Identification of new bacterial species in the Xanthomonas genus pathogenic to genipap (Genipa americana) by biochemical, phisiological, pathogenic and molecular characterization

• Grant number: 12/11760-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2013
• End date: October 31, 2014
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Suzete Aparecida Lanza Destéfano
• Grantee: Thais Massanet
• 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

The genipap is a vegetal of economical importance due its forest essence and by the utilization of its fruits in food production, mainly in the Northeast of Brazil, where the genipap has also great social and cultural importance. The smooth trunk of up to 15 m tall provides a white wood easy to handle and with good quality for use in furniture manufacturing and construction; its fermented juice is used in the preparation of wine and liquor; all parts of this plant are used in folk medicine; its leaves and crushed fruits are eaten by goats, cattle and pigs and also this tree is indicated in the recovery of degraded areas since it is a species that stands up well to flooding. Regarding to pests and diseases that affect the genipap, the literature mentions some phytopathogenic fungi, occurring mainly in the north and northeast of Brazil, but there are no reports of phytopathogenic bacteria. In 2007, Rodrigues Neto et al. isolated one bacterium, belonging to Xanthomonas genus, causing large necrotic lesions on genipap leaves on fields located in the county of Ilha Solteira, state of São Paulo, Brazil; and preliminary tests indicated the that it is, probably, a new bacterial species within the genus. Although the isolates had produced xanthomonadina, characteristic of the Xanthomonas genus, differences were observed with respect to cultural characteristics, such as slow development of the culture (5-7 days), growing only in artificial media supplemented, unusual features in this genus. Moreover, in the molecular tests of PCR-RFLP (restriction fragment length polymorphism) of the 16S rDNA, using nine different restriction enzymes, it was found that the isolates showed different genetic profiles comparing with 21 genomic species of Xanthomonas. This project aims the characterization of nine strains of Xanthomonas sp. isolated from genipap through biochemical and physiological tests, molecular tests using multilocus analysis with ATPA genes, dnaK, fyuA, gyrB, recA, rpoA, rpoB, and rpoD, and pathogenicity tests on different host plants of the Rubiaceae family through artificial inoculation.