Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China.
National Engineering Laboratory for Crop Molecular Breeding, Beijing, 100081, People's Republic of China.
BMC Plant Biol. 2021 Jan 9;21(1):34. doi: 10.1186/s12870-020-02806-5.
Heterosis refers to superior traits exhibiting in a hybrid when compared with both parents. Generally, the hybridization between parents can change the expression pattern of some proteins such as non-additive proteins (NAPs) which might lead to heterosis. 'Zhongdan808' (ZD808) and 'Zhongdan909' (ZD909) are excellent maize hybrids in China, however, the heterosis mechanism of them are not clear. Proteomics has been wildly used in many filed, and comparative proteomic analysis of hybrid and its parents is helpful for understanding the mechanism of heterosis in the two maize hybrids.
Over 2000 protein groups were quantitatively identified from second seedling leaves of two hybrids and their parents by label-free quantification. Statistical analysis of total identified proteins, differentially accumulated proteins (DAPs) and NAPs of the two hybrids revealed that both of them were more similar to their female parents. In addition, most of DAPs were up-regulated and most of NAPs were high parent abundance or above-high parent abundance in ZD808, while in ZD909, most of DAPs were down-regulated and most of NAPs were low parent abundance or below-low parent abundance. Pathway enrichment analysis showed that more of stress response-related NAPs in ZD808 were high parent abundance or above-high parent abundance, and most of PS related NAPs in ZD909 were high parent abundance or above-high parent abundance. Finally, four stress response-related proteins and eight proteins related to PS were verified by PRM, ten of them had significant differences between hybrid and midparent value.
Even though every one of the two hybrids were more similar to its female parent at proteome level, the biological basis of heterosis is different in the two maize hybrids. In comparison with their parents, the excellent agronomic traits of hybrid ZD808 is mainly correlated with the high expression levels of some proteins related to stress responses and metabolic functions, while traits of ZD909 is mainly correlated with high expressed proteins related to photosynthesis. Our proteomics results support previous physiological and morphological research and have provided useful information in understanding the reason of valuable agronomic traits.
杂种优势是指杂种与双亲相比表现出的优良性状。一般来说，双亲杂交可以改变一些蛋白质的表达模式，如非加性蛋白质（NAPs），这可能导致杂种优势。“中单 808”（ZD808）和“中单 909”（ZD909）是中国优秀的玉米杂交种，但它们的杂种优势机制尚不清楚。蛋白质组学已广泛应用于许多领域，对杂种及其双亲的比较蛋白质组学分析有助于理解这两个玉米杂种的杂种优势机制。
通过无标记定量法，从两个杂种及其双亲的第二幼苗叶片中定量鉴定了 2000 多个蛋白质组。对两个杂种的总鉴定蛋白、差异积累蛋白（DAPs）和 NAPs 的统计分析表明，它们都更类似于其母本。此外，ZD808 中的大多数 DAPs 上调，大多数 NAPs 为高亲本丰度或高亲本丰度以上，而 ZD909 中的大多数 DAPs 下调，大多数 NAPs 为低亲本丰度或低亲本丰度以下。途径富集分析表明，ZD808 中更多与应激反应相关的 NAPs 为高亲本丰度或高亲本丰度以上，ZD909 中与 PS 相关的大多数 NAPs 为高亲本丰度或高亲本丰度以上。最后，通过 PRM 验证了四个与应激反应相关的蛋白质和八个与 PS 相关的蛋白质，其中十个蛋白质在杂种与中亲值之间有显著差异。
尽管两个杂种中的每一个在蛋白质组水平上更类似于其母本，但它们的杂种优势的生物学基础是不同的。与亲本相比，杂种 ZD808 的优良农艺性状主要与一些与应激反应和代谢功能相关的高表达蛋白有关，而 ZD909 的性状主要与光合作用相关的高表达蛋白有关。我们的蛋白质组学结果支持了之前的生理和形态学研究，并为理解有价值的农艺性状提供了有用的信息。
