Systemic Resistance Induced by Volatile Organic Compounds Emitted by Plant Growth-Promoting Fungi in Arabidopsis thaliana

Abstract

Volatile organic compounds (VOC) were extracted and identified from plant growth-promoting fungi (PGPF), Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography–mass spectrometry (GC-MS). Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp.) significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst). Subsequently, m-cresol and methyl benzoate (MeBA) were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR) against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA) or Jasmonic acid (JA)/ethylene (ET) signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases.

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

“…Similar to our finding, the induced expression of PR1 was observed by VCs emitted by Paenibacillus polymyxa E681 and T. asperellum IsmT5 and by specific compounds (e.g. tridecane, m -cresol and methyl benzoate) (Lee et al 2012; Naznin et al 2014; Kottb et al 2015). However, our analysis of VCs produced by these F. oxysporum strains did not reveal the production of these compounds (Bitas et al 2015), suggesting the involvement of different compounds in activating the expression of PR1 .…”

“…Previous studies reported that VCs emitted by several plant growth promoting fungi, including Ampelomyces sp., Cladosporium sp. and Trichoderma sp., reduced disease symptoms through the activation of signalling pathways that involve SA and JA/ET (Naznin et al 2014; Kottb et al 2015). However, Ryu et al (2004) reported that ISR elicited by VCs emitted by B. amyloliquefaciens GB03 was mediated by ET signalling but did not require the SA or JA signalling pathway.…”

Enhanced Iron and Selenium Uptake in Plants by Volatile Emissions of Bacillus amyloliquefaciens (BF06)

“…This BF06 strain was cultured in 10 mL solid phase micro-extraction (SPME) vials. Then, the vials were conditioned at 50 • C with SPME fibers, and the fibers were inserted into the headspace above bacterial samples for 1 h. Subsequently, the fibers were desorbed and injected in a Gas Chromatography-Mass Spectrometer (GC-MS) (Agilent 5975C, Santa Rosa, CA, USA) according to the method described by Miyazawa et al [42]. The compositions of VOCs were analyzed using a U.S. National Institute of Standards and Technology (NIST) 2.0 mass spectra database search.…”

Protection induced by volatile limonene against anthracnose disease in Arabidopsis thaliana

“…perviridis. In recent years, large efforts with A. thaliana and other plant species have been made to understand the roles of volatile organic compounds in plants as well as the physiological effects of these compounds in relation to induced defenses against pathogens (Blom et al 2011;Kishimoto et al 2005Kishimoto et al , 2006Kishimoto et al , 2007Kishimoto et al , 2008Naznin et al 2014;Yamagiwa et al 2011). As mentioned, D-limonene is GRAS in the Code of Federal Regulations; the oral LD 50 for D-limonene in mice and rats is 5.6-6.6 and 4.4-5.1 g/kg body weight, respectively (Sun 2007).…”