The complete plastid genome sequence of Passiflora cincinnata: genome rearrangements, massive plastid gene losses and implications to genome-plastome incompatibility

• Ano de defesa: 2016
• Autor(a) principal: Pacheco, Túlio Gomes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Passiflora cincinnata; Genômica; Evolução; Plastomas; Fisiologia Vegetal
• Link de acesso: http://www.locus.ufv.br/handle/123456789/11539

The plastid genome (plastome) organization, gene content and order is well conserved in most angiosperms, but there are some exceptions. The Passiflora genus is one of those exceptions, because there are evidences of some unusual plastid gene losses to species of this genus. However, none plastome of Passiflora has been published to date, making studies related to the evolution and putative high instability of plastome in this group difficult. In parallel, the study of the causes of nucleus-plastome incompatibility, observed in interspecific hybrids of Passiflora, has remained obscure due to the lack of plastid sequences in the database. In the context, starting to fill these gaps and to enable the characterization of plastid genetic markers and the construction of vectors for plastid transformation in Passiflora, the aim of the present study was the sequencing, assembly, analysis and characterization of complete P. cincinnata plastome. The data indicate a massive loss of plastid genes that are essential for cell viability (infA, rps7, rps16, rpl20, rpl22, ycf1 and ycf2), which very likely were functionally transferred to the nucleus and its products are imported into plastid. This genome also showed a high rate of nucleotide substitution in several genes, such as accD and clpP. Despite this high divergence, the translated amino acid sequences of these genes retain most of functional domains predicted indicating that they can still encode functional proteins. In addition, multiple inversions were detected in the P. cincinnata plastome, changing the order of several genes. Taken together, the data suggest a markedly uncommon evolution of P. cincinnata plastome, characterized for gene losses, multiple inversions and genes with accelerated nucleotide substitution rates. Thus, it is possible to suggest that the genomic instability and essential genes losses, observed here, may be related to the genome- plastome incompatibility observed in Passiflora hybrids. This relation can be established and investigated of an accurate manner with the sequencing of other Passiflora plastomes. Finally, the complete plastome sequence of P. cincinnata obtained in this work enables the plastid transformation to this species, aiming biotechnology applications and studies of evolution and functional genetics.