University of Graz, Institute of Plant Sciences, Graz, Austria.
BMC Plant Biol. 2011 Mar 26;11:54. doi: 10.1186/1471-2229-11-54.
The antioxidant glutathione fulfills many important roles during plant development, growth and defense in the sporophyte, however the role of this important molecule in the gametophyte generation is largely unclear. Bioinformatic data indicate that critical control enzymes are negligibly transcribed in pollen and sperm cells. Therefore, we decided to investigate the role of glutathione synthesis for pollen germination in vitro in Arabidopsis thaliana accession Col-0 and in the glutathione deficient mutant pad2-1 and link it with glutathione status on the subcellular level.
The depletion of glutathione by buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, reduced pollen germination rates to 2-5% compared to 71% germination in wildtype controls. The application of reduced glutathione (GSH), together with BSO, restored pollen germination and glutathione contents to control values, demonstrating that inhibition of glutathione synthesis is responsible for the decrease of pollen germination in vitro. The addition of indole-3-acetic acid (IAA) to media containing BSO restored pollen germination to control values, which demonstrated that glutathione depletion in pollen grains triggered disturbances in auxin metabolism which led to inhibition of pollen germination.
This study demonstrates that glutathione synthesis is essential for pollen germination in vitro and that glutathione depletion and auxin metabolism are linked in pollen germination and early elongation of the pollen tube, as IAA addition rescues glutathione deficient pollen.
抗氧化剂谷胱甘肽在孢子体的植物发育、生长和防御中发挥着许多重要作用，然而，在配子体世代中，这种重要分子的作用在很大程度上还不清楚。生物信息学数据表明，关键控制酶在花粉和精子细胞中的转录可忽略不计。因此，我们决定研究谷胱甘肽合成对拟南芥 Col-0 花粉体外萌发的作用，以及在谷胱甘肽缺陷突变体 pad2-1 中的作用，并将其与亚细胞水平上的谷胱甘肽状态联系起来。
谷胱甘肽合成抑制剂丁硫氨酸亚砜（BSO）耗尽谷胱甘肽，使花粉萌发率从野生型对照的 71%降至 2-5%。还原型谷胱甘肽（GSH）与 BSO 一起应用，使花粉萌发和谷胱甘肽含量恢复到对照值，表明谷胱甘肽合成的抑制是导致体外花粉萌发减少的原因。在含有 BSO 的培养基中添加吲哚-3-乙酸（IAA）可使花粉萌发恢复到对照值，这表明花粉粒中谷胱甘肽的耗竭触发了生长素代谢的紊乱，导致花粉萌发的抑制。
本研究表明，谷胱甘肽合成对于体外花粉萌发是必不可少的，谷胱甘肽耗竭和生长素代谢在花粉萌发和花粉管早期伸长中是相关的，因为 IAA 的添加可以挽救谷胱甘肽缺乏的花粉。
