Jasmonate (JA) is a crucial hormone that modulates multiple physiological processes, and biotic and abiotic stress responses. Recent studies have provided evidence for the involvement of JA in leaf senescence and cold responses. However, the molecular basis of JA-mediated leaf senescence and cold responses remains limited. 

By consulting a large amount of literature, Prof. YU Diqiu and his team from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences summarized current knowledge concerning the roles of JA in leaf senescence (i.e. a developmental program that is regulated by intrinsic and environmental factors) and tolerance to cold stress.  

According to research, there is crosstalk among different phytohormone signaling pathways. Concentrations of JA are much higher in senescent leaves compared with those in non-senescent ones. Treatment with exogenous JA induced leaf senescence and expression of senescence-associated genes.  

In response to cold stress, exogenous application of JA enhances Arabidopsis freezing tolerance with or without cold acclimation. Consistently, biosynthesis of endogenous JA is activated in response to cold exposure.  

Mechanistic studies have revealed that JA positively modulates the CBF (C-REPEAT BINDING FACTOR) pathway leading to accumulation of cryoprotective compounds, such as polyamine, glutathione, and anthocyanins.  

Studies show that JA may interact with other phytohormones, such as ethylene, abscisic acid (ABA), and gibberellin (GA), to mediate cold-stress responses. However, the molecular mechanisms underlying these crosstalks remain poorly known.  

The researchers considered that identification and analysis of the novel components that mediate crosstalk between JA and other regulatory signals will contribute to dissecting the molecular mechanisms involved in tolerance to cold stress. 

The researchers therefore suggested that further studies are needed to identify more critical components mediating JA-signaled leaf senescence and cold tolerance in Arabidopsis and crops. They also proposed further studies to determine the key components that integrate JA and other hormone pathways. 

The review entitled “Jasmonate regulates leaf senescence and tolerance to cold stress: crosstalk with other phytohormones” has been published in Journal of Experimental Botany.