Gibberellin biosynthesis and signal transduction is essential for internode elongation in deepwater rice

MADOKA AYANO, TAKAHIRO KANI, MIKIKO KOJIMA, HITOSHI SAKAKIBARA, TAKUYA KITAOKA, TAKESHI KUROHA, ROSALYN B. ANGELES-SHIM, HIDEMI KITANO, KEISUKE NAGAI, MOTOYUKI ASHIKARI
Plant, Cell & Environment, 2014, 37(10): 2313-2324  DOI: 10.1111/pce.12377     追溯原文......本站官方QQ群:62473826
gibberellin

Under flooded conditions, the leaves and internodes of deepwater rice can elongate above the water surface to capture oxygen and prevent drowning. Our previous studies showed that three major quantitative trait loci (QTL) regulate deepwater‐dependent internode elongation in deepwater rice. In this study, we investigated the age‐dependent internode elongation in deepwater rice. We also investigated the relationship between deepwater‐dependent internode elongation and the phytohormone gibberellin (GA) by physiological and genetic approach using a QTL pyramiding line (NIL‐1 + 3 + 12). Deepwater rice did not show internode elongation before the sixth leaf stage under deepwater condition. Additionally, deepwater‐dependent internode elongation occurred on the sixth and seventh internodes during the sixth leaf stage. These results indicate that deepwater rice could not start internode elongation until the sixth leaf stage. Ultra‐performance liquid chromatography tandem mass‐spectrometry (UPLC‐MS/MS) method for the phytohormone contents showed a deepwater‐dependent GA1 and GA4 accumulation in deepwater rice. Additionally, a GA inhibitor abolished deepwater‐dependent internode elongation in deepwater rice. On the contrary, GA feeding mimicked internode elongation under ordinary growth conditions. However, mutations in GA biosynthesis and signal transduction genes blocked deepwater‐dependent internode elongation. These data suggested that GA biosynthesis and signal transduction are essential for deepwater‐dependent internode elongation in deepwater rice.

赤霉素生物合成和信号传导在调控深水稻节间伸长过程中至关重要

在水淹环境下,深水稻的叶和节间能够伸长到水面之上来捕获氧和防止水淹。我们以前的研究发现在深水稻中存在3个调控深水依赖的节间伸长的主效数量性状位点(QTL)。本文我们研究了深水稻年龄依赖的节间伸长。通过对近等基因系(NIL)的生理和遗传研究,我们还研究了深水依赖的节间伸长与植物激素赤霉素之间的关系。水淹条件下,深水稻六叶期前节间不能伸长。此外,水淹依赖的节间伸长发生在六叶期的第六和第七节间。这些结果表明深水稻在六叶期之前节间伸长不能起始。超高效液相色谱串联质谱(UPLC-MS/MS)检测到深水稻中赤霉素GA1和GA4的积累是水淹依赖的。此外,GA抑制剂能够终止深水稻水淹依赖的节间伸长。相反,外施GA使得正常条件下的节间伸长跟水淹相似。然而,GA生物合成(OsGA20ox2)和信号传导基因(SLR和GID1)的突变能够阻断深水依赖的节间伸长。这些数据表明GA生物合成和信号传导对于深水稻在水淹环境下的节间伸长过程发挥着重要作用。


基因列表
  细长秆基因; GRAS家族转录因子; GRAS蛋白 SLR1; OsGAI; Slr1-d
  半矮秆基因 sd1; OsGA20ox2; qSD1-2
  GA不敏感矮秆基因 GID1