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Flowering time is an important agronomic trait that coordinates the plant life cycle with regional adaptability and thereby impacts yield potentials for cereal crops. The CONSTANS ( CO )-like gene family plays vital roles in the regulation of flowering time. CO-like proteins are typically divided into four phylogenetic groups in rice. Several genes from groups I, III, and IV have been functionally characterized, though little is known about the genes of group II in rice. We report the functional characterization in rice of a constitutive floral inhibitor, OsCOL16 , encoding a group-II CO-like protein that delays flowering time and increases plant height and grain yield. Overexpression of OsCOL16 resulted in late heading under both long-day and short-day conditions. OsCOL16 expression exhibits a diurnal oscillation and serves as a transcription factor with transcriptional activation activity. We determined that OsCOL16 up-regulates the expression of the floral repressor Ghd7 , leading to down-regulation of the expression of Ehd1 , Hd3a , and RFT1 . Moreover, genetic diversity and evolutionary analyses suggest that remarkable differences in flowering times correlate with two major alleles of OsCOL16 . Our combined molecular biology and phylogeographic analyses revealed that OsCOL16 plays an important role in regulating rice photoperiodic flowering, allowing for environmental adaptation of rice. [ABSTRACT FROM AUTHOR]

A rice mutant with light-green leaves was discovered from a transgenic line of Oryza sativa . The mutant has reduced chlorophyll content and abnormal chloroplast morphology throughout its life cycle. Genetic analysis revealed that a single nuclear-encoded recessive gene is responsible for the mutation, here designated as lgl1. To isolate the lgl1 gene, a high-resolution physical map of the chromosomal region around the lgl1 gene was made using a mapping population consisting of 1984 mutant individuals. The lgl1 gene was mapped in the 76.5 kb region between marker YG4 and marker YG5 on chromosome 12. Sequence analysis revealed that there was a 39 bp deletion within the fourth exon of the candidate gene Os12g0420200 (TIGR locus Os12g23180) encoding a chloroplast stem-loop-binding protein of 41 kDa b (CSP41b). The lgl1 mutation was rescued by transformation with the wild type CSP41b gene. Accordingly, the CSP41b gene is identified as the LGL1 gene. CSP41b was transcribed in various tissues and was mainly expressed in leaves. Expression of CSP41b-GFP fusion protein indicated that CSP41b is localized in chloroplasts. The expression levels of some key genes involved in chlorophyll biosynthesis and photosynthesis, such as ChlD , ChlI , Hema1 , Ygl1 , POR , Cab1R , Cab2R , PsaA , and rbcL , was significantly changed in the lgl1 mutant. Our results demonstrate that CSP41b is a novel gene required for normal leaf color and chloroplast morphology in rice. [ABSTRACT FROM AUTHOR]