Arginine decarboxylase expression, polyamines biosynthesis and reactive oxygen species during organogenic nodule formation in hop
Arginine decarboxylase expression, polyamines biosynthesis and reactive oxygen species during organogenic nodule formation in hop
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DOI：
10.4161/psb.6.2.14503
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发表时间：
2011-01-01
影响因子：
2.9
通讯作者：
Pais, Maria S.
中科院分区：
文献类型：
--
作者：
Fortes, Ana M.;Costa, Joana;Pais, Maria S.
啤酒花（Humulus lupulus L.）是用于啤酒生产和作为保健药物的经济上重要的植物物种。啤酒花节间在逆境胁迫下发育成可用于遗传转化和微繁殖的器官发生结节。多胺参与植物发育和逆境反应。精氨酸脱羧酶（ADC; EC 4.1.1.19）是植物中参与腐胺生物合成的关键酶。在这里，我们表明，ADC蛋白越来越多地表达在啤酒花节间培养的早期阶段（12小时）。蛋白质继续积累，直到28天后形成器官性结节，此后下降。观察到ADC转录物的相同谱，表明形态发生期间ADC基因表达的转录调控。培养28天后观察到的最高转录物和蛋白质水平伴随着腐胺水平的峰值。活性氧在结节组织中的积累可能是由于体外条件下固有的压力和增强的多胺催化剂。在根瘤再生植株过程中，结合多胺含量增加，表明其参与了植株的形成和/或游离多胺水平的调控。免疫金标记显示ADC定位于根瘤细胞的质体、细胞核和细胞质中。在空泡化细胞中，质体中的ADC免疫标记使分生组织细胞中的前质体的信号加倍。ADC在不同亚细胞区室中的位置可能表明其在这些区室中发生的代谢途径中的作用，这些数据表明，多胺在器官根瘤的形成中起着重要作用，并代表了理解这些生长调节剂在植物形态建成中所起作用的进展。
Hop (Humulus lupulus L.) is an economically important plant species used in beer production and as a health-promoting medicine. Hop internodes develop upon stress treatments organogenic nodules which can be used for genetic transformation and micropropagation.Polyamines are involved in plant development and stress responses. Arginine decarboxylase (ADC; EC 4.1.1.19) is a key enzyme involved in the biosynthesis of putrescine in plants. Here we show that ADC protein was increasingly expressed at early stages of hop internode culture (12 h). Protein continued accumulating until organogenic nodule formation after 28 days, decreasing thereafter. The same profile was observed for ADC transcript suggesting transcriptional regulation of ADC gene expression during morphogenesis. The highest transcript and protein levels observed after 28 days of culture were accompanied by a peak in putrescine levels. Reactive oxygen species accumulate in nodular tissues probably due to stress inherent to in vitro conditions and enhanced polyamine catabolism. Conjugated polyamines increased during plantlet regeneration from nodules suggesting their involvement in plantlet formation and/or in the control of free polyamine levels.Immunogold labeling revealed that ADC is located in plastids, nucleus and cytoplasm of nodular cells. In vacuolated cells, ADC immunolabelling in plastids doubled the signal of proplastids in meristematic cells. Location of ADC in different subcellular compartments may indicate its role in metabolic pathways taking place in these compartments.Altogether these data suggest that polyamines play an important role in organogenic nodule formation and represent a progress towards understanding the role played by these growth regulators in plant morphogenesis.