Pyruvate decarboxylase provides growing pollen tubes with a competitive advantage in petunia
Pyruvate decarboxylase provides growing pollen tubes with a competitive advantage in petunia
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DOI：
10.1105/tpc.105.033290
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发表时间：
2005-08-01
期刊：
影响因子：
11.6
通讯作者：
Kuhlemeier, C
中科院分区：
文献类型：
--
作者：
Gass, N;Glagotskaia, T;Kuhlemeier, C
花粉管的快速生长对能量生产和生物合成能力提出了独特的要求。这项工作的目的是了解初级新陈代谢如何满足如此快速增长的需求。在有氧条件下生长的花粉会大量产生乙醇。乙醇发酵途径由丙酮酸脱羧酶(PDC)和乙醇脱氢酶(ADH)两种酶组成。因为ADH突变不会影响雄配子体的功能，所以一个明显的问题是，如果没有ADH突变，为什么花粉会合成一种丰富的酶。利用矮牵牛转座子标记，我们在花粉特异的Pdc2中分离到一个零突变体。在与野生型花粉竞争时，突变花粉管通过花柱的生长减少，突变等位基因通过雄性的传播减少。我们认为，不是ADH，而是PDC是一种新的花粉特异性途径的关键酶。这一途径绕过了丙酮酸脱氢酶，从而在花粉-雌蕊相互作用的独特条件下保持生物合成能力和能量产生。
Rapid pollen tube growth places unique demands on energy production and biosynthetic capacity. The aim of this work is to understand how primary metabolism meets the demands of such rapid growth. Aerobically grown pollen produce ethanol in large quantities. The ethanolic fermentation pathway consists of two committed enzymes: pyruvate decarboxylase ( PDC) and alcohol dehydrogenase ( ADH). Because adh mutations do not affect male gametophyte function, the obvious question is why pollen synthesize an abundant enzyme if they could do just as well without. Using transposon tagging in Petunia hybrida, we isolated a null mutant in pollen- specific Pdc2. Growth of the mutant pollen tubes through the style is reduced, and the mutant allele shows reduced transmission through the male, when in competition with wild- type pollen. We propose that not ADH but rather PDC is the critical enzyme in a novel, pollen- specific pathway. This pathway serves to bypass pyruvate dehydrogenase enzymes and thereby maintain biosynthetic capacity and energy production under the unique conditions prevailing during pollen - pistil interaction.