Conservation and Divergence of SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE ( SPL ) Gene Family between Wheat and Rice.

The SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE ( SPL ) gene family affects plant architecture, panicle structure, and grain development, representing key genes for crop improvements. The objective of the present study is to utilize the well characterized SPL s' functions in rice to facilitate the functional genomics of TaSPL genes. To achieve these goals, we combined several approaches, including genome-wide analysis of TaSPL s, comparative genomic analysis, expression profiling, and functional study of TaSPL3 in rice. We established the orthologous relationships of 56 TaSPL genes with the corresponding OsSPL s, laying a foundation for the comparison of known SPL functions between wheat and rice. Some TaSPL s exhibited different spatial-temporal expression patterns when compared to their rice orthologs, thus implicating functional divergence. TaSPL2 / 6 / 8 / 10 were identified to respond to different abiotic stresses through the combination of RNA-seq and qPCR expression analysis. Additionally, ectopic expression of TaSPL3 in rice promotes heading dates, affects leaf and stem development, and leads to smaller panicles and decreased yields per panicle. In conclusion, our work provides useful information toward cataloging of the functions of TaSPL s, emphasized the conservation and divergence between TaSPL s and OsSPL s, and identified the important SPL genes for wheat improvement.