Dipartimento di Chimica, via Taramelli 12, 27100 Pavia, Italy.
Plant Physiol Biochem. 2012 Nov;60:196-206. doi: 10.1016/j.plaphy.2012.07.031. Epub 2012 Sep 1.
Farmers and growers are constantly looking for high quality seeds able to ensure uniform field establishment and increased production. Seed priming is used to induce pre-germinative metabolism and then enhance germination efficiency and crop yields. It has been hypothesized that priming treatments might also improve stress tolerance in germinating seeds, leaving a sort of 'stress memory'. However, the molecular bases of priming still need to be clarified and the identification of molecular indicators of seed vigor is nowadays a relevant goal for the basic and applied research in seed biology. It is generally acknowledged that enhanced seed vigor and successful priming depend on DNA repair mechanisms, activated during imbibition. The complexity of the networks of DNA damage control/repair functions has been only partially elucidated in plants and the specific literature that address seeds remains scanty. The DNA repair pathways hereby described (Nucleotide and Base Excision Repair, Non-Homologous End Joining, Homologous Recombination) play specific roles, all of them being critical to ensure genome stability. This review also focuses on some novel regulatory mechanisms of DNA repair (chromatin remodeling and small RNAs) while the possible use of telomere sequences as markers of aging in seed banks is discussed. The significant contribution provided by Electron Paramagnetic Resonance in elucidating the kinetics of seed aging, in terms of free radical profiles and membrane integrity is reported.
农民和种植者一直在寻找高质量的种子,以确保田间种植的一致性和产量的提高。种子引发是用来诱导预萌发代谢,从而提高发芽效率和作物产量。有人假设,引发处理也可能提高发芽种子的抗逆性,留下一种“应激记忆”。然而,引发的分子基础仍有待阐明,目前,鉴定种子活力的分子指标是种子生物学基础和应用研究的一个相关目标。人们普遍认为,增强的种子活力和成功的引发取决于在吸胀过程中激活的 DNA 修复机制。在植物中,DNA 损伤控制/修复功能的网络的复杂性仅部分得到了解析,而专门针对种子的特定文献仍然很少。本文描述了 DNA 修复途径(核苷酸和碱基切除修复、非同源末端连接、同源重组),它们都起着特定的作用,对于确保基因组的稳定性至关重要。本文还重点介绍了 DNA 修复的一些新的调控机制(染色质重塑和小 RNA),同时讨论了端粒序列作为种子库中衰老的标志物的可能用途。报告了电子顺磁共振在阐明种子衰老动力学方面的重要贡献,包括自由基谱和膜完整性。