Tomato yellow leaf curl virus is spread mainly by the whitefly Bemisia tabaci and can cause severe yield and quality losses, especially in susceptible tomato cultivars. Current control depends on insecticides, resistant varieties, crop rotation and physical barriers. Yet repeated insecticide use can drive whitefly resistance, raise production costs and harm non-target organisms, while genetic resistance may weaken under high temperatures or vary with the crop’s genetic background. Natural products, synthetic chemicals and plant immunity inducers have shown promise, but relatively few compounds combine strong antiviral activity with a clearly defined mechanism. Based on these challenges, in-depth research is needed into antiviral compounds that can suppress tomato yellow leaf curl virus (TYLCV) while activating durable, multitarget host defenses.
Researchers from Shenyang Agricultural University, Liaoning Agricultural Vocational and Technical College, and the Liangshan Prefecture Branch of Sichuan Tobacco Company reported the work in Horticulture Research, published (DOI: 10.1093/hr/uhag120) online on April 6, 2026. Using the tomato cultivar Solanum lycopersicum ‘Micro-Tom’, the team evaluated YYH-6 against TYLCV and combined phenotypic testing with RNA sequencing (RNA-seq), reverse transcription quantitative polymerase chain reaction (RT-qPCR), virus-induced gene silencing (VIGS), activity-based protein profiling (ABPP), liquid chromatography–tandem mass spectrometry (LC–MS/MS), and molecular docking to clarify how the compound works.
The researchers first screened 13 related compounds using foliar treatments before and after TYLCV inoculation. At 500 micrograms per milliliter, YYH-6 produced the strongest response, reducing viral accumulation in upper leaves by 83.26% and preventing visible disease symptoms. Dose testing from 100 to 400 micrograms per milliliter showed inhibition rising from 37.3% to 77.2%. RNA-seq revealed 1,158 differentially expressed genes after infection and 265 genes altered by YYH-6 treatment, including 86 genes shared between the two comparisons. The treatment also increased antioxidant and transcription-regulator activity. Defense-related pathways included plant–pathogen interaction, mitogen-activated protein kinase (MAPK) signaling and phenylpropanoid biosynthesis. VIGS then showed that silencing the genes RPP13 and ALS2 increased TYLCV accumulation by 4.2-fold and 22.4-fold, respectively, supporting their roles in YYH-6-induced resistance. To find protein targets, the team synthesized a biotin-labeled YYH-6 probe and used ABPP and LC–MS/MS to capture candidate binding proteins. Functional silencing indicated that STI1 domain-containing protein (STI1CP) and serine hydroxymethyltransferase (SHMT) act as host susceptibility factors: reducing their expression lowered viral accumulation by 46% and 52%, respectively. Docking analysis also supported direct binding between YYH-6 and these proteins.
The authors said the findings can be summarized this way: “YYH-6 appears to protect tomato plants by coordinating several defensive routes rather than depending on one narrow antiviral action. It strengthens resistance-associated gene activity while also engaging host proteins that may support viral infection.” They said this layered response could help researchers design crop-protection compounds that are harder for rapidly evolving viruses to overcome. “The next step is to test whether this protection remains reliable across commercial tomato varieties, natural whitefly transmission and diverse field environments, while carefully evaluating formulation, persistence and crop safety,” they said.
YYH-6 could provide a starting point for a new class of plant antivirals that complement resistant cultivars, vector management and existing farm practices. By acting through host defense networks and potential susceptibility proteins, the compound may reduce reliance on repeated insecticide applications aimed solely at whiteflies. The findings also offer molecular markers—particularly RPP13, ALS2, STI1CP and SHMT—for screening future antiviral candidates or breeding strategies. However, the work was conducted in controlled experiments with ‘Micro-Tom’ plants and artificial TYLCV inoculation. Before agricultural use, researchers will need field trials, tests against naturally transmitted infections, environmental and non-target assessments, residue studies, optimized formulations, and evidence that performance remains stable across climates, cultivars and production systems.
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References
DOI
10.1093/hr/uhag120
Original Source URL
https://doi.org/10.1093/hr/uhag120
Funding information
This work was supported by the Foundation of Liaoning Provincial Department of Education (JYTYB2024001), Research and Management of Major Non-Infectious Leaf Spot Diseases (SCYC202513), and Green Prevention and Control Technologies for Insect-transmitted Viral Diseases in Sichuan Province (SCYC202605), Enterprise Doctoral Innovation and Entrepreneurship Program of Yingkou City (YKSCJH2024-020).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.