Characterization of Soybean mosaic virus resistance derived from inverted repeat-SMV-HC-Pro genes in multiple soybean cultivars.

Le Gao, Xueni Ding, Kai Li, Wenlin Liao, Yongkun Zhong, Rui Ren, Zhitao Liu, Karthikeyan Adhimoolam, Haijian Zhi

TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik 2015 Aug

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Soybean mosaic virus resistance was significantly improved in multiple soybean cultivars through genetic transformation induced by inverted repeat-SMV- HC - Pro genes based on RNAi and post-transcriptional gene silencing. Here, we demonstrate Soybean mosaic virus (SMV) resistance in transgenic soybean plants. Transformation of five soybean genotypes with a construct containing inverted repeat-SMV-HC-Pro genes-induced high-level SMV resistance. Through leaf-painting assays, polymerase chain reaction (PCR) verification and LibertyLink(®) strip detection, 105 T0 and 1059 T1 plants were confirmed as transgene-positive. Southern blotting confirmed insertion of the T-DNA into the genomic DNA and revealed a low-copy integration pattern. Most T0 plants were fertile and transmitted the exogenous genes to their progenies (ratios of 3:1 or 15:1). In the T1 generation, virus resistance was evaluated visually after inoculation with SMV (strain SC3) and 441 plants were highly resistant (HR). SMV disease rating was classified on a scale with 0 = symptomless and 4 = mosaic symptoms with severe leaf curl. In the positive T1 plants, the disease rating on average was 1.42 (range 0.45-2.14) versus 3.2 (range 2-4) for the nontransformed plants. With the T2 generation, 75 transgene-positive plants were inoculated with SC3, and 57 HR plants were identified. Virus-induced seed coat mottling was eliminated in the resistant lines. Analysis of SMV levels in the plants was performed using quantitative real-time PCR and double-antibody sandwich enzyme-linked immunosorbent assays; the results revealed no virus or a gradual reduction over time in the viral content, thereby supporting the visual examination results. This is the first report demonstrating pathogen-derived resistance to SMV induced by inverted repeat-SMV-HC-Pro genes in multiple soybean cultivars. Our findings contribute positively to the study of transgenic SMV-resistance using RNA interference.

Citation

Le Gao, Xueni Ding, Kai Li, Wenlin Liao, Yongkun Zhong, Rui Ren, Zhitao Liu, Karthikeyan Adhimoolam, Haijian Zhi. Characterization of Soybean mosaic virus resistance derived from inverted repeat-SMV-HC-Pro genes in multiple soybean cultivars. TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik. 2015 Aug;128(8):1489-505