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Hd1 ,a CONSTANS ortholog in rice, functions as an Ehd1 repressor through interaction with monocot‐specific CCT‐domain protein Ghd7
Author(s) -
Nemoto Yasue,
oue Yasunori,
Yano Masahiro,
Izawa Takeshi
Publication year - 2016
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13168
Subject(s) - repressor , biology , activator (genetics) , genetics , arabidopsis , gene , reporter gene , promoter , regulation of gene expression , transcription factor , gene expression , mutant
Summary Flowering time is an important agronomic trait that affects crop yields. In cereals, several CCT ‐domain proteins unique to monocots, such as Grain number , plant height , and heading date 7 ( Ghd7 ) gene, have been identified as key floral repressors, although the corresponding molecular mechanisms have been unknown until now. In rice, a short‐day plant, Heading date 1 ( Hd1 ) gene, a rice ortholog of Arabidopsis floral activator CONSTANS ( CO ), represses flowering under non‐inductive long‐day ( LD ) conditions and induces it under inductive short‐day ( SD ) conditions. Here, we report biological interactions between Ghd7 and Hd1 , which together repress Early heading date 1 ( Ehd1 ), a key floral inducer under non‐inductive LD conditions. In addition to this genetic interaction between them, Co‐ IP experiments further demonstrated that a Ghd7‐Hd1 protein formed a complex in vivo and Ch IP and luciferase reporter analyses suggested that this complex specifically binds to a cis ‐regulatory region in Ehd1 and represses its expression. These findings imply that Hd1 , an evolutionally conserved transcriptional activator, can function as a strong transcriptional repressor within a monocot‐specific flowering‐time pathway through with Ghd7 .