Banca de QUALIFICAÇÃO: ISABELLA DE CAMPOS MORAES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: ISABELLA DE CAMPOS MORAES
DATA: 04/03/2021
HORA: 08:00
LOCAL: Departamento de Biologia - Remoto
TÍTULO:

Karyotype analysis and mode of reproduction of two Urochloa P. Beauv. species

PALAVRAS-CHAVES:

Brachiaria. Apomixis. Allopoliploidy. FISH. rDNA sites. Genome size.

PÁGINAS: 25
GRANDE ÁREA: Ciências Biológicas
ÁREA: Genética
RESUMO:

Grasses with desirable traits for agriculture and livestock production are continually being sought. The genus Urochloa comprises many species of good forage potential, although studies have mostly focused on commercial cultivars. Karyotype data can be used to characterize species, generate information for taxonomy, evolutionary studies, and contributes to breeding programs. The mode of reproduction is also an essential piece of information to determine breeding strategies. This study aimed to characterize the karyotypes of Urochloa arrecta and a pentaploid cytotype of Urochloa brizantha, including the mapping of ribosomal DNA (rDNA) sites, nuclear DNA content, and confirm the mode of reproduction. Slides were prepared using the flame drying technique and were subjected to fluorescent in situ hybridization (FISH) with 35S and 5S rDNA probes. DNA content was estimated by flow cytometry. The identification of the reproduction mode was based on the amplification of the primers N14 and p779/p780. Urochloa arrecta presented 2C=2.66 pg of DNA, karyotype formula 2n=4x=34m+2sm, four chromosomes with 35S rDNA sites, and four other chromosomes with 5S rDNA sites. The reproduction mode was confirmed as sexual, based on the absence of amplification products with the primers N14 and p779/p780. Urochloa brizantha presented 2C=4.52 pg of DNA and karyotype formula 2n=5x=45m. Five chromosomes presented 35S rDNA, and eight other chromosomes displayed 5S rDNA sites. PCR results indicated that this cytotype has an apomictic mode of reproduction. The organization of karyotypes suggests an allopolyploid origin for both genotypes. Possible applications of the information found are discussed.

MEMBROS DA BANCA:
Externo à Instituição - CRISTINA MARIA PINTO DE PAULA - UFMG (Membro)
Externo à Instituição - GABRIELA BARRETO DOS REIS - UNA (Suplente)
Externo à Instituição - LUDMILA CRISTINA OLIVEIRA - UFLA (Membro)
Presidente - VANIA HELENA TECHIO (Membro)
Interno - WELISON ANDRADE PEREIRA (Membro)