Proceedings of the XLVII Italian
Society of Agricultural Genetics - SIGA Annual Congress
Verona,
Italy - 24/27 September, 2003
ISBN 88-900622-4-X
Poster
Abstract - 1.26
PLUM POX VIRUS
(PPV) RESISTANCE: PRODUCTION OF TRANSGENIC PLANTS EXPRESSING RECOMBINANT
INTRON-SPLICED PPV HAIRPIN RNAs
E. DI
NICOLA-NEGRI, A. BRUNETTI, V. INNOCENZI, V. ILARDI
Istituto
Sperimentale per la Patologia Vegetale, Via C.G. Bertero 22, 00156 Rome, Italy,
Fax +39.06.86802296
fisiopatologia@ispave.it
PPV,
transgenic plants, RNA silencing
Sharka is the
most important disease of stone fruits in terms of agronomic impact and
economic importance. The disease is caused by Plum pox potyvirus (PPV)
a single-stranded RNA virus. There are five PPV strains but the two major and
agronomically important are D and M. Until now no useful natural resistance has
been found against this pathogen.
Transgenic
expression of pathogen-derived sequences encoding self-complementary
“hairpin” RNA that undergo to an efficient and predictable
posttranscriptional silencing (Smith et al., 2000. Nature,
407:319-320) is a new and agricultural sustainable strategy to obtain
virus-resistant plants avoiding the production of transgenic viral proteins.
Four PPV genomic
sequence regions, highly homologous between D and M strains, were selected by in
silico analysis as potential silencing targets. One of the
four sequences starts at the 5’ end of PPV genome and includes a part of
the P1 gene, the other three partially cover the HC-Pro gene that encodes the
viral suppressor of RNA silencing. Each predicted-region was amplified by
RT-PCR from a PPV M Italian isolate and arranged to form an intron-spliced RNA
hairpin structure. The four sequences were introduced by Agrobacterium
transformation into Nicotiana benthamiana plants under the
transcriptional control of a cauliflower mosaic virus 35S promoter. Virus
resistance experiments to test the ability of the different constructs to
interfere with PPV replication are in progress.