MdbZIP44-MdCPRF2-like-Mdα-GP2 regulate starch and sugar metabolism in apple under nitrogen supply

Abstract

Nitrogen (N) is regarded as an essential macronutrient and is tightly associated with carbon (C) metabolism in plants. The transcriptome data obtained from this study showed that the expression level of the apple basic leucine zipper (bZIP) transcription factor (TF) MdbZIP44 was up-regulated in ‘Oregon Spur Delicious’ (Malus domestica Borkh.) apple fruits under nitrogen supply. MdbZIP44 bound to the promoter of Mdα-GP2 gene and inhibited its expression, thereby promoting starch accumulation and decreasing glucose content in apple and tomato fruits. Besides, overexpression of MdbZIP44 promoted sucrose accumulation by regulating the activities of sucrose metabolism-related enzymes and the expression of sugar metabolism-related genes in apple callus and tomato fruits. Furthermore, biochemical assays indicated that MdbZIP44 directly interacted with MdCPRF2-like, another bZIP gene in apple. Meanwhile, this study found that MdCPRF2-like, along with the MdbZIP44 and MdCPRF2-like complex, could activate the expression of Mdα-GP2, respectively. In conclusion, this study provides a new reference for potential mechanisms underlying that MdbZIP44-MdCPRF2-like-Mdα-GP2 regulates starch and sugar metabolism under nitrogen supply.

Acknowledgements

This research was supported by the Science and Technology Major Project of Gansu Province (22ZD6NA045), Natural Science Foundation of China (31860530), and the ‘Double-First Class’ Key Scientific Research Project of Education Department in Gansu Province (GSSYLXM-02).

Author contributions

B.C. and J.M. designed and coordinated the research; X.C., P.W., and S.L. conducted most of the experiments and data analysis; X.C. and Z.G. jointly performed the collection, analysis, and preservation of the experimental data; X.C., Z.M., and W.L. revised the manuscript. All authors contributed to writing and editing the final manuscript.

Data availability

All data supporting the findings are available within the paper or from the corresponding author upon request. All transcriptome sequencing data have been deposited in the NCBI Sequence Read Archive under the BioProject ID PRJNA1043230.

Conflict of interest statement

The authors declare that they have no conflicts of interest associated with this work.

Supplementary data

Supplementary data is available at Horticulture Research online.

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