The ERECT PANICLE 3 gene of rice encodes a peptide that exhibits more than 50% sequence identity with the Arabidopsis F-box protein HAWAIIAN SKIRT (HWS). Ectopic expression of the Os02g15950 coding sequence, driven by the HWS (At3g61950) promoter, rescued the hws-1 flower phenotype in Arabidopsis confirming that EP3 is a functional orthologue of HWS. In addition to displaying an erect inflorescence phenotype, loss-of-function mutants of Os02g15950 exhibited a decrease in leaf photosynthetic capacity and stomatal conductance. Analysis of a range of physiological and anatomical features related to leaf photosynthesis revealed no alteration in Rubisco content and no notable changes in mesophyll size or arrangement. However, both ep3 mutant plants and transgenic lines that have a T-DNA insertion within the Os02g15950 (EP3) gene exhibit smaller stomatal guard cells compared with their wild-type controls. This anatomical characteristic may account for the observed decrease in leaf photosynthesis and provides evidence that EP3 plays a role in regulating stomatal guard cell development.
水稻ERECT PANICLE 3基因編碼的多肽與擬南芥F-box蛋白HWS的同源性超過(guò)50%。HWS (At3g61950)啟動(dòng)子驅(qū)動(dòng)Os02g15950編碼序列的異位表達(dá)，能夠恢復(fù)擬南芥hws-1花表型，表明EP3是一個(gè)有功能的HWS同源基因。除了表現(xiàn)為直立穗表型外，Os02g15950功能缺失突變體還表現(xiàn)出葉片光合能力和氣孔導(dǎo)度均減弱。一系列與葉片光合作用相關(guān)的生理學(xué)和解剖學(xué)特征分析表明，Rubisco含量以及葉肉細(xì)胞大小和排布均沒(méi)有明顯變化。但是，ep3突變體和在Os02g15950 (EP3)基因內(nèi)有一個(gè)T-DNA插入的轉(zhuǎn)基因株系均表現(xiàn)出氣孔保衛(wèi)細(xì)胞小于它們的野生型對(duì)照。這個(gè)解剖學(xué)特征可以解釋觀察到的葉片光合作用減弱現(xiàn)象，并表明EP3在調(diào)控氣孔保衛(wèi)細(xì)胞發(fā)育中發(fā)揮重要作用。