Regulation of the SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE genes/microRNA 156 Module by the Homeodomain Proteins PENNYWISE and POUND-FOOLISH in Arabidopsis  

作　　者：Shruti Lal Leo Bryan Pacis Harley M.S. Smith 

机构地区：[1]Genetics, Genomics and Bioinformatics Graduate Program, University of California, Riverside, CA, 92521, USA [2]Center for Plant Cell Biology, Institute of Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside CA, 92521, USA

出　　处：《Molecular Plant》2011年第6期1123-1132,共10页分子植物（英文版）

摘　　要：The morphology of inflorescences is regulated in part by the temporal and spatial events that regulate flower specification. In Arabidopsis, an endogenous flowering time pathway mediated by a subset of SQUAMOSA PROMOTER- BINDING PROTEIN-LIKE （SPL） transcription factors, including SPL3, SPL4, and SPL5, function to specify flowers by activating floral meristem identity genes. During shoot development, SPL3, SPL4, and SPL5 are post-transcriptionally regulated by microRNA156 （miR156）. The photoperiod regulated florigenic signal, FLOWERING LOCUS T （FT）, promotes floral induction, in part by activating SPL3, SPL4, and SPL5. In turn, these SPLs function in parallel with FT to specify flower meristems. Two related BELLl-like homeobox genes PENNYWISE （PNY） and POUND-FOOLISH （PNF） expressed in the shoot apical meristem are absolutely required for the specification of floral meristems. Genetic studies show that the floral specification function of FT depends upon PNYand PNF; however, the interplay between these homeodomain proteins and SPLs is not known. In this manuscript, we show that the photoperiodic floral induction of SPL3, SPL4, and SPL5 is dependent upon PNY and PNE Further, PNY and PNF also control SPL3, SPL4, and SPL5 expression by negatively regulating miR156. Lastly, ectopic expres- sion of SPL4 partially rescues the pny pnf non-flower-producing phenotype, while overexpression of SPL3 or SPL5 in pny pnf plants was unable to restore flower specification. These results suggest that： （1） SPL3, SPL4, and SPL5 function is dependent upon PNY and PNF, or （2） expression of multiple SPLs is required for floral specification in pny pnf plants.The morphology of inflorescences is regulated in part by the temporal and spatial events that regulate flower specification. In Arabidopsis, an endogenous flowering time pathway mediated by a subset of SQUAMOSA PROMOTER- BINDING PROTEIN-LIKE （SPL） transcription factors, including SPL3, SPL4, and SPL5, function to specify flowers by activating floral meristem identity genes. During shoot development, SPL3, SPL4, and SPL5 are post-transcriptionally regulated by microRNA156 （miR156）. The photoperiod regulated florigenic signal, FLOWERING LOCUS T （FT）, promotes floral induction, in part by activating SPL3, SPL4, and SPL5. In turn, these SPLs function in parallel with FT to specify flower meristems. Two related BELLl-like homeobox genes PENNYWISE （PNY） and POUND-FOOLISH （PNF） expressed in the shoot apical meristem are absolutely required for the specification of floral meristems. Genetic studies show that the floral specification function of FT depends upon PNYand PNF; however, the interplay between these homeodomain proteins and SPLs is not known. In this manuscript, we show that the photoperiodic floral induction of SPL3, SPL4, and SPL5 is dependent upon PNY and PNE Further, PNY and PNF also control SPL3, SPL4, and SPL5 expression by negatively regulating miR156. Lastly, ectopic expres- sion of SPL4 partially rescues the pny pnf non-flower-producing phenotype, while overexpression of SPL3 or SPL5 in pny pnf plants was unable to restore flower specification. These results suggest that： （1） SPL3, SPL4, and SPL5 function is dependent upon PNY and PNF, or （2） expression of multiple SPLs is required for floral specification in pny pnf plants.

关 键 词：Development MERISTEM HOMEODOMAIN flowering microRNA. 

分 类 号：Q522[生物学—生物化学] S852.65[农业科学—基础兽医学]