Characterization of Squamosa Promoter Binding Protein-LIKE genes in wheat

Abstract

Common wheat (Triticum aestivum) is an allohexaploid (AABBDD), with Triticum urartu (AA) and Aegilops tauschii (DD) as its A and D genome donors. Squamosa Promoter Binding Protein-Like (SPL) genes play important roles in plant development; however, a systematic study of this gene family in wheat is still lacking. Here, we mined the wheat genomes for SPLs and found 19 SPL genes each from the T. urartu and Ae. tauschii genomes. We also identified 58 SPL genes from the hexaploid wheat genome. We then compared the conservation and divergence of SPLs between the two diploid species in gene structures, tissuespecific expression patterns and responses to salt stress, drought and low temperature. For functional studies, two hexaploid wheat SPLs, TaSPL3 (with miR156 site mutated) and TaSPL6, were overexpressed in Arabidopsis and found to be involved in flowering time and biomass accumulation. In addition, a mutant allele (TaSPL6-D R ) with a 47 bp duplication upstream of the SBP domain was found to be associated with maturity date and grain number per spike among landraces from a Chinese wheat mini-core collection. Collectively, our work provides useful knowledge on the sequences and functions of wheat SPL genes that may help future functional studies and molecular breeding.