Method of increasing grain crop

Abstract

The present invention provides a method of compiling a plant functional gene profile, a method of changing the phenotype or biochemistry of a plant, a method of determining a change in phenotype or biochemistry of a plant, a method of determining the presence of a trait in plant, and a method of increasing grain crop. The methods comprise expressing transiently a nucleic acid sequence of a plant into a host plant to affect phenotypic or biochemical changes in the host plant. A viral vector functional genomic screen has been developed to identify nucleotide sequences in transfected plants by systemically knocking out endogenous gene expression in an antisense mechanism. Once the presence of a trait in a plant is identified by phenotypic or biochemical changes in the host plant, the nucleic acid insert in the cDNA clone or in the vector that results in the changes is then sequenced. The present invention exemplifies that genes encoding GTP binding proteins in one plant can silence endogenous gene expression in a different plant.

What is claimed is:  
     
         1 . A method of increasing yield of a grain crop, said method comprising the steps of: 
 (a) preparing a library of cDNAs, genomic DNAs, or a pool of RNAs of a donor plant;    (b) constructing recombinant viral nucleic acids obtained from a tobamo virus comprising an unidentified nucleic acid insert obtained from said library in an antisense orientation relative to said DNA or RNA sequence of said donor plant;    (c) infecting host grain crops with said recombinant viral nucleic acids, and transiently expressing said unidentified nucleic acids in the infected host grain crops; and    (d) selecting host grain crops that have stunted growth and increased seed production.    
     
     
         2 . The method according to  claim 1 , wherein said nucleic acid insert comprises a GTP binding protein open reading frame.  
     
     
         3 . The method according to  claim 1 , wherein said grain crop is rice.  
     
     
         4 . The method according to  claim 1 , wherein said tobamo virus is a tobacco masaic virus.