Submitted to: Plant Cell Tissue And Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 14, 2011
Publication Date: January 29, 2012
Citation: Kamo, K.K., Aebig, J., Guaragna, M.A., James, C., Hsu, H., Jordan, R.L. 2012. Transgenic Gladiolus plants containing single-chain fragment antibodies to Cucumber mosaic virus. Plant Cell Tissue And Organ Culture. 110:13-21. Interpretive Summary: Cucumber mosaic virus (CMV) is a major problem for over 800 plant species including Gladiolus and other flower bulb crops. Gladiolus crops are propagated vegetatively along with the virus each year. The virus causes streaking of the flowers making them unmarketable, and results in a decrease in plant size and corm yield. There are no commercial cultivars of Gladiolus that are resistant to CMV. This study describes the use of single chain variable fragment antibodies to CMV for conferring resistance to CMV. Six out of 88 Gladiolus plant lines with the single chain variable fragment antibodies to CMV were found resistant to CMV 1-2 months after the plants were challenged with CMV. This demonstrates the possibility of using this gene for developing Gladiolus plants resistant to CMV, but other genes have been shown to confer resistance in Gladiolus at a higher frequency.
Technical Abstract: Transgenic plants of Gladiolus ‘Peter Pears’ or ‘Jenny Lee’ were developed that contain single-chain variable fragments (scFv) to Cucumber mosaic virus (CMV) subgroup I or II. The CMV subgroup I heavy and light chain scFv fragments were placed under control of either the duplicated CaMV 35S or sugarcane Ubi9 promoters. Integration of the transgenes was verified by Southern hybridization. Plants were challenged in vitro by inoculating with purified CMV using the Helios hand-held gene gun. An initial pathogen challenge was performed using 6 plants/plant line for the 51 lines containing the CMV subgroup I and 37 lines with the CMV subgroup II scFv fragments. Four plant lines with the CMV subgroup I scFv and 4 lines with the CMV subgroup II scFv were selected for further challenging. Less than 30% of the plants challenged from two plant lines with the CMV subgroup I scFv and three plant lines with the CMV subgroup II scFv were resistant and did not have CMV as compared to 70% for the non-transformed control plants. Less than 40% of the plants from two other plant lines with the CMV subgroup I scFv were shown to be resistant 1-2 months after challenge. These eight plant lines that showed resistance and two susceptible lines expressed the transgene as determined by Northern hybridization and reverse transcriptase PCR.