Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Workshop: Barley
The construction of cDNA libraries within virus vectors allows gene function to be assessed by screening infected plant hosts for both gain and loss of function effects, through either protein over-expression or virus induced gene silencing (VIGS). Barley stripe mosaic virus (BSMV) is a tripartite, positive strand RNA virus that infects many agriculturally important monocot species such as barley, oat, wheat and corn. We developed a BSMV vector that successfully expressed a large set of heterologous plant and animal proteins in the monocot host, barley. Foreign proteins expressed from this BSMV vector accumulate to high levels, and the foreign protein can be targeted to any organellar domain within the cytosol or to the plant apoplast. Another type of expression system was developed for expression of multiple proteins in a cell culture system. This system shows remarkable promise for building pathways of enzymes into plant cells. VIGS has only been demonstrated in dicot hosts. We also constructed a novel BSMV vector to express either sense or antisense fragments of phytoene desaturase (PDS) from corn, rice, or barley. Leaves of barley plants infected with these constructs became bleached and accumulated phytoene (the substrate for PDS) in a manner identical to plants treated with the chemical inhibitor of PDS, Norflurazon. Subsequently, a rice cDNA library was cloned into this vector and inoculated onto barley to screen for phenotypic effects. Several clones were identified that induced reproducible phenotypes as a result of VIGS.