Preliminary evaluations of biotechnology strategies to citrus canker control (Xanthomonas axonopodis pv. citri) in lemon plant.

FILIPPONE, M. P.; SENDÍN, L. N.; VILLA, P.; RAMALLO, J.; MARANO, M. R.; VOJNOV, A.; CASTAGNARO, A. P.

Santo Domingo, República Dominicana

Otro; V Encuentro Latinoamericano y del Caribe de Biotecnología Agrícola (REDBIO 2004); 2004

REDBIO

Citrus canker is a disease of commercial citrus cultivars and some citrus relatives caused by the bacterium Xanthomonas axonopodis pv. Citri (Xac). In this research was evaluated the potential capacity to protect against this disease in lemon plants, of two commercial products used for the diseases biocontrol: BTH (benzo (1,2,3) thiadaizole-7-carbothioic acid S-methyl ester) and Gluticid (bioproduct obtained from  Pseudomonas aeruginosa, strain PSS). Also was evaluated a mutant of Xanthomonas campestris pv campestris  (Xcc 8557) which overproduced DSF (a dodecenoic cis-methyl-2-acid, a a,b unsaturated fatty acid), involved in virulence factors regulation through of cellular density or “quorum sensing” in Xcc. Eureka and Lisboa lemon plants (Citrus limon) at one year-old, were sprayed with BTH  at 1.5 mM or Gluticid at 500ppm, two weeks before the inoculation with Xac. The inoculation was realized by spraying a Xac suspension (DO= 0.1) over leaves which was previously injured with a sharp needle. In case of treatment with Xcc 8557, it was co-inoculated with Xac by infiltration a suspension at DO= 0.5 and 0.1, respectively, in the leave adaxial side. Then of inoculation, the plants were maintained under controlled conditions. The gluticid treatment was more effective than BTH, since in the first one there was not cankers development, in the second only there was a symptoms severity reduction. On the  same way, the co-inoculation treatment shown a strong disease inhibition. These results show three promising alternatives of biocontrol for citrus canker less harmful for the environment than the synthetic agrochemical based on copper commonly used.