LOOSE FLOWER, a WUSCHEL‐like Homeobox gene, is required for lateral fusion of floral organs in Medicago truncatula. (7th January 2015)

• Record Type: Journal Article
• Authors: Niu, Lifang; Lin, Hao; Zhang, Fei; Watira, Tezera W.; Li, Guifen; Tang, Yuhong; Wen, Jiangqi; Ratet, Pascal; Mysore, Kirankumar S.; Tadege, Million
• Is Part Of: Plant journal. Volume 81:Number 3(2015:Feb.)
• Page Start: 480
• Page End: 492
• Publication Date: 2015-01-07
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12743
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" id="tpj12743-abs-0001"> <title>Summary</title> <p>The <italic>Medicago truncatula WOX</italic> gene, <italic>STENOFOLIA</italic> (<italic>STF</italic>), and its orthologs in <italic>Petunia</italic>, pea, and <italic>Nicotiana sylvestris</italic> are required for leaf blade outgrowth and floral organ development as demonstrated by severe phenotypes in single mutants. But the Arabidopsis <italic>wox1</italic> mutant displays a narrow leaf phenotype only when combined with the <italic>prs/wox3</italic> mutant. In maize and rice, <italic>WOX3</italic> homologs are major regulators of leaf blade development. Here we investigated the role of <italic>WOX3</italic> in <italic>M. truncatula</italic> development by isolating the <italic>lfl/wox</italic>3 loss‐of‐function mutant and performing genetic crosses with the <italic>stf</italic> mutant. Lack of <italic>WOX3</italic> function in <italic>M. truncatula</italic> leads to a <italic>loose‐flower</italic> (<italic>lfl</italic>) phenotype, where defects are observed in sepal and petal development, but leaf blades are apparently normal. The <italic>stf lfl</italic> double mutant analysis revealed that <italic>STF</italic> and <italic>LFL</italic> act mainly independently with minor redundant functions in flower development, but <italic>LFL</italic> has no obvious role in leaf blade outgrowth in <italic>M. truncatula</italic> on its own or in combination with <italic>STF</italic>. Interestingly, LFL acts as a transcriptional repressor by recruiting TOPLESS in the same manner as STF does, and can substitute for STF function in leaf blade and flower development if expressed under the <italic>STF</italic> promoter. <italic>STF</italic> also complements the <italic>lfl</italic> mutant phenotype in the flower if expressed under the <italic>LFL</italic> promoter. Our data suggest that the <italic>STF/WOX1</italic> and <italic>LFL/WOX3</italic> genes of <italic>M. truncatula</italic> employ a similar mechanism of action in organizing cell proliferation for lateral outgrowth but may have evolved different <italic>cis</italic> elements to acquire distinct functions.</p> </abstract>