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Identification and Characterization of the Defensin-Like Gene Family of Grapevine

August 2012 , Volume 25 , Number  8
Pages  1,118 - 1,131

Lisa Giacomelli,1 Valentina Nanni,2 Luisa Lenzi,1 Jun Zhuang,3 Mauro Dalla Serra,4 Mark J. Banfield,5 Christopher D. Town,3 Kevin A. T. Silverstein,6 Elena Baraldi,2 and Claudio Moser1

1IASMA Research and Innovation Centre, Fondazione Edmund Mach, via E. Mach 1, 38010 San Michele all'Adige, (TN), Italy; 2DIPROVAL-Criof, University of Bologna, viale Fanin 46, 40127, Bologna Italy; 3The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, U.S.A.; 4Institute of Biophysics, National Research Council & Bruno Kessler Foundation, via alla Cascata 56/C, 38123 Trento, Italy; 5Department of Biological Chemistry, John Innes Centre, Colney Lane, Norwich, NR4 7UH, U.K.; 6Department of Biostatistics and Bioinformatics, Masonic Cancer Center, University of Minnesota, 425 Delaware Street, SE MMC 806, Minneapolis 55455, U.S.A.

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Accepted 12 April 2012.

Defensins are a class of small and diverse cysteine-rich proteins found in plants, insects, and vertebrates, which share a common tertiary structure and usually exert broad-spectrum antimicrobial activities. We used a bioinformatic approach to scan the Vitis vinifera genome and identified 79 defensin-like sequences (DEFL) corresponding to 46 genes and allelic variants, plus 33 pseudogenes and gene fragments. Expansion and diversification of grapevine DEFL has occurred after the split from the last common ancestor with the genera Medicago and Arabidopsis. Grapevine DEFL localization on the ‘Pinot Noir’ genome revealed the presence of several clusters likely evolved through local duplications. By sequencing reverse-transcription polymerase chain reaction products, we could demonstrate the expression of grapevine DEFL with no previously reported record of expression. Many of these genes are predominantly or exclusively expressed in tissues linked to plant reproduction, consistent with findings in other plant species, and some of them accumulated at fruit ripening. The transcripts of five DEFL were also significantly upregulated in tissues infected with Botrytis cinerea, a necrotrophic mold, suggesting a role of these genes in defense against this pathogen. Finally, three novel defensins were discovered among the identified DEFL. They inhibit B. cinerea conidia germination when expressed as recombinant proteins.

© 2012 The American Phytopathological Society