Banca de QUALIFICAÇÃO: ROSEANE RODRIGUES DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ROSEANE RODRIGUES DOS SANTOS
DATE: 08/02/2024
TIME: 14:00
LOCAL: https://meet.google.com/mcx-mudk-znn
TITLE:

Associations between chromosomes and habit in Orchidaceae: insights from the Epidendroideae subfamily

PAGES: 132
BIG AREA: Ciências Biológicas
AREA: Genética
SUBÁREA: Genética Vegetal
SUMMARY:

The Orchidaceae is one of the most diverse botanical families, both in morphological, cytogenetic, and ecological characteristics. Epidendroideae stands out by encompassing 76% of the species and reflecting a significant portion of the diversity observed in the family. The relevance of changes in chromosomal number (CN) and genome size (GS) in macroevolutionary and macroecological processes, as well as understanding the adaptive potential of these two traits, has been the subject of ongoing discussion. Given its prominence as an excellent model, we employed the group of epidendroids to understand the evolution of cytogenetic characters and assess the existence of associations between NC and/or TG with habit types. To achieve these objectives, data were collected and organized in an online database (http://orchidcountsdb.epizy.com/). The reconstructed phylogenetic tree using markers ycf1, matK, ITS, and atpB-rbcL was used in evolutionary analyses, employing phylogenetic comparative methods to estimate phylogenetic signal (Pagel's λ) and assess the mode (Kappa - κ) and time (delta - δ) of character evolution, as well as the evolutionary model (BM, OU, EB, and White-noise). Ancestral state reconstruction of CN for basal tribes, Cymbidieae, Vandeae, and Epidendreae was performed using chromEvol, and for the entire subfamily, it was carried out using heterogeneous models of chromosomal evolution. Ancestral GS was inferred by MP and ML. To assess associations between cytogenetic features and habit, we regressed cytogenetic variables against the set of habit variables using PGLS. The obtained phylogenetic hypothesis is the most extensive and robust for Epidendroideae to date. CN showed low phylogenetic signal (λ=0.53), while GS exhibited high phylogenetic signal (λ=0.95). The mode and time of evolution suggest that both CN and GS undergo punctuated evolution (κ < 1), with long branches contributing more to the evolution of both traits (δ > 1). White Noise was considered the best model for both cytogenetic characters in Epidendroideae, as well as for most tribes. CN varied 24x in the subfamily, while GS variation was 119x. The suggested basic number for the subfamily was x=21, with reductions to x=19 and increases to x=24, highlighting aneuploidy as the main chromosomal rearrangement. MP reconstruction suggested 1C=10.16 pg as the ancestral TG in the subfamily, while ML reconstruction indicated the lowest value, 1C=2.59 pg. Associations between CN and GS with habit variables suggest that genome size is associated with chromosomal number and exclusive terrestrial habit. As genome size increases in Epidendroideae, there is a tendency to abandon epiphytism. The low phylogenetic signal and evolutionary model suggested for NC indicate that this trait seems to be less informative. On the other hand, the high phylogenetic signal for genome size suggests that this trait is adaptive and has a clear association with the exclusive terrestrial habit. Our data suggest that polyploidy is involved in the ability to occupy more extreme environments, with significant reversions to the terrestrial environment observed in Epidendreae.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 922.544.200-97 - ANA PAULA DE MORAES - UNICAMP
Membro Titular - Examinador(a) Interno ao Programa - 1308531 - TIAGO FERNANDES CARRIJO
Membro Titular - Examinador(a) Externo à Instituição - GÉSSICA SOUZA SANTOS - UNEB
Membro Suplente - Examinador(a) Interno ao Programa - 108.558.777-07 - ELTON JOHN DE LÍRIO - OUTRA
Membro Suplente - Examinador(a) Externo à Instituição - MARIA JOSÉ GOMES DE ANDRADE - UNEB