Bioeffectors as Biotechnological Tools to Boost Plant Innate Immunity: Signal Transduction Pathways Involved

Abstract

The use of beneficial rhizobacteria (bioeffectors) and their derived metabolic elicitors are efficient biotechnological alternatives in plant immune system elicitation. This work aimed to check the ability of 25 bacterial strains isolated from the rhizosphere of Nicotiana glauca, and selected for their biochemical traits from a group of 175, to trigger the innate immune system of Arabidopsis thaliana seedlings against the pathogen Pseudomonas syringae pv. tomato DC3000. The five strains more effective in preventing pathogen infection were used to elucidate signal transduction pathways involved in the plant immune response by studying the differential expression of Salicylic acid and Jasmonic acid/Ethylene pathway marker genes. Some strains stimulated both pathways, while others stimulated either one or the other. The metabolic elicitors of two strains, chosen for the differential expression results of the genes studied, were extracted using n-hexane, ethyl acetate, and n-butanol, and their capacity to mimic bacterial effect to trigger the plant immune system was studied. N-hexane and ethyl acetate were the most effective fractions against the pathogen in both strains, achieving similar protection rates although gene expression responses were different from that obtained by the bacteria. These results open an amount of biotechnological possibilities to develop biological products for agriculture.

Pseudomonas palmensis sp. nov., a Novel Bacterium Isolated From Nicotiana glauca Microbiome: Draft Genome Analysis and Biological Potential for Agriculture

“…The biological assay in the intensive olive orchard was conducted aiming to demonstrate the ability of the strain to improve plant adaptation to stress situations, especially the lack of water, as this situation becomes more and more frequent nowadays. The mechanisms involved in plant adaptation to stress are common to many other stressful situations such as salinity or biotic stress, through common signaling pathways ( Martin-Rivilla et al, 2020 ). Plant adaptive mechanisms involve ionic homeostasis and modulation of redox balance among others ( Kangasjärvi et al, 2014 ; Kollist et al, 2019 ).…”

Tomato Bio-Protection Induced by Pseudomonas fluorescens N21.4 Involves ROS Scavenging Enzymes and PRs, without Compromising Plant Growth

“…Further studies have defined the priming phase as the period between the triggering stimuli and challenge, involving ROS changes together with undetectable genetic reprogramming, and the post-challenged priming state where protection is associated with synthesis of phytoalexins or defensive molecules [ 7 , 8 ]. Furthermore, although ROS generation is one of the earliest responses of plant to pathogen, as it is involved in the signaling pathways of defense reactions [ 9 ], ISR is also mediated by alteration of the redox status of cells, as it is involved in signal transduction [ 10 , 11 , 12 ].…”

“…Its capacity to trigger plant growth and protection against leaf pathogens in Arabidopsis thaliana , tomato and soybean has been shown [ 21 , 22 , 23 ], as well as its ability to trigger secondary metabolism in soybean and blackberry [ 24 , 25 ]. Furthermore, isolation of putative metabolites responsible to trigger a physiological response have been identified [ 26 ] and the metabolic pathway involved in the defensive response has been envisaged [ 12 ]. However, the metabolic events underlying the systemic response in terms of ISR and antioxidant metabolism have not been studied in detail.…”

Bioenergy Underground: Challenges and opportunities for phenotyping roots and the microbiome for sustainable bioenergy crop production

“…Plants mediate and drive belowground biological interactions and activities in the rhizosphere through root exudation (Inderjit et al., 2003). These exudates, along with other rhizodeposits, stimulate microbial activity and help drive synergistic activities of diverse and functional groups of soil microbes, including N‐fixing bacteria, P‐solubilizing siderophore‐producing microbes, as well as arbuscular mycorrhizal fungi and ectomycorrhizal (ECM) fungi, which help promote plant growth and resilience through provisioning plant nutrition and by priming plant immunity (Li et al., 2020; Martin‐Rivilla et al., 2020; Wang & Feng, 2021; Jiang et al., 2021).…”