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Papaya CpbHLH1/2 regulate carotenoid biosynthesis-related genes during papaya fruit ripening

Papaya CpbHLH1/2 regulate carotenoid biosynthesis-related genes during papaya fruit ripening

Authors :
Dong Zhou
Yanhong Shen
Ping Zhou
Mahpara Fatima
Jishan Lin
Jingjing Yue
Xingtan Zhang
Li-Yu Chen
Ray Ming
Source :
Horticulture Research, Vol 6, Iss 1, Pp 1-13 (2019)
Publication Year :
2019
Publisher :
Oxford University Press, 2019.

Abstract

Abstract The ripening of papaya is a physiological and metabolic process associated with accumulation of carotenoids, alternation of flesh color and flavor, which depending on genotype and external factors such as light and hormone. Transcription factors regulating carotenoid biosynthesis have not been analyzed during papaya fruit ripening. RNA-Seq experiments were implemented using different ripening stages of papaya fruit from two papaya varieties. Cis-elements in lycopene β-cyclase genes (CpCYC-B and CpLCY-B) were identified, and followed by genome-wide analysis to identify transcription factors binding to these cis-elements, resulting in the identification of CpbHLH1 and CpbHLH2, two bHLH genes. The expressions of CpbHLH1/2 were changed during fruit development, coupled with transcript increase of carotenoid biosynthesis-related genes including CpCYC-B, CpLCY-B, CpPDS2, CpZDS, CpLCY-E, and CpCHY-B. Yeast one-hybrid (Y1H) and transient expression assay revealed that CpbHLH1/2 could bind to the promoters of CpCYC-B and CpLCY-B, and regulate their transcriptions. In response to strong light, the results of elevated expression of carotenoid biosynthesis-related genes and the changed expression of CpbHLH1/2 indicated that CpbHLH1/2 were involved in light-mediated mechanisms of regulating critical genes in the carotenoid biosynthesis pathway. Collectively, our findings demonstrated several TF family members participating in the regulation of carotenoid genes and proved that CpbHLH1 and CpbHLH2 individually regulated the transcription of lycopene β-cyclase genes (CpCYC-B and CpLCY-B). This study yielded novel findings on regulatory mechanism of carotenoid biosynthesis during papaya fruit ripening.

Details

Language :
English
ISSN :
20527276
Volume :
6
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Horticulture Research
Publication Type :
Academic Journal
Accession number :
edsdoj.651cd3feb7746098c7d8890934670d6
Document Type :
article
Full Text :
https://doi.org/10.1038/s41438-019-0162-2