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Like Heterochromatin Protein 1b represses fruit ripening via regulating the H3K27me3 levels in ripening‐related genes in tomato
Author(s) -
Liang Qi,
Deng Heng,
Li Yuxiang,
Liu Ziyu,
Shu Peng,
Fu Rao,
Zhang Yaoxin,
Pirrello Julien,
Zhang Yang,
Grierson Don,
Bouzayen Mondher,
Liu Yongsheng,
Liu Mingchun
Publication year - 2020
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.16550
Subject(s) - ripening , chromatin immunoprecipitation , biology , epigenetics , heterochromatin , prc2 , chromatin , microbiology and biotechnology , climacteric , histone , rna interference , immunoprecipitation , gene , gene expression , genetics , rna , histone h3 , botany , promoter , menopause
Summary Polycomb group (PcG) proteins play vital roles in plant development via epigenetically repressing the transcription of target genes. However, to date, their function in fruit ripening is largely unknown. Combining reverse genetic approaches, physiological methods, yeast two‐hybrid, co‐immunoprecipitation, and chromatin immunoprecipitation assays, we show that Like Heterochromatin Protein 1b (SlLHP1b), a tomato Polycomb Repressive Complex 1 (PRC1)‐like protein with a ripening‐related expression pattern, represses fruit ripening via colocalization with epigenetic mark H3K27me3. RNA interference (RNAi)‐mediated downregulation of SlLHP1b advanced ripening initiation, climacteric ethylene production, and fruit softening, whereas SlLHP1b overexpression delayed these events. Ripening‐related genes were significantly upregulated in SlLHP1b RNAi fruits and downregulated in overexpressing fruits compared with wild‐type. Furthermore, SlLHP1b protein interacts with ripening regulator MSI1, a subunit of the PRC2 complex. Moreover, SlLHP1b also binds the epigenetic histone mark H3K27me3 in vivo and chromatin immunoprecipitation–quantitative PCR results showed binding occurs preferentially to regions of ripening‐associated chromatin marked by histone H3K27me3. Furthermore, the H3K27me3 levels in chromatin of ripening‐related genes is negatively correlated with accumulation of their transcripts in SlLHP1b down or upregulated fruits during ripening. Our findings reveal a novel regulatory function of SlLHP1b in fruit and provide new insights into the PcG‐mediated epigenetic regulation of climacteric fruit ripening.