Detecção de resistência a Fusarium oxysporum f. sp. lycopersici e biocontrole da murcha de fusário em tomateiro com Bacillus sp.

• Ano de defesa: 2014
• Autor(a) principal: Carrer Filho, Renato
• Orientador(a): Cunha, Marcos Gomes da
• Banca de defesa: Dianese, Érico de Campos, Nascimento , Abadia dos Reis, Ferreira, Adriane Wendland, Neves, Dora Marchiori Silva, Macagnan, Dirceu
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Agronomia (EAEA)
• Departamento: Escola de Agronomia e Engenharia de Alimentos - EAEA (RG)
• País: Brasil
• Palavras-chave em Português: Controle biológico; Melhoramento genético; Parasitismo; Solanaceae
• Palavras-chave em Inglês: Biological control; Genetic breeding; Parasitism; Solanaceae
• Área do conhecimento CNPq: AGRONOMIA::FITOSSANIDADE; FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/5008

The tomato is a solanaceous plant who became quite prominent in the last century, not only by the pleasant taste, but also for being a rich source of amino acids, organic acids, vitamins, as well as the high concentration of beneficial substances, including lycopene. To meet the growing demand for tomatoes, various breeding programs were executed, aiming an increment in production, productivity and fruit quality, such as the reduction of secondary metabolites. By proceeding crossings to improve agronomic traits of the culture, genes conferring hardiness and hence resistance to disease were probably lost, favoring the increased attack of pests and diseases. Among the most troubling diseases stands the vascular wilt caused by Fusarium oxysporum f. spp. lycopersici. The difficulty of controlling this disease comes from the intrinsic characteristics of the pathogen, such as high adaptability to the underground environment while associated with the host and the production of resistance structures that remain viable in the soil for a long time. Genetic resistance stands out as the main tool in the control of this pathogen, which requires a continuous accession characterization program and the identification of sources of resistance, ensuring the introgression of 'I' genes that express resistance to physiologic races of the pathogen. Coupled with genetic resistance, the use of microorganisms as antagonists and their introduction in the pathogen´s microhabitat has become a promising alternative in the context of the management of root diseases of tomato, highlighting the colonizing bacteria from the rhizosphere of plants, termed rhizobacteria, as the main biocontrol agents. This study aimed to identify resistant tomato accessions to three physiological races of Fusarium oxysporum f. spp. lycopersici, by morphological and molecular methods, as well as detect multiple sources of resistance from the germplasm bank of EMBRAPA CNPH. The assay consisted of an evaluation of 28 varieties, 3 hybrids, 32 strains and 19 wild accessions, totaling 82 accessions. The susceptibility or resistance was confirmed by visualization of DNA bands on an agarose gel generated by specific molecular markers capable of amplifying regions of the target genes I-1, I-2 and I-3, expressing resistance to classes 1, 2 and 3 of F. oxysporum f. spp. lycopersici, respectively. To enhance the durability of this resistance, 10 rhizobacteria of the Bacillus genus were tested as biocontrol agents of wilt in greenhouse assays. In parallel, in vitro root colonization, antibiosis and detection of potential biocontrol genes involved in the tests were conducted. All Bacillus isolates showed variable levels of control of the pathogen in vitro, while the UFG-07 (Bacillus subtilis) and UFG-10 (Bacillus circulans) isolates have excelled in disease suppression in the greenhouse, which reinforces the hypothesis of substances acting as an antimicrobial control.