水稻粒宽突变体gw87的基因定位及候选基因分析

【目的】对水稻粒宽突变体gw87（grain width 87）进行表型鉴定、遗传分析、基因定位及候选基因分析,为探明该基因调控水稻籽粒大小的分子机制及应用潜力奠定基础。【方法】利用甲基磺酸乙酯诱变籼稻恢复系材料676R,获得一份籽粒宽度和千粒重显著增加的突变体gw87。对该突变体进行表型观察、农艺性状调查及外源油菜素内酯（BL）敏感性、叶绿素含量、光合参数测定,了解其表型特征及生理特性。调查gw87与676R杂交F₁的表型和F₂群体的分离情况,分析其遗传行为;选取该群体中的突变植株进行高通量测序,并利用gw87与粳稻品种日本晴杂交的F₂代作为定位群体,通过MutMap分析和分子标记定位,遴选候选基因并进行DNA和cDNA测序验证。利用qRT-PCR分析gw87和676R中BR合成途径基因OsDWARF4、D11和D2的表达差异。【结果】与野生型亲本676R相比,gw87突变体的株高降低,节间缩短,其中,倒一节间长度缩短最大,并呈现出扭曲的形态;叶片长度减少,宽度增加;单株有效穗数、主穗穗长和结实率显著降低,但籽粒宽度和千粒重显著增大。BL敏感性试验显示,gw87突变体幼苗对外源BL的敏感性降低。光合色素和光合参数测定表明,gw87光合色素含量增加,光合速率也有所增加。遗传分析表明gw87的突变性状是由1对隐性核基因控制。MutMap分析显示gw87突变基因位于第5染色体中部,在该染色体区域仅有1个碱基突变引起编码氨基酸变化;分子标记连锁分析表明该突变基因位于InDel标记X2和X3之间约101 kb的染色体区域;综合这两方面分析结果,最后遴选出gw87候选基因是编码一个含有AP2/EREBP DNA绑定结构域的转录因子基因LOC_Os05g32270。对该候选基因进行DNA和cDNA测序验证,发现gw87突变体中该基因DNA的第1 041位的碱基由G突变为A,导致与该位点相邻的76 bp内含子序列被剪接为外显子,引起阅读框移码,蛋白翻译提前终止。qRT-PCR分析显示gw87突变体中BR合成途径基因的表达量显著上调,表明gw87突变体中BR信号减弱。【结论】gw87是smos1、shb、rla1、ngr5的新等位突变体,但与这些突变体表型不同,gw87籽粒的宽度和千粒重显著增加,可能是LOC_Os05g32270的突变位点不同,导致其编码蛋白的功能活性不同所造成。     

高效液相色谱-蒸发光散射检测器测定14-羟基芸苔素甾醇

建立了高效液相色谱-蒸发光散射检测器(HPLC-ELSD)测定14-羟基芸苔素甾醇含量的分析方法。在优化好的ELSD条件(漂移管温度50℃、增益值10、辅助气压力3.5bar)下,采用Eclipse XDB C_(18)色谱柱(250mm×4.6mm,5μm),以乙腈/水(V/V=25:75)等度洗脱,流速为1.0mL/min,柱温为30℃,14-羟基芸苔素甾醇和杂质在10min内能达到基线分离。14-羟基芸苔素甾醇在16.1~513.8mg/L浓度范围内,峰面积的对数与质量浓度对数线性关系良好,回归方程的相关系数为0.999 6,7次平行测定的相对标准偏(RSD/%)为1.55,平均回收率为100.76%。该方法简单实用,可为14-羟基芸苔素甾醇及其它芸苔素甾醇的质量控制提供了一种准确可行的方法。     

Genetic variation of seedling traits responded to brassinosteroid and gibberellin inhibitors in maize (Zea mays) doubled haploid lines

The purpose of this study was to examine the genotypic variation in maize doubled haploid (DH) lines response to brassinosteroid and gibberellin inhibitors. Plant responses to hormone inhibitors were determined in growth chamber experiments using germination paper for three different seedling treatments: application of propiconazole (Pcz), uniconazole (Ucz) or water (control). Mesocotyl length (ML) was more sensitive to hormone inhibitors, especially to the Ucz treatment, than other seedling traits. ML was significantly correlated with other traits in the Ucz treatment. All the seedling traits showed moderate-to-high broad sense heritability values, ranging from 0.39 to 0.82. The Euclidian genetic distances of inbred line pairs ranged from 1.27 to 19.94, indicating there was a high level of variability across the maize DH lines used in this study. DH lines with extreme MLs were identified, which can provide valuable breeding resources for improving abiotic stress tolerance, and for further genetic studies.     

油菜素甾醇对沟叶结缕草长期培养愈伤组织生长和再生的影响

为了维持长期培养植物愈伤组组织的高再生率,以应用于体细胞无性系进行变异筛选.本研究以继代15年的沟叶结缕草[Zoysia matrella(L.)Merr.]胚性愈伤组织为材料,用不同浓度的表油菜素内酯(EBL)处理,研究油菜素甾醇(BR)对其生长和再生的影响,选出可提高长期离体培养愈伤组织生长及再生效率的最优EBL浓...     

油菜素甾醇对萝卜芽菜生物活性物质的影响

为探究油菜素甾醇对萝卜芽菜生物活性物质的影响,用表油菜素内酯及其类似物高芸薹素单独或者与氯化钠共同处理萝卜芽菜,测定并分析其芥子油苷、花青素、维生素C和总多酚的含量以及抗氧化能力的变化。结果表明,20 nmol·L~(-1)表油菜素内酯单独处理时,芥子油苷含量显著降低,但与40mmol·L~(-1)氯化钠共处理时,芥子油苷含量显著上升;20 nmol·L~(-1)高芸薹素单独处理或者与40 mmol·L~(-1)氯化钠共处理则对芥子油苷含量无显著影响。此外,表油菜素内酯和高芸薹素单独处理或者分别与氯化钠共处理均能显著提高花青素和维生素C的含量,但对总多酚含量和抗氧化能力均无显著影响。综上,表油菜素内酯与氯化钠共处理是提高萝卜芽菜中芥子油苷、花青素以及维生素C等主要生物活性物质的有效手段,这为通过化学调控的方法改良萝卜芽菜的品质提供了理论依据和技术支撑。     

植物BZR家族基因调控非生物胁迫应答和生长发育的研究进展

由于固着生长的特性,植物在生长发育过程中会遭遇各种不利环境的影响,因此植物发展出复杂的调控机制来抵御胁迫危害。油菜素内酯(brassinosteroid,BR)是一类甾醇类植物内源激素,广泛参与植物生命周期中各种生命活动的调节。近年来,植物BR生物合成、代谢及信号转导过程相关研究已取得重要进展。油菜素唑抗性因子(brassinazole resistant,BZR)作为BR信号通路中特有的一类转录因子,在该通路中发挥重要作用。本文概述了植物BZR家族成员的基本结构及其生物学功能,重点阐述了BZR在植物非生物胁迫应答和生长发育中的调控作用,特别归纳了油料作物BZR研究进展,并对一些尚未明确的问题进行了探讨,旨在为深入理解BR介导的分子调控网络、改良作物抗逆性并提高作物生产力提供理论依据。     

Improving Water Relations and Gas Exchange with Brassinosteroids in Rice under Drought Stress

Drought stress is the most pervasive threat to sustainable rice production and mainly disrupts membrane structure and cell-water relations. Exogenously applied brassinosteroids (BRs) may produce profound changes that may improve drought tolerance in rice. In this study, we monitored some physiological basis of the exogenously applied BRs in improving drought tolerance in fine grain aromatic rice ( Oryza sativa L.). Two BRs i.e. 28-homobrassinolide (HBL) and 24-epibrassinolide (EBL) were used both as seed priming and foliar spray. To prime, the seeds were soaked in 0.01 μ m aerated solution each of HBL and EBL for 48 h and dried back to original weight. Treated and untreated seeds were sown in plastic pots with normal irrigation in a phytotron. At four-leaf stage (3 weeks after sowing), plants were subjected to drought stress at 50 % field capacity by cutting down the water supply. For foliar spray, 0.01 μ m of HBL and EBL solutions were sprayed at five-leaf stage. Drought stress severely reduced fresh and dry weights, whilst exogenously applied BRs improved net CO₂ assimilation, water use efficiency, leaf water status, membrane properties, production of free proline, anthocyanins, soluble phenolics, but declined the malondialdehyde and H₂O₂ production. In conclusion, BRs application improved the leaf water economy and CO₂ assimilation, and enabled rice to withstand drought. Moreover, foliar spray had better effect under drought than seed treatments and of the two BRs, EBL proved more effective.     

油菜素内酯信号传递在水稻中的研究进展

油菜素甾醇(brassinosteroids,BR)是植物界广泛存在的一类植物激素,对植物生长发育的诸多方面有调节作用,也调控植物对环境逆境的胁迫响应。由于BR对与水稻产量相关的株高、籽粒大小、叶夹角、分蘖等性状产生影响,因而其合成和信号传递途径及如何调控BR信号以改善水稻农艺性状和产量,引起了业界的广泛关注。中国科学家在解析水稻BR信号传递因子方面,做出了突出的贡献。文章对近十余年来水稻BR信号传递的主要研究进展进行综述,并对未来可能的研究和应用领域及方向作了展望。     

Ameliorative Effects of Brassinosteroid on Excess Manganese-Induced Oxidative Stress in Zea mays L. Leaves

Manganese （Mn） is becoming an important factor limiting crop growth and yields especially on acid soils. The present study was designed to explore the hypothesis that brassinosteroid application can enhance the tolerance of maize （Zea mays L.） to Mn stress and if so, whether or not the mechanism underlying involves regulation of antioxidative metabolism in leaves. The effects of 24-epibrassinosteroid （EBR） on the growth, photosynthesis, water status, lipid peroxidation, accumulation of reactive oxygen species, and activities or contents of antioxidant defense system in maize plants under Mn stress were investigated by a pot experiment. At supplemented Mn concentrations of 150-750 mg kg^-1 soil, the growth of plants was inhibited in a concentration-dependent manner. The semi-lethal concentration was 550 mg Mn kgq soil. Foliage application with 0.1 mg L^-1 EBR significantly reduced the decrease in dry mass, chlorophyll content, photosynthetic rate, leaf water content, and water potential of plants grown in the soil spiked with 550 mg kg^-1 Mn. The oxidative stress caused by excess Mn, as reflected by the increase in malondialdehyde （MDA） content and lipoxygenase （LOX, EC 1.13.11.12） activity, accumulation of superoxide radical and H2O2, was greatly decreased by EBR treatment. Further investigations revealed that EBR application enhanced the activities of superoxide dismutase （SOD, EC 1.15.1.1）, peroxidase （POD, EC 1.11.1.7）, catalase （EC 1.11.1.6）, ascorbate peroxidase （APX, EC 1.11. 1.11）, dehydroascorbate reductase （DHAR, EC 1.8.5.1）, and glutathione reductase （GR, EC 1.6.4.2）, and the contents of reduced ascorbate and glutathione, compared with the plants without EBR treatment. It is concluded that the ameliorative effects of EBR on Mn toxicity are due to the upregulation of antioxidative capacity in maize under Mn stress.     

油菜素内酯调控植物根系发育机制研究进展

油菜素甾醇(brassinosteroids,BRs)是20世纪后期发现的一类新型植物激素,参与调控植物生长发育的诸多方面,其中对植物根系发育过程具有重要的调控作用.油菜素内酯(brassinolide,BL)是最先确定结构的高活性BR.首先介绍了BR的发现、BR调控根系生长信号通路的进展,进一步阐述了BR通路转录因子...