Transgene expression of lilies grown in the greenhouse and outdoors

Authors: Kamo, Kathryn

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2013
Publication Date: 1/28/2014
Publication URL: http://handle.nal.usda.gov/10113/58539
Citation: Kamo, K.K. 2014. Transgene expression of lilies grown in the greenhouse and outdoors. Scientia Horticulturae. 167:158-163.

Interpretive Summary: Lilies are one of the most important flowers marketed as a cutflower, pot plant, and for the garden. They are multiplied by bulbs, and a small bulb will produce a large flower that can be marketed after three seasons of growth in the field. The main problem in the U.S. when growing lilies in the field is nematodes. Because we are interested in genetic engineering of lilies for nematode resistance, it is important to investigate the expression of a transgene during growth under actual environmental conditions outdoors and in a greenhouse and to verify continuous transgene expression during several seasons of growth. This study compares expression of two selectable marker genes (bar and neomycin phosphotransferase) and the GUS reporter gene in genetically engineered lilies grown two seasons in the greenhouse and outdoors. During the first year there was no difference in bar protein level between plants grown in the greenhouse and outdoors, but the second year two of the seven transgenic plant lines grown outdoors showed a significantly higher level of the bar protein than plants grown in the greenhouse. Expression of three transgenes was stable in lilies grown two seasons in the greenhouse or outdoors confirming the stability of transgene expression over multiple seasons of outdoor growth.

Technical Abstract: Lilium longiflorum cv. Nellie White plants were transformed with either the bar-uidA fusion gene or the npt II and uidA genes and grown for two seasons in the greenhouse and outdoors in containers. All transgenes were under control of the CaMV 35S promoter. During the first year there was no difference in bar protein level between plants grown in the greenhouse and outdoors, but the second year two of the seven transgenic plant lines grown outdoors showed a significantly higher level of the bar protein than plants grown in the greenhouse. The most pronounced differences in expression of the bar protein occurred between the two seasons. Six of the seven transgenic lines showed a higher level of the bar protein the second year as compared to the first year. One plant line contained the npt II gene, and npt II protein expression was comparable when plants were grown in the greenhouse or outdoors for two seasons. Four plant lines expressed GUS as determined by histochemical staining of their leaves. Three of these four plant lines showed dark blue staining along the cut edges of the leaf when plants were grown either in the greenhouse or outdoors for both seasons. The fourth plant line showed either dark blue staining along the cut edge of the leaf or small, light blue spots on parts of the leaf depending on the plant stained. Expression of the three genes was confirmed using semi-quantitative RT-PCR.