Genome-wide diversity analysis of TCP transcription factors revealed cases of selection from wild to cultivated barley.

Abstract

Plant-specific TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL FACTORS 1/2 (TCP) transcription factors have known roles in inflorescence architecture. In barley, there are two family members INTERMEDIUM-C (INT-c/HvTB1-1) and COMPOSITUM 1 (COM1/HvTCP24) which are involved in the manipulation of spike architecture, whereas the participation of TCP family genes in selection from wild (Hordeum vulgare subsp. spontaneum, Hs) to cultivated barley (Hordeum vulgare subsp. vulgare, Hv) remains poorly investigated. Here, by conducting a genome-wide survey for TCP-like sequences in publicly-released datasets, 22 HsTCP and 20 HvTCP genes encoded for mature proteins were identified and assigned into two classes (I and II) based on their functional domains and the phylogenetic analysis. Each counterpart of the orthologous gene in wild and cultivated barley usually represented a similarity on the transcriptional profile across the tissues. The diversity analysis of TCPs in 90 wild barley accessions and 137 landraces with geographically-referenced passport information revealed the detectable selection at three loci including INT-c/HvTB1-1, HvPCF2, and HvPCF8. Especially, the HvPCF8 haplotypes in cultivated barley were found correlating with their geographical collection sites. There was no difference observed in either transactivation activity in yeast or subcellular localization in Nicotiana benthamiana among these haplotypes. Nevertheless, the genome-wide diversity analysis of barley TCP genes in wild and cultivated populations provided insight for future functional characterization in plant development such as spike architecture.