A Robust Functional Genomics Approach to Identify Effector Genes Required for Thrips (Frankliniella occidentalis) Reproductive Performance on Tomato Leaf Discs

Interaction of Whitefly Effector G4 with Tomato Proteins Impacts Whitefly Performance

The phloem-feeding insect Bemisia tabaci is an important pest, responsible for the transmission of several crop-threatening virus species. While feeding, the insect secretes a cocktail of effectors to modulate plant defense responses. Here, we present a set of proteins identified in an artificial diet on which B. tabaci was salivating. We subsequently studied whether these candidate effectors can play a role in plant immune suppression. Effector G4 was the most robust suppressor of an induced- reactive oxygen species (ROS) response in Nicotiana benthamiana. In addition, G4 was able to suppress ROS production in Solanum lycopersicum (tomato) and Capsicum annuum (pepper). G4 localized predominantly in the endoplasmic reticulum in N. benthamiana leaves and colocalized with two identified target proteins in tomato: REF-like stress related protein 1 (RSP1) and meloidogyne-induced giant cell protein DB141 (MIPDB141). Silencing of MIPDB141 in tomato reduced whitefly fecundity up to 40%, demonstrating that the protein is involved in susceptibility to B. tabaci. Together, our data demonstrate that effector G4 impairs tomato immunity to whiteflies by interfering with ROS production and via an interaction with tomato susceptibility protein MIPDB141. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Bulked Segregant RNA Sequencing Revealed Difference Between Virulent and Avirulent Brown Planthoppers

The brown planthopper (Nilaparvata lugens Stål, BPH) is one of the most devastating insect pests of rice (Oryza sativa L.), but BPH populations have varying degrees of virulence to rice varieties carrying different resistance genes. To help efforts to characterize these variations we applied bulked segregant RNA sequencing (BSR-seq) to identify differentially expressed genes (DEGs) and genetic loci associated with BPH virulence to YHY15 rice plants carrying the resistance gene Bph15. BPHs that are highly virulent or avirulent to these plants were selected from an F2 population to form two contrasting bulks, and BSR-seq identified 751 DEGs between the bulks. Genes associated with carbohydrate, amino acid and nucleotide metabolism, the endocrine system, and signal transduction were upregulated in the avirulent insects when they fed on these plants. The results also indicated that shifts in lipid metabolism and digestive system pathways were crucial for the virulent BPHs' adaptation to the resistant rice. We identified 24 single-nucleotide polymorphisms (SNPs) in 21 genes linked with BPH virulence. Possible roles of genes apparently linked to BPH virulence are discussed. Our results provide potentially valuable information for further studies of BPH virulence mechanisms and development of robust control strategies.

Host plant resistance to thrips (Thysanoptera: Thripidae) - current state of art and future research avenues

Integrated Pest Management (IPM) is endorsed as the future standard for crop protection worldwide. This holistic concept integrates preventative and curative measures amongst which host plant resistance (HPR) plays an essential role. Up to now HPR has been a somewhat under-utilized tool in pest management due to widespread use of pesticides and technological hindrance. Thrips are key pests in agriculture and horticulture worldwide. Here we provide an overview on the current status of research on constitutive and induced HPR including thrips-host relationships and thrips as virus vectors. We stress modulation of plant defense responses by abiotic and biotic elicitors to increase HPR and provide an outlook on the increasing potential of HPR inspired by the fast advancement of -omics techniques.

Invasion Biology, Ecology, and Management of Western Flower Thrips

Western flower thrips, Frankliniella occidentalis, first arose as an important invasive pest of many crops during the 1970s-1980s. The tremendous growth in international agricultural trade that developed then fostered the invasiveness of western flower thrips. We examine current knowledge regarding the biology of western flower thrips, with an emphasis on characteristics that contribute to its invasiveness and pest status. Efforts to control this pest and the tospoviruses that it vectors with intensive insecticide applications have been unsuccessful and have created significant problems because of the development of resistance to numerous insecticides and associated outbreaks of secondary pests. We synthesize information on effective integrated management approaches for western flower thrips that have developed through research on its biology, behavior, and ecology. We further highlight emerging topics regarding the species status of western flower thrips, as well as its genetics, biology, and ecology that facilitate its use as a model study organism and will guide development of appropriate management practices.