Banca de QUALIFICAÇÃO: Sheila Freitas de Almeida

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Sheila Freitas de Almeida
DATE: 31/03/2023
TIME: 08:30
LOCAL: Videoconferência
TITLE:

"DIVERSITY AND DISTRIBUTION OF A NEW SPECIES, Meloidogyne izalcoensis, PARASITING COFFEE PLANTS IN THE TRIÂNGULO MINEIRO: RESISTANCE AND MECHANISMS IN GENOTYPES OF Coffea spp."

KEY WORDS:

Coffea arabica, Coffea canephora, genetic variability, resistance to nematodes.

PAGES: 160
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Root-knot nematodes (RKNs), Meloidogyne spp. are considered important pathogens of coffee crops that can limit production and cause economic losses. Meloidogyne izalcoensis was recently detected in Brazil parasitizing coffee trees in Triângulo Mineiro, MG. The objectives of this research were: (i) to identify species of Meloidogyne spp. in coffee plantations present in the Triângulo Mineiro and delimit areas with occurrence of M. izalcoensis, (ii) study the diversity of Brazilian and foreign populations of M. izalcoensis, using RAPD, AFLP, ITS, D2D3, COII and Hsp90 markers, (iii) evaluate the resistance reaction of coffee cultivars available in Brazil to Meloidogyne izalcoensis, (iv) to analyze the hostability reaction of different intercrops and antagonistic plants to M. izalcoensis and (v) to carry out the comparative histopathology study of the susceptible cultivar Mundo Novo and of the resistant cultivar to be selected from Coffea spp. to M. izalcoensis in order to understand the resistance mechanisms involved. Considering that, SCAR-coffee makers were used, this kit can detect all species from Brazil in multiplex. Based on esterase phenotypes and SCAR markers, RKNs were detected in 79.17% of the total samples. The species M. exigua (562 bp), M. incognita (399 bp), M. paranaensis (208 bp), and M. izalcoensis (670 bp), were 3 detected in 41.67%, 33.33%, 20.83% and 4.17% of samples, respectively. Mixed populations were observed also in 20.83%, i.e. M. paranaensis + M. exigua (8.33%) or M. incognita + M. exigua (12.5%). Meloidogyne exigua was the prevalent species, occurring in most samples. This survey confirmed that M. izalcoensis has a restricted occurrence in the region, where it was initially detected and confirmed the occurrence of other coffee Meloidogyne species in the state of Minas Gerais. Based on random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers, low intraspecific variability was detected among M. izalcoensis populations from Africa, Vietnam and Brazil, but the population from El Salvador showed fewer genetic differences from the other populations. Phylogenetically, all populations of M. izalcoensis from different locations (El Salvador, Kenya, Tanzania, Vietnam and Brazil) grouped with 90% and 69% bootstrap support for COII and HSP90 regions, respectively, indicating that these markers are highly conserved for the species. In addition, both markers enabled separation of M. izalcoensis populations from other important coffee Meloidogyne species, including M. exigua, M. paranaensis, M. incognita, M. arabicida and M. lopezi. In resistance studies, most genotypes tested that had resistance to other Meloidogyne spp. (Amphillo × Catuaí, Hybrid of Timor, IAPAR 59, IPR 99, IPR 100, IPR 102, IPR 103, IPR 105, IPR 106, IPR 107 and IPR 108) were found to be susceptible to M. izalcoensis, except for the rootstock cv. Apoatã IAC 2258, which proved to be moderately resistant, with a genetic segregation for this character of 43.8%. In the two intercrop host status assays, most of the botanical species tested were classified as non-hosts or immune to M. izalcoensis, and only tomato showed good host (RF=13.9 and RF 20.6). In the first experiment, five plants were classified as bad hosts: Echinocloa crus-galli L. P. Beauv, Echinocloa colonum (L.) Link, Panicum maximum Jacq, Glycine max L. Mer. and Triticum aestivum L. In the second experiment, four were classified as bad hosts: Avena sativa L., Echinocloa colonum (L.) Link, Eleusine indica L. and Glycine max L. Mer.

BANKING MEMBERS:
Externo à Instituição - JADIR BORGES PINHEIRO - EMBRAPA
Externo à Instituição - JANSEN RODRIGO PEREIRA SANTOS - UFSM
Presidente - 6404906 - JUVENIL ENRIQUE CARES
Externo ao Programa - 1713558 - MARCELO FAGIOLI
Externo à Instituição - OLIVEIRO GUERREIRO FILHO - IAC
Externo à Instituição - VALDIR RIBEIRO CORREIA - IFTO