Priming by Rhizobacterium Protects Tomato Plants from Biotrophic and Necrotrophic Pathogen Infections through Multiple Defense Mechanisms

Abstract

A selected strain of rhizobacterium, Pseudomonas putida strain LSW17S (LSW17S), protects tomato plants (Lycopersicon esculentum L. cv. Seokwang) from bacterial speck by biotrophic Pseudomonas syringae pv. tomato strain DC3000 (DC3000) and bacterial wilt by necrotrophic Ralstonia solanacearum KACC 10703 (Rs10703). To investigate defense mechanisms induced by LSW17S in tomato plants, transcription patterns of pathogenesis-related (PR) genes and H 2 O 2 production were analyzed in plants treated with LSW17S and subsequent pathogen inoculation. LSW17S alone did not induce transcriptions of employed PR genes in leaves and roots. DC3000 challenge following LSW17S triggered rapid transcriptions of PR genes and H 2 O 2 production in leaves and roots. Catalase infiltration with DC3000 attenuated defense-related responses and resistance against DC3000 infection. Despite depriving H 2 O 2 production and PR1b transcription by the same treatment, resistance against Rs10703 infection was not deterred significantly. H 2 O 2 is indispensable for defense signaling and/or mechanisms primed by LSW17S and inhibition of bacterial speck, however, it is not involved in resistance against bacterial wilt.

Induced systemic resistance in tomato (Solanum lycopersicum) against Botrytis cinerea by biochar amendment involves jasmonic acid signaling

“…JA is generally crucial to defense against pathogens with various life styles (Thaler et al 2004). The phytohormone is involved in symbiotic interactions and moreover, it is well established that resistance which is induced by PGPR is JAmediated in many cases (Ahn et al 2011;Pieterse et al 1996;Pozo et al 2005;Van der Ent et al 2008; Van der Ent et al 2009;Van Loon et al 1998). Biochar amendment of soil has been shown to modify the composition of microbial communities in the bulk soil as well as in the plant rhizosphere (Hu et al 2014;Kolton et al 2011;Lehmann et al 2011;Thies et al 2015;Warnock et al 2007).…”

“…H 2 O 2 accumulation was detected as an early response induced by bacterial speck infection in tomato pre-treated by the biocontrol agent P. putida (Ahn et al 2011). In the cases of the SAR inducing agents, DL-β-aminobutyric acid (BABA) or thiamine, activation of H 2 O 2 production takes place prior to pathogen infection (Baysal et al 2005;Boubakri et al 2012).…”

Control of Tomato yellow leaf curl virus disease by Enterobacter asburiaeBQ9 as a result of priming plant resistance in tomatoes

“…This implies that BQ9 primed the plant for an accelerated and enhanced capacity to systemically activate cellular defense responses, which were induced only upon pathogen attack. While we inferred that treatment with the BQ9 strain protected tomato plants from TYLCV infection through priming defense-related mechanisms, the same phenomenon was determined in the tomatoPseudomonas putida strain LSW17S interaction (Ahn et al, 2011) and the Arabidopsis-Bacillus cereus strain AR156 interaction (Niu et al, 2011).…”

“…In the leaves of tomato plants pretreated with BQ9, the H 2 O 2 burst occurred more rapidly and to a greater extent upon challenge with TYLCV than the burst that occurred in the leaves of viral control plants, and this finding supports the above assertion. H 2 O 2 has important functions in the infected plants; it is an early molecular signal that systemically induces resistance in the fortification of apoptotic tissues and causes apoptosis of infested cells (Ahn et al, 2011). The H 2 O 2 burst, an essential signal that primes defense responses, is a typical response to pathogen infection in primed plants (Zhang et al, 2009).…”

Negative Regulation of Pathogenesis in Pseudomonas syringae pv. tabaci 11528 by ATP-Dependent Lon Protease

“…P. syringae strains were grown at 26°C in King's medium B (KMB) or M9 minimal medium (M9MM) (Ahn et al, 2011;Cha et al, 2008). When necessary, antibiotics were added to the media at the following concentrations: ampicillin (100 µg ml -1 ), rifampicin (50 µg ml -1 ), and tetracycline (20 µg ml -1 ).…”