Banca de QUALIFICAÇÃO: RIZELLE DE OLIVEIRA BARROS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RIZELLE DE OLIVEIRA BARROS
DATE: 27/01/2023
TIME: 14:00
LOCAL: CCAB-UFCA, Sala M401
TITLE:

Diversity of Rhizoctonia anastomosis groups associated with alliums in Brazil

KEY WORDS:

Allium spp. Soilborne fungi. Root pathogen. ITS sequences. Phylogeny. Aggressiveness

PAGES: 60
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Several factors can cause losses in the production of alliums (garlic, leeks, onions, and chives), but diseases are very important. Among these, the damping-off of seedlings and dwarfing of adult plants, caused by the fungus of the genus Rhizoctonia, stand out. The identification of this fungus is based mainly on the classification into hyphal anastomosis groups (AGs). The present study was undertaken to determine which Rhizoctonia species and AGs occur in alliums production areas in Brazil using internal transcribed spacer region (ITS) sequencing of ribosomal DNA (rDNA). Garlic, leeks, onions, and chives plants with damping-off of seedlings and dwarfing of adult plants were collected in 38 production areas located in 12 municipalities and five Brazilian states from 2018 to 2022. From symptomatic plant materials were performed isolations of the associated fungi and obtained Rhizoctonia pure cultures. Forty-nine Rhizoctonia isolates were obtained from alliums in Brazil. Genomic DNA was extracted from all Rhizoctonia isolates, and PCR amplifications from the ITS-rDNA region were made with the ITS1 and ITS4 primers. PCR products were purified and sequenced. Nucleotide sequences from Rhizoctonia reference isolates obtained from GenBank were included in the analyses, and phylogenetic relationships were analyzed by Maximum Likelihood method. Phylogenetic analysis of the ITS region allowed the identification of four AGs, two from R. solani (AG-4 HGI and AG-4 HGIII) and four from Rhizoctonia binucleate (AGA-A, AG-F, AG-K, and Lineage 1). Two isolates did not cluster with any AG described so far. This is the first report worldwide of the association of AG-4 HGIII with alliums. AG-A was the most frequent (38.8%), found in 13 production areas, followed by AG-4 HGI (306%), found in 12 production areas. This is the first detailed report of the AG composition of Rhizoctonia associated to alliums in Brazil and expands the knowledge on this subject in Brazil and in the world.

BANKING MEMBERS:
Presidente - KAMILA CAMARA CORREIA
Interno - CLAUDENER SOUZA TEIXEIRA
Interno - JUAN CARLOS ALVAREZ PIZARRO
Externa à Instituição - ANA PAULA OLIVEIRA DE BARROS - UFRPE