Zhong Zhengzheng, Wu Yawen, Zhang Peng, Hu Guocheng, Fu Dong, Yu Guoping, Tong Hanhua
State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou 311400, China.
State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.
Plants (Basel). 2023 Mar 14;12(6):1309. doi: 10.3390/plants12061309.
Heterosis is the phenomenon in which some hybrid traits are superior to those of their parents. Most studies have analyzed the heterosis of agronomic traits of crops; however, heterosis of the panicles can improve yield and is important for crop breeding. Therefore, a systematic study of panicle heterosis is needed, especially during the reproductive stage. RNA sequencing (RNA Seq) and transcriptome analysis are suitable for further study of heterosis. Using the Illumina Nova Seq platform, the transcriptome of ZhongZheYou 10 (ZZY10), an elite rice hybrid, the maintainer line ZhongZhe B (ZZB), and the restorer line Z7-10 were analyzed at the heading date in Hangzhou, 2022. 581 million high-quality short reads were obtained by sequencing and were aligned against the Nipponbare reference genome. A total of 9000 differential expression genes were found between the hybrids and their parents (DG). Of the DG, 60.71% were up-regulated and 39.29% were down-regulated in the hybrid. Comparative transcriptome analysis revealed that 5235 and 3765 DG were between ZZY10 and ZhongZhe B and between ZZY10 and Z7-10, respectively. This result is consistent with the transcriptome profile of ZZY10 and was similar to Z7-10. The expression patterns of DG mainly exhibited over-dominance, under-dominance, and additivity. Among the DG-involved GO terms, pathways such as photosynthesis, DNA integration, cell wall modification, thylakoid, and photosystem were significant. 21 DG, which were involved in photosynthesis, and 17 random DG were selected for qRT-PCR validation. The up-regulated PsbQ and down-regulated subunits of PSI and PSII and photosynthetic electron transport in the photosynthesis pathway were observed in our study. Extensive transcriptome data were obtained by RNA-Seq, providing a comprehensive overview of panicle transcriptomes at the heading stage in a heterotic hybrid.
杂种优势是指某些杂交性状优于其亲本的现象。大多数研究分析了作物农艺性状的杂种优势；然而，穗部杂种优势可以提高产量，对作物育种很重要。因此，需要对穗部杂种优势进行系统研究，尤其是在生殖阶段。RNA测序（RNA Seq）和转录组分析适用于杂种优势的进一步研究。利用Illumina Nova Seq平台，在2022年杭州抽穗期对优良水稻杂交种中浙优10号（ZZY10）、保持系中浙B（ZZB）和恢复系Z7-10的转录组进行了分析。通过测序获得了5.81亿条高质量短读段，并与日本晴参考基因组进行比对。在杂种与其亲本之间共发现9000个差异表达基因（DG）。在这些DG中，杂种中有60.71%上调，39.29%下调。比较转录组分析表明，ZZY10与中浙B之间以及ZZY10与Z7-10之间分别有5235个和3765个DG。这一结果与ZZY10的转录组图谱一致，且与Z7-10相似。DG的表达模式主要表现为超显性、亚显性和加性。在涉及DG的GO术语中，光合作用、DNA整合、细胞壁修饰、类囊体和光系统等途径具有显著性。选择了21个参与光合作用的DG和17个随机DG进行qRT-PCR验证。在本研究中观察到光合作用途径中上调的PsbQ以及PSI和PSII的下调亚基和光合电子传递。通过RNA-Seq获得了大量转录组数据，全面概述了杂种优势杂交种抽穗期的穗部转录组情况。
