Project description:BACKGROUND: Western flower thrips are considered the major insect pest of horticultural crops worldwide, causing economic and yield loss to Solanaceae crops. The eggplant (Solanum melongena L.) resistance against thrips remains largely unexplored. This work aims to identify thrips-resistant eggplants and dissect the molecular mechanisms underlying this resistance using the integrated metabolomic and transcriptomic analyses of thrips-resistant and -susceptible cultivars. RESULTS: We developed a micro-cage thrips bioassay to identify thrips-resistant eggplant cultivars, and highly resistant cultivars were identified from wild eggplant relatives. Metabolomic profiles of thrips-resistant and -susceptible eggplant were compared using the gas chromatography-mass spectrometry (GC-MS)-based approach, resulting in the identification of a higher amount of quinic acid in thrips-resistant eggplant compared to the thrips-susceptible plant. RNA-sequencing analysis identified differentially expressed genes (DEGs) by comparing genome-wide gene expression changes between thrips-resistant and -susceptible eggplants. Consistent with metabolomic analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs revealed that the starch and sucrose metabolic pathway in which quinic acid is a metabolic by-product was highly enriched. External application of quinic acid enhances the resistance of susceptible eggplant to thrips. CONCLUSION: Our results showed that quinic acid plays a key role in the resistance to thrips. These findings highlight a potential application of quinic acid as a biocontrol agent to manage thrips and expand our knowledge to breed thrips-resistant eggplant.
Project description:The EFSA Panel on Plant Health (PLH) performed a pest categorisation of Thrips palmi (Thysanoptera: Thripidae), for the EU. T. palmi is listed in Annex IAI of 2000/29 EC. Using molecular methods, cryptic speciation has been shown although no new species from the group have been formally described. Here, we consider T. palmi sensu lato as a defined species native to southern Asia, which has spread to tropical and subtropical countries in Asia, the Pacific, North, Central and South America, Africa and Australia. T. palmi has been reported from many different hosts in 20 botanical families; Cucurbitaceae, Solanaceae and Orchidaceae are of primary importance. T. palmi has been intercepted many times on plants from these families. Wild and cultivated hosts are widespread in the EU. However, as a subtropical and tropical species, only a small area of the EU provides climatic conditions where establishment may be possible outdoors. Several host plants are cultivated in glasshouses where conditions may be more favourable for establishment in year-round crops. There have been past outbreaks of T. palmi in EU glasshouses and outdoors in Portugal. T. palmi causes feeding and oviposition damage and populations in Asia are competent vectors of tospoviruses. Impacts could occur on many hosts, especially Cucurbitaceae, Solanaceae and ornamental plants particularly in glasshouses. Phytosanitary measures aim to prevent the entry of T. palmi specifically on cut flowers of Orchidaceae and fruits of Momordica and Solanum melongena. The species meets all the criteria assessed by the PLH Panel to satisfy the definition of a Union quarantine pest, while it does not satisfy all the criteria for it to be regarded as a Union regulated non-quarantine pest (RNQP).