精氨酸酶在植物胁迫应答中功能研究进展

精氨酸酶是精氨酸代谢的关键酶,催化L-精氨酸水解产生L-鸟氨酸和尿素,维持体内精氨酸的动态平衡,参与尿素循环及氮素再利用等过程,对植物生长发育极其重要。本综述概述了精氨酸酶在植物精氨酸代谢途径中的作用,总结了精氨酸酶在植物非生物胁迫和生物胁迫响应的最新研究进展,并从参与ABA/JA途径、调控直接或间接代谢产物(脯氨酸,多胺,一氧化氮)等多个角度详细解析植物精氨酸酶调控植物抗逆的分子机制,旨在为进一步的研究和育种实践提供启示。     

氮代谢参与植物低氮胁迫研究进展

环境的日益恶化迫使人们放弃高肥生产的观念,转向低肥绿色环保生产的理念。本文主要从低氮胁迫下氮代谢相关的酶、氮素同化途径、初级代谢、次级代谢以及氮代谢相关基因五方面综述了植物体内不同的代谢水平、形态、生理和分子响应,探讨了不同生长阶段植物的耐低氮策略,阐述了氮利用效率(NUE)相关的酶及其调控过程抵御氮胁迫过程中的作用机理。本文提出今后可针对不同植物或同一植物的不同生长期的低氮耐受差异,以及关键基因表达产物之间的关系,从多学科、多角度系统全面的研究植物在低氮胁迫下的分子响应机制,为氮代谢参与植物低氮胁迫研究提供理论参考。     

硼在植物体内的生理效应及其对几种重要代谢产物影响的研究进展

硼是植物必需的重要微量元素之一,在植物体内起着重要的作用,但是硼在植物中属于难移动的元素,加上我国缺硼土壤分布广泛,因此植物中的缺硼现象比较严重。为了更好的了解硼在植物体内详细的代谢规律,本文综述了微量元素硼在植物体内的生理效应及其调控机制,总结了植物的主要缺硼症状及不同硼水平条件下对植物的生理伤害,并着重分析了硼对几种重要代谢产物包括糖类、蛋白质、核酸、激素等的影响,介绍了微量元素硼影响植物的多种生理代谢过程,指出了硼在影响细胞膜稳定性、蛋白质数量、酚类、酶类等的代谢与分布的关系上仍需进一步深入探讨。     

植物体内草酸(盐)的形成、降解及其作用

草酸通常被认为是新陈代谢最终的惰性产物.近期的研究表明:在植物体内草酸(盐)可以被进一步分解,其分解产物又参与了特定的生长发育过程及抗生物胁迫反应,因此植物体内草酸(盐)的代谢又引起了人们的广泛关注.本文就植物体内草酸(盐)的生物合成、存在形态及其被分解过程中的生理生化作用作一简要概述.     

植物类胡萝卜素生物合成及其调控与遗传操作

类胡萝卜素是生物体内通过类异戊二烯途径合成的、自然界广泛存在的一大类天然色素物质的总称。近年来,类胡萝卜素生物合成基因的分离和功能鉴定与有关类胡萝卜素生物合成调控机制研究的新进展,使通过遗传操作调控植物体内类胡萝卜素生物合成途径成为可能。本文主要综述了近年来类胡萝卜素生物合成及其调控研究的进展,并介绍了应用转基因技术改变植物体内类胡萝卜素成分与含量的成功事例。     

植物对硒的吸收、转运及代谢机制研究进展

硒元素是人和动物必需的微量元素之一，人体缺硒会引发诸多疾病甚至导致死亡。我国是缺硒大国，全国有2/3的人口处于缺硒地区。目前，食物补硒是提高人体摄硒量的最佳途径，同时也决定着食物链中硒的水平。本文从环境角度介绍了植物对土壤中不同硒元素的吸收利用途径，综述了硒在植物体内的转运和代谢机制，为开发富硒农产品提供参考。     

一氧化碳(CO)在植物体内的生理生化作用研究进展

为了促进一氧化碳(CO)在植物生理生化方面的研究,本文归纳了CO在植物体中的生物合成途径,CO作为信号分子对植物各种生理功能的调控,以及CO与其他信号分子之间的相互作用。经过分析得出,CO在植物生物胁迫过程中的作用及其作用机制方面的研究还很少,因此,CO在这方面的研究将会成为今后的研究重点。     

氮素缓解花生干旱胁迫的生理和转录调控机制

干旱胁迫下氮素施用对植物生长发育具有重要的影响。为明确氮素提高花生抗旱性的生理和转录调控机制,本研究对施氮、干旱及旱氮同存处理下的花生生理指标和根系转录组进行了测定。结果表明,旱氮同存处理提高了干旱胁迫下花生生物量和叶片相对含水量。施用氮肥增加了干旱胁迫下花生根系的总酚和类黄酮含量,提高其过氧化物酶(POD)和过氧化氢酶(CAT)活性,降低其丙二醛(MDA)含量,提高花生抗旱性。转录组分析表明,施用氮肥产生5396个差异表达基因,这些基因主要参与谷胱甘肽代谢、氮代谢和碳代谢相关过程及应激和防御反应。干旱处理和旱氮同存处理下,次生代谢物生物合成、运输和分解代谢及碳水化合物运输和代谢这两类功能差异表达基因富集。旱氮同存处理下酚类代谢物质相关的3种途径中有51个差异基因上调表达, 207个基因下调表达。由此表明,施用氮肥通过调控花生次生产物代谢、碳水化合物代谢等途径提高干旱胁迫下花生植株的抗氧化能力,从而提高花生的抗旱性。     

植物三萜代谢途径中角鲨烯合成酶研究进展

三萜类化合物是植物中一类重要的生物活性产物,具有广泛的药用与经济价值。角鲨烯合成酶(squalene synthase,SQS)为植物中三萜代谢合成途径中下游分支关键酶,可将异戊二烯通路中的碳通量引至三萜生物合成,其生成物角鲨烯同时也是合成三萜化合物的重要前体物质,且角鲨烯合成酶的活性决定了植物中三萜化合物的产量。主要综述了植物三萜合成途径、角鲨烯合成酶的催化机制、结构,SQS基因的克隆及调控表达,以期为今后提高植物中三萜化合物含量研究提供理论依据。     

兰科植物花香成分研究进展

从兰科植物花香成分及其合成调控等方面进行综述,重点总结了常见兰花的主要花香成分、影响检测花香成分时的主要因素,以及花香生物合成途径中相关分子调控机制。分析表明,萜烯类化合物是兰花最主要花香成分,采样时期、部位、环境和检测技术等都会导致花香成分变化,萜类合成酶基因(TPS)和MYB类转录因子是花香物质代谢途径中主要调控基因。发现兰科植物相关花香成分完整代谢途径及分子调控机制的研究缺乏,是兰科植物花香性状研究现状存在的主要问题,深入挖掘与利用兰花香花基因、完善相关代谢途径将会是兰科植物花香性状未来的研究重点。     

小麦磷饥饿前后根系蛋白质组差异表达谱建立及差异表达蛋白的鉴定

以耐低磷的小麦基因型洛夫林10号为材料, 采用蛋白质双向电泳技术, 结合质谱鉴定, 分析了正常磷供应和无磷处理7天后根系中的蛋白质组表达谱差异, 以期为深入探讨小麦响应磷胁迫的分子机理提供蛋白水平上的数据和资料。研究发现, 在可重复检测到的1 144个蛋白点中, 有87个在磷胁迫处理前后发生了明显的表达改变,占总数的7.6%,包括磷胁迫前特异表达、磷胁迫后特异表达、磷胁迫后上调和磷胁迫后下调表达等4种差异表达模式。在87个差异蛋白点中,有39个通过质谱技术被成功鉴定,涉及到代谢、细胞生长和分裂、转录和翻译、抗病、信号转导、转座元件及未知功能蛋白等功能类别,说明小麦可能通过细胞的代谢状态和基因表达改变来适应磷胁迫,进而维持体内磷含量的平衡状态。最后,我们还对差异表达点与磷胁迫的关系进行了分析和讨论。     

The effect of nitrate nutrition on iron chlorosis and leaf growth in sunflower (Helianthus annuus L.)

The objective of this work was to investigate the effects of nutrient solution pH, nitrogen form (NO₃, NH₄NO₃), bicarbonate and different Fe concentrations in the nutrient solution on the Fe concentration in roots and on the development of Fe deficiency symptoms in sunflower plants (Helianthus annuus L.). High pH in the nutrient solution induced by nitrate supply or by a pH-stat device led to increased Fe concentrations in roots and low leaf Fe concentrations associated with a significant decrease in leaf chlorophyll concentration manifested by yellow leaves. Plants of the nitrate fed treatments with 1 μM Fe in the nutrient solution were also characterized by reduced leaf growth and by the suppression of new leaf formation. The reduced leaf growth and the suppression of new leaves only occurred with nitrate and not with NH₄NO₃ in all treatments with 1 μM Fe in the nutrient solution. All symptoms were removed by a high Fe concentration in the nutrient solution (100 μM) at low external pH proving that suppression of leaf formation, reduced leaf growth and low chlorophyll concentration were caused by Fe deficiency. In the nitrate treatment with a low Fe supply (1 μM Fe) and pH 4 in the nutrient solution leaf chlorophyll concentrations similar to the controls were found. In comparison to control plants (NH₄NO₃, 1 μM Fe), leaf growth was still significantly reduced, and new leaf formation was suppressed. The chlorophyll concentration and CO₂ assimilation rate did not differ from those of the control plants. These results show that Fe deficiency is also characterized by small green leaves and the suppression of leaf formation. At the onset of leaf development, leaf growth and new leaf formation may respond more sensitively to poor Fe efficiency than chlorophyll concentration. In experiments with NO₃ plus HCO₃, simulating soil solution conditions prevailing in calcareous soils, the Fe efficiency of the youngest leaves was poor, showing retarded leaf growth and low chlorophyll concentration.     

NPR在SA信号通路中的研究进展

长期以来,水杨酸(SA)被认为是植物的内源信号分子,并与植物体内的多种抗性相关。病程相关基因非表达子(NPR)是SA信号通路中的关键性因子,能够介导该信号转导途径的顺利进行。为了详尽地阐述近年来多项研究对NPR研究的进展,本研究在分子水平上介绍了NPR的研究起源、SA受体,归纳了NPR1与其旁系同源物NPR3和NPR4之间相互协调的关系,分析了SA信号通路与SA提高植物抗性的机制。指出在多种植物体内,虽然NPR在SA信号通路中扮演着不可或缺的角色,但是由SA所诱导的植物抗病机制是一个复杂、精密的网络,现有的生物分子技术仍然无法使NPR的作用完全透明化。而且,在不同的植物体和相同植物的不同部位中,各种信号的转导方式也未必相同。因此,需要通过进一步确认整个信号通路中各组分及其功能、对模式植物进行详细研究来使该过程完整化。     

蔗糖代谢中蔗糖磷酸合成酶(SPS)的研究进展

蔗糖磷酸合成酶(sucrose phosphate synthase,SPS)参与植物的生长发育,而植物生长发育所需要的光合产物大部分以蔗糖的形式供应和运输,其中蔗糖磷酸合成酶是蔗糖进入各种代谢途径所必需的关键酶之一。本文综述了蔗糖磷酸合成酶生物学功能,基因表达调控及进化,SPS基因的克隆及遗传转化植株的表现;并进一步对蔗糖磷酸合成酶的研究作出设想。     

The genetic architecture of zinc and iron content in maize grains as revealed by QTL mapping and meta-analysis

Micronutrient malnutrition, especially zinc (Zn) and iron (Fe) deficiency in diets, has aroused worldwide attention. Biofortification of food crops has been considered as a promising approach for alleviating this deficiency. Quantitative trait locus (QTL) analysis was performed to dissect the genetic mechanism of Zn and Fe content in maize grains using a total of 218 F_2:3 families derived from a cross between inbred lines 178 and P53. Meta-analysis was used to integrate genetic maps and detect Meta-QTL (MQTL) across several independent QTL researches for traits related to Zn or Fe content. Five significant QTLs and 10 MQTLs were detected. Two informative genomic regions, bins 2.07 and 2.08, showed a great importance for Zn and Fe content QTLs. The correlation between Zn and Fe level in maize grains was proposed by MQTLs as 8 of the 10 involved both traits. The results of this study suggest that QTL mapping and meta-analysis is an effective approach to understand the genetic basis of Zn and Fe accumulation in maize grains.     

Silicon Application in Cultivated Rices (Oryza sativa L and Oryza glaberrima Steud) Alleviates Iron Toxicity Symptoms Through the Reduction in Iron Concentration in the Leaf Tissue

Iron (Fe) toxicity is a constraint commonly encountered in waterlogged conditions. Under anaerobic conditions, reduced Fe is massively absorbed by plants and may induce the generation of reactive oxygen species. This oxidative stress is responsible for physiological perturbations, growth reduction and yield losses. Rice is known as a silicon (Si) accumulator. Although Si is not considered as essential, it is known to play a beneficial role in the resistance to biotic and abiotic stresses through diverse and sometimes unknown mechanisms. The aim of this study was to determine the alleviation of Fe toxicity through Si application in different genotypes. Therefore, cultivars of both cultivated rice species (Oryza sativa and Oryza glaberrima) and lines from a segregating population issued from a cross between IR64 (O. sativa subsp. indica) and Azucena (O. sativa subsp. japonica) were grown in hydroponics under standard or excessive Fe(II) conditions, with or without the addition of Si. The application of Si on Fe‐treated plants strongly alleviated Fe toxicity symptoms. The reduced Fe uptake by Si‐treated plants suggested that an avoidance mechanism would be involved in this alleviation. Moreover, an additive effect of the Si and Fe treatments on the absorption of other nutrients by plants was revealed. These promising results gave insights into the understanding of rice resistance mechanisms to Fe toxicity, opening new perspectives in its management through Si fertilization. Finally, plant response to Si application was greatly influenced by the genotype. Thus, selection of stronger Si‐accumulating varieties could also be of valuable interest in the improvement of rice resistance to Fe toxicity.     

喀斯特区不同果园土壤有效态微量元素特征变化

为正确评价喀斯特区土壤肥力状况,合理施用微量元素肥料及有效利用土壤资源,以FAST(大射电)核心区西番莲、猕猴桃、八月瓜、冷饭团4种果园为研究对象,采集0～20 cm、20～40 cm土层土壤,分析土壤有效态微量元素(Fe、Mn、Cu、Zn)含量,并根据土壤有效态微量元素含量及评价标准,评定土壤微量元素丰缺状况.结果表...     

Molecular basis of Iron Biofortification in crop plants; A step towards sustainability

Iron is one of the most important micronutrients for crop plants due to its use in important physiological processes such as photosynthesis, mitochondrial respiration, metal homeostasis, and chlorophyll synthesis. Crop plants have adapted different strategies for uptake, transport, accumulation, and storage of iron in tissues and organs which later can be consumed by humans. Estimates indicate that about 2 billion people (33% of human population) are at risk of iron deficiency in which infants, children, and pregnant women are potentially compromised. Biofortification refers to the increase in concentration of micronutrients in edible parts of plants and understanding the pathways for iron accumulation in plants is necessary for breeding iron‐enriched crops. Iron‐biofortified crops are also one of the key factors in achieving multiple United Nations Sustainable Development goals. This review article covers different strategies of iron acquisition and transport in plants, its bioavailability, coping with the iron deficiency as a global perspective, the current status of iron biofortification, and how breeding future biofortified crops could be helpful in combating the said issue in a sustainable manner.