IBBM   21076
INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
ihpCP Sweet Orange transgenic lines are resistant to Psorosis A and Psorosis B
Autor/es:
GARCIA, M.L.; COSTA, N.; DE FRANCESCO, A.
Lugar:
Chongqing
Reunión:
Conferencia; XX Conference of the IOCV; 2016
Institución organizadora:
International Organization of Citrus Virologists (IOCV)
Resumen:
Citrus psorosis is a serious disease caused by Citrus psorosis virus (CPsV). Two different psorosis syndromes has been described, called Psorosis A (PsA) and Psorosis B (PsB). The most common PsA affects only the trunk and main branches, showing bark scaling and gum accumulation, and PsB, the most aggressive, shows severe lesions in the bark causing its detachment and gum accumulation and pustules, even on young branches.Transgenic Pineapple sweet orange (Citrus sinensis L. Osb.) were generated expressing hairpin structures containing a fragment of the viral coat protein (cp) gene from CPsV 90-1-1 isolate. These transgenic lines, called ihpCP induced post transcriptional gene silencing for cp gene, and were resistant to the homologous isolate, which causes a PsA syndrome. IhpCP plants resulted asymptomatic and no virus was detected by RT-PCR and TAS-ELISA (Reyes et al., 2011).In this work we selected the lines ihpCP-10 and -15, which were propagated on rough lemon and challenged with the heterologous CPsV 189-34 isolate from Concordia (Entre Rios, Argentina), which causes strong PsB syndrome. A local alignment between CPsV 189-34 (PsB) and CPsV 90-1-1 (Ps A) sequences was performed showing identity of 93%.Plants were challenged with CPsV 189-34 by grafting, and the evolution of infection was analyzed through three successive flushes. The ihpCP-15 line resulted totally resistant in 8 of the 8 inoculated plants, without psorosis symptoms, and no virus was detected by molecular tests. The ihpCP-10 plants showed partial resistance. Some individuals became infected from the second flush, but with lower viral titers and fainter PsB symptoms than non-transgenic control. This results show that the ihpCP transgene protects the plants against not only PsA, but also Ps B. Besides the ihpCP- 15 line is more efficient against a heterologous isolate than ihpCP-10 in the first three successive flushes.