CLE14 peptide delays broccoli senescence by regulating chlorophyll metabolism and reactive oxygen species homeostasis

CLE (CLAVATA3/Endosperm surrounding region-related) is a peptide hormone with multiple biological functions in plants. Previous studies have demonstrated that it plays an important role in modulating leaf senescence in Arabidopsis. However, the role of the CLE in broccoli senescence remains largely unknown. Here, we found that the expression of BoCLE14 was highly induced in broccoli during storage, and exogenous application of 50 µM CLE14 significantly delayed the senescence of broccoli. Transcriptomic analysis revealed that chlorophyll metabolism and peroxisomes are involved in CLE14-mediated broccoli senescence. qRT-PCR analysis showed that the expression of the chlorophyll degradation genes BoPPH, BoPAO, BoNYC1 and BoCLH2 were inhibited by CLE14 treatment, resulting in higher levels of chlorophyll. Moreover, CLE14 treatment also prevented reactive oxygen species (ROS) accumulation by increasing antioxidant enzyme activities and the O2•− scavenging rate. Overall, these results demonstrate that CLE14 treatment delays broccoli senescence by inhibiting chlorophyll degradation and improving the antioxidant capacity of broccoli, which provides both theoretical foundations and practical strategies for developing bioactive peptide-based green preservation technologies.