Bermudagrass (Cynodon dactylon) is popular for turf establishment, sports fields, and ecological restoration projects due to its high tolerance to trampling, strong regenerative ability, and relatively low maintenance costs. However, as a warm-season grass, it is sensitive to low temperatures, which limits its growth and survival. While studies have associated jasmonic acid (JA) with plant cold responses, the precise mechanisms remain unclear.

To address this issue, researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences have revealed that applying methyl jasmonate (MeJA) increases freezing tolerance in bermudagrass by raising levels of jasmonoyl-isoleucine (JA-Ile) and MeJA during cold stress. Their findings were published in Plant Physiology.

The researchers identified 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 confirmed CdJACG1 as a key positive regulator of cold tolerance.

Further investigation revealed that CdMYC2, a well-known regulator of cold tolerance, 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, this study reveals 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 clarify how transcriptional machinery supports adaptation to low temperatures in warm-season grasses and identify promising targets for breeding cold-tolerant varieties.