| Autor: |
Zhang, Lihua, Wang, Changzhi, Jia, Runpu, Yang, Nanxiang, Jin, Ling, Zhu, Lingcheng, Ma, Baiquan, Yao, Yu-xin, Ma, Fengwang, Li, Mingjun |
| Zdroj: |
Horticulture Research; January 2022, Vol. 9 Issue: 1 |
| Abstrakt: |
The types and proportions of soluble sugar and organic acid in fruit significantly affect flavor quality. However, there are few reports on the crosstalk regulation between metabolism of organic acid and sugar in fruit. Here, we found that the overexpression of cytoplasmic malate dehydrogenase genes (MdcyMDHs) not only increased the malate content but also increased the sucrose concentration in transgenic apple calli and mature fruit. Enzyme activity assays indicated that the overexpression of MdcyMDH1and MdcyMDH5enhanced sucrose phosphate synthase (SPS) activity in transgenic materials. RNA-seq and expression analysis showed that the expression levels of SPSgenes were up-regulated in MdcyMDH1-overexpressed apple fruit and MdcyMDH5-overexpressed apple calli. Further study showed that the inhibition of MdSPSB2or MdSPSC2expression in MdcyMDH1transgenic fruit could reduce or eliminate, respectively, the positive effect of MdcyMDH1on sucrose accumulation. Moreover, some starch cleavage-related genes (MdBAM6.1/6.2, MdBMY8.1/8.2, MdISA1) and the key gluconeogenesis-related phosphoenolpyruvate carboxykinase MdPEPCK1gene were significantly up-regulated in the transcriptome differentially expressed genes of mature fruit overexpressing MdcyMDH1. These results indicate that alteration of malate metabolism mediated by MdcyMDHmight regulate the expression of MdSPSsand SPS activity via affecting starch metabolism or gluconeogenesis, and thus accelerate sucrose synthesis and accumulation in fruit. |
| Databáze: |
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