Induction of Antiviral Responses by Acibenzolar-S-Methyl Against Cucurbit chlorotic yellows virus in Melon

Abstract

Cucurbit chlorotic yellows virus (CCYV) (family Closteroviridae, genus Crinivirus) is an emerging virus which causes severe diseases on melon (Cucumis melo) plants. CCYV-infected melon plants display yellowing, mottling, chlorosis, or chlorotic spots on leaves. To develop a new control strategy, the potential for 1,2,3-benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester (ASM) to suppress CCYV infection was evaluated. ASM treatment on melon plants greatly increased the expression levels of pathogenesis-related 1a gene, a marker gene for systemic acquired resistance. ASM treatment on melon plants before inoculation of CCYV suppressed systemic symptoms and decreased CCYV accumulation. ASM treatment on melon even after inoculation of CCYV reduced disease severity and accumulation levels of CCYV. The results show the potential for ASM treatment on attenuation of the CCYV disease symptoms.

Role of salicylic acid glucosyltransferase in balancing growth and defence for optimum plant fitness

“…A SAGT ‐specific primer was used for efficient reverse transcription of SAGT . Comparative qPCR targeting of a host gene and CMV RNA was performed by using THUNDERBIRD SYBR qPCR Mix (Toyobo) and the Thermal Cycler Dice RealTime System Single TP850 (Takara Bio) according to the procedure of the manufacturer and Takeshita et al (). Each reaction mixture (total 20 μl) was prepared using 10 μl of THUNDERBIRD SYBR qPCR Mix, 1 μl of 10 pmol of each forward and reverse primer, 1 μl of cDNA template, and 7 μl of water.…”

“…Primers used in RT‐qPCR are listed in Table . Samples were analysed by relative RT‐qPCR as done by Takeshita et al (). Transcript accumulation of each target gene was normalized by the quantification of EF1 α from N. tabacum and L23 from N. benthamiana .…”

“…Transcript accumulation of each target gene was normalized by the quantification of EF1 α from N. tabacum and L23 from N. benthamiana . The EF1 α and L23 were selected as normalizers after analyses by geNorm essentially according to Takeshita et al (). These values were calculated according to the ΔΔ C t method (Pfaffl et al , ) and plotted with standard errors.…”

“…For synthetic immune induction, benzothiadiazole (BTH), also known as 1,2,3-benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester (ASM), is one of the most commonly used chemical inducers. BTH can induce host resistance against a wide range of pathogens, including plant viruses (Ishii et al, 1999;Narusaka et al, 1999aNarusaka et al, , 1999bAnfoka, 2000;Pappu et al, 2000;Oostendorp et al, 2001;Cools and Ishii, 2002;Smith-Becker et al, 2003;Mandal et al, 2008;Lin and Ishii, 2009;Takeshita et al, 2013;Frąckowiak et al, 2019). This immune induction by BTH is correlated with an increase in gene expression of resistance-related genes, including the pathogenesis-related protein 1 gene (PR1), a wellknown marker of SA-induced SAR.…”

Control of Cucurbit Viruses

“…These chemicals do not act specifically against viruses, but they can also reduce losses caused by bacteria or fungi. Recently, application of acibenzolar-S-methyl resulted in decreased accumulation of CCYV in the treated plants and attenuated systemic symptoms in melon plants (Takeshita et al, 2013). In contrast, applications of the commercially available resistance-inducing treatment BioYield™ did not reduce WMV incidence in squash (Murphy, Eubanks, & Masiri, 2009).…”