Comparative Genomics, Evolution, and Drought-Induced Expression of Dehydrin Genes in Model Brachypodium Grasses

DECENA, MARIA ANGELES; GÁLVEZ-ROJAS, SERGIO; AGOSTINI, FEDERICO; SANCHO, RUBEN; CONTRERAS-MOREIRA, BRUNO; DES MARAIS, DAVID L.; HERNANDEZ, PILAR; CATALÁN, PILAR

Plants

MDPI

Lugar: Basel; Año: 2021 vol. 10

Dehydration proteins (dehydrins, DHNs) confer tolerance to water-stress deficit in plants.We performed a comparative genomics and evolutionary study of DHN genes in four model Brachypodium grass species. Due to limited knowledge on dehydrin expression under water deprivationstress in Brachypodium, we also performed a drought-induced gene expression analysis in 32 ecotypesof the genus? flagship species B. distachyon showing different hydric requirements. Genomic sequenceanalysis detected 10 types of dehydrin genes (Bdhn) across the Brachypodium species. Domain andconserved motif contents of peptides encoded by Bdhn genes revealed eight protein architectures.Bdhn genes were spread across several chromosomes. Selection analysis indicated that all the Bdhngenes were constrained by purifying selection. Three upstream cis-regulatory motifs (BES1, MYB124,ZAT) were detected in several Bdhn genes. Gene expression analysis demonstrated that only fourBdhn1-Bdhn2, Bdhn3, and Bdhn7 genes, orthologs of wheat, barley, rice, sorghum, and maize genes,were expressed in mature leaves of B. distachyon and that all of them were more highly expressedin plants under drought conditions. Brachypodium dehydrin expression was significantly correlatedwith drought-response phenotypic traits (plant biomass, leaf carbon and proline contents and wateruse efficiency increases, and leaf water and nitrogen content decreases) being more pronounced indrought-tolerant ecotypes. Our results indicate that dehydrin type and regulation could be a keyfactor determining the acquisition of water-stress tolerance in grasses.