Open AccessA High Level of Transgenic Viral Small RNA Is Associated with Broad Potyvirus Resistance in Cucurbits
Author(s) -
Diana Leibman,
Dalia Wolf,
Vinod Saharan͙,
Aaron Zelcer,
Tzahi Arazi,
Yoel Moshe Shiboleth,
Victor Gaba,
Amit GalOn
Publication year - 2011
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi-05-11-0128
Subject(s) - potyvirus , zucchini yellow mosaic virus , biology , small interfering rna , rna silencing , rna interference , gene silencing , virology , transgene , melon , gene , rna , genetically modified crops , microbiology and biotechnology , small rna , plant virus , virus , genetics , horticulture
Gene-silencing has been used to develop resistance against many plant viruses but little is known about the transgenic small-interfering RNA (t-siRNA) that confers this resistance. Transgenic cucumber and melon lines harboring a hairpin construct of the Zucchini yellow mosaic potyvirus (ZYMV) HC-Pro gene accumulated different levels of t-siRNA (6 to 44% of total siRNA) and exhibited resistance to systemic ZYMV infection. Resistance to Watermelon mosaic potyvirus and Papaya ring spot potyvirus-W was also observed in a cucumber line that accumulated high levels of t-siRNA (44% of total siRNA) and displayed significantly increased levels of RNA-dependent RNA (RDR)1 and Argonaute 1, as compared with the other transgenic and nontransformed plants. The majority of the t-siRNA sequences were 21 to 22 nucleotides in length and sense strand biased. The t-siRNA were not uniformly distributed throughout the transgene but concentrated in “hot spots” in a pattern resembling that of the viral siRNA peaks observed in ZYMV-infected cucumber and melon. Mutations in ZYMV at the loci associated with the siRNA peaks did not break this resistance, indicating that hot spot t-siRNA may not be essential for resistance. This study shows that resistance based on gene-silencing can be effective against related viruses and is probably correlated with t-siRNA accumulation and increased expression of RDR1.