▁evidence ▁support ▁the ▁idea ▁that ▁R ip T AL s ▁function ▁as ▁effect or ▁prote ins , ▁prom oting ▁b acter ial ▁growth ▁or ▁disease ▁by ▁manip ulating ▁the ▁expression ▁of ▁plant ▁gen es . ▁They ▁are ▁secret ed ▁into ▁plant ▁cells ▁by ▁the ▁Type ▁III ▁secret ion ▁system , ▁which ▁is ▁the ▁main ▁delivery ▁system ▁for ▁effect or ▁prote ins . ▁They ▁local ize ▁to ▁the ▁cell ▁nucle us ▁and ▁are ▁able ▁to ▁function ▁as ▁sequence - specific ▁trans cription ▁factors ▁in ▁plant ▁cells . ▁In ▁addition ▁a ▁stra in ▁lack ing ▁its ▁R ip T AL ▁was ▁shown ▁to ▁grow ▁slower ▁inside ▁egg plant ▁leaf ▁t issue ▁than ▁the ▁wild ▁type . ▁Furthermore , ▁a ▁study ▁based ▁on ▁DNA ▁polym orph isms ▁in ▁rip T AL ▁repeat ▁domain ▁sequences ▁and ▁host ▁plants ▁found ▁a ▁statist ically ▁significant ▁connection ▁between ▁host ▁plant ▁and ▁repeat ▁domain ▁variants . ▁This ▁is ▁expected ▁if ▁the ▁R ip T AL s ▁of ▁different ▁stra ins ▁are ▁adapted ▁to ▁target ▁gen es ▁in ▁specific ▁host ▁plants . ▁Despite ▁this , ▁no ▁target ▁gen es ▁have ▁been ▁identified ▁for ▁any ▁R ip T AL , ▁. ▁ ▁B AT s ▁ ▁Disc overy ▁The ▁publication ▁of ▁the ▁gen ome ▁of ▁b acter ial ▁stra in ▁Par ab urk holder ia ▁rh iz ox in ica ▁H K I ▁ 4 5 4 , ▁in ▁ 2 0 1 1 ▁ ▁led ▁to ▁the ▁discovery ▁of ▁a ▁set ▁of ▁T A LE - like ▁gen es ▁that ▁differ ed