Do volatile compounds produced by Fusarium oxysporum and Verticillium dahliae affect stress tolerance in plants?

Abstract

Volatile compounds (VCs) produced by diverse microbes seem to affect plant growth, development and/or stress tolerance. We investigated how VCs released by soilborne fungi Fusarium oxysporum and Verticillium dahliae affect Arabidopsis thaliana responses to abiotic and biotic stresses. Under salt stress, VCs from both fungi helped its growth and increased chlorophyll content. However, in contrast to wild-type A. thaliana (Col-0), V. dahliae VCs failed to increase leaf surface area in auxin signalling mutants aux1-7, tir1-1 and axr1-3. Compared to wild-type Col-0, the degree of lateral root density enhanced by V. dahliae VCs in these mutants was also reduced. Consistent with the involvement of auxin signalling in fungal VC-mediated salt torelance, A. thaliana line carrying DR5::GUS displayed increased auxin accumulation in root apex upon exposure to V. dahliae VCs, and 1-naphthylphthalamic acid, an auxin transport inhibitor, adversely affected V. dahliae VC-mediated salt tolerance. F. oxysporum VCs induced the expression of PR1 but not PDF1.2 in A. thaliana lines containing PR1::GUS and PFD1.2::GUS. When challenged with Pseudomonas syringae after the exposure to F. oxysporum VCs, A. thaliana showed reduced disease symptoms. However, the number of bacterial cells in F. oxysporum VC-treated plants was not significantly different from that in control plants.

Volatile Compound-Mediated Recognition and Inhibition Between Trichoderma Biocontrol Agents and Fusarium oxysporum

“…To prevent physical contact and exposure to secreted molecules diffused through medium while studying how VCs from each side affect the other, we initially evaluated I plate. This plate contains two compartments separated by a central divider and has been used for studying how fungal VCs affect plants (Bitas et al, 2015 ; Li and Kang, 2018 ; Li et al, 2018 ). However, because Trichoderma jumped over the divider even after we removed a strip of medium along the divider in both compartments, we used a method reported by Dennis and Webster ( 1971 ).…”

“…Plant VCs function as homing cues to pollinators, seed dispersers, and parasitoids (Baldwin, 2010 ; Herrmann, 2010 ), mediate communication within and between plants (Baldwin, 2010 ), and protect plants from diverse predators (Baldwin, 2010 ; Huang et al, 2012 ; Arasimowicz-Jelonek and Floryszak-Wieczorek, 2014 ). Similarly, microbial VCs appear to participate in microbial interactions (Bailly and Weisskopf, 2012 ; Bennett et al, 2012 ; Bitas et al, 2013 ) and also affect plant growth, development, and stress resistance (Bailly and Weisskopf, 2012 ; Bitas et al, 2013 ; Li et al, 2016 ; Li and Kang, 2018 ). VCs produced by biocontrol agent Paenibacillus polymyxa and soilborne fungal pathogen Verticillium longisporum appeared to affect the production of antimicrobial VCs and other metabolites in the other side (Rybakova et al, 2017 ).…”

Genetic Basis of Fiber Improvement and Decreased Stress Tolerance in Cultivated Versus Semi-Domesticated Upland Cotton

“…In present study, we found most stress response genes were down-regulated during domestication, and this is responsible for the decreased stress tolerance of upland cotton ( Figure 5 ). PR1 gene is a useful molecular marker for the salicylic acid (SA) response and has been reported to play crucial roles in systemic acquired resistance in Arabidopsis (Li and Kang, 2018). VIGS assay showed that silencing of PR1 significantly reduced the disease resistance of cotton ( Figure 6 ).…”

Microbial Derived Compounds Are a Promising Approach to Mitigating Salinity Stress in Agricultural Crops

“…For instance, Pseudomonas aeruginosa and Bacillus anthracis are associated with a number of human diseases (Forni et al, 2017), yet they produce high levels of compounds such as ACC deaminase. The fungus Fusarium oxysporum is a pathogen of many crop species, yet it produces VOCs that mitigated salinity stress effects in the model plant Arabidopsis thaliana, increasing chlorophyll content and leaf area (Li and Kanga, 2018). In such cases, isolating compounds in isolated and controlled conditions, from such microbes can be the most suitable way of using them to enhance plant growth, without resulting in risk to plants and humans.…”