Genome Duplication and Evolution of Heat Shock Transcription Factor (HSF) Gene Family in Four Model Angiosperms

Abstract

Whole-genome duplication events played important roles in the evolution of angiosperms. Many modern angiosperms genomes have experienced one or more rounds of paleopolyploidy. Given that an ancient large-scale duplication will result in an excess of relatively old duplicated genes with similar ages, we analyzed the timing of duplication pairs in four model angiosperms (Populus trichocarpa, Arabidopsis thaliana, Oryza sativa, and Vitis vinifera). By searching for intraspecies microsynteny, we identified 18 paralogous gene pairs of duplicated segments resulting from a whole-genome duplication in poplar, Arabidopsis, and rice. Notably no paralogous gene pairs existed in grapevine. However, by comparing interspecies microsynteny, we confirmed that the majority of HSF-containing segments in the Arabidopsis, rice, and grapevine genomes show extensive conservation with duplicated regions in poplar. Microarray and quantitative reverse transcriptase PCR analysis showed that most of the poplar HSF genes are differentially expressed upon exposure to various stresses. In conclusion, this study comprehensively analyzed the evolution and duplication relationship of HSF across four model angiosperms, which demonstrated the rates of gene gain in different species.