背景:欧洲山毛榉(FagussylvaticaL.)树不规则地产生种子;因此,有必要储存山毛榉种子进行造林。尽管在发育过程中获得了干燥耐受性,山毛榉种子被归类为中间体,因为它们在长期储存过程中比典型的正统种子更快地失去生存能力。在这项研究中,山毛榉种子在最佳条件下短期(3年)或长期(20年)储存,并显示92%和30%的发芽能力,分别,进行了比较。
结果:老化的种子显示膜损伤增加,表现为电解质渗漏和脂质过氧化水平。分析是基于胚胎轴,在老化的种子中含有较高水平的活性氧(ROS)和较高水平的蛋白质结合的甲硫氨酸亚砜(MetO)。使用无标记的定量蛋白质组学,鉴定了3,949种蛋白质,其中2,442个被可靠地量化,指出在长期储存条件下山毛榉种子中24个更丰富的蛋白质和35个不那么丰富的蛋白质。基于基因本体论注释的功能分析揭示了核酸结合活性(分子功能),核糖体组织或生物发生和跨膜运输(细胞过程),翻译蛋白(蛋白质类)和膜解剖实体(细胞区室)在老化的种子中受到影响。要验证MetO是否,可以通过蛋氨酸亚砜还原酶(Msr)酶的作用逆转的蛋白质的氧化翻译后修饰,参与了山毛榉种子的老化,我们鉴定并定量了226种含有MetO的蛋白质,其中9和19表现出显著上调和下调的MetO水平,分别,在长期储存条件下的山毛榉种子中。几种Msr亚型被鉴定为MsrA1样,MsrA4,MsrB5和MsrB5类似山毛榉种子。在老化的种子中,只有MsrA1样的丰度降低。
结论:我们证明,与MetO/Msr系统相比,膜蛋白丰度升高所反映的膜完整性丧失对种子老化进程的影响更大。蛋白质组分析使我们能够提出蛋白质Sec61和甘油醛-3-磷酸脱氢酶作为山毛榉种子中潜在的长寿调节剂。
BACKGROUND: European beech (Fagus sylvatica L.) trees produce seeds irregularly; therefore, it is necessary to store beech seeds for forestation. Despite the acquisition of desiccation tolerance during development, beech seeds are classified as intermediate because they lose viability during long-term storage faster than typical orthodox seeds. In this study, beech seeds stored for short (3 years) or long (20 years) periods under optimal conditions and displaying 92 and 30% germination capacity, respectively, were compared.
RESULTS: Aged seeds displayed increased membrane damage, manifested as electrolyte leakage and lipid peroxidation levels. Analyses have been based on embryonic axes, which contained higher levels of reactive oxygen species (ROS) and higher levels of protein-bound methionine sulfoxide (MetO) in aged seeds. Using label-free quantitative proteomics, 3,949 proteins were identified, of which 2,442 were reliably quantified pointing to 24 more abundant proteins and 35 less abundant proteins in beech seeds under long-term storage conditions. Functional analyses based on gene ontology annotations revealed that nucleic acid binding activity (molecular function), ribosome organization or biogenesis and transmembrane transport (cellular processes), translational proteins (protein class) and membranous anatomical entities (cellular compartment) were affected in aged seeds. To verify whether MetO, the oxidative posttranslational modification of proteins that can be reversed via the action of methionine sulfoxide reductase (Msr) enzymes, is involved in the aging of beech seeds, we identified and quantified 226 MetO-containing proteins, among which 9 and 19 exhibited significantly up- and downregulated MetO levels, respectively, in beech seeds under long-term storage conditions. Several Msr isoforms were identified and recognized as MsrA1-like, MsrA4, MsrB5 and MsrB5-like in beech seeds. Only MsrA1-like displayed decreased abundance in aged seeds.
CONCLUSIONS: We demonstrated that the loss of membrane integrity reflected in the elevated abundance of membrane proteins had a higher impact on seed aging progress than the MetO/Msr system. Proteome analyses enabled us to propose protein Sec61 and glyceraldehyde-3-phosphate dehydrogenase as potential longevity modulators in beech seeds.