Increased consumption of vegetables has been recommended worldwide as a part of a healthy diet; therefore, determining gene function among breeding materials is crucial for vegetable improvement to meet the sustainable development of new vegetable varieties. However, genetic transformation is time-consuming and laborious, which limits the exploration of gene function for various vegetable crops. Virus-Induced Gene Silencing (VIGS) can perform large-scale and rapid gene silencing in plants due to a reduction in the experimental period and its independence from the stable genetic transformation, providing an excellent opportunity for functional research. VIGS can accelerate model plant research and make it easier to analyze gene function and validation in vegetable crops. Moreover, with the advent of technologies such as virus-mediated heterologous protein expression and the development of CRISPR/Cas9 technology, virus-mediated genetic tools have ushered in a new era in genetics and crop improvement. This study summarizes recent achievements in VIGS and Virus-Induced Gene Editing (VIGE) in vegetables. We also identify several challenges in the current state of VIGS technology in vegetables, serving as a guide for future research.

SMALL AUXIN UP-REGULATED RNA (SAURs) genes are acknowledged as auxin-responsive genes that play crucial roles in modulating adaptive growth under abiotic stress conditions. Low temperatures constitute a primary limiting factor that significantly impairs the development, growth, and fruit quality of watermelon plants during the winter and spring seasons. Despite their potential importance, SAURs have not yet been thoroughly investigated or characterized in watermelon. In this study, we identified a positive regulator of the chilling stress response among watermelon SAURs, designated as ClSAUR1. Subcellular localization analysis demonstrated that the protein is directed to both the nucleus and cytoplasm. Quantitative real-time PCR (qRT-PCR) analysis indicated that ClSAUR1 is ubiquitously expressed across various watermelon tissues, with pronounced expression in the roots and leaves. Moreover, qRT-PCR and promoter::β-glucuronidase (GUS) staining assays revealed that the expression of ClSAUR1 is significantly upregulated in response to exogenous abscisic acid (ABA) and chilling stress. The overexpression of ClSAUR1 in tobacco lines was contrasted and analyzed, revealing an increased tolerance to chilling stress. This was evidenced by a reduced degree of wilting and chlorosis compared to wild-type (WT) plants. Furthermore, the overexpressed lines showed reduced reactive oxygen species (ROS) accumulation and increased antioxidant enzyme activity. The qRT-PCR results further indicated that the expression levels of genes associated with abscisic acid (ABA), antioxidant enzymes, and CBF–COR cold-responsive pathways were upregulated in the transgenic tobacco lines. This study provides new insights into the role of ClSAURs in enhancing the cold resistance of watermelon.

Valine-glutamine (VQ) motif-containing proteins play important roles in diverse plant developmental processes and signal transduction in response to biotic and abiotic stresses. However, no systematic investigation has been conducted on VQ genes in watermelon. In this study, we identified 31 watermelon VQ genes, which were classified into six subfamilies (I–VI). All of the deduced proteins contained a conserved FxxxVQxL/F/VTG motif. Eleven ClVQs were involved in segment duplication, which was the main factor in the expansion of the VQ family in watermelon. Numerous stress- and hormone-responsive cis-elements were detected in the putative promoter region of the ClVQ genes. Green fluorescent protein fusion proteins for ten selected ClVQs were localized in the nucleus, but three ClVQs also showed signals in cell membranes and the cell wall, thus confirming their predicted divergent functionality. Quantitative real-time PCR (qRT-PCR) analysis indicated that the majority of ClVQ genes were specifically or preferentially expressed in certain tissues or organs, especially in the male flower. Analyses of RNA-sequencing data under osmotic, cold, and drought stresses and Cucumber green mottle mosaic virus (CGMMV) infection revealed that the majority of ClVQ genes, especially those from subfamily IV, were responsive to these stresses. The results provide useful information for the functional characterization of watermelon ClVQ genes to unravel their biological roles.

Plant grafting is one of the oldest agricultural technologies, capable of improving biotic and abiotic stress resistance, regulating plant growth, and increasing crop output and quality. Recent analytical technology has revealed that massive numbers of RNAs can move via the phloem to regulate the gene expression in the scion. However, there are currently no high-throughput methods for validating the role of these long-distance RNAs in grafting, which limits the development of rootstock resources. In this study, methodologies were developed for infection of TRSV vectors in germinating melon seeds. Efficient infection was achieved in Védrantais with completely white first-true leaves and above. Grafting was performed after the gene silencing phenotype appeared in the rootstock, resulting in gene silencing of cucurbit crops as the scion. Furthermore, different RNA viral vectors were utilized to demonstrate that the transfer of viral vectors across the graft union induced gene silencing of the scion. The approach established in this study can provide a valuable research tool for future transfer RNA function studies and rootstock breeding.

Grafting is a pivotal horticultural technique for enhancing vegetable crop productivity; however, the specific molecular mechanisms governing rootstock-induced vigor remain insufficiently elucidated. This study deciphers how bottle gourd rootstock augments growth in melon scions through an integrated approach combining physiology, transcriptomics, phytohormone profiling, and functional genetics. Phenotypic analysis confirmed a significant increase in plant height, fresh weight, and stem diameter in heterografted scions compared to controls. Transcriptome sequencing of scion apices identified 663 core differentially expressed genes (DEGs) specifically modulated by the bottle gourd rootstock. These DEGs were prominently enriched in carbohydrate metabolism and plant hormone signal transduction pathways. Consistent with this, hormonal assays revealed a specific elevation in cytokinin and ethylene levels in the scion, accompanied by the upregulation of key pathway genes, including MELO3C016881 (LOG) and MELO3C007769 (ERF060). Crucially, virus-induced gene silencing of either gene completely abolished the rootstock-conferred growth advantage. Our findings preliminarily unveil the secret behind scion vigor, providing a foundational mechanistic framework for how rootstocks reprogram scion development. The identified genes, MELO3C016881 and MELO3C007769, offer direct molecular targets for the precision breeding of superior scions in melon.