gibberellins thus promoting plant growth, tackle environmental contaminations, produce phytohormones such as gellan gum and sphingan Kandel et al, 2015 ; Khan et al, 2017 ; Asaf et al, 2020 Curtobacterium sp., Hybrid poplar, sugarcane, grapevines, soybean, maize, sorghum, black pepper Tackle plant salinity stress, phosphate solubilization, siderophores, growth promotion (IAA), stress relief, produce chitinase that helps in resistance of diseases, nitrogen fixation Senthilkumar et al, 2007 ; Khan et al, 2016 ; Dimkić et al, 2021 ; Acinetobacter calcoaceticas Douglas-fir, Lemna aoukikusa , Augmentation of phytoremediation of polluted soil, antagonistic activity, plant growth stimulation Suzuki et al, 2014 ; Khan et al, 2015 ; Chen et al, 2015 ; Paentbacillus spp. Ryegrass, Quercus robur Nitrogen fixation, procurement of iron in the soil, improved solubilization of phosphate, stimulation of plant development, and biocontrol agent against several diseases Castanheira et al, 2017 ; Daud et al, 2019 ; Vaitiekūnaitė et al, 2021 ; Singh and Wesemael, 2022

Fig. 1 Overview of bacterial endophytes in plants and the benefits.

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