Mitochondrial citrate synthase plays important roles in anthocyanin synthesis in petunia

• Published in: Plant science (Limerick) 2021-04, Vol.305, p.110835-110835, Article 110835
• Main Authors: Zhao, Huina, Chen, Guoju, Sang, Lina, Deng, Ying, Gao, Lili, Yu, Yixun, Liu, Juanxu
• Format: Article
• Language: English
• Subjects: Anthocyanin synthesis; Citrate synthase; Flower development; Leaf development; Petunia
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2021.110835

•Identified the entire CS gene family in petunia and isolated the genes encoding the isoenzymes: PhmCS, PhCSY1 and PhCSY2.•PhmCS is involved in the development of leaves and flowers.•PhmCS is involved in the anthocyanins synthesis.•Citrate involved in anthocyanins synthesis comes from mitochondria rather than from microbodies in petunia.•The extended pathway for anthocyanin synthesis was confirmed. Anthocyanins are important flavonoid pigments in plants. Malonyl CoA is an important intermediate in anthocyanin synthesis, and citrate, formed by citrate synthase (CS) catalysing oxaloacetate, is the precursor for the formation of malonyl-CoA. CS is composed of two isoforms, mitochondrial citrate synthase (mCS), a key enzyme of the tricarboxylic acid (TCA) cycle, and citrate synthase (CSY) localizated in microbodies in plants. However, no CS isoform involvement in anthocyanin synthesis has been reported. In this study, we identified the entire CS family in petunia (Petunia hybrida): PhmCS, PhCSY1 and PhCSY2. We obtained petunia plants silenced for the three genes. PhmCS silencing resulted in abnormal development of leaves and flowers. The contents of citrate and anthocyanins were significantly reduced in flowers in PhmCS-silenced plants. However, silencing of PhCSY1 and/or PhCSY2 did not cause a visible phenotype change in petunia. These results showed that PhmCS is involved in anthocyanin synthesis and the development of leaves and flowers, and that the citrate involved in anthocyanin synthesis mainly derived from mitochondria rather than microbodies in petunia.