State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China.
Sci Rep. 2017 Jan 10;7:40139. doi: 10.1038/srep40139.
Polyploid rice hybrids have a powerful biological and yield potential that may become a new way for rice breeding; however, low fertility is major hindrance in commercial utilization. Here, we developed a neo-tetraploid rice that could overcome the sterility of autotetraploid rice and produce high heterosis. Transcriptome analysis of F hybrid developed by crossing neo-tetraploid with autotetraploid rice displayed 807, 663 and 866 differentially expressed genes that uniquely associated with F and specific to (DEGFu-sp) anther, ovary and leaf, respectively. Of the DEGFu-sp, 1224 genes displayed nonadditive expression; 44 and 10 genes were annotated as TFs and methyltransferase or hydroxymethyltransferase, respectively. Gene ontology enrichment and co-expression analysis revealed specific differential gene expressions in the DEGFu-sp to leaf, anther and ovary, such as genes related to photosynthesis, metabolic process and transport, and co-expression network including fertility, resistance and epigenetic elements. Of the DEGFu-sp to anther, 42 meiosis stage-specific genes, eight meiosis-related genes, such as RAD51 and SMC2, were identified. We identified 38 miRNAs from DEGFu-sp to anther, and their targets were associated with pollen fertility and retrotransposon protein. Our study provides new germplasm for polyploid rice breeding, and revealed complex regulatory mechanisms that might be associated with heterosis and fertility.
同源四倍体水稻杂种具有强大的生物学和产量潜力，可能成为水稻育种的新途径；然而，低育性是商业利用的主要障碍。在这里，我们开发了一种新型的同源四倍体水稻，它可以克服同源四倍体水稻的不育性，并产生高杂种优势。通过将新型同源四倍体与同源四倍体水稻杂交得到的 F1 杂种的转录组分析显示，有 807、663 和 866 个差异表达基因与 F1 杂种独特相关，分别特异于花药、子房和叶片。在 DEGFu-sp 中，有 1224 个基因表现出非加性表达；44 个和 10 个基因分别被注释为 TF 和甲基转移酶或羟甲基转移酶。基因本体论富集和共表达分析显示，DEGFu-sp 到叶片、花药和子房的特定差异基因表达，如与光合作用、代谢过程和运输相关的基因，以及包括育性、抗性和表观遗传元件的共表达网络。在 DEGFu-sp 到花药中，鉴定出 42 个减数分裂阶段特异性基因和 8 个减数分裂相关基因，如 RAD51 和 SMC2。我们从 DEGFu-sp 到花药中鉴定出 38 个 miRNA，其靶标与花粉育性和逆转座子蛋白相关。我们的研究为同源四倍体水稻的育种提供了新的种质资源，并揭示了可能与杂种优势和育性相关的复杂调控机制。
