Banca de DEFESA: PLÍNIO BEZERRA PALÁCIO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : PLÍNIO BEZERRA PALÁCIO
DATA : 03/03/2020
HORA: 14:00
LOCAL: Centro de Ciências Agrárias e da Biodiversidade (CCAB)
TÍTULO:

DIVERSITY AND PATHOGENICITY OF RHIZOCTONIA ANASTOMOSIS GROUPS ASSOCIATED WITH CAUPI BEANS FROM CARIRI REGION OF CEARA STATE - BRAZIL 

PALAVRAS-CHAVES:

Rhizoctonia. Vigna unguiculata. Anastomosis group. ITS sequences. Phylogeny.

PÁGINAS: 45
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

The fungus of the genus Rhizoctonia causes one of the main diseases of cowpea, the most important food legume in the Northeast of Brazil and with large planted area in the Cariri cearense region. The identification of this fungus is based mainly on the classification into hyphal anastomosis groups (AGs). The present study was undertaken to determine: a) which Rhizoctonia species and AGs that occur in cowpea production areas in Cariri cearense using internal transcribed spacer region (ITS) sequencing of ribosomal DNA (rDNA), and b) the variation in aggressiveness among the different AGs associated with this legume. Cowpea plants with stem and root rot symptoms, typical of those induced by Rhizoctonia, were collected in 32 production areas located in 18 municipalities of Cariri cearense, during 2018 and 2019. From symptomatic plant materials were performed isolations of the associated fungi and obtained Rhizoctonia pure cultures. Forty-one Rhizoctonia isolates were obtained from cowpea areas in Cariri cearense. 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 analyzes and phylogenetic relationships were analyzed by Maximum Likelihood methods. The pathogenicity and aggressiveness of isolates representing the AGs identified were tested on cowpea plants. Phylogenetic analysis of the ITS region allowed the identification of four AGs, two from R. solani (AG-4 HGI and AG-4 HGIII) and two from Rhizoctonia binucleate (AG-Fa and AG-L). This is the first report worldwide of the association of AG-4 HGIII, AG-Fa and AG-L with cowpea. AG-4 HGI was the most frequent (53.7%), being widely distributed in Cariri cearense. Among the cowpea producing municipalities in this region, Mauriti presented the highest diversity of AGs (AG-4 HGI, AG-4 HGIII and AG-Fa). All isolates were pathogenic to cowpea and there was a difference in aggressiveness between the different isolates within the same Rhizoctonia AG. To our knowledge, this is the first detailed report of the AG composition of Rhizoctonia associated to cowpea in Cariri cearense and expands the knowledge on this subject in Brazil and in the world.

MEMBROS DA BANCA:
Externo à Instituição - ELIANE MAYUMI INOKUTI - UFC
Interno - 2185176 - FRANCISCO NASCIMENTO PEREIRA JUNIOR
Presidente - 1123441 - KAMILA CAMARA CORREIA
Externo ao Programa - 1528282 - MARCOS ANTONIO PEREIRA DE LIMA