Hypoxic germination tolerance is an important trait for seedling establishment of direct-seeded rice. Our comparative metabolomics analysis revealed that weedy rice accumulated more sugar and amino acids than cultivated rice accumulated in the embryo and coleoptile tissues under hypoxic stress. At the transcriptional level, oxidative phosphorylation activity in weedy rice was higher than in cultivated rice that likely led to more efficient energy metabolism during hypoxic stress. Based on our comparative proteomics analysis, enriched proteins related to cell wall implied that the advantages in energy metabolism of weedy rice were ultimately reflected in the formation of tissue structures. In this study, we found that most of key hypoxic germination tolerance (HGT) genes shared the same genetic backgrounds with Oryza japonica, however, several of them genetically similar to other Oryza plant also play important roles. Our findings suggest weedy rice can serve as genetic resources for the improvement of direct-seeding rice.

耐缺氧发芽是直播水稻育苗的重要性状。我们的比较代谢组学分析表明，在缺氧胁迫下，杂草稻比栽培稻在胚胎和胚芽鞘组织中积累的糖和氨基酸更多。在转录水平上，氧化磷酸化杂草稻中的活性高于栽培稻，这可能导致在缺氧应激期间更有效的能量代谢。根据我们的比较蛋白质组学分析，与细胞壁相关的富集蛋白质暗示杂草稻在能量代谢方面的优势最终体现在组织结构的形成上。在这项研究中，我们发现大多数关键的耐缺氧发芽（HGT）基因与粳稻具有相同的遗传背景，但其中一些与其他稻植物的遗传相似也起着重要作用。我们的研究结果表明杂草稻可以作为改良直播稻的遗传资源。