To study molecules secreted from cultured plant cells that promote development, maize microspores were transferred into culture and the conditioned media were collected over time and analysed. Electrophoresis indicated that both non-glycosylated and glycosylated proteins including arabinogalactan proteins (AGPs) appeared in the medium and their concentration increased during the time of culture. The development of embryos was correlated with the presence of specific extracellular proteins, using an experimental system based on a tunicamycin inhibition test. In addition, a precise protein analysis was conducted using MALDI-TOF and ESI-MS-MS techniques. These approaches have allowed the identification of 5 other types of proteins: a cell wall invertase, two thaumatin isoforms, one 1-3 beta-glucanase and two chitinase isoforms. Altogether these experiments and results open ways for research aimed at understanding which molecules stimulate embryo formation. Moreover, AGPs may be used to stimulate the development of microspores (pollen embryogenesis) prepared from non-responsive genotypes.

中文翻译：

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玉米小孢子培养过程中分泌的蛋白质的表征：阿拉伯半乳聚糖蛋白（AGP）刺激胚胎发育。

为了研究培养植物细胞分泌的促进生长的分子，将玉米小孢子转移到培养物中，并随时间收集条件培养基并进行分析。电泳表明，培养基中同时出现了非糖基化和糖基化蛋白，包括阿拉伯半乳聚糖蛋白（AGP），并且它们的浓度在培养期间增加。使用基于衣霉素抑制试验的实验系统，胚胎的发育与特定细胞外蛋白的存在相关。此外，使用MALDI-TOF和ESI-MS-MS技术进行了精确的蛋白质分析。这些方法已鉴定出5种其他类型的蛋白质：一种细胞壁转化酶，两种thaumatin同工型，一种1-3β-葡聚糖酶和两种几丁质酶同工型。这些实验和结果共同为旨在了解哪些分子刺激胚胎形成的研究开辟了道路。此外，AGP可用于刺激从无反应基因型制备的小孢子（花粉胚发生）的发育。