| A reverse genetics approach was taken to investigate the role(s) of small RNA in rice, Oryza sativa L., using T-DNA and chemically mutagenized lines. T-DNA tagged lines of RNA-dependent RNA polymerase 6 (Osrdr6) were homozygous lethal. However, two lines, a T-DNA line with disrupted expression of the gene encoding S&barbelow;uppressor of G&barbelow;ene S&barbelow;ilencing3 (OsSGS3) and a chemically mutagenized line with a single nucleotide polymorphism (SNP) in the intronic 2 region of this gene, were characterized. Homozygous Ossgs3 mutant lines showed abnormal leaf curling. This suggests that these lines are hyperresponsive to auxin since they do not produce to-siRNA which is involved in targeting and degrading Auxin Response Factor, leading to changes in leaf morphology. The homozygous Ossgs3 SNP mutant showed increased sensitivity to the rice blast pathogen strain BNIII. This suggests that small RNA's, also, target and degrade fungal m RNA transcripts, decreasing pathogen virulence. |
