Auxin controls Arabidopsis anther dehiscence by regulating endothecium lignification and jasmonic acid biosynthesis
Auxin controls Arabidopsis anther dehiscence by regulating endothecium lignification and jasmonic acid biosynthesis
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DOI：
10.1111/tpj.12130
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发表时间：
2013-05-01
期刊：
影响因子：
7.2
通讯作者：
Cardarelli, Maura
中科院分区：
文献类型：
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作者：
Cecchetti, Valentina;Altamura, Maria Maddalena;Cardarelli, Maura
有人认为，在拟南芥中，生长素控制花药开裂的时间，可能是通过防止过早的内皮木质化。我们在这里表明，生长素含量在花药开裂开始前的峰值和降低时，药室内壁木质化发生。结果表明，在生长素感受突变体afb 1 -3和tir 1 afb 2 afb 3中，药室内壁木质化和花药开裂发生早于野生型，并且编码药室内壁木质化所需的转录因子MYB 26的基因在早期特异性过表达;一致的是，MYB 26的表达在萘乙酸处理的花药中减少，并且afb 1 myb 26双突变体显示没有内皮木质化，这表明生长素通过MYB 26起作用。由于茉莉酸（JA）控制花药开裂，我们分析了生长素和JA如何相互作用。在JA缺陷opr 3突变体，不裂花药表现出正常的时间内皮木质化，这表明JA不控制这一事件。我们发现，OPR 3和DAD 1 JA生物合成基因的表达增强afb 1 -3和tir 1 afb 2 afb 3花蕾，但减少在萘乙酸处理的花蕾，这表明生长素负调控JA生物合成。双突变体afb 1 opr 3表现出过早的药室内壁木质化，如afb 1 -3，和不裂花药由于缺乏JA，这是所需的气孔开放。用JA处理afb 1、opr 3和opr 3花序，结果表明，高JA含量和药室内壁木质化均有助于诱导花药早期开裂。我们认为，生长素控制花药开裂的时间通过负调控两个关键事件：通过MYB 26的药室内壁木质化，和通过JA生物合成的控制气孔开放。
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 afb1-3 and tir1 afb2 afb3, 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, MYB26 expression is reduced in naphthalene acetic acid-treated anthers, and afb1 myb26 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 opr3 mutant, indehiscent anthers show normal timing of endothecium lignification, suggesting that JA does not control this event. We show that expression of the OPR3 and DAD1 JA biosynthetic genes is enhanced in afb1-3 and tir1 afb2 afb3 flower buds, but is reduced in naphthalene acetic acid-treated flower buds, suggesting that auxin negatively regulates JA biosynthesis. The double mutant afb1 opr3 shows premature endothecium lignification, as in afb1-3, and indehiscent anthers due to lack of JA, which is required for stomium opening. By treating afb1 opr3 and opr3 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.