Banca de DEFESA: Helena Beatriz da Silva Mota

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Helena Beatriz da Silva Mota
DATE: 05/04/2024
TIME: 08:30
LOCAL: Online
TITLE:

"Identification of a new Emaravirus in Urochloa (syn. Brachiaria) hybrid through highthroughput sequencing and genomic analyses of the viruses".

KEY WORDS:

High-throughput sequencing, Emaravirus, forage crops.

PAGES: 30
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Brazil is the second-largest producer of beef in the world, and the Brazilian beef production system is extensive, characterized by free-range animal grazing in large pasture areas during a significant portion of the animal's fattening period. Tropical forages, particularly grasses of the Urochloa genus (syn. Brachiaria), are commonly planted for this purpose. Despite limited literature on viral infections in forages, it is known that these plants are currently affected by such pathogens. These infections contribute to a decline in pasture quality, and the identification of these pathogens is not always straightforward, making it challenging to establish specific measures for diagnosis and proper management. High-throughput sequencing (HTS) has been crucial in identifying new viral species due to the substantial amount of data generated. Therefore, the aim of this study was to detect a new viral species infecting forage plants using high-throughput sequencing. A novel emaravirus was discovered through HTS in a commercial hybrid cultivar derived from Urochloa ruziziensis, U. decumbens, and U. brizantha. A genome sequence was confirmed through Sanger sequencing and comprises five segments of negative-sense RNA. RNA1 consists of 6,867 nucleotides, encoding a RNA-dependent RNA polymerase (RdRp) protein of 2,289 amino acids. RNA2 consists of 2,043 nt, encoding a glycoprotein (G) of 681 aa. RNA3 consists of 981 nt, encoding a nucleocapsid protein (NC) of 327 aa. RNA4 consists of 1,041 nt, encoding a movement protein of 374 aa. RNA5 consists of 1,008 nt, encoding a gene silencing suppressor protein. Phylogenetic analysis based on predicted amino acid sequences of RdRp and G showed a 33.9% closeness to Emaravirus tritici, while analysis based on amino acid sequences of NC revealed a distant relationship to fifteen different species, namely E. vitis, E. sorbi, E. actinidiae, E. syringae, E. cercidis, E. cajani, E. aceris, E. populi, E. pistaciae, E. rubi, E. rosae, E. fraxini, E. kiwii, E. toordali, and E. fici. These data suggest that the discovered virus is a member of a new species in the genus Emaravirus, for which the binomial name Emaravirus brachiariae is proposed.

COMMITTEE MEMBERS:
Externo à Instituição - ERICH YUKIO TEMPEL NAKASU - EMBRAPA
Externa à Instituição - MARILIA SANTOS SILVA PATRIOTA - EMBRAPA
Interna - 1723060 - RITA DE CASSIA PEREIRA CARVALHO
Presidente - 1623558 - TATSUYA NAGATA