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The regulatory module Md PUB 29‐Mdb HLH 3 connects ethylene biosynthesis with fruit quality in apple
Author(s) -
Hu DaGang,
Yu JianQiang,
Han PengLiang,
Xie XingBin,
Sun CuiHui,
Zhang QuanYan,
Wang JiaHui,
Hao YuJin
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15511
Subject(s) - ubiquitin ligase , ripening , climacteric , ethylene , arabidopsis , biochemistry , biology , biosynthesis , gene , ubiquitin , transcription factor , chemistry , microbiology and biotechnology , botany , genetics , mutant , menopause , catalysis
Summary The plant hormone ethylene is critical for climacteric fruit ripening, while glucose and anthocyanins determine the fruit quality of climacteric fruits such as apple. Understanding the exact molecular mechanism for this process is important for elucidating the interconnection of ethylene and fruit quality. Overexpression of apple Mdb HLH 3 gene, an anthocyanin‐related basic helix–loop–helix transcription factor ( bHLH TF ) gene, promotes ethylene production, and transgenic apple plantlets and trees exhibit ethylene‐related root developmental abnormalities, premature leaf senescence, and fruit ripening. Biochemical analyses demonstrate that Mdb HLH 3 binds to the promoters of three genes that are involved in ethylene biosynthesis, including Md ACO 1 , Md ACS 1 , and Md ACS 5A , activating their transcriptional expression, thereby promoting ethylene biosynthesis. High glucose‐inhibited U‐box‐type E3 ubiquitin ligase Md PUB 29, the ortholog of Arabidopsis At PUB 29 in apple, influences the expression of ethylene biosynthetic genes and ethylene production by direct ubiquitination of the Mdb HLH 3 protein. Our findings provide new insights into the ubiquitination of Mdb HLH 3 by glucose‐inhibited ubiquitin E3 ligase Md PUB 29 in the regulation of ethylene biosynthesis as well as indicate that the regulatory module Md PUB 29‐Mdb HLH 3 connects ethylene biosynthesis with fruit quality in apple.