Salicylic Acid Is Involved in the Basal Resistance of Tomato Plants to Citrus Exocortis Viroid and Tomato Spotted Wilt Virus

Abstract

Tomato plants expressing the NahG transgene, which prevents accumulation of endogenous salicylic acid (SA), were used to study the importance of the SA signalling pathway in basal defence against Citrus Exocortis Viroid (CEVd) or Tomato Spotted Wilt Virus (TSWV). The lack of SA accumulation in the CEVd- or TSWV-infected NahG tomato plants led to an early and dramatic disease phenotype, as compared to that observed in the corresponding parental Money Maker. Addition of acibenzolar-S-methyl, a benzothiadiazole (BTH), which activates the systemic acquired resistance pathway downstream of SA signalling, improves resistance of NahG tomato plants to CEVd and TSWV. CEVd and TSWV inoculation induced the accumulation of the hydroxycinnamic amides p-coumaroyltyramine, feruloyltyramine, caffeoylputrescine, and feruloylputrescine, and the defence related proteins PR1 and P23 in NahG plants earlier and with more intensity than in Money Maker plants, indicating that SA is not essential for the induction of these plant defence metabolites and proteins. In addition, NahG plants produced very high levels of ethylene upon CEVd or TSWV infection when compared with infected Money Maker plants, indicating that the absence of SA produced additional effects on other metabolic pathways. This is the first report to show that SA is an important component of basal resistance of tomato plants to both CEVd and TSWV, indicating that SA-dependent defence mechanisms play a key role in limiting the severity of symptoms in CEVd- and TSWV-infected NahG tomato plants.

Genome-Wide Transcriptomic Analysis Reveals Insights into the Response to Citrus bark cracking viroid (CBCVd) in Hop (Humulus lupulus L.)

“…Similarly, genes involved in IAA, ET, and BA-biosynthesis and responses were induced in PSTVd-infected tomato plants [ 69 ]. Salicylic acid (SA) has recently received attention in rendering basal resistance of tomato plants against citrus exocortis viroid (CEVd) [ 70 ]. However, changes of expression of genes that are involved in SA metabolism or response were not observed.…”

Global Transcriptomic Changes Induced by Infection of Cucumber (Cucumis sativus L.) with Mild and Severe Variants of Hop Stunt Viroid

“…Among these induced proteins are members of a group of PR proteins (Linthorst and Van Loon, 1991 ). When infected by apple stem grooving virus (ASGV), apple genes encoding PR proteins PR1 and PR1a were up-regulated (Chen et al, 2014 ); similarly, PR1 expression in tomato was also induced by infection with tomato spotted wilt virus (TSWV) (López-Gresa et al, 2016 ) and CEVd (Conejero et al, 1990 ; López-Gresa et al, 2016 ). The up-regulation of cucumber PR1 gene expression, which we observed following either HSVd-h or HSVd-g54 infection (Table S7 ), is consistent with the results of these previous studies.…”

“…Therefore, both RNA-silencing and SA-mediated defense mechanism could act together to limit viroid and virus infection. Comparing with the corresponding parental plants, the lack of SA accumulation in the CEVd- or TSWV-infected NahG transgenic tomato plants led to early symptoms, thus showing that SA is an important component of basal resistance of tomato plants to CEVd and TSWV (López-Gresa et al, 2016 ). Silencing of SA biosynthetic and signaling genes in Nicotiana benthamiana plants increased susceptibility to tobacco mosaic virus (TMV), indicating that SA was required for systemic resistance response against this virus (Zhu et al, 2014 ).…”

The impact of microbes in the orchestration of plants’ resistance to biotic stress: a disease management approach

“…maculicola ES4326Defense genes enabled the movement of AZA by binding to lipid-AZA and induced systemic resistance in the plantCecchini et al (2015)Ammonium ion (NH 4 + )Tomato Pseudomonas syringae pv. tomato DC3000Improved the accumulation of hydrogen peroxide which triggered the abscicis acid signaling pathway and induced the closure of stomata as well as accumulation of putrescine in the plantFernández-Crespo et al (2015)PeBA1 proteinTobacco Tobacco mosaic virus , Botrytis cinerea Induced defensive genes for the production of salicylic acid, phenylalanine ammonia lyase, jasmonic acid, hydrogen peroxide, and phenolic compoundsWang et al (2016)BenzothiadiazoleTomatoTomato spotted wilt virus and citrus exocortis viroidActivated the salicylic acid signaling pathway and improved the plant resistance to the viral infectionLopez-Gresa et al (2016)BenzothiadiazoleSunflower Sclerotinia sclerotiorum Hindered the development of fungal hyphae in the plant and increased the establishment of mycorrhizae in the plant rootBan et al (2017)Methyl jasmonateWhitebark pine Cronartium ribicola mountain pine beetle (MBP, Dendroctonus ponderosae )It triggered the plant reprogramming of the transcriptome profile, a set of DEG (differentially expressed genes) associated with plant defense signaling, etc.Liu et al (2017)Salicylic acid or methyl jasmonateCassava Xanthomonas axonopodis pv . manihotisElevated the defense action of cassava plant to the bacterial pathogenYoodee et al (2018)Benzoylsalicylic acidTobacco, ArabidopsisTobacco mosaic virusIt enhanced plant resistance to the virus and induce the expression of non-expressor of pathogenesis-related gene 1 (NPR1), hypersensitivity-related molecules, mitogen activated protein kinase (MARK) as well as WRKY genes in the plantKamatham et al (2016)NingnanmycinTobaccoTobacco mosaic virusInhibited polymerization of tobacco mosaic virus protein coat and induced systemic resistance and accumulation of pathogenesis-related proteins in the plantHan et al (2014)3-Acetonyl-3-hydroxyoxindole (AHO) Nicotiana tabacum Tomato spotted wilt virusInduced the activation of differentially expressed genes (PR1 and PR10) that facilitated the priming and expression of metabolic pathways for synthesis of phenyl propanoid, sesquiterpenoid, triterpenoid for protecting plant cuticle, and waxChen et al (2017)N-decanoyl-homoserine lactoneTomato Botrytis cinerea Induced plant jasmon...…”