Bermudagrass (Cynodon dactylon) is known for its high tolerance to trampling, strong regenerative ability, and relatively low maintenance costs, making it popular for turf establishment, sports fields, and ecological restoration projects. However, as a typical warm-season turfgrass, it is sensitive to low temperatures, limiting its growth and survival. Studies have associated jasmonic acid (JA) with plant cold responses, but the precise mechanisms are still unclear.

Researchers at the Wuhan Botanical Garden of the Chinese Academy of Sciences reveal that applying methyl jasmonate (MeJA) enhances freezing tolerance in bermudagrass by increasing endogenous jasmonoyl isoleucine (JA-Ile) and MeJA levels during cold stress. The research team identifies a protein, named C. dactylon JA-Activated Cold-responsive Gene 1 (CdJACG1), whose accumulation rises with cold stress and is further promoted by MeJA treatment. Functional analyses confirm CdJACG1 as a key positive regulator of cold tolerance.

Further investigation shows that CdMYC2, a well-known cold tolerance regulator, directly binds to the CdJACG1 promoter and activates its expression. Both CdJACG1 and CdMYC2 activate the promoters of key JA biosynthesis genes, CdAOS2 and CdOPR1, leading to increased JA levels in a feedback loop. Additionally, the findings suggest that CdJACG1 links the JA pathway with the CBF/DREB1-mediated cold signaling pathway. CdJACG1 directly activates CdDREB1.3, an important positive regulator of cold tolerance. Therefore, CdJACG1 functions at the intersection of hormonal and transcriptional cold-response mechanisms.

In summary, the findings reveal a regulatory pathway involving the CdMYC2-CdJACG1-CdAOS2/CdOPR1-CdDREB1.3 module, which links JA signaling with the CBF/DREB1 pathway to improve cold tolerance in bermudagrass. These results explain how the transcriptional machinery supports low-temperature adaptation in warm-season grasses and highlight promising targets for breeding cold-tolerant varieties.

The research findings were published in the international academic journal Plant Physiology under the title "CdJACG1 integrates JA signaling and CBF pathways to confer cold tolerance in bermudagrass (Cynodon dactylon)". Dr. HUANG Xuebing is the first author, and Professor CHEN Liang is the corresponding author.