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1.
Introgression of antioxidant activity into cassava (Manihot esculenta C.): an effective technique for extending fresh storage roots shelf life 
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下载免费PDF全文 Physiological postharvest deterioration (PPD) of cassava is the main constraint affecting its nutritional and economical values. PPD is induced by wounds when detaching storage roots from mother plant during harvesting. It is accelerated by the reactive oxygen species (ROS) such as oxygen ion (O2) and peroxide (O2)?2. The carotenoid content and its antioxidant property can help in extending shelf life of cassava storage roots. The primary mode of action of carotenoids as antioxidant is to quench singlet oxygen. Cassava breeding was reported to successfully introgress and improve carotenoid content into cassava. The two types of phytoene synthase (PSY) enzymes (PSY1 and PSY2) are key regulators of carotenoids accumulation in cassava. Carotenoids formation and accumulation in cassava storage roots are induced by a single nucleotide polymorphism in PSY2 which causes a non‐conservative amino acid exchange. This single nucleotide polymorphism in PSY gene is co‐segregated with β‐carotene in cassava storage roots, a phenomenon that could help to unravel the mechanism of introgression of carotenoids into cassava. This article investigates breeding feasibility for improving quality of cassava landraces in developing countries. 相似文献
2.
Cassava roots have a short shelf life due to a process known as post-harvest physiological deterioration (PPD). Within 2–3 d undesirable vascular streaking in the root develops. Tolerance to PPD was recently reported in different cassava genotypes, opening up new opportunities to analyze biochemical changes in stored roots and in the functional properties of their starches. Roots from PPD-susceptible (HMC-1) and tolerant (AM 206-5) clones were harvested and stored for up to 14 d in ambient tropical conditions. AM 206-5 is also characterized by amylose-free starch. Roots and starch were analyzed each day. PPD levels differed significantly between the two clones (35% and 8% at day 14) and showed a relation to scopoletin synthesis, which reached maximum levels around day 3 or 4 of storage. Roots lost weight consistently during storage (≈10% in two weeks). Starch loss per day of root storage was estimated at about 1%. This could be the result of consistent increases in total sugars and respiration of root tissue. Important changes in starch properties were observed. Gel clarity decreased gradually during storage, with more pronounced changes occurring in starches from HMC-1. Swelling power decreased only in the case of AM 206-5. Gel viscosity increased in both genotypes. Improved tolerance to PPD could significantly reduce the economic impact of the short shelf life of ordinary cassava root processing. It remains to be seen, however, whether changes in stored roots positively or negatively affect the quality of the final product. 相似文献
3.
Cassava (Manihot esculenta Crantz) roots spoil 2–3 days after harvest due to post-harvest physiological deterioration (PPD), which had remained an unsolved problem until recent reports of genetic variation for tolerance to it. PPD is a genetically active, oxidative process triggered when the harvested roots are separated from their mother plant. The short shelf life of harvested roots results in large losses and high transport and marketing costs. Recent reports on positive genetic variation for tolerance to PPD will facilitate breeding for extended shelf life of the roots and a better understanding of the biochemical and genetic events leading to PPD. However, PPD scoring is difficult and prone to large experimental errors. It is often the case that roots from the same plant can have 0 and 100% PPD score due to injuries during the harvest process, variation in dry matter content and, most likely, other variables yet to be identified. Therefore, sampling a root for biochemical or genetic studies and measuring PPD in a different root, is not a reliable approach. A device has been developed and tested for the possibility of extracting a core of root parenchyma, filling the space with melted paraffin (to reduce oxygen availability), and then one or two weeks later visually quantifying PPD in the same root. Sampling the roots did not have any significant effect on PPD suggesting that the protocol can be used for biochemical composition and gene expression studies related to the causes of PPD and the possibilities of developing tolerance to it. 相似文献
4.
14-3-3蛋白结构与功能预测及其在木薯成熟期的表达分析 总被引：1，自引：0，他引：1
为了深入研究木薯14-3-3蛋白结构和功能,也为研究木薯块根淀粉积累的分子调控提供新思路。本研究采用生物信息学方法对木薯14-3-3蛋白家族的组成成分与理化性质、系统发育进化、导肽、亚细胞定位、二级结构、功能结构域、三级结构及亲水性、疏水性进行分析和预测,并对14-3-3基因在不同木薯品种中进行差异表达分析。结果表明：（1）木薯14-3-3蛋白家族16个异构体存在多个不同的保守结构域,二级结构相似的亲水性蛋白家族成员在进化关系上可划分为2大不同的类别;（2）14-3-3基因家族16个成员在花叶木薯、ZM-Seaside和华南9号(SC9)块根成熟期的表达水平存在显著性差异(P<0.05),与花叶木薯和SC9相比,产量较高的木薯品系ZM-Seaside块根中14-3-3基因表达水平显著下降(P<0.05),推测14-3-3蛋白在木薯块根成熟期的淀粉积累过程中可能起着负调控作用。 相似文献
5.
木薯块根有色体分离及其蛋白质组学的研究 总被引：1，自引：0，他引：1
木薯(Manihot esculenta Crantz)块根有色体是类胡萝卜素贮藏和调控多种生理生化过程的场所。本研究发现Percoll密度梯度离心法最适合于木薯块根有色体的提取,利用光学显微镜观察发现40%~50%Percoll梯度层富含完整有色体,Western blot分析显示该层的线粒体标志酶Vdac1杂交信号较低,而质体标志酶Rbc L杂交信号最高,并以此确定木薯块根有色体的分离方法。利用蛋白质组学方法显示SC9块根有色体存在34个差异蛋白质,其中上调表达17个,下调表达17个;涉及碳代谢及能量代谢相关蛋白所占比例最高。STRING蛋白质互作网络显示,Enolase 2与Elongation Factor互作关系最多,是整个互作网络的核心蛋白质。q RT-PCR定量分析显示Enolase 2在高类胡萝卜素的蛋黄木薯SC9的表达水平显著高于低类胡萝卜素品种SC6068。推测其可能是影响SC9与SC6068类胡萝卜素差异的主要蛋白质之一。 相似文献
6.
I. R. M. Benesi M. T. Labuschagne L. Herselman N. M. Mahungu J. K. Saka 《Euphytica》2008,160(1):59-74
When cassava is harvested too early, it often leads to reduction in yield, while delayed harvest leads to development of woody
and fibrous tuberous roots, and reduction in starch content. The optimum harvest time is not known. The objectives of this
study were to determine the effect of genotype, location and season on starch extraction in order to find an optimum harvest
regime for cassava, and to find the best parameter for monitoring starch levels in cassava tuberous roots. Results showed
that genotypic effect was large for starch weight, starch extraction rate on fresh weight basis, and root dry matter content.
This suggested that high starch weights could be realised by selection of suitable varieties for starch extraction. It was
found that cassava harvesting and starch extractions should be done between October and November since the highest starch
extraction rates were achieved during that period, and drying of the extracted starch using the open air method was fast and
convenient. The results also suggested that starch levels can efficiently be monitored using starch extraction rate on fresh
root weight basis. Starch content on fresh root basis and root dry matter content can also be used to determine the optimum
time to harvest cassava for starch extraction but were inferior to starch extraction on fresh root weight basis. 相似文献
7.
Yuanhuai Han Rocío Gómez-Vásquez Kim Reilly Hongying Li Joe Tohme Richard M. Cooper John R. Beeching 《Euphytica》2001,120(1):59-70
The storage roots of cassava (Manihot esculenta Crantz) suffer from a rapid post-harvest deterioration that is a major constraint to their increased exploitation. In many
ways this deterioration resembles wound responses in other better studied plant systems, though it appears to lack an adequate
wound repair response. A cDNA clone (cMeHRGP1) for a hydroxyproline-rich glycoprotein expressed during the deterioration response
was isolated and characterised. This clone proved to be an antisense pairing, coding for part of phosphoserine aminotransferase
on its complementary strand. Messenger RNA corresponding to cMeHRGP1 accumulated in deteriorating cassava roots from day three
after harvest, by which time the deterioration response was well advanced. There by confirming that aspects of the wound repair
response were inadequate in harvested cassava roots.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
通过田间试验,分析不同外源硒施用水平下食用木薯的营养品质、抗氧化性及采后生理变质等方面的差异,探索外源硒对食用木薯品质的影响。结果表明:在一定施用范围内,外源硒能促进淀粉、蛋白质、总糖、黄酮的积累,提高超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GHS-Px）活性,其中在0.9kg/hm 2处理下与对照的差异均达到显著水平;外源硒处理下食用木薯块根采后生理变质的速度均小于对照,但与对照的差异均不显著;外源硒降低了类胡萝卜素和氢氰酸的积累及过氧化物酶（POD）活性,而对支链淀粉含量和干物质率的作用不明显。综上,施用适量的外源硒能改善食用木薯的品质。 相似文献
9.
低钾胁迫下烟草根系差异表达基因的cDNA-AFLP分析 总被引：1，自引：0，他引：1
烟叶含钾量是评价优质烟叶重要品质指标,大量研究认为钾元素的吸收和积累是由植物基因型所控制,而在烟草转录水平上的低钾胁迫的应答机制方面,尚未见报道.本实验为鉴定烟草低钾胁迫响应基因,应用,cDNA-AFLP技术,对低钾胁迫下烟草NC89根系基因表达进行了mRNA指纹分析,通过240对引物组合的筛选,共得到324个差异表达转录衍生片段.对其中9个TDF进行了克隆、测序和序列分析.结果表明:其中7个TDF涉及逆境响应,氨基酸的转运与代谢,转录调控及钾吸收,2个TDF为功能未知. 相似文献
10.
11.
甘蓝型油菜NCa细胞质雄性不育系统花药败育前期的基因差异表达 总被引：2，自引：0，他引：2
采用cDNA-AFLP技术研究了甘蓝型油菜NCa不育系、保持系和可育F1花药败育前期的基因差异表达谱。用224对引物对不育系、保持系及育性恢复F1等3个材料的cDNA进行AFLP分析。回收、克隆可能与花药育性有关的差异条带,筛除假阳性,获得41条阳性差异条带（TDFs）;经测序、同源比对、功能预测,归并为35个非重复的TDFs。大多数TDFs在甘蓝型油菜中属首次报道。将已知功能的28个TDFs按其推测功能分为2大类10小类,82%的TDFs与细胞形态建成和降解、蛋白质合成、加工和转运、能量代谢、信号传导有关;基本涵盖花药发育相关的关键代谢过程。对其中7个TDFs基因进行了RT-PCR分析。结果表明,果胶甲酯酶基因和氨基酸通透酶基因都在不育系花蕾中大量表达,果胶甲酯酶基因在不育系叶片、保持系的花蕾、叶片中都没有检测到;而氨基酸通透酶基因有微量表达。驱动蛋白和乙醛脱氢酶主要在保持系花蕾中大量表达,而在不育系花蕾、叶片以及保持系叶片中都只有微量表达。玉米黄素环氧化酶（ZEP）和单脱氧抗坏血酸还原酶则在保持系花蕾、叶片和不育系叶片中大量表达,而在不育系花蕾中微量表达。花粉油体蛋白在不育系和保持系的花蕾中都有表达,不过保持系花蕾中的表达量约2倍于不育系花蕾;但是在两者的叶片组织中都没有检测到。本试验获得的差异表达基因对于了解油菜花药育性形成的调控机制提供了重要的分子信息。 相似文献
12.
Mapping wound-response genes involved in post-harvest physiological deterioration (PPD) of cassava (Manihot esculenta Crantz) 总被引：6，自引：0，他引：6
Diego Fernando Cortés Kim Reilly Emmanuel Okogbenin John R. Beeching Carlos Iglesias Joe Tohme 《Euphytica》2002,126(1):47-53
The genome locations of the wound-response genes that were expressedduring the post-harvest physiological deterioration (PPD) of cassava, suchas phenylalanine ammonia lyase, -1.3 glucanase, hydroxyprolinerich glycoprotein, catalase, 1-aminocyclopropane 1-carboxylate, cysteineprotease inhibitor, aspartic protease, a partial cDNA for serine/threonineprotein kinase and peroxidase, have been identified on the frameworkmolecular genetic map of cassava. Also, molecular markers linked toputative quantitative trait loci (QTLs) influencing PPD of cassava weremapped using an F1mapping population derived from elite parentallines (TMS 30572 × cm 2177-2). A molecular linkage map previouslyconstructed based on the segregation of 240 RFLP, 100 RAPD, 85microsatellite and five isoenzyme markers on 144 F1 individuals wasused for the QTL mapping.A set of 10 molecular markers with a significant association with putativeQTLs for PPD were identified based on probability values < 0.005in order to minimize the detection of false positives. Based on single-markerregression, eight putative QTLs located on the linkage groups G, P, L, U,and X of the female-derived framework map were found to explain between 5–12% of the phenotypic variance of the PPD. In the male-derived frameworkmap, two putative QTLs on linkage groups C and L explained 13% and11% of this variance, respectively. This study thus identified the majorgenome regions of cassava related to physiological post-harvestdeterioration, thereby providing tools for the identification of gene(s)controlling this trait. 相似文献
13.
蔗糖合酶(sucrose synthase,SuSy)是催化蔗糖代谢的关键酶之一,参与蔗糖的分解、淀粉的生物合成等代谢过程,在植物的生长发育中发挥着至关重要的调控作用。本研究从牛大力转录组数据库筛选并克隆得到两个蔗糖合酶基因CsSuSy1与CsSuSy2,CsSuSy1全长2326 bp,包括2307 bp的完整开放阅读框(open reading frame,ORF),编码768个氨基酸;CsSuSy2基因全长3028 bp,包括2439 bp的ORF,编码812个氨基酸。CsSuSy1与CsSuSy2的蛋白结构预测分子量分别为87.8 kD与92.6 kD,理论等电点分别为5.91与5.75,二级结构主要为α-螺旋与无规则卷曲。保守结构域分析结果显示它们属于PLN00142超级家族成员,包含蔗糖合酶结构域(Sucrose_synth)与糖基转移酶结构域(Glycos_transf_1)两个保守结构域,与同科其它近缘种的SuSys氨基酸序列具有较高的相似性。系统进化树分析显示主要分为两个大分支。qRT-PCR检测结果显示CsSuSy1和CsSuSy2分别在块根膨大初期、块根膨大初期和中期高表达,且表达量显著高于茎、叶和成熟种子。鉴于在牛大力块根发育过程中CsSuSys1基因表达量与多糖含量呈极显著负相关、与淀粉含量呈显著负相关,CsSuSys2基因表达量与多糖含量呈显著负相关,推测CsSuSys1和CsSuSys2在块根膨大前期或中期协同参与催化蔗糖降解,促进块根中多糖和淀粉的积累。本研究结果为揭示蔗糖合酶参与牛大力块根膨大过程的蔗糖代谢提供证据,有助于进一步阐明牛大力块根膨大的分子机制。 相似文献
14.
Cassava is predominantly an upland crop that is also cultivated in inland valley swamps (IVS). Identifying physiological traits that can withstand excess moisture stress can aid in the selection and use of stable cassava cultivars in IVS. Three cassava cultivars were evaluated for growth and yield in the upland and IVS ecologies in the 1993–94 crop seasons using a randomized complete block design. In the upland, 80/40 outyielded 87/29 and 'coco', while in the IVS, 87/29 had the highest yield. Highest yielding cultivars in each ecology also had the highest tuberous root bulking rate (TBR), dry matter (DM) production, crop growth rate (CGR), relative growth rate, net assimilation rate (NAR), leaf area index, leaf production rate and leaf life. Positive correlations between these parameters and tuberous root yield were noted. High yield of 87/29 in IVS was partly due to its low tuberous root rotting. High root rotting in 80/40 was partly as a result of the greater depth of tuberous roots in the soil (0.3–0.6 m) as compared to the other cultivars (0.15–0.3 m) where roots were in contact with stressful water levels earlier than others. The yield and yield components, growth and leaf characters were all drastically reduced when the cultivars were grown in IVS as compared to upland. For example, root yields of 'coco', 87/29 and 80/40 were reduced by 53 %, 60 % and 92 %, respectively, in IVS. Selection of cassava cultivars with longer leaf life and leaf area maintenance leading to high CGR, TBR, NAR and harvest index (in IVS and upland), coupled with a shallow tuberous root formation zone (in IVS) can give higher root and leaf yields in the two ecologies. 相似文献
15.
本研究以木薯花芽与叶芽为材料,通过Illumina HiSeqTM4000测序平台对其进行转录组测序,结果获得高质量序列45 010 506个、碱基数13.46 Gb,GC含量在43.5%以上、比对效率在78%以上。筛选得到3 782个差异表达基因(DEGs),其中上调2 409个、下调1 373个。DEGs涉及的主要功能有一般功能预测,翻译,复制、重组与修复,信号传导机制,次生产物合成、运输与代谢,翻译后修饰、蛋白质周转和分子伴侣,氨基酸运输与代谢,碳水化合物运输与代谢。DEGs显著富集的KEGG通路主要有植物激素信号传导、苯丙烷类生物合成、淀粉和蔗糖代谢、苯丙氨酸代谢、氨基酸的生物合成和碳代谢。获得植物开花相关基因47个,其中39个上调表达、8个下调表达。研究结果在一定程度上解析了木薯花芽分化的分子机制,并为后续的深入研究提供了基础数据。 相似文献
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18.
旨在获得黄精转录组数据库并挖掘参与其种子发育和休眠解除相关基因,以休眠解除前后的黄精种胚为试材,利用新一代高通量测序手段对供试样品进行转录组测序,并进行系统的生物信息学分析。黄精种子休眠解除前后样品中共得到79716个差异表达基因,上调的表达基因有60074个,下调的表达基因有19642个。休眠解除前后的黄精种胚中共有130284个差异表达基因被GO功能注释到生物进程、分子功能和细胞组分3个大类56个亚类,注释的差异表达基因与代谢过程、生物调控、细胞组分合成和酶催化活性等密切相关。KEGG代谢通路结果表明,共有65038个差异表达基因,涉及138个代谢通路,主要参与碳代谢、次生代谢产物的生物合成和多糖的代谢。基于KEGG数据库中注释结果,共发现15条与黄精种胚休眠解除相关的代谢通路。黄精种子发育与休眠解除过程,大量的种胚形态建成、多糖分解及蛋白质合成差异基因参与表达,并涉及到多个代谢途径的相互作用,构成复杂的休眠解除调控网络。 相似文献
19.
小麦抗/感白粉病近等基因系基因表达差异的研究 总被引：2，自引：0，他引：2
采用cDNA-AFLP(cDNA-amplified fragment length polymorphism)技术,对小麦抗白粉病近等基因系Mardler/7*百农3217和百农3217材料的不同处理,于接菌后不同时间点的基因表达进行了表达分析。Mardler/7*百农3217及其感病轮回亲本百农3217在表达上存在差异;利用46对引物在抗/感近等基因系和感病轮回亲本DCINA处理发现283条差异带,对其中42条片段进行克隆测序,同源性分析发现包括信号转导相关的基因片段、与细胞壁的组成和结构相关的基因片段和与过敏性反应相关的基因片段。此研究结果发现其中的一些差异显示片段对小麦的抗白粉病机理的揭示具有重要作用。 相似文献
20.
A. L. Chávez T. Sánchez G. Jaramillo J. M. Bedoya J. Echeverry E. A. Bolaños H. Ceballos C. A. Iglesias 《Euphytica》2005,143(1-2):125-133
About 70 million people obtain more than 500 cal per day from cassava roots. The crop is fundamental as food security of poor rural communities, but little is known about variability of root nutritional and quality traits. Roots from 2457 genotypes comprising landraces and improved clones, were screened for their nutritional (cyanogenic potential, carotene, minerals, and sugars contents) and agronomic (dry matter content, color intensity, and postharvest physiological deterioration) traits. The objective was to assess the range of variation for the traits evaluated to define future research strategies. Results are mostly based on unreplicated measurements. Carotene contents in the roots ranged from 0.102 to 1.040 mg/100 g fresh tissue and correlated positively with color intensity (ρ = 0.860) and cyanogenic potential (ρ = 0.305). Average levels of Fe and Zn were 17.1 and 7.5 mg/kg, respectively. Many clones derived from Meso-America showed high protein levels in the roots, probably as a result of the introgression from wild relatives only found in that region. The observed values for carotene, proteins and minerals contents suggest the potential for improving the nutritive value of cassava. 相似文献