PIN6 is required for nectary auxin response and short stamen development
PIN6 is required for nectary auxin response and short stamen development
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DOI：
10.1111/tpj.12184
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发表时间：
2013-06-01
期刊：
影响因子：
7.2
通讯作者：
Carter, Clay J.
中科院分区：
文献类型：
--
作者：
Bender, Ricci L.;Fekete, Megan L.;Carter, Clay J.
PIN蛋白家族以参与生长素的极性运输和向性反应而闻名。PIN 6（At 1g 77110）是拟南芥中剩余的PIN家族成员之一，其生物学功能尚未被赋予。在这里，我们报告说，PIN 6是一个花蜜丰富的基因，其表达水平与总花蜜产量呈正相关，在拟南芥中，其功能是所需的短雄蕊的适当发展。PIN 6在内膜中积累与ER一致，并且多条证据表明PIN 6是蜜腺中生长素依赖性反应所需的。野生型植物表达生长素响应DR 5：GFP或DR 5：GUS报告显示强烈的信号在侧蜜腺，但pin 6侧蜜腺显示很少或没有这些报告的信号。此外，外源生长素处理增加花蜜产量超过10倍的野生型植物，但花蜜产量没有增加pin 6突变体时，用生长素处理。相反，生长素转运抑制剂N-1-naphthylphthalamic acid（NPA）使野生型植物的花蜜产量降低了两倍以上，但对pin 6株系没有显著影响。有趣的是，MYB 57转录因子突变体myb 57 -2与功能丧失突变体pin 6 -2密切表型相似。然而，PIN 6表达不依赖于MYB 57，并且pin 6 -2和myb 57 -2突变蜜腺的RNA-seq分析显示差异表达基因几乎没有重叠。累积起来，这些结果表明，PIN 6是必需的适当的生长素反应和蜜腺功能在拟南芥。这些结果也确定生长素作为一个重要的因素，在花蜜生产的调节，并牵连短雄蕊侧蜜腺的成熟。
The PIN family of proteins is best known for its involvement in polar auxin transport and tropic responses. PIN6 (At1g77110) is one of the remaining PIN family members in Arabidopsis thaliana to which a biological function has not yet been ascribed. Here we report that PIN6 is a nectary-enriched gene whose expression level is positively correlated with total nectar production in Arabidopsis, and whose function is required for the proper development of short stamens. PIN6 accumulates in internal membranes consistent with the ER, and multiple lines of evidence demonstrate that PIN6 is required for auxin-dependent responses in nectaries. Wild-type plants expressing auxin-responsive DR5:GFP or DR5:GUS reporters displayed intense signal in lateral nectaries, but pin6lateral nectaries showed little or no signal for these reporters. Further, exogenous auxin treatment increased nectar production more than tenfold in wild-type plants, but nectar production was not increased in pin6 mutants when treated with auxin. Conversely, the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) reduced nectar production in wild-type plants by more than twofold, but had no significant effect onpin6lines. Interestingly, a MYB57 transcription factor mutant, myb57-2, closely phenocopied the loss-of-function mutant pin6-2. However, PIN6 expression was not dependent on MYB57, and RNA-seq analyses of pin6-2 and myb57-2 mutant nectaries showed little overlap in terms of differentially expressed genes. Cumulatively, these results demonstrate that PIN6 is required for proper auxin response and nectary function in Arabidopsis. These results also identify auxin as an important factor in the regulation of nectar production, and implicate short stamens in the maturation of lateral nectaries.