Auxin controls Arabidopsis anther dehiscence by regulating endothecium lignification and jasmonic acid biosynthesis. (4th March 2013)

• Record Type: Journal Article
• Authors: Cecchetti, Valentina; Altamura, Maria Maddalena; Brunetti, Patrizia; Petrocelli, Valentina; Falasca, Giuseppina; Ljung, Karin; Costantino, Paolo; Cardarelli, Maura
• Is Part Of: Plant journal. Volume 74:Number 3(2013:May)
• Page Start: 411
• Page End: 422
• Publication Date: 2013-03-04
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12130
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" xml:lang="en" id="tpj12130-abs-0001"> <title>Summary</title> <p>It has been suggested that, in Arabidopsis, auxin controls the timing of anther dehiscence, possibly by preventing premature endothecium lignification. We show here that auxin content in anthers peaks before the beginning of dehiscence and decreases when endothecium lignification occurs. We show that, in the auxin‐perception mutants <italic>afb1‐3</italic> and <italic>tir1 afb2 afb3</italic>, endothecium lignification and anther dehiscence occur earlier than wild‐type, and the gene encoding the transcription factor MYB26, which is required for endothecium lignification, is over‐expressed specifically at early stages; in agreement, <italic>MYB26</italic> expression is reduced in naphthalene acetic acid‐treated anthers, and <italic>afb1 myb26</italic> double mutants show no endothecial lignification, suggesting that auxin acts through MYB26. As jasmonic acid (JA) controls anther dehiscence, we analysed how auxin and JA interact. In the JA‐defective <italic>opr3</italic> mutant, indehiscent anthers show normal timing of endothecium lignification, suggesting that JA does not control this event. We show that expression of the <italic>OPR3</italic> and <italic>DAD1 </italic>JA biosynthetic genes is enhanced in <italic>afb1‐3</italic> and <italic>tir1 afb2 afb3</italic> flower buds, but is reduced in naphthalene acetic acid‐treated flower buds, suggesting that auxin negatively regulates JA biosynthesis. The double mutant <italic>afb1 opr3</italic> shows premature endothecium lignification, as in <italic>afb1‐3</italic>, and indehiscent anthers due to lack of JA, which is required for stomium opening. By treating <italic>afb1 opr3</italic> and <italic>opr3</italic> inflorescences with JA, we show that a high JA content and precocious endothecium lignification both contribute to induction of early anther dehiscence. We propose that auxin controls anther dehiscence timing by negatively regulating two key events: endothecium lignification via MYB26, and stomium opening via the control of JA biosynthesis.</p> </abstract>