转FRO2基因番茄突变体的抗缺铁黄化特性

为了增加植物的抗缺铁黄化能力,研究了转FRO2基因番茄突变体抗黄化特性.结果显示FRO2基因转化番茄后,使生长在缺铁胁迫下的植株根系铁还原酶活性大大增强(转FRO2基因番茄植株根系酶活性是对照2倍),番茄铁吸收能力和有效铁还原能力大大加强,植株中有效铁含量增加(转FRO2基因番茄植株叶片有效铁含量是对照的1.5倍),转FRO2基因番茄的植株叶片颜色显著比对照绿,黄化程度减轻,黄化指数降低(对照的黄化指数是转FRO2基因番茄的1.3倍),植株生长量显著高于对照(转基因植株株高高于对照50%).在正常条件下,转FRO2基因番茄根系的FRO2基因表达量增加,铁还原酶活性增加了1.75倍,转FRO2基因番茄植株叶片有效铁含量是对照植株的2倍,是其他耐贮藏转基因番茄的(转反义NR、ACC、CTR1基因)2～3.5倍以上.     

FRO2基因表达与铁还原酶活性及有效铁吸收的关系

研究了转FRO2基因苹果突变体AFRO2的FRO2基因表达、铁还原酶活性和根系对有效铁的吸收.结果显示,FRO2基因在缺铁条件下大量表达;其表达量在根系中最强,其次是果实,叶片中最弱;在正常培养条件下,转基因AFRO2表达高于对照和其它非转基因品种;在缺铁胁迫下转基因AFRO2根系铁还原酶活性增加最多,吸收有效铁也最多.综合分析表明：FRO2基因表达量、铁还原酶活性、叶片有效铁含量3个指标有相同的变化规律,均为缺铁胁迫下最强.这说明,由于FRO2基因的转化和在八棱海棠苹果中的过量表达,使其编码的铁还原酶活性增加,根系还原和吸收的有效铁增多,致使其叶片中有效铁的积累最多.     

FRO2基因表达与铁还原酶活性及有效铁吸收的关系

研究了转FRO2基因苹果突变体AFRO2的FRO2基因表达、铁还原酶活性和根系对有效铁的吸收. 结果显示, FRO2基因在缺铁条件下大量表达; 其表达量在根系中最强, 其次是果实, 叶片中最弱; 在正常培养条件下, 转基因AFRO2表达高于对照和其它非转基因品种; 在缺铁胁迫下转基因AFRO2根系铁还原酶活性增加最多, 吸收有效铁也最多. 综合分析表明: FRO2基因表达量、铁还原酶活性、叶片有效铁含量3个指标有相同的变化规律, 均为缺铁胁迫下最强. 这说明, 由于FRO2基因的转化和在八棱海棠苹果中的过量表达, 使其编码的铁还原酶活性增加, 根系还原和吸收的有效铁增多, 致使其叶片中有效铁的积累最多.     

不同转基因番茄GalUR的表达与Vc含量

为了得到高维生素C（Vc）含量新品种,克隆和构建了GalUR半乳糖醛酸还原酶基因,并转入了番茄.通过不同转基因突变体GalUR基因表达和Vc含量分析发现：GalUR基因在转GalUR基因番茄中得到了过量表达;在转FRO2-铁还原酶基因的番茄突变体中表达量增加了60%;在耐贮藏转基因番茄F3、F2、F1中也均高于对照,其中F3的表达量最高,是对照的2～3倍;在非转基因中蔬4号和6号的表达量高于丽春番茄1倍;所有供试GalUR基因表达量均为红果最多、粉红果次之,青果最少.转基因番茄果实Vc含量变化与上述GalUR基因的表达有相同规律.转GalUR3基因番茄果实和叶片Vc含量高于对照2倍以上.GalUR基因的表达还与乙烯合成酶基因ACS、CTR1和铁还原酶FRO2基因的表达有关.     

不同转基因番茄GalUR的表达与Vc含量

为了得到高维生素C(Vc)含量新品种, 克隆和构建了GalUR半乳糖醛酸还原酶基因, 并转入了番茄. 通过不同转基因突变体GalUR基因表达和Vc含量分析发现: GalUR 基因在转GalUR 基因番茄中得到了过量表达; 在转FRO2-铁还原酶基因的番茄突变体中表达量增加了60%; 在耐贮藏转基因番茄F3、 F2、 F1中也均高于对照, 其中F3的表达量最高, 是对照的2～3倍; 在非转基因中蔬4号和6号的表达量高于丽春番茄1倍; 所有供试GalUR 基因表达量均为红果最多、粉红果次之, 青果最少. 转基因番茄果实Vc含量变化与上述GalUR基因的表达有相同规律. 转GalUR3基因番茄果实和叶片Vc含量高于对照2倍以上. GalUR基因的表达还与乙烯合成酶基因ACS、 CTR1和铁还原酶FRO2基因的表达有关.     

转番茄铁载体基因（LeIRT2）八棱海棠对缺铁胁迫的响应

 在低铁(铁浓度为10-6mol·L-1)水培条件下，2个转番茄铁载体蛋白基因八棱海棠（Malus robusta Rehd.）株系表现出较强的抗缺铁胁迫能力。叶片叶绿素含量和净光合速率显著高于对照；叶片细胞间隙CO2浓度显著低于对照；根系的质子分泌和三价铁螯合物还原酶（FCR）活性均升高，明显强于同样条件下的非转基因植株。根系扫描电镜结果显示，转基因株系根系的吸收区和根毛的表面结构皱折增多，表面积增大。     

杜梨根系铁吸收关键基因生物信息学分析及缺铁胁迫对其表达的影响

为了探究缺铁胁迫对杜梨根系铁吸收关键基因表达的影响,对杜梨根系铁吸收关键基因三价铁还原酶(Pb FRO2)基因和铁转运蛋白(Pb IRT1)基因的氨基酸序列进行了多重序列比对和进化树分析;采用改良的Hoagland营养液水培杜梨的方法,研究了缺铁胁迫对杜梨根系Pb FRO2和Pb IRT1基因相对表达量以及根系铁和锌含量的影响。结果表明,Pb FRO2蛋白具有还原酶特性,Pb IRT1蛋白属于二价金属离子转运蛋白家族—ZIP家族;缺铁胁迫9 d内,杜梨根系Pb FRO2和Pb IRT1的表达量整体上呈现出先升高后降低的趋势,胁迫3 d表达量达到最高点且与对照(加FeEDTA)差异显著;缺铁胁迫30 d,杜梨根系中铁含量比对照降低77.46%,而锌含量提高1 139.40%。综上可知,缺铁胁迫可诱导杜梨根系铁吸收关键基因表达量升高,进而促进二价金属离子转运蛋白的活性提高。     

转番茄铁载体基因（LeIRT2）八棱海棠株系的鉴定

 【目的】选育具有抗缺铁能力的苹果属植物新种质。【方法】通过半定量式RT-PCR检测、印迹杂交、营养液pH的变化和低铁(铁浓度为10-6 mol•L-1)水培条件下，根系和叶片的金属元素含量分析。【结果】在通过Southern杂交获得的9个转番茄铁载体蛋白基因八棱海棠（Malus robusta Rehd.）株系中，有6个转基因株系成功转录，目的基因在叶片和根系中都有表达。其中2个在缺铁情况下显著提高了根系总铁的含量和叶片中活性铁的含量，同时也大幅度提高了根系和叶片中锌的含量。【结论】转番茄铁载体蛋白基因八棱海棠株系表现出较强的抗缺铁胁迫能力。     

不同铁浓度对苹果砧木Fe3+还原酶活性的影响

通过营养液培养的方法,研究了不同铁浓度处理对4种苹果砧木植物铁含量以及根系Fe3+还原酶活性的影响.结果表明,缺铁导致砧木根系Fe3+还原酶活性增加.砧木种类不同,培养溶液中铁浓度不同,Fe3+还原酶活性也有所不同.随着培养液中铁浓度的增加,根中Fe3+还原酶活性逐渐降低.在缺铁胁迫条件下,各砧木根系中Fe3+还原酶活性达最高水平,即小金海棠＞M26＞八棱海棠＞SH40.在最适铁浓度水平下,SH40和八棱海棠根系中铁含量高于枝叶中铁含量,对缺铁较敏感,容易表现缺铁黄化现象.而小金海棠和M26根系中铁含量低于枝叶中铁含量,对缺铁不敏感,不易表现出缺铁黄化现象.     

喷施复合氨基酸铁肥对猕猴桃果实品质的影响

【目的】研究喷施复合氨基酸铁肥对猕猴桃叶片铁含量及果实品质和产量的影响,筛选用于猕猴桃缺铁黄化病防治及果实品质提高的复合氨基酸铁肥的最佳喷施浓度。【方法】以黄化程度为4级,树龄5年的"秦美"猕猴桃为供试品种,采用田间试验,以喷施清水为对照,测定猕猴桃叶片中的铁含量、猕猴桃产量和果实中的还原糖、可滴定酸、维生素C、铁含量,研究喷施不同浓度复合氨基酸铁肥(分别稀释1 500,1 000,500倍)对石灰性土壤条件下猕猴桃果实品质的影响。【结果】与对照相比,喷施不同浓度复合氨基酸铁肥均可显著提高缺铁黄化猕猴桃叶片的铁含量。在一定喷施浓度范围内,猕猴桃果实中的可溶性固形物、还原糖、维生素C含量及糖酸比随着复合氨基酸铁肥喷施浓度的增加呈先增加后降低的趋势,可滴定酸含量随着复合氨基酸铁肥喷施浓度的增加呈先降低后增加的趋势,其中喷施稀释1 000倍复合氨基酸铁肥时果实的维生素C、可溶性固形物、还原糖含量最高,可滴定酸含量最低,风味最佳;而喷施稀释500倍复合氨基酸铁肥的果实铁含量最高。与对照相比,喷施复合氨基酸铁肥对猕猴桃产量的影响不明显。【结论】综合考虑作用效果,稀释1 000倍是石灰性土壤条件下改善猕猴桃品质的最佳复合氨基酸铁肥的使用浓度。     

缺铁胁迫对沙梨叶片黄化、再复绿和根系中Fe(Ⅲ)还原酶活性的影响

在水培条件下,研究了缺铁胁迫对梨砧木沙梨(Pyrus pyrifolia Nakai)叶片黄化、复绿和分根培养时其根系Fe(Ⅲ)还原酶活性(FCR)变化的影响。结果表明,黄化植株转移到含铁营养液后,上部叶片复绿明显快于中部叶片;含铁和不含铁处理间的FCR活性差异显著,不含铁处理的根FCR活性高于含铁处理,但随着培养时间的延长,活性逐渐降低,不含铁和含铁处理之间具显著的相关,相关系数为0.91。     

香橙和枳的三价铁螯合还原酶诱导研究

三价铁螯合还原酶是植物吸收铁过程中非常重要的酶。在田间表现耐缺铁的香橙在缺铁胁迫下,三价铁螯合还原酶活性在胁迫4周时即达到最强,增加约20倍;而在田间表现极易缺铁的枳在铁胁迫4周时,三价铁螯合还原酶活性仅增加约3倍。香橙根系在铁胁迫前后分泌质子的能力增显著强于枳。表明三价铁螯合还原酶对香橙忍耐缺铁起着非常重要的作用,并且香橙具有很强的调节微根际环境PH的能力。     

Changes of Nitrate Reductase Activity in Cucumber Seedlings in Response to Nitrate Stress

In China, nitrogen fertilizer application rates in intensive agricultural systems have increased dramatically in recent years, especially in protected vegetable production systems. This excessive use of nitrogen fertilizer has resulted in soil secondary salinization, which has become a significant environmental stress for crops such as cucumber, in the protected farmland of China. So it is necessary to illuminate how crops respond to nitrate stress. The objective of this work was to examine the effects of increased nitrate concentration [14 （CK） and 140 mmol L^-1 （T）] on NO3- concentration, and in vitro and in vivo nitrate reductase activities in the roots and leaves of cucumber （Cucumis sativus L. cv. Xintaimici） seedlings with hydroponic culture. The results showed that the NO3- concentration in the roots and leaves of T seedlings significantly increased over treatment course, and at 12 d increased by 1.08 and 1.72 times with respect to CK seedlings, respectively; in vitro nitrate reductase activity of T was increased dramatically to 1.74 times of CK in the roots at 2 d and 1.56 times of CK in the leaves at 6 d, and then decreased. At 12 d, in vitro activity was still 24.3% higher in the roots and only 9.9% lower in the leaves than CK. Compared with in vitro nitrate reductase activity, in vivo activity responded differently to the increase of treatment time. At the beginning, in vivo nitrate reductase activity in the roots and leaves of T had no significant difference from CK, whereas with the increase of treatment duration, the activity decreased. At 12 d, in vivo activity in the roots and leaves of T lowered by 20.1 and 52.8% with respect to CK, respectively. This evidence suggests that posttranslational activation of nitrate reductase in cucumber seedlings may be seriously inhibited by nitrate stress.     

干旱和乙烯介导下番茄生长生理反应及NR基因的表达

通过干旱与乙烯介导下的番茄幼苗三重反应、植株的生理变化、幼苗生长表现及NR基因表达的研究,探讨干旱对乙烯信号转导的影响。结果表明:干旱诱导ABA和乙烯的产生,因而表现番茄幼苗三重反应;ABA又强烈地诱导乙烯受体蛋白NR基因的表达,促进了乙烯信号的转导;继而发生一系列与乙烯处理相同的生理、生长反应———细胞膜透性、蒸腾作用、呼吸作用和气孔导度增强,植株叶片黄化、衰老和脱落。干旱造成的危害与ABA诱导的NR基因的表达有密切关系。     

Overexpression of IbSnRK1 enhances nitrogen uptake and carbon assimilation in transgenic sweetpotato

Nitrogen is an important nutrient for plant development. Nitrogen and carbon metabolisms are tightly linked to physiological functions in plants. In this study, we found that the IbSnRK1 gene was induced by Ca(NO₃)₂. Its overexpression enhanced nitrogen uptake and carbon assimilation in transgenic sweetpotato. After Ca(¹⁵NO₃)₂ treatment, the ¹⁵N atom excess, ¹⁵N and total N content and nitrogen uptake efficiency (NUE) were significantly increased in the roots, stems, and leaves of transgenic plants compared with wild type (WT) and empty vector control (VC). After Ca(NO₃)₂ treatment, the increased nitrate N content, nitrate reductase (NR) activity, free amino acid content, and soluble protein content were found in the roots or leaves of transgenic plants. The photosynthesis and carbon assimilation were enhanced. These results suggest that the IbSnRK1 gene play a important role in nitrogen uptake and carbon assimilation of sweetpotato. This gene has the potential to be used for improving the yield and quality of sweetpotato.     

Effect of Salt Stress on Nitrogen Assimilation of Functional Leaves and Root System of Rice in Cold Region

The aims were to investigate the effect of salt stress on key enzyme activity of nitrogen metabolism and the concentration of nitrate nitrogen and ammonium nitrogen response to salt stress.Two rice cultivars,Mudanjiang 30 (sensitive cultivar) and Longdao 5 (salt-tolerant cultivar),were treated with different salt concentrations (CK 0%,S1 0.075%,S2 0.15%,S3 0.225% and S4 0.3%).The results showed that the activities of nitrate reductase (NR),glutamine synthase (GS),glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with those of the CK,the activities of NR,GS and GOGAT of rice in cold region decreased,but the activity of GDH increased in the heading stage under salt stress.The variation for key enzyme activity of nitrogen metabolism was the highest under S4 treatment.The activities of NR,GS and GOGAT in the functional leaves significantly decreased compared with those in roots;the concentrations of nitrate nitrogen and ammonium nitrogen in the functional leaves and roots of rice in cold region presented a single peak curve change and the peak occurred in the heading stage;compared with that of the CK,the concentration of nitrate nitrogen decreased in leaves and roots,the concentration of ammonium nitrogen decreased and the concentration of ammonium nitrogen in roots increased under salt stress.The variations for the activities of NR,GS and GOGAT in the functional leaves and roots of Longdao 5 were less than those of Mudanjiang 30 under the same concentration of salt stress.     

不同丛枝菌根真菌对番茄生长及相关生理因素的影响

对番茄中杂9号接种6种不同的丛枝菌根真菌(Glomus versiforme,Glomus mossea-2,Glomus intraradices,Glomus diuphauam,Glomus mossea,Glomus etuni-catum1),通过测定不同菌种对番茄的生长效应及叶片生理变化,表明不同丛枝菌根真菌对番茄有不同程度的生长促进作用,处理番茄的叶片可溶性糖、可溶性蛋白、硝酸还原酶(NR)活性均比对照有所增加,其中对叶片可溶性糖的影响最为显著,它与番茄根系的菌根侵染率呈极显著正相关,还与植株总干重显著正相关,菌根侵染率亦与植株干重显著正相关。故此提出叶片可溶性糖含量可作为丛枝菌根影响番茄生长的生理鉴定指标,依此指标筛选出Glomus versiforme,Glomusmossea-2是对番茄生长促进效果最好的菌种。     

转反义GVDE基因烟草的叶绿素荧光参数及抗氧化酶活性的变化

 【目的】研究姜紫黄质脱环氧化酶基因（GVDE）的功能。【方法】以烟草为试材,构建反义抑制表达载体。将从姜中克隆的GVDE基因反向转入烟草,对获得的抗性植株用PCR和PCR-Southern检测分析。同时测定烟草叶片荧光参数变化和抗氧化物酶（APX、SOD、POD）活性。【结果】反义基因已整合到烟草的基因组中。转反义GVDE基因烟草的NPQ、Fv/Fm始终低于对照,APX、SOD和POD等抗氧化酶活性也低于对照植株。【结论】在转反义GVDE基因的烟草中,强光下耗散过剩光能的非辐射能量耗散能力明显降低。     

茉莉酸合成相关基因Spr2与LePrs在番茄抗根结线虫中的作用

 【目的】研究茉莉酸合成相关基因Spr2与LePrs对番茄抗根结线虫的影响，探讨茉莉酸在番茄抗根结线虫病中的作用。【方法】以番茄茉莉酸合成突变体spr2、茉莉酸过量表达转基因番茄35S::PS及野生型CM为试材，研究外源喷施茉莉酸甲酯及不同番茄试材相互嫁接对接种根结线虫后番茄根结数、蛋白质酶抑制剂PI-II表达及Spr2、LePrs基因转录水平的影响。【结果】番茄茉莉酸合成突变体spr2较野生型与茉莉酸过量表达转基因番茄35S::PS容易感染根结线虫，外源喷施茉莉酸甲酯降低了番茄根结数。以茉莉酸过量表达转基因番茄35S::PS为砧木，可以提高嫁接植株对根结线虫的抵抗能力。【结论】Spr2突变降低了番茄对根结线虫的抗性， LePrs过量表达可以提高植株对根结线虫的抗性。因此，茉莉酸在番茄抗根结线虫病中起到了一定的作用。