Banca de QUALIFICAÇÃO: Gustavo Henrique Silva Peixoto

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Gustavo Henrique Silva Peixoto
DATE: 03/11/2022
TIME: 08:00
LOCAL: Videoconferência - Teams
TITLE:

Etiology of pink root and evaluation of sources of resistance in garlic and onion. 

KEY WORDS:

fungi, plant pathology, phytopathology, alliaceae, taxonomy.

PAGES: 59
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Pink root is the main disease of garlic and onion in plantations carried out in periods of drought stress and high temperatures, and/or areas with successive garlic and/or onion crops. The symptoms of the disease are easily seen due to the light pink coloration of the roots. These symptoms progress to short, waterlogged roots of intense purple coloration that disintegrate and die. The newly formed roots are infected and cause delay in growth, etiolation and wilting of the leaves that result in the formation of smaller and poor quality bulbs for storage. The soil-borne fungi, Setophoma terrestris and Fusarium spp., are often associated with the pink root. While S. terrestris is considered the main causal agent of the disease in garlic and onions, the association of Fusarium species with the disease is not well understood in the literature. Both genera have a wide range of hosts, therefore, the combination of genetic resistance associated with crop rotation with non-host plants is an efficient strategy for managing the disease. Therefore, this project aims to (i) clarify the etiology of the pink root of garlic and onion; (ii) determine the predominant species in the cultivation areas; (iii) to evaluate the pathogenicity of Setophoma and Fusarium isolates in garlic and onion; (iv) determine the potential for multiplication and survival of S. terrestris in the main hosts cultivated in areas where garlic and onion are planted; (v) to evaluate the reaction of garlic and onion genotypes to S. terrestris; (vi) estimating the size of the S. terrestris genome; (vii) assemble and annotate S. terrestris mitochondrial and nuclear genome sequences; (viii) annotate the mating-type locus of S. terrestris to demonstrate haploid or diploid genomic organization. The isolates were collected in the states of Bahia, Goiás, Minas Gerais, Paraná, São Paulo, Santa Catarina and Distrito Federal and obtained from garlic, leeks, brachiara, onions, chives and corn with typical symptoms of pink root. Cultures obtained from the tip of the hypha were used for morphological characterization and sequencing of the genomic regions internal transcribed spacer of rDNA (ITS), elongation factor (EF1-α), glyceraldehyde-3- phosphate dehydrogenase (GAPDH), RNA Polymerase II (RPB2), larger rDNA subunit (28S rDNA) and β-tubulin (TUB). Among the 81 isolates, 50 were identified as Setophoma terrestris while the others were recognized as Fusarium annulatum, F. acutatum, F. bostrycoides (=Neocosmospara bostrycoides), F. elaeidis, F. fabacearum, F. falciformis (=Neocosmospara falciformis), F. lacertarum, F. nirenbergiae¸ F. proliferatum and F. solani (=Neocosmospara solani). Pathogenicity tests prove that only S. terrestris causes pink root in garlic and onions. The sequencing of the S. terrestris genome using the Illumina NovaSeq 6000 Platform allows estimating a genome of approximately 53 MB. The genome draft assembly contains 6,094 scaffolds, with the largest scaffold size being 177,660 bp and the N50 value of 21,707 bp. Pathogenicity tests in different hosts and the reaction of garlic and onion genotypes will be performed with the isolate CCUB2754. The genome sequencing of S. terrestris using the PacBio platform will also be performed for complete genome assembly and annotation of the mating-type locus. The new information obtained in this project will be fundamental for breeders and plant pathologists in the development of garlic and onion genotypes that are more tolerant to pink root and will help the efficient management of the disease in the field.

BANKING MEMBERS:
Externo à Instituição - EVERALDO ANTONIO LOPES - UFV
Externo ao Programa - 1701961 - CLEBER FURLANETTO
Presidente - 2254987 - DANILO BATISTA PINHO
Externo ao Programa - 1703888 - HELSON MARIO MARTINS DO VALE
Interno - 3051226 - MAURICIO ROSSATO
Interno - 2644635 - ROBERT NEIL GERARD MILLER