Homeoboxtranscriptionfactorsparticipateinthegrowthanddevelopmentofplantsbyregulatingcelldifferentiation,morphogenesisandenvironmentalsignalresponse.Torevealthefunctionsofthesetranscriptionfactorsinrice,weconstructedtheRNAivectorsofOsHox9,amemberofhomeoboxfamily,andanalyzedthefunctionofOsHox9usingreversegenetics.TheplantheightandtilleringnumberofRNAitransgenicplantsdecreasedcomparedwiththoseofwild-typeplants.Reversetranscription-polymerasechainreactionanalysisshowedthatOsHox9expressionreducedinthetransgenicplantswithphenotypicvariance,whereasthatinthetransgenicplantswithoutphenotypicvariancewassimilartothatinthewild-typeplants.ThisresultsuggeststhatthephenotypesofthetransgenicplantswerecausedbyRNAieffects.Thetissue-specificityofOsHox9expressionindicatedthatitwasexpressedindifferentorgans,withhighexpressioninstemapicalmeristemandyoungpanicles.SubcellularlocationofOsHox9demonstratedthatitwaslocalizedonthecellmembrane.