Abstract Detail

Comparative Genomics/Transcriptomics

Decena Rodriguez , Maria Angeles [1], Galvez-Rojas, Sergio [2], Contreras-Moreira, Bruno [3], Hernandez, Pilar [4], Catalan, Pilar [5].

Structure and evolution of drought responsive dehydrin genes across species and ecotypes of the monocot Brachypodium model system.

Dehydrins (DHNs) belong to group 2 LEA (Late-Embryogenesis-Abundant) proteins which play an important role in plant responses to abiotic stresses. Brachypodium is a model system for grasses and monocots but its DHN genes have been poorly studied to date. Genomic data was used to perform in silico comparative genomics and evolutionary analyses of dehydrin genes in four Brachypodium species, 54 B. distachyon ecotypes and five cereal outgroups. Our analysis detected 10 Bdhn gene copies in Brachypodium. All genes contained a single DHN domain, although Bdhn9 showed two additional Dna J-X and Dna J domains in the annual Brachypodium species. Y_nSK_n was the most common architecture of the dehydrin domain, having a variable number of Y and K segment copies in the Bdhn3-Bdhn9 genes, whereas the Bdhn1-Bdhn2 and the Bdhn10 genes presented FSKn and K*S architectures, respectively. The Bdhn genes were distributed in different numbers and copies along the five B. distachyon chromosomes [Bd1: Bdhn3, Bdhn10; Bd2: Bdhn9; Bd3: Bdhn2, Bdhn4, Bdhn5, Bdhn6, Bdhn7, Bdhn8; Bd4: Bdhn2, Bdhn4, Bdhn5, Bdhn6, Bdhn7, Bdhn8; Bd5: Bdhn1, Bdhn 6, Bdhn 9]. Although their chromosomal positions were mostly conserved, 5 genes showed chromosomal translocations across the 54 examined ecotypes. Different types and numbers of cis-regulatory elements were detected in the promoters of the Bdhn genes. Putative Methyl-Jasmonate responsive elements (Me-JaRE) were the most represented, followed by dehydration sensitive (DRE), sulphur responsive (SURE), anaerobic induction element (ARE) and water deficit (ABA) responsive elements. At the diploid genome level, the humid perennial Brachypodium sylvaticum harbours the largest number of predicted regulatory elements (57 Bdhn), followed by the mesic annual B. distachyon (47) and the xeric annual B. stacei (26). Phylogenetic analyses of Bdhn genes across the studied grasses showed a large divergence of the K*S Bdhn10 clade from the rest, followed by the branching off of the duplicated FSKn Bdh1-Bdh2 clade and then that of the members of the Y_nSK_n clade (SF14 Bdh5, SF19 Bdhn6, SF23 Bdhn3, XERO I Bdhn9, and SF23 Bdhn3 and duplicated Bdhn7/Bdhn8 subclades). A general evolutionary trend of early diverging B. stacei and its derived B. hybridum–S subgenome copies, followed by those of B. distachyon and its derived B. hybridum–D subgenome copies, and those of B. sylvaticum, was observed within each clade. However, B. sylvaticum, a moist-environment Eurasian perennial species, showed four Bdhn genes highly divergent from any of the 10 Bdhn genes present in the annual Mediterranean Brachypodium species.

1 - UNIZAR, Department of Agricultural and Environmental Sciences, Carretera de Cuarte s/n, Huesca, Aragon, 22071, España
2 - School of Computer Science Engineering, Lenguajes y ciencias de la computación, Bulevar Louis Pasteur, 35, 29071 Málaga, Málaga, Andalucía, 29071, España
3 - EMBL-EBI, Ensembl Plants, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK
4 - Institute for sustainable agriculture, Genomics of crop adaptation, Calle Obispo Cubero, 0 , Córdoba, Andalucía, 14004, España
5 - Escuela Politecnica Ctra. Cuarte Km 1, Huesca, HU, 22071, Spain

Keywords:
Bdhn genes
Brachypodium
cis-regulatory elements
comparative genomics
dehydrins
Phylogenetic analysis.

Presentation Type: Poster
Session: P, Comparative Genomics and Transcriptomics Posters
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 5:00 PM Time and date to be determined
Number: PGT001
Abstract ID:380
Candidate for Awards:None