Genome-Wide Characterization and Expression Profiling of Plant-Specific PLATZ Transcription Factor Family Genes in Brassica rapa L.

Plant AT-rich sequence and zinc-binding (PLATZ) proteins constitute a plant-specific transcription factor family with two conserved zinc-dependent DNA-binding domains. The PLATZ proteins operate significant functions in regulating plant development and resistance. To date, PLATZ genes have been studied only in a few model plants, including Arabidopsis, rice, maize and soybean, but not yet in any Brassica species. We identified 24 Brassica rapa PLATZ gene family (BrPLATZ) genes through genome-wide characterization and profiled their expression using available RNA-Sequencing data. We divided 153 PLATZ proteins from eight plant species into seven groups based on sequence alignment and phylogeny. The BrPLATZ genes were generally conserved in groups with similar motif and exon-intron distribution. The 24 BrPLATZ genes were located in eight of the ten B. rapa chromosomes, with segmental duplication detected in 20 paralogs. Analysis of Ka/Ks ratios revealed that the duplicated genes were under purifying selection. Cis-elements analysis implied that BrPLATZ genes are diverse in functions including tissue-specific, stress and hormone responsive expressions. Furthermore, expression profiling based on RNA-sequencing data revealed that the BrPLATZ genes were expressed in various tissues, with most genes preferentially expressed in flower and silique compared to other tissues. Systematic analysis revealed structural and functional diversity among BrPLATZ proteins, which indicated the possibility of diverse functions of BrPLATZ genes in development and stress resistance. The characterization of PLATZ gene family members may aid in the selection of appropriate candidate genes responsible for biological functions in B. rapa and relevant species.