Genome-wide mining of wheat B-BOX zinc finger (BBX) gene family provides new insights into light stress responses

Abstract

The B-BOX (BBX) proteins are an important class of zinc-finger transcription factors involved in the regulation of plant growth and development, and have been identified in many plant species. However, there is no systematic study of common wheat (Triticum aestivum L.) BBX genes. Through comprehensive bioinformatics analysis, we identified and characterised 96 BBX genes from wheat, and provided the genes with a unified nomenclature. We describe the chromosomal location, gene structure, conserved domains, phylogenetic relationships and promoter cis-elements of TaBBX family members. The expression patterns under different conditions, especially under different hormones and light–dark conditions, were studied in detail. According to the diversity of conserved domains, we divided TaBBX proteins into five subfamilies. Gene-duplication analysis showed that duplication of chromosome segments was the main reason for the expansion of the TaBBX gene family. Detecting the expression profiles of six TaBBX genes in different tissues by quantitative real-time PCR, we found that the six genes are regulated under light–dark treatment, and that some TaBBX genes (TaBBX2.11, TaBBX2.13, TaBBX2.15 and TaBBX3.10) are strongly induced by the plant hormones abscisic acid, indole-3-acetic acid and salicylic acid. Our analysis of wheat BBX genes at the genomic level will provide a solid foundation for further identifying the functions of specific genes in light stress responses.