Poster: Plant Pathogen/Symbiont Interactions

Abs # 760: Generation of barley plants containing Ds-bordered transgenes encoding antifungal proteins: a resource for generating marker-free plants with stable expression of fungal resistance

Presenter:	Yu, Xiao-Hong , XHYu@nature.berkeley.edu
Authors	Yu, Xiao-Hong  (A)   Bregitzer, Phil P. (B)   Cho, Myeong-Je  (A)   Chung, Michael L. (A)   Yoo, Hyun-Sook  (A)   Lemaux, Peggy G. (A)
Affiliations:	(A): University of California, Berkeley (B): USDA-ARS, Idaho, ID

Scab, caused by Fusarium graminearum, is a major, worldwide fungal disease of barley and wheat. Infected barley grain is often contaminated by the mycotoxin, deoxynivalenol, and thus unacceptable for malting and brewing. We are producing transgenic plants containing transgenes encoding putative antifungal proteins, which are bordered by Ds sequences derived from maize. Via hybridization with plants engineered to express the maize Ac transposase (AcTPase), we will use the Ac/Ds system to produce marker-free plants that stably express the putative antifungal proteins, tlp1 and tlp4 from oat and tri101 and tri12 from F. sporotrichioide. These genes were cloned into a Ds-bordered, maize ubiquitin- or rice actin promoter-driven expression cassette. These constructs, with pAHC20 (ubi promoter-bar-nos) or pAct1IHpt4 (actin promoter-hpt-nos), were introduced via bombardment into scutellar tissues of immature embryos or highly regenerative, green tissues of 2 spring barley cultivars, Golden Promise (GP, 2-rowed variety) and Drummond (DM, elite 6-rowed variety). Plants derived from 3 DsUbiTlp1 and 3 DsUbiTlp4 transgenic GP lines are bar-positive. Two DsActTlp1, 1 DsActTlp4 and 3 DsActTri101 hygromycin-resistant lines were generated from highly regenerative, green tissues from DM . Also, five putative lines with the AcTPase gene driven by its own promoter was developed using highly regenerative, green tissues of DM. The AcTPase gene is also being introduced into DM via backcrossing from transgenic AcTPase GP lines. To characterize the level of transgene expression, antibodies to the TLP1, TLP4, Tri101 proteins were developed. Further analyses of transgenic lines and expression of their transgenes is ongoing.