The interaction between DcCaM7 and DcCAMTA6 promotes γ-aminobutyric acid (GABA) accumulation via regulating GABA shunt in fresh-cut carrots

• Published in: Postharvest biology and technology 2023-10, Vol.204, p.112478, Article 112478
• Main Authors: Zhang, Jinglin, Li, Yanfei, Zuo, Xiaoxia, Ru, Xueyin, You, Wanli, Xu, Feng, Jin, Peng, Zheng, Yonghua, Cao, Shifeng
• Format: Article
• Language: English
• Subjects: Calcium; Calmodulin; CAMTA transcription factor; Fresh-cut carrot; GABA shunt
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2023.112478

The potential regulatory mechanisms of 1 % calcium chloride (CaCl2) treatment on the γ-aminobutyric acid (GABA) accumulation of fresh-cut carrots were investigated. The results indicated that CaCl2 application enhanced the contents of GABA shunt-related substances and activated the GABA shunt via enhancing the activities and genes expression of glutamate decarboxylase (GAD) and GABA transaminase (GABA-T). Moreover, CaCl2 treatment enhanced the levels of [Ca2+]cyt, as well as up-regulated the expression of DcCaM7 and DcCAMTA6. However, the EGTA, a Ca2+ chelating agent treatment had the opposite effect on both GABA shunt and calcium signal-related components. Importantly, DcCaM7 interacted with DcCAMTA6 through an IQ motif, forming a heterodimer that facilitated the enhanced transcriptional regulation of DcCAMTA6 in the expression of DcGAD and DcGABA-T genes. Therefore, our results indicated that DcCaM7-DcCAMTA6 complex positively regulate GABA accumulation by activating GABA shunt in fresh-cut carrots. •CaCl2 treated-shredded carrots maintained higher GABA and glutamate content.•CaCl2 treatment activated GABA shunt and calcium signal of fresh-cut carrots.•CaCl2 promoted the expression of DcCaM7 and DcCAMTA6.•DcCaM7 protein physically interacted with DcGAD/DcCAMTA6.•GABA shunt modulated by Ca2 + -CaM7-CAMTA6 signal transduction pathway.