Characterization of taxtomina a produced by Streptomyces spp. strains and evaluation of commercial cultivars for resistance to potato scab

• Grant number: 16/19709-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2017
• End date: June 30, 2018
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Suzete Aparecida Lanza Destéfano
• Grantee: Marcel Costa Alpiste
• Host Institution: Instituto Biológico (IB). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Potato is a crop of great economic importance in many countries and its productivity increasing. However, the production is considered low due to diseases such as potato scab, caused by different species of Streptomyces. The pathogenic mechanism of most species of this genus involves different factors such as Nec1 and tomatinase proteins which help in evading the defense of the host and Thaxtomin-A, responsible for penetration, colonization and development of the lesions. This study aims to characterize the phytotoxin thaxtomin-A produced by different strains of Streptomyces and verify if there is correlation between its production and severity of the disease. Moreover, the project will also evaluate the resistance of commercial varieties to potato scab by means of in vitro assays. Ten strains of Streptomyces.spp, provided by the Phytobacteria Culture Collection of Instituto Biológico (IBSBF), Campinas, SP, and considered with high, moderate and low virulence will be used for the tests of production and extraction of thaxtomin-A. The phytotoxin will be analyzed by Thin Layer Chromatography (TLC) and its concentration will be determined by High Performance Liquid Chromatography (HPLC). In the pathogenicity tests in vitro, the susceptibility of potato cultivars will be investigated against ten strains of Streptomyces on potato tuber slices, provided by the Associação Brasileira da Batata (ABBA). Thus, it is expected to be possible to correlate the amount of thaxtomin-A produced with the virulence of the strains. It is also expected to select cultivars less susceptible to this important disease on potato. (AU)