柑橘CsaccA基因功能鉴定

为改良柑橘果实品质,以一个推测与柑橘果实品质相关的CsaccA基因为研究对象进行功能鉴定。通过该基因过表达转化Micro-Tom番茄,利用PCR和GUS染色鉴定,植株表型观察和生理生化指标测定等方法系统研究CsaccA基因功能。CsaccA基因显著促进植株的生物量,转基因植株根茎叶生物量均显著高于对照,植株生长速度显著快于对照。转基因植株果实提前转色,果实成熟期明显提前。转基因果实品质分析显示,番茄果实主要的糖组分葡萄糖和果糖含量显著增高,主要的酸组分柠檬酸含量显著降低。CsaccA基因有提升果实糖酸比的功能,可为果实品质改良提供参考。     

花生RuBPCase小亚基基因的克隆与序列分析

根据已知植物的核酮糖-1,5-二磷酸羧化/加氧酶(RuBPCase)小亚基基因序列设计简并引物,采用RT-PCR技术从花生叶片中克隆得到RuBPCase小亚基基因,命名为AhrbcS,Genbank登录号为KF607110,该基因编码区长度为549 bp,编码182个氨基酸.序列比对结果表明,AhrbcS编码蛋白与绿豆、菜豆、大豆、短绒野大豆和烟豆等具有较高的相似性.     

Molecular bases for resistance to acetyl-coenzyme A carboxylase inhibitor in Japanese foxtail (Alopecurus japonicus)

BACKGROUND: Haloxyfop‐R‐methyl is a widely used herbicide to control Poaceae weeds. Alopecurus japonicus, a widespread annual grass, can no longer be controlled by haloxyfop‐R‐methyl after continuous use of this herbicide for several years. RESULTS: Dose‐response experiments have established that the Js‐R biotype of A. japonicas has evolved resistance to aryloxyphenoxypropionates (APPs). Target‐site enzyme sensitivity experiments have established that the haloxyfop (free acid) rate causing 50% inhibition of acetyl‐CoA carboxylase (ACCase) activity (I₅₀) for the resistant (Js‐R) biotype is 11 times higher than that for the susceptible (Js‐S) biotype. In many cases, resistance to ACCase‐inhibiting herbicides is due to a resistant ACCase enzyme. Full‐length DNA and mRNA sequences of the plastidic ACCase gene were amplified. Eight single‐nucleotide differences were detected in this region. Four of the nucleotide changes were silent mutations. However, the other four nucleotide mutations caused four amino acid substitutions, replacing Arg‐1734 with Gly, Met‐1738 with Leu, Thr‐1739 with Ser and Ile‐2041 with Asn in the R biotype respectively; the substitution at position 2041 had been reported, while the other three had not. CONCLUSION: The ACCase in the Js‐R biotype was less susceptible to haloxyfop‐R‐methyl than that in the Js‐S biotype. Moreover, the amino acid substitution of Ile‐2041 with Asn might confer resistance to haloxyfop‐R‐methyl in A. japonicas. Copyright © 2012 Society of Chemical Industry     

盐胁迫下野大麦耐盐生理机制初探

以盐生植物野大麦、甜土植物中国春小麦为材料,研究了NaCl胁迫对野大麦、小麦幼苗叶片质膜透性、含水量、地上和根部离子含量、脯氨酸含量、磷酸烯醇式丙酮酸羧化酶(PEPCase)活性的影响。结果表明,随盐胁迫浓度增加,野大麦的细胞膜透性、Na 含量、脯氨酸含量、Na /K 、PEPCase活性增加,含水量、K 含量下降;但在相同盐胁迫条件下野大麦地上部和根部Na 含量明显低于小麦,而根中K 含量高于小麦,表明野大麦可能具有拒绝吸收Na 和维持高K 含量的能力;野大麦的脯氨酸含量增加幅度小于小麦,表明在盐胁迫下野大麦不是通过脯氨酸的积累来达到体内渗透平衡的;野大麦PEPCase活性增加明显高于小麦,说明提高光合效率可能是野大麦实现盐适应的主要措施之一。     

低温和NaCl对玉米叶片离体PEPCase活性及其调节特性的影响

对玉米叶片磷酸烯醇丙酮酸羧化酶(PEPCase)的低温失活现象的研究结果表明,低温贮存期间,玉米叶片离体PEPCase活性随贮存时间的延长而明显降低.对效应剂G6p、Gly和2.4—D的敏感性也减弱.甘油对低温贮存期间酶的活性和对2.4—D的敏感性均有保护效应;G6p单独存在时对酶的活性和2.4—D的敏感性均无保护效应,但同一浓度的G6p在与Gly和甘油同时作用时对酶的活性和2.4—D的敏感性均有保护效应,其保护程度优于同浓度的甘油.NaCl对PEP-Case活性有抑制作用.对酶对效应剂的敏感性影响较小.对低温贮存期间酶的活性和对效应剂的敏感性均无保护效应,并能加速酶的低温失活和对效应剂敏感性的减弱.上述试剂对低温贮存期间酶对效应剂敏感性的保护程度与对其活性的保护程度相一致,表明低温贮存期间酶对效应剂敏感性减弱与其低温失活有直接关系.     

荧光抗体在热带作物小粒种咖啡的C_3/C_4属性鉴别中的应用

用从烟草提纯的 1,5-二磷酸核酮糖 ( Ru BP)羧化酶制备兔抗 Ru BP羧化酶抗体 ,并以异硫氰酸盐荧光素 ( FITC)标记抗体 .采用直接免疫荧光法对典型 C3植物水稻、C4 植物甘蔗和小粒种咖啡等进行了 Ru BP羧化酶的组织化学定位 .结果表明 :C3和 C4 植物叶切片中 Ru BP羧化酶的分布明显不同 ,C3植物的特异荧光位于叶肉细胞 ,C4 植物的特异荧光绝大部分位于维管束鞘细胞 ;小粒种咖啡的特异荧光仅分布在叶肉细胞 .因此认为 ,小粒种咖啡应属 C3植物     

Determination of photosynthetic parameters Vcmax and Jmax for a C3 plant (spring hulless barley) at two altitudes on the Tibetan Plateau

On the Tibetan Plateau, the unique alpine climate factors of low air pressure, low CO₂ partial pressure and low air temperature have significant but non-explicit influences on the photosynthetic capacity of plants. To evaluate these influences, we measured the net photosynthetic rates for spring hulless barley leaves at two altitudes of 3688 m (the low altitude) and 4333 m (the high altitude), respectively. Two photosynthetic parameters—Vc_max, the maximum rate of Rubisco carboxylase activity, and J_max, the maximum rate of photosynthetic electron transport—were determined. The net photosynthetic rate and the photosynthetic parameters Vc_max and J_max were higher for leaves from plants grown at the high altitude than for those at the low altitude. Vc_max and J_max were approximately 24% and 22% greater, respectively, for leaves from plants grown at the high altitude. The CO₂ and air temperature at the high altitude were lower than those at the low altitude. As a consequence, plants exposed to lower CO₂ partial pressure and lower air temperature have a higher photosynthetic capacity on the Tibetan Plateau. The optimal temperatures for Vc_max and J_max were approximately 6.5% and 3.5% higher, respectively, in leaves from plants grown at the high altitude than those grown at the low altitude, and the ratio of J_max to Vc_max was 12.7% lower at the low altitude. Simulation analyses revealed that the photosynthetic capacities of plants decreased after long-term increases in CO₂ partial pressure and temperature associated with global climate change on the Tibetan Plateau.