Genome-wide identification and expression profiling of the SPL family genes in wheat

Abstract

The SQUAMOSA promoter-binding protein-like (SPL) proteins constitute a family of plant-specific transcription factors that play a vital role in plant development. Wheat (Triticum aestivum, AABBDD) is universally well-known as a cash crop; however, the SPLs of this important crop have not been systematically investigated as yet. In this study, we conducted a genome-wide survey in wheat and found 56 SPL genes belonging to 19 homologous groups. The SPL genes were divided into seven classes using phylogenetic tree analyses. We mapped these genes onto the wheat chromosomes and examined their structures and conserved motifs. Moreover, we performed a synteny analysis on wheat, and summarized the SPL family as well as the evolutionary relationships between SPLs. Thereafter, we compared the expression patterns of wheat SPLs under different conditions, confirming that SPLs play an important role in spike development. To conclude, the SPLs in triplets have analogous structures and similar expression patterns. The three-pair triplet response to jasmonic acid (JA) and abscisic acid (ABA) was determined by quantitative real-time polymerase chain reaction (qRT-PCR). This work provides a comprehensive understanding of the SPL gene family in wheat. Our investigation of the wheat SPL gene family provides a starting point for additional functional studies of these significant transcription factors in wheat.