The invention provides a high capacity binary shuttle vector having T-DNA
region and Ri ori and capable to integrate a large genome fragment in it;
a genomic library having the ability to transform a plant, especially
monocotyledonous ones; a plant transformed with the high capacity binary
shuttle vector; and a method of searching for a useful gene by use of the
above vector. The present high capacity binary shuttle vector can
introduce a large genome fragment of 10 kb or more, easily, efficiently
and stably into a plant, especially monocotyledonous ones under those
conditions in which the rearrangement or deletion of these genome
fragments does not occur. The invention also provides some other vectors
derived from the above Ri ori driven vectors, which can integrate circular
genome library plasmids with a lox site, or which can efficiently
transform plants with genes of arbitrary expression properties. The
invention includes also the assessment method for the functions of genome
fragments inserted in the above vectors by complementation assay. In
addition, a useful gene or gene complex can be efficiently examined so its
isolation is also made easy.
