一个水稻低温移栽白条纹突变体wltt的鉴定和基因定位

【目的】叶色突变相关基因的鉴定与克隆为研究叶绿体发育、叶绿素合成和光合作用等分子机制提供理论基础。【方法】从常规粳稻镇糯19杂交后代中分离出一个低温移栽后叶色转成白条纹的自然变异突变体,命名为wltt (white stripe leaf after transplanting at low temperature)。成熟期测定野生型和wltt的主要农艺性状,分别在苗期、移栽后15 d和同时期直播条件下测定新生叶片的色素含量并观察叶绿体的超微结构;将wltt和野生型正反交进行遗传分析;用wltt与籼稻9311杂交产生的F_2作为定位群体进行基因定位;采用RT-qPCR分析叶绿体发育、叶绿素合成和光合作用相关基因在野生型和wltt中的表达水平。【结果】wltt突变体在苗期表现正常绿色,移栽15 d后心叶出现白条纹叶表型,至分蘖末期心叶叶色恢复;而不经移栽,突变体不会出现白条纹叶。人工模拟实验表明该表型是由低温条件下根损伤引起的。与野生型相比,wltt突变体移栽后的新生叶色素含量显著降低,光合速率下降;同时株高变矮,穗长、剑叶长和每穗粒数均显著降低。叶绿体的超微结构显示,突变体的叶肉细胞中,仅少数细胞含有正常的叶绿体,其余大部分叶肉细胞不含叶绿体。进一步研究发现,突变体中部分光合系统相关基因和叶绿体发育相关基因表达下调,叶绿素生物合成相关的14个基因表达也下调。遗传分析表明,该突变性状受一对隐性核基因控制。利用wltt突变体/9311的F_2群体,将该基因定位于水稻第2染色体着丝粒附近853kb区间内。目前,该区间内没有叶色相关基因的报道。【结论】WLTT是低温条件下移栽调控叶片转色的关键基因,在叶绿体发育过程中发挥重要作用。     

水稻新型黄化转绿叶色突变体的遗传分析与育种利用

在育种实践中,叶色变异可作为标记性状,在种子生产和纯度鉴定等方面得到利用。本研究中,对一个水稻新型叶色黄化转绿型自然突变体进行了形态特征观察、遗传分析和育种利用,比较了突变体与野生型的主要农艺性状,利用突变体与正常绿色水稻材料构建遗传群体对该突变体进行经典遗传学分析,通过回交选育了带叶色标记的新不育系。形态观察发现,突变体植株从苗期到分蘖剑叶全展以前的整个叶片生长发育期能持续观察到各个叶片从叶尖向叶基部由黄转绿的发育特性。突变体的主要农艺性状和产量性状与野生型基本一致;遗传分析表明突变体受1对隐性核基因控制。利用突变体与三系不育系回交转育而成的实用型黄化转绿型标记叶色不育系标记性状明显、败育彻底、配合力和可恢复性好。该突变体不同于其它叶色突变体的叶色表达特性具有很好的基础研究和育种利用价值。     

水稻淡绿叶基因PGL11的鉴定与精细定位

【目的】叶片是水稻进行光合作用的主要场所,叶片颜色的变化与水稻的生长发育直接相关。发掘水稻叶色突变体,是水稻功能基因组学研究的重要遗传基础。【方法】利用EMS诱变日本晴获得一个能稳定遗传的淡绿叶突变体,暂命名为pgl11(pale green leaf 11)。在不同生育期测定野生型与突变体的叶绿素含量。在苗期,取野生型与突变体叶片进行叶绿体结构的透射电镜观察。在分蘖期,测定野生型与突变体的光合参数并观察气孔结构。在成熟期,测定野生型和pgl11的主要农艺性状。以pgl11为母本,南京6号为父本构建相应的F2群体,采用图位克隆的方法,对该基因进行定位。【结果】从苗期开始,突变体pgl11的每一片新叶均表现为淡绿色,叶绿素含量显著降低,叶绿体发育异常。随着叶片的生长,叶色由淡绿逐渐转绿,至抽穗期时叶绿素含量亦无明显差异。pgl11还表现光合速率、气孔导度明显下降,胞间CO_2浓度上升。扫描电镜观察发现,突变体pgl11的气孔发育异常。与野生型相比,突变体的农艺性状如株高、剑叶宽、二次枝梗数、每穗粒数、粒长、粒宽、千粒重以及结实率等均显著降低。对叶绿素合成、光合作用以及质体发育相关基因的表达量测定表明,突变体pgl11中参与叶绿体转录和翻译相关基因的表达量显著升高,而叶绿素合成和光合作用相关基因的表达量显著下降。遗传分析表明,该突变表型受一对隐性核基因控制。通过图位克隆的方法将该基因定位于第1染色体上的C6和C8标记之间,物理距离约为110 kb。【结论】该定位区间内未见有叶色相关基因报道,推测PGL11基因可能是一个新的水稻叶色基因。     

水稻斑马叶突变体zl7的鉴定与基因的精细定位

【目的】斑马叶突变体作为水稻叶色突变体的重要种质资源，是研究植物光合作用机制和高光效育种的理想材料，对于解析光合作用机理和提高水稻产量具有重要意义。【方法】用甲基磺酸乙酯（EMS）诱变粳稻品种春江06建立突变体库，从突变体库中筛选到1份苗期为斑马叶的突变体，该突变体被命名为zl7(zebra leaf7)。在常规大田种植条件下分别比较突变体与野生型在苗期、抽穗期和成熟期叶色表型和产量性状差异，通过透射电镜实验分析叶片叶绿体发育情况，利用图位克隆方法克隆候选基因，利用荧光定量PCR方法分析参与叶绿素合成和叶绿体发育相关基因的表达水平。【结果】从苗期开始，突变体zl7表现出典型的斑马叶，叶绿素含量降低，直到抽穗期，斑马叶表型消失，叶片逐渐复绿，叶绿素含量无明显差异。光合速率测定和电镜观察结果显示，突变体zl7的光合速率、气孔导度下降，叶绿体发育异常。与野生型相比，突变体的株高、分蘖、穗长、一次枝梗、二次枝梗和每穗粒数均显著降低，而粒长、粒宽和千粒重均略有增加。荧光定量PCR结果表明突变体中参与叶绿素降解相关基因的表达量显著升高，而参与叶绿素合成和叶绿体发育相关基因的表达量显著降低。遗传分析...     

一个水稻新型叶色突变体的形态结构与遗传定位

 所用水稻叶色突变体为自然突变,并命名为白淮稻7号,其叶色表型为绿 白 绿,且突变表型只有在移栽等因素引起的机械损伤信号胁迫下才会产生。研究结果表明,叶色转白前,突变体生长态势、叶色、叶绿素a含量和叶绿体超显微结构与野生型差异不大;叶色转白后,突变体总叶绿素、叶绿素a、叶绿素b和类胡萝卜素含量都显著低于野生型和叶色转白前,而叶绿体中的类囊体逐渐降解,基粒片层减少、基粒数量明显减少,且在成熟后突变体叶色黄化、植株变矮小。遗传分析表明,突变性状由1对隐性核基因控制。以该突变体与江西1587的F2群体为定位群体,将突变基因定位于水稻第11染色体分子标记L59.2 7和L64.8 11之间大约740.5 kb的区间内。认为该突变基因是一个新的水稻叶色突变基因,暂命名为GWGL。     

水稻条斑和颖花异常突变体st fon的鉴定与遗传分析

 在水稻遗传转化过程中发现一个不含外源基因的条斑和颖花异常的双突变体,暂命名为st fon。该突变体除茎、叶、穗出现白条斑外,花器数目增多,颖花开裂。其极端表型为同一颖花中长出几朵小花或小花中枝梗伸长为花序。利用透射电镜对苗期叶片白色组织细胞超微结构进行观察,发现质体结构异常,不能发育成正常叶绿体所具有的片层和类囊体,叶绿体的发育阻断在质体发育早期。利用扫描电镜和石蜡切片对花器官形态发生过程进行观察,发现花分生组织生长具有无序和无限性。对扭曲的叶片石蜡切片观察,发现维管束鞘细胞过度生长,或一些泡状细胞增大。将突变体与4个叶色正常的材料进行杂交和回交,遗传分析表明突变性状呈细胞质遗传。     

水稻温敏转绿突变体osv15的鉴定和遗传分析

【目的】本研究旨在鉴定和克隆水稻温敏转绿新基因,揭示其参与叶绿体发生发育和光合作用的分子机制,为高光效育种提供理论支撑。【方法】利用辐射诱变的方法,从粳稻品种日本晴中筛选获得叶片黄化突变体osv15,并对其表型、农艺性状和遗传方式进行详细分析。构建了突变体与Kasalath的F₂群体,利用多态性分子标记对目的基因进行定位和测序分析。【结果】osv15幼苗期在22℃低温下叶片黄化,叶绿素含量仅为野生型的10%,光化学效率下降,叶绿体结构异常;随着温度的升高,osv15的叶色由黄转绿,30℃时叶绿素含量恢复到野生型的68%,光化学效率和叶绿体发育与野生型相近。在自然环境下,osv15突变体从苗期至成熟期均表现为叶片黄化,且株高、分蘖数和产量等农艺性状与野生型相比差异显著。遗传分析表明osv15突变体的表型由一对隐性核基因控制。将OsV15基因定位到第6染色体多态性标记S4和S5之间84 kb的区间内,定位区间测序发现突变体中编码分子伴侣蛋白的基因Cpn60β1(LOC_Os06g02380)发生单碱基缺失。【结论】osv15是一个新的水稻温敏转绿突变体,Cpn60β1可能为突变基因。     

安吉白茶特异性状的生理生化本质

安吉白茶的特异性主要表现在春季发芽时新梢嫩叶叶色的可逆性白化现象, 在白化过程中新梢的叶绿素含量急剧下降和氨基酸含量显著上升。研究表明, 安吉白茶是一个温度敏感的自然突变体, 其白化表达的温度阈值在20 ～22 ℃之间, 但该温度仅在芽萌发初期发挥作用; 其正常复绿的启动温度在16 ～18℃之间。叶片白化期的主要生理生化变化是叶绿体膜结构发育发生障碍, 叶绿体退化解体, 叶绿素合成受阻, 质体膜上各种色素蛋白复合体缺失, 导致了叶色的变化; RuBP羧化酶的大、小亚基含量及酶活性下降, 同时伴随蛋白水解酶活性的升高, 终因叶绿体不能继续发育, 多余的可溶性蛋白水解, 导致游离氨基酸含量显著上升。文中对其返白机理进行了讨论, 认为该温度敏感型突变体的突变很可能是由核基因或核质互作控制的。     

波罗蜜叶片突变体叶绿素含量测定和超微结构观察

波罗蜜（Artocarpus heterophyllus）是一种热带果树,至今对其突变体的研究少有报道。本研究以波罗蜜叶片为试验材料,探究其叶片出现白化和返绿现象的可能原因。（1）用分光光度计法、比色法测定波罗蜜叶片突变体和正常绿叶的叶绿素及叶绿素前体物质含量;（2）用叶绿素酶Elisa试剂盒测定叶绿素酶活性;（3）用透射电子显微镜对叶绿体的超微形态结构进行观察。研究结果表明：（1）不同叶色所产生的叶绿素a含量、叶绿素b含量、叶绿素总含量、类胡萝卜素含量均存在显著差异;（2）波罗蜜叶片突变体和正常绿叶的叶绿素合成前体物质含量之间并没有出现显著性差异;（3）对波罗蜜叶片的叶绿素酶活性进行测定时,发现其活性出现显著差异,但对其叶绿素含量的差异性并没有产生较大影响;（4）观察波罗蜜叶片内叶绿体超微形态结构时,发现正常绿叶的叶绿体形态完好且数量较多,白化叶和返绿叶的叶绿体内部结构存在缺陷,其原因是叶绿体基粒构建阶段受阻;基于测定波罗蜜叶片中的叶绿素、叶绿素前体物质含量和叶绿素酶活性,并观察波罗蜜叶片内叶绿体的超微形态结构,对得到的数据结果进行比较分析。本研究推测是在叶绿素合成阶段,原脱植基叶绿素合成叶绿素时受阻及叶绿体发不良导致波罗蜜出现白化和返绿现象,为今后进一步综合研究波罗蜜突变体提供理论依据。     

白条纹水稻突变体的光合特性分析

从水稻组织培养突变体中发现可稳定遗传的白色条纹突变体,其生育期呈现白色和绿色条带相间的表型。电镜观察表明突变体绿色条带叶肉细胞具有正常的叶绿体发育,白色条带叶肉细胞则表现出叶绿体缺失。与野生型相比,突变体单位重量叶片叶绿素含量显著下降,但叶绿素光能吸收强度略有上升。突变体类囊体膜上的光系统II产生的激发能量降低,并将更多的激发能分配给光系统I。突变体保持叶片光合效率稳定的机制是通过提高胡萝卜素与叶绿素比值来补偿光合色素含量和激发能的降低引起的光合效率下降。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.