Liu Shu-Jun, Xu Heng-Heng, Wang Wei-Qing, Li Ni, Wang Wei-Ping, Lu Zhuang, Møller Ian Max, Song Song-Quan
Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Hunan Hybrid Rice Research Center/State Key Laboratory of Hybrid Rice, Changsha 410125, China.
J Plant Physiol. 2016 Jun 1;196-197:79-92. doi: 10.1016/j.jplph.2016.02.021. Epub 2016 Apr 2.
Seed germination is a critical phase in the plant life cycle, but the mechanism of seed germination is still poorly understood. In the present study, rice (Oryza sativa L. cv. Peiai 64S) seeds were sampled individually when they reached different germination stages, quiescent, germinated sensu stricto, germinated completely and seedling, and were used to study the changes in the embryo proteome. A total of 88 protein spots showed a significant change in abundance during germination in water, and the results showed an activation of metabolic processes. Cell division, cell wall synthesis, and secondary metabolism were activated at late seed germination and during preparation for subsequent seedling establishment. Cycloheximide (CHX) at 70μM inhibited seedling establishment without an apparent negative effect on seed germination, while CHX at 500μM completely blocked seed germination. We used this observation to identify the potentially important proteins involved in seed germination (coleoptile protrusion) and seedling establishment (coleoptile and radicle protrusion). Twenty-six protein spots, mainly associated with sugar/polysaccharide metabolism and energy production, showed a significant difference in abundance during seed germination. Forty-nine protein spots, mainly involved in cell wall biosynthesis, proteolysis as well as cell defense and rescue, were required for seedling establishment. The results help improve our understanding of the key events (proteins) involved in germination and seedling development.
种子萌发是植物生命周期中的一个关键阶段，但种子萌发的机制仍未得到充分了解。在本研究中，水稻（Oryza sativa L. cv. Peiai 64S）种子在达到不同萌发阶段时分别取样，即静止期、严格意义上的萌发期、完全萌发期和幼苗期，并用于研究胚蛋白质组的变化。共有88个蛋白质斑点在水中萌发期间丰度发生了显著变化，结果显示代谢过程被激活。细胞分裂、细胞壁合成和次生代谢在种子萌发后期以及随后幼苗建立的准备过程中被激活。70μM的放线菌酮（CHX）抑制幼苗建立，但对种子萌发没有明显的负面影响，而500μM的CHX则完全阻断种子萌发。我们利用这一观察结果来鉴定参与种子萌发（胚芽鞘突出）和幼苗建立（胚芽鞘和胚根突出）的潜在重要蛋白质。26个主要与糖/多糖代谢和能量产生相关的蛋白质斑点在种子萌发期间丰度有显著差异。49个主要参与细胞壁生物合成、蛋白水解以及细胞防御和修复的蛋白质斑点是幼苗建立所必需的。这些结果有助于增进我们对参与萌发和幼苗发育的关键事件（蛋白质）的理解。
