Cooperative action of the paralogous maize lateral organ boundaries (LOB) domain proteins RTCS and RTCL in shoot‐borne root formation. Issue 4 (22nd April 2015)

• Record Type: Journal Article
• Authors: Xu, Changzheng; Tai, Huanhuan; Saleem, Muhammad; Ludwig, Yvonne; Majer, Christine; Berendzen, Kenneth W.; Nagel, Kerstin A.; Wojciechowski, Tobias; Meeley, Robert B.; Taramino, Graziana; Hochholdinger, Frank
• Is Part Of: New phytologist. Volume 207:Issue 4(2015)
• Page Start: 1123
• Page End: 1133
• Publication Date: 2015-04-22
• Subjects: Botany -- Periodicals; 580
• DOI: 10.1111/nph.13420
• Languages: English
• ISSNs: 0028-646X

Abstract

<abstract abstract-type="main" id="nph13420-abs-0001"> <title>Summary</title> <p> <list id="nph13420-list-0001" list-type="bullet"> <list-item> <p>The paralogous maize (<italic>Zea mays</italic>) <italic>LBD</italic> (<italic>Lateral Organ Boundaries Domain</italic>) genes <italic>rtcs</italic> (<italic>rootless concerning crown and seminal roots</italic>) and <italic>rtcl</italic> (<italic>rtcs‐like</italic>) emerged from an ancient whole‐genome duplication. RTCS is a key regulator of crown root initiation.</p> </list-item> <list-item> <p>The diversity of expression, molecular interaction and phenotype of <italic>rtcs</italic> and <italic>rtcl</italic> were investigated.</p> </list-item> <list-item> <p>The <italic>rtcs</italic> and <italic>rtcl</italic> genes display highly correlated spatio‐temporal expression patterns in roots, despite the significantly higher expression of <italic>rtcs</italic>. Both RTCS and RTCL proteins bind to <italic>LBD</italic> downstream promoters and act as transcription factors. In line with its auxin inducibility and binding to auxin response elements of <italic>rtcs</italic> and <italic>rtcl</italic> promoters, ARF34 (AUXIN RESPONSE FACTOR 34) acts as transcriptional activator. Yeast two‐hybrid screening combined with bimolecular fluorescence complementation (BiFC) experiments revealed conserved and unique interaction partners of RTCS and RTCL. The <italic>rtcl</italic> mutation leads to defective shoot‐borne root elongation early in development. Cooperative action of RTCS and RTCL during shoot‐borne root formation was demonstrated by <italic>rtcs</italic>‐dependent repression of <italic>rtcl</italic> transcription in coleoptilar nodes.</p> </list-item> <list-item> <p>Although RTCS is instrumental in shoot‐borne root initiation, RTCL controls shoot‐borne root elongation early in development. Their conserved role in auxin signaling, but diverse function in shoot‐borne root formation, is underscored by their conserved and unique interaction partners.</p> </list-item> </list> </p> </abstract>