Biocontrol strain of Bacillus subtilis AF 1 rapidly induces lipoxygenase in groundnut (Arachis hypogaea L.) compared to crown rot pathogen Aspergillus niger

Metabolic products of polyunsaturated fatty acids have been variously implicated in control of microbial pathogens. Induced resistance has been shown as one of the mechanisms of biological control by plant growth promoting rhizobacteria (PGPR). This paper reports a significant lipoxygenase (LOX) activity in groundnut seedlings with production of 13-hydroperoxyoctadecadienoic acid (13-HPODE) and 13-hydroperoxyoctadecatrienoic acid (13-HPOTrE) as major products with linoleic acid (LA) and -linolenic acid (ALA), respectively. Both the hydroperoxides are inhibitory to the growth of Aspergillus niger as measured in micro titer plates. Ours is the first report on induction of LOX activities in groundnut on treatment with a PGPR strain Bacillus subtilis AF 1, and with crown-rot pathogen, A. niger. Treatment with B. subtilis AF 1 enhanced LOX levels in groundnut similarly but earlier to A. niger – treatment. This induction of LOX during activation of growth and pathogen infection was discussed in light of the reported involvement of LOX both in growth and development as well as in plant-pathogen interaction, particularly induced disease resistance.     

大豆脂氧化酶与种子劣变关系的研究

大豆存在和缺失脂氧化酶同功酶近等基因系种子,含水量分别为14％和12％左右,在冰箱（0－2℃）和室温下贮藏3－6个月。结果表明,在冰箱贮藏条件下,无论脂化酶存在或缺失,含水量高（14％左右）或低（12％左右）种子油脂酸、碘价及种子活力均变化不大。在室温条件下贮藏,脂氧化酶存在比缺失近等基因系种子酸价明显高,碘价降低,活力指数也降低较大,这种变化在含水量较高的情况下更加明显。由此可见,脂氧化酶在贮藏温度较高、含水量较高的条件下,对种子劣变有促进作用。     

Diversity and geographical distribution of seed lipoxygenase‐1 thermostability types in barley

To understand the diversity in the thermostability of the seed lipoxygenase‐1 (LOX‐1), 1040 cultivars of worldwide barley (Hordeum vulgare ssp. vulgare) genetic resources were investigated. The relative thermostability of LOX‐1 (LOX‐RTS) in these lines showed a bimodal frequency distribution and these lines were categorized into the high and low thermostability types (H‐type and L‐type, respectively). The H‐type lines predominated in the wild progenitor, ssp. spontaneum. The geographical distribution of these types in the cultivars was surveyed. The frequencies of the H‐ and L‐types were almost equal to one another in southwestern Asia. The occurrence of the H‐type predominated in eastern Asia and Africa, whereas in Europe and Turkey, the L‐type did. The predominance of the L‐type in Europe and Turkey can be understood through the hypothesis that the Fertile Crescent domestication contributed the majority of diversity in Europe. The uneven geographical distribution of the LOX‐1 thermostability types in the cultivars may reflect a polyphyletic origin of barley.     

Response dynamics of three defense related enzymes in cotton leaves to the interactive stress of Helicoverpa armigera (Hübner) herbivory and omethoate application

In order to explore the response dynamics of the activities of defense related enzymes in cotton leaves towards the interactive stress of Helicoverpa armigera herbivory and omethoate application, the activities of phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), and polyphenol oxidase (PPO) were examined from 6 to 126 h after cotton leaves were treated 12 h of H. armigera herbivory, and then sprayed with 800 mg L–1 omethoate. The results showed that the changes in the activities of PAL, LOX and PPO that occured under the interactive stress of H. armigera herbivory and omethoate application reflected the interactive effects of the two stresses on cotton defense. The similarity between the response dynamics of PAL, LOX, and PPO activities in cotton leaves under the interactive stress and that under H. armigera herbivory treatment alone showed that the induction of H. armigera herbivory on the activities of PAL, LOX and PPO in cotton leaves played a leading role in the interactive effects, and the effect of omethoate application played only a minor role. A joint factor analysis was performed according to a method which has been used to analyze the joint toxicity of pesticides; this analysis sought to clarify if there was a synergistic, antagonistic, or additive effect on PAL, LOX, and PPO activity in cotton leaves resulting from the interactive H. armigera herbivory and omethoate treatment. In the interactive effect on the response of PAL activity in cotton leaves, antagonistic effects of the omethoate application towards H. armigera herbivory were observed at 6 and 12 h. Synergistic effects were then observed at 18 and 30 h. Antagonistic effects were observed from 54 to 78 h and synergistic effects were finally observed at 126 h. The correlation between H. armigera herbivory and omethoate application in the interactive effect on cotton defense responses of LOX activity also fluctuated from synergism to antagonism during the time course. In the interactive effect on PPO activity, only antagonism was observed between H. armigera herbivory and omethoate application. In the interactive stress of H. armigera herbivory and omethoate application on cotton defense responses, omethoate affected the defense responses of cotton to H. armigera herbivory by producing antagonistic and synergistic effects. These results will be useful to understand the relationship between host plant and herbivorous pest.     

大豆种子脂肪氧化酶的缺失对其农艺性状的影响

为探明大豆种子脂肪氧化酶的缺失是否会对大豆的农艺性状造成影响,对从中国南方10省（市）征集的174份大豆种质资源中筛选出的种子脂肪氧化酶缺失体与非缺失体材料和从国外引种的缺失体近等位基因系农艺性状间的差异进行了研究,结果表明,大豆种子脂肪氧化酶的缺失对开花期、生育期、株高、节数、分枝数、单株荚数、单株粒数、单株产量、百粒重、害虫危害种子程度、脂肪和蛋白质含量等主要农艺性状都没有明显影响,对大豆资源的统计分析结果表明,大豆种子脂肪氧化酶的缺失频率与生态类型无关,与籽粒颜色、形状和脐色有关。     

鲫的挥发性成分

新鲜鲫具有以草腥味、泥土味等混合的气味,其强度以内脏最强,皮次之,肌肉最弱。采用GC－嗅觉感官试验和GC－MS鉴定分析结果表明：同鲫特征气味最为相关的成分为己醛;其他相关物质有1－戊烯－3－酮、2,3－戊二酮、1－戊烯－3－醇、反－2,顺－4－庚二烯醛、1－门牌烯－3－醇、1,5－辛二烯－3－醇等C5－C8的羰基化合物和醇类。鲫的鱼皮和鳃的粗酶液中存在着类脂肪氧化酶活性,由底物花生四烯酸生成3种C8挥发性成分。     

胡萝卜素漂白法快速筛选耐储藏水稻品种

根据水稻种胚脂氧合酶的主要同工酶LOX-3的活性缺失可以提高耐贮性的特性,研究了快速测定LOX-3酶活性以筛选耐储藏水稻品种的方法。报道了水稻种胚LOX-3具有共氧化的次生反应特性,并根据该特性建立了快速筛选其缺失体的胡萝卜素漂白法（检测时间为3 h）,优化了反应体系。推测在正常氧压下水稻种胚LOX-1和LOX-2不具备或仅具备相对较弱的共氧化次生反应能力。与LOX-3缺失体的单克隆抗体技术和I2-KI比色法相比,胡萝卜漂白法具有方法简单、成本低、快速的优点。还探讨了胡萝卜素漂白法在耐储藏水稻品种改良和相关分子克隆研究中的应用前景。     

均质/加热条件下组分缺失型原料豆乳理化特性研究

为探究脂氧酶缺失型大豆品种东富3、7S球蛋白缺失型大豆品种东富2为原料生产的豆乳理化性质,以普通大豆品种黑农64为对照,分别探究均质（80MPa）、加热工艺（95℃、25min）对3种原料豆乳理化性质的影响。结果显示未均质加热前,东富3生豆乳的蛋白溶解度、游离巯基含量在3种豆乳中最高,平均粒径、浊度、粘度、离心沉淀率最低;东富2生豆乳的蛋白溶解度、游离巯基含量显著低于正常品种黑农64生豆乳（p＜0.05）,平均粒径、浊度、粘度、离心沉淀率显著大于黑农64生豆乳（p＜0.05）,即生豆乳中东富3物理稳定性最高,东富2物理稳定性最低。均质后,所有豆乳的蛋白溶解度、游离巯基含量均增加,平均粒径、浊度、粘度均降低。东富2和黑农64豆乳均质后离心沉淀率显著下降（p＜0.05）,而东富3豆乳离心沉淀率与均质前无显著差异（p＞0.05）,但物理稳定性仍然最高,东富2均质豆乳物理稳定性仍最低。加热后3种豆乳的蛋白溶解度、平均粒径、粘度均增加,而游离巯基含量、离心沉淀率均下降,较与均质,加热对豆乳物理稳定性提升效果更显著（p＜0.05）。加热后东富3豆乳平均粒径和离心沉淀率仍然最低,尽管受热后东富2豆乳粒径增加幅度大于其他2个品种,但较高的粘度使其离心沉淀率下降程度最大,物理稳定性优于加热后的黑农64豆乳。豆乳微观结构图显示均质、加热前后3种豆乳油滴尺寸变化与粒径结果一致。     

非变性PAGE在鉴定大豆脂肪氧化酶类型中的应用

为解决脂肪氧化酶检测复杂、费用昂贵、剧毒试剂对人体影响等问题,研究出一种安全、快速而经济有效的大豆脂氧酶检测技术。以Suzuyutaka脂氧酶缺失近等基因系和非缺失类型大豆冀豆12为材料,利用聚丙烯酰胺凝胶电泳探索非变性PAGE分析大豆脂肪氧化酶,通过对不同样品浓度、电泳条件和分离胶浓度的比较,摸索鉴定大豆Lox缺失类型的最佳条件。通过电泳条件优化分析发现,电泳样品中预样品的浓度为30%、分离胶浓度为11%、电泳时间为6 h时,3种脂肪氧化酶分辨清晰度最高;通过重复电泳的相对迁移率分析,表明在上述电泳条件下的检测结果比较稳定且重复性好;通过3种脂肪氧化酶酶带与缺失酶带对照比较和分子量测定两方面验证了所得到的3条脂肪氧化酶酶带。非变性PAGE是一种简单、经济、快捷而安全的检测分析大豆脂肪氧化酶同功酶的方法,因而可以用于资源分析、良种繁育以及生产、收购和加工利用中的大豆脂氧酶缺失类型鉴定。     

唐菖蒲脂氧合酶基因GhLOX1 对球茎膨大的影响

 以唐菖蒲（Gladiolus hybridus）品种‘Rose Supreme’的球茎为试材,应用Real time RT-PCR技术,分析唐菖蒲球茎在不同浓度的茉莉酸甲酯（methyl jasmonate,MJ）0.1、0.2、0.5 mmol · L^-1和水杨酸异羟肟酸（salicylhydroxamic acid,SHAM）0.5、0.75、1.0 mmol · L^-1处理后脂氧合酶（LOX）基因的的表达水平,并且对LOX活性、内源MJ含量以及球茎鲜样质量与体积进行测定。分析结果表明,GhLOX1表达水平、脂氧合酶活性、内源MJ含量以及球茎的鲜样质量与体积均随着MJ浓度的增加而逐渐提高。与此相反,经过不同浓度的LOX抑制剂SHAM处理后,以上各项指标随着SHAM浓度的增加而逐渐降低。同时,构建35S-GhLOX1过表达载体,利用根癌农杆菌介导法将GhLOX1导入马铃薯栽培品种‘中薯3号’的试管薯薄片中,转基因马铃薯植株块茎的数量、体积和鲜样质量分别得到了不同程度的提高。