Poster: Plant-pathogen interactions

Abs # 540: Strategies to Improve Agrobacterium-mediated Transformation of Plants

Presenter:	Sandal, Indra , sandalindra@yahoo.com
Authors	Sandal, Indra  (A)   Ye, Xingguo  (A)   Sato, Shirley  (B)   Gu, Sanjun  (A)   Li, Jianxiong  (C)   Tzfira, Tzvi  (C)   Clemente, Tom  (A) (D)
Affiliations:	(A): Dept of Agronomy & Horticulture,University of Nebraska, Lincoln (B): Center for Biotechnology, University of Nebraska, Lincoln (C): Dept. of Biochemistry & Cell Biology State University of New york (D): Plant science Initiative, University of Nebraska, Lincoln

Two approaches that have been used to modulate transformation frequencies of Agrobacterium tumefaciens gene transfer protocols of plants, enhancing factors of A. tumefaciens, and/or altering the phenotype of the plant cell to be more competent for T-DNA transfer and/or integration. We are exploring avenues addressing both of these aspects. With respect to the former, we are attempting to generate a suicide A. tumefaciensstrain by integrating into the bacterial genome the sacB gene that encodes for levansucrase, thereby circumventing antibiotic media supplements required for counter selection of the bacterial cells during the regeneration steps. We address the latter approach by expressing an Arabidopsis putative transcription factor designated VIP1, which has previously been shown to directly interact with the T-DNA via VirE2 and assist in guiding the T-complex to the nuclear compartment. Moreover, expression of VIP1 in tobacco resulted in enhanced transformation frequency in subsequent re-transformation experiments. To test this in a major crop plant, we simultaneously delivered a VIP1 cassette via a two T-DNA binary plasmid to derive marker-free transgenic soybean. A total 4 lines have been generated that highly express the VIP1 transgene and are free of the corresponding marker gene cassette. Studies are underway to characterize the suicide A. tumefaciens strain, and the impact of VIP1 expression in soybean as a means to enhance transformation frequencies.