Gravitropic curvature growth of Arabidopsis hypocotyls mainly occurred in the rapid growing Elongation Zone(EZI),not in the slow-growing Elongation Zone(EZII).By examining reorientation of Microtubules(MT)and phenotyp...Gravitropic curvature growth of Arabidopsis hypocotyls mainly occurred in the rapid growing Elongation Zone(EZI),not in the slow-growing Elongation Zone(EZII).By examining reorientation of Microtubules(MT)and phenotype of the cell wall in the EZI and the EZII of Arabidopsis hypocotyls under normal gravitational condition,it is found that MTs in the rapid growing epidermal cells were mainly in the transverse direction,while those in the non-growing epidermal cells were in the longitudinal directions.However,this difference in cortical MT arrays between the EZI and EZII cells disappeared when the seedlings were exposed to the simulated microgravity condition on a horizontal clinostat.Field emission scanning electron microscopy revealed that the surface texture of epidermal cells,like the direction of the MT,in the EZI and the EZII also became similar when exposed to the simulated microgravity condition.This result indicated that simulate microgravity could modify the potential differentiation between the EZI and the EZII by affecting the orientation of cortical MT in the epidermal cells.展开更多
高等植物在高于最适温度且低于逆境高温的温和高温范围内,发生的一系列形态变化统称为热形态建成。在这些形态变化中,以高温诱导的下胚轴伸长受到的关注最多,研究也最为深入。SMALL AUXIN UP RNA(SAUR)基因家族在促进生长和细胞伸长过...高等植物在高于最适温度且低于逆境高温的温和高温范围内,发生的一系列形态变化统称为热形态建成。在这些形态变化中,以高温诱导的下胚轴伸长受到的关注最多,研究也最为深入。SMALL AUXIN UP RNA(SAUR)基因家族在促进生长和细胞伸长过程中发挥着重要作用。然而,对于高温调控SAURs的分子机制还知之甚少。该研究以拟南芥(Arabidopsis thaliana)Col-0野生型、pif4-2突变体和4种转基因植物为材料,采用实时荧光定量PCR、染色质免疫共沉淀、双荧光素酶报告基因检测和表型分析的方法探索了热形态建成中高温调控SAUR1~SAUR4的分子机制。结果表明:高温促进SAUR1~SAUR4转录,并且这一促进作用需要转录因子PHYTOCHROME-INTERACTING FACTOR 4(PIF4);转录因子PIF4结合SAUR1~SAUR4启动子区中含有E-box的区域,并且温和高温会提高这些结合的强度;在热形态建成信号转导通路中SAUR1处于PIF4的下游;PIP4对SAUR1~SAUR4的调控需要生长素信号转导通路的参与。以上结果表明,高温通过影响PIF4与SAUR1~SAUR4启动子染色质的结合强度来调控这4个基因的转录。该研究有助于理解热形态建成中高温调控下胚轴伸长的下游分子机制,从而丰富抗热育种理论。展开更多
SAUR(SMALL AUXIN UP RNA)基因家族是促进下胚轴伸长的重要下游基因,然而在高温诱导的下胚轴伸长中SAURs受调控的分子机制尚有很多不明之处。热形态建成被定义为高等植物在最适温度和逆境高温之间的温和高温范围内发生的一系列形态变化...SAUR(SMALL AUXIN UP RNA)基因家族是促进下胚轴伸长的重要下游基因,然而在高温诱导的下胚轴伸长中SAURs受调控的分子机制尚有很多不明之处。热形态建成被定义为高等植物在最适温度和逆境高温之间的温和高温范围内发生的一系列形态变化。其中,高温诱导的下胚轴伸长是研究最为透彻的一个。该研究以拟南芥Col野生型、hy5突变体、35 S::HY5-HA/Col过表达植物和烟草为材料,采用抑制剂NPA处理实验、定量RT-PCR、染色质免疫共沉淀和双荧光素酶报告基因检测方法探索了高温调控SAUR1/2/3/4的分子机制。结果表明:(1)热形态建成信号转导通路中生长素处于HY5(ELONGATED HYPOCOTYL 5)的下游。(2)在20℃和29℃中,HY5抑制了SAUR1/2/3/4的转录。(3)在常温和高温中,HY5与SAUR1/2/3/4的启动子区染色质含有E-box的部分结合且这些结合被高温所抑制。(4)HY5对SAUR1/2/3/4的调控依然需要生长素的参与。综上认为,高温通过影响HY5与SAUR1/2/3/4启动子染色质的结合强度来调控这4个基因的转录,并且此调控过程需要生长素。该研究结果为高温调控下胚轴伸长下游基因的分子机制提供了新的见解。展开更多
基金Supported by the China Manned Space Flight Technology Project TG-2the National Natural Science Foundation of China(31670864)+2 种基金the National Natural Fund Joint Fund Project(U1738106)the Strategic Pioneer Projects of CAS(XDA15013900)the National Science Foundation for Young Scientists of China(31500687)
文摘Gravitropic curvature growth of Arabidopsis hypocotyls mainly occurred in the rapid growing Elongation Zone(EZI),not in the slow-growing Elongation Zone(EZII).By examining reorientation of Microtubules(MT)and phenotype of the cell wall in the EZI and the EZII of Arabidopsis hypocotyls under normal gravitational condition,it is found that MTs in the rapid growing epidermal cells were mainly in the transverse direction,while those in the non-growing epidermal cells were in the longitudinal directions.However,this difference in cortical MT arrays between the EZI and EZII cells disappeared when the seedlings were exposed to the simulated microgravity condition on a horizontal clinostat.Field emission scanning electron microscopy revealed that the surface texture of epidermal cells,like the direction of the MT,in the EZI and the EZII also became similar when exposed to the simulated microgravity condition.This result indicated that simulate microgravity could modify the potential differentiation between the EZI and the EZII by affecting the orientation of cortical MT in the epidermal cells.
