The cultivation of rice varieties with high seed vigour is vital for the direct seeding of rice, and the molecular basis of regulation of seed vigour remains elusive. Here, we cloned a new gene OsHIPL1, which encodes hedgehog-interacting protein-like 1 protein as a causal gene of the major QTL qSV3 for rice seed vigour. OsHIPL1 was mainly localized in the plasma membrane and nucleus. RNA sequencing (RNA-seq) revealed that the ABA-related genes were involved in the OsHIPL1 regulation of seed vigour in rice. The higher levels of endogenous ABA were measured in germinating seeds of OsHIPL1 mutants and NIL-qsv3 line compared to IR26 plants, with two up-regulated ABA biosynthesis genes (OsZEP and OsNCED4) and one down-regulated ABA catabolism gene OsABA8ox3. The expression of abscisic acid-insensitive 3 (OsABI3), OsABI4 and OsABI5 was significantly up-regulated in germinating seeds of OsHIPL1 mutants and NIL-qsv3 line compared to IR26 plants. These results indicate that the regulation of seed vigour of OsHIPL1 may be through modulating endogenous ABA levels and altering OsABIs expression during seed germination in rice. Meanwhile, we found that OsHIPL1 interacted with the aquaporin OsPIP1;1, then affected water uptake to promote rice seed germination. Based on analysis of single-nucleotide polymorphism data of rice accessions, we identified a Hap1 haplotype of OsHIPL1 that was positively correlated with seed germination. Our findings showed novel insights into the molecular mechanism of OsHIPL1 on seed vigour.

中文翻译：

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OsHIPL1，一种刺猬相互作用蛋白样1蛋白，增加水稻种子活力

高种子活力水稻品种的培育对于水稻直播至关重要，而调控种子活力的分子基础仍然难以捉摸。在这里，我们克隆了一个新基因OsHIPL1，它编码hedgehog-interacting protein-like 1蛋白作为水稻种子活力主要QTL qSV3的因果基因。OsHIPL1主要定位于质膜和细胞核。RNA测序（RNA-seq）显示ABA相关基因参与了水稻种子活力的OsHIPL1调控。与 IR26 植物相比，在OsHIPL1突变体和 NIL -qsv3系的发芽种子中测量到更高水平的内源 ABA ，其中两个上调的 ABA 生物合成基因（OsZEP和OsNCED4）和一个下调的 ABA 分解代谢基因OsABA8ox3。与IR26植物相比， OsHIPL1突变体和NIL -qsv3系的萌发种子中脱落酸不敏感3 ( OsABI3 )、OsABI4和OsABI5的表达显着上调。这些结果表明，OsHIPL1种子活力的调节可能是通过调节内源性 ABA 水平和改变OsABIs来实现的。水稻种子萌发过程中的表达。同时，我们发现OsHIPL1与水通道蛋白OsPIP1;1相互作用，进而影响水分吸收，促进水稻种子萌发。基于对水稻种质单核苷酸多态性数据的分析，我们鉴定了与种子萌发呈正相关的OsHIPL1的Hap1单倍型。我们的研究结果显示了对OsHIPL1对种子活力的分子机制的新见解。