【摘要】 为揭示水稻穗发芽抗性的品种差异机制，本研究选取3种不同穗发芽抗性的水稻品种，检测其开花后不同时期的整穗发芽率特性、相对含水量、总可溶性糖含量、糖组分含量以及α-淀粉酶活性等指标。结果表明，随着开花后时间延长，水稻种子内总可溶性糖、蔗糖和海藻糖含量逐渐上升，且在花后35 d后整穗发芽显现品种间差异。花后35 d整穗的人工模拟发芽研究显示，易穗发芽材料-苏垦118内源糖信号相关基因（OsTOR、OsRaptor1、OsSnRK1A和OsHXK5）的表达被率先显著诱导，进而导致脱落酸（ABA）分解基因（OsABA8ox1和OsABA8ox3）和赤霉素（GA）合成基因（OsGA3ox1）表达增强，随后α-淀粉酶水解基因（RAmy1A）表达也被诱导增加，最终表现为高发芽率；而抗穗发芽材料-南粳9108种子内糖含量变化不明显，且糖信号相关基因的诱导较迟，ABA合成基因（OsNCED1）表达随处理时间的延长快速上调，RAmy1A的表达水平也较低，表现为低发芽率特征。综上所述，水稻对糖水平的敏感性差异与其穗发芽抗性差异有密切关系。本研究可为从糖信号角度解析水稻穗发芽抗性的品种差异提供新视角。更多还原

【Abstract】 To reveal the physiological mechanism underlying the varietal difference in pre-harvest sprouting(PHS) resistance of rice, three rice varieties with different PHS resistance levels(the resistant type-Nanjing 9108, the sensitive type-Suken 118 and the moderate resistant type-Nanjing 505) were selected for this study. Indicators including panicle germination rate, relative water content, total soluble sugar content, sugar component contents, and α-amylase activity were measured at different stages post-anthesis. The results showed that the contents of total soluble sugars, sucrose, and trehalose in rice seeds gradually increased with post-flowering, and varietal differences in panicle germination became apparent 35 days after flowering(DAF). Artificially simulation germination tests on panicles at 35 DAF indicated that in the PHS-susceptible variety Suken 118, the expression levels of endogenous sugar signal-related gene(OsTOR, OsRaptor1, OsSnRK1A, and OsHXK5) was significantly induced early. This induction further unregulated the expression levels of abscisic acid(ABA) degradation genes(Os ABA8 ox1 and Os ABA8 ox3) and gibberellin(GA) biosynthesis gene(Os GA3 ox1), followed by an increase in the expression level of the α-amylase hydrolysis gene(RAmy1A), ultimately resulting in a high germination rate. In contrast, in the PHS-resistant variety Nanjing 9108, changes in sugar content were insignificantly, and the induction of sugar signal-related genes was delayed. The expression of ABA biosynthesis gene(OsNCED1) was rapidly upregulated with the prolonged treatment, while the expression level of RAmy1A was low, exhibiting characteristics of the low germination rate. In conclusion, the differences in sensitivity to sugar levels among rice varieties is closely related to theirdifferences in PHS resistance. This study provides the new clues for analyzing varietal difference in rice PHS resistance from in the perspective of sugar signaling.更多还原