Garlic Volatile Diallyl Disulfide Induced Cucumber Resistance to Downy Mildew

Abstract

Allicin compositions in garlic are used widely as fungicides in modern agriculture, in which diallyl disulfide (DADS) is a major compound. Downy mildew, caused by Pseudoperonospora cubensis (P. cubensis), is one of the most destructive diseases and causes severe yield losses in cucumbers. To explore the potential mechanism of DADS-induced cucumber resistance to downy mildew, cucumber seedlings were treated with DADS and then inoculated with P. cubensis at a 10-day interval. Symptom observation showed that DADS significantly induced cucumber resistance to downy mildew. Furthermore, both lignin and H2O2 were significantly increased by DADS treatment to responding P. cubensis infection. Simultaneously, the enzyme activities of peroxidase (POD) in DADS-treated seedlings were significantly promoted. Meanwhile, both the auxin (IAA) and salicylic acid (SA) contents were increased, and their related differentially expressed genes (DEGs) were up-regulated when treated with DADS. Transcriptome profiling showed that many DEGs were involved in the biological processes of defense responses, in which DEGs on the pathways of ‘phenylpropanoid biosynthesis’, ‘phenylalanine metabolism’, ‘MAPK signaling’, and ‘plant hormone signal transduction’ were significantly up-regulated in DADS-treated cucumbers uninoculated with the pathogen. Based on the results of several physiological indices and transcriptomes, a potential molecular mechanism of DADS-induced cucumber resistance to downy mildew was proposed and discussed. The results of this study might give new insight into the exploration of the induced resistance mechanism of cucumber to downy mildew and provide useful information for the subsequent mining of resistance genes in cucumber.

Perillaldehyde Functions as a Potential Antifungal Agent by Triggering Metacaspase-Independent Apoptosis in Botrytis cinerea

“…It is difficult for the pathogens to obtain allicin resistance and as a consequence, allicin has been used to control gray mold in table grape and strawberry ( 7 , 8 ). In addition, allicin can affect cell division and promote root growth in tomato ( 9 ). Perillaldehyde (PA) is a natural monoterpenoid compound extracted from Perilla frutescens , which has been historically used as a popular leafy vegetable.…”

Novel 1‐Indanone derivatives containing oxime and oxime ether moieties as immune activator to resist plant virus

“…It is an effective approach to resist pathogens using endogenous and exogenous plant activators such as salicylic acid (SA), jasmonic acid (JA), abscisic acid, BTH, DFL, diallyl disulfide, and so on. These plant activators act on the host by activating immunologic mechanisms to prevent the pathogen invasion, which involve plant hormone signal transduction, phenylpropanoid biosynthesis, and MAPK signaling pathway 43–45 . In this work, the top two KEGG pathways of DEGs were enriched on plant hormone signal transduction and phenylpropanoid biosynthesis.…”

“…These plant activators act on the host by activating immunologic mechanisms to prevent the pathogen invasion, which involve plant hormone signal transduction, phenylpropanoid biosynthesis, and MAPK signaling pathway. [43][44][45] In this work, the top two KEGG pathways of DEGs were enriched on plant hormone signal transduction and phenylpropanoid biosynthesis. There are two up-regulated JA responsive genes (JAZ and MYC2), three ethylene (ET)-responsive genes (ETR, CTR1, and EBF1/2), and one SA-responsive gene (TGA) in plant hormone signal transduction.…”

Full-length transcriptome and RNA-Seq analyses reveal the resistance mechanism of sesame in response to Corynespora cassiicola

“…Previous transcriptome analysis has revealed that starch and sucrose metabolism and plant hormone signal transduction may play important roles in the resistance mechanism of plants [ 49 , 50 ]. In this study, 17 DEGs were significantly enriched in the plant hormone signal transduction pathway.…”