Jasmonic acid (JA) is a plant hormone that acts as a first line of defense against insects and diseases — but not all plants produce enough of it to stay protected. Now, researchers have identified a key gene in a wild tea species that drives high levels of JA accumulation, offering a promising path toward breeding pest-resistant crops without heavy reliance on chemical pesticides.
Tea plants are highly susceptible to pests, and the mountainous terrain of Guizhou Province — a major tea-growing region in China — only complicates control efforts. While Jasmonic acid (JA) is known to trigger protective responses against herbivorous insects, the genetic basis of JA-mediated resistance in tea has remained largely unexplored. Due to these challenges, there is a critical need for in-depth research into the genes that regulate JA biosynthesis and insect tolerance in tea germplasm.
A team led by Suzhen Niu at Guizhou University in China has published (DOI: 10.1093/hr/uhag142) findings on April 22, 2026, in Horticulture Research showing that the gene CtOPR2 from the wild tea species Camellia tachangensis plays an essential role in JA production and insect defense. Using genome-wide association studies (GWAS) across 350 tea accessions, the researchers identified CtOPR2 as a key regulator of JA biosynthesis, and validated its function through both gene-silencing and overexpression experiments.
The team first measured JA content across 350 tea accessions over two years and found that C. tachangensis — a wild species native to Guizhou — consistently exhibited the highest JA levels. Through genotyping-by-sequencing (GBS), they generated 100,720 high-quality single nucleotide polymorphisms (SNPs) and performed GWAS, identifying 60 SNPs and 9 candidate genes associated with JA accumulation. Among these, CtOPR2 encodes 12-oxophytodienoate reductase 2, an enzyme that catalyzes the conversion of 4,5-didehydro-JA into active JA — a previously less-understood step in the JA biosynthesis pathway.
Using antisense oligonucleotides (asODN) to suppress CtOPR2 expression in tea shoots, the researchers observed a significant drop in both gene activity and JA content, along with reduced expression of JA-responsive genes such as CtMYC2 and CtWRKY18 . Conversely, when they overexpressed CtOPR2 in transgenic tobacco plants, the modified plants accumulated more JA and showed substantially less damage from Spodoptera litura (a common caterpillar pest) compared to wild-type controls — with the insect bite area on transgenic leaves significantly smaller within 28 hours of feeding. These results demonstrate that CtOPR2 functions as a positive regulator of JA-mediated insect defense.
“We were struck by how clearly the gene’s activity tracked with JA levels — when we turned it down, JA fell; when we turned it up, JA rose and the plants became noticeably more resistant to insects,” the authors said. “This tells us that CtOPR2 is not just a minor player but a core component of the plant’s natural defense machinery. The fact that this gene comes from a wild tea species, which has evolved under natural stress for centuries, makes it especially valuable as a genetic resource for crop improvement.”
The discovery provides a direct genetic target for marker-assisted selection (MAS) in tea breeding programs, potentially accelerating the development of tea varieties with elevated JA content and enhanced pest resistance. Beyond tea, the findings may extend to other crops facing similar insect threats, offering a sustainable alternative to chemical pesticides. The study also lays the groundwork for integrating CtOPR2 into plant hormone gene databases, supporting future efforts in precision breeding and climate-resilient agriculture.
###
References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhag142
Funding information
National Key R&D Program of China [2021YFD1200203-1]; Guiyang Science and Technology Plan [2023-48-21]; Guizhou Provincial Science and Technology Projects (ZK [2022] General 111); Guizhou Provincial Major Science and Technology Projects (QiankeheZhongda [2025] 044); Guizhou University Basic Research Project [GDJC (2024)04].
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.
Horticulture Research
Not applicable
Mining of CtOPR2 as an essential gene regulating jasmonic acid mediated insect tolerance in Camellia tachangensis through genome-wide association studies
22-Apr-2026
The authors declare that they have no competing interests。