外源茉莉酸和茉莉酸甲酯诱导植物抗虫作用及其机理

综述了茉莉酸(jasmonic acid, JA)和茉莉酸甲酯(methyl jasmo nate, MJA)的分子结构和应用其诱导的植物抗虫作用及其机制。植物受外源茉莉酸或茉莉酸甲酯刺激后,一条反应途径是由硬脂酸途径激活防御基因,另一条途径是直接激活防御基因。防御基因激活后导致代谢途径重新配置,并可能诱导植物产生下列4种效应：（1）直接防御,即植物产生对害虫有毒的物质、抗营养和抗消化的酶类,或具驱避性和妨碍行为作用的化合物;（2）间接防御,即产生吸引天敌的挥发物;（3）不防御,即无防御反应;（4）负防御,即产生吸引害虫的挥发物。     

茉莉酸及其甲酯在植物诱导抗病性中的作用

茉莉酸类物质被认为是植物抗病防卫反应的内源及中间信号分子。本文介绍了茉莉酸及其甲酯在植物抗病性中的作用,从它们在体内激活的代谢途径及相关基因表达探讨有关作用机制以及有可能在农业上应用的前景。     

茉莉酸与植物抗性相关基因的表达

茉莉酸(jasmonic acid,JA)及其甲酯(MeJA)是调节高等植物的发育、应答外界刺激、调节基因表达的天然高等植物激素.JA最初是从真菌Lasiodiplodia theobromae培养液中分离到的.已研究过的所有高等植物中都有JA,估计其正常水平＜10μmol·L-1.植物组织中JA的水平在花和果实等繁殖器官特别是未成熟的果皮中最高,根和成熟的叶片中则低得多.JA在植物组织中的液相和气相中可快速运动.1nmol·L-1的JA和1μmol·L-1的MeJA就能诱导植物基因表达水平的变化[1].     

茉莉酸信号转导及其与脱落酸信号转导的关系

介绍了植物体内茉莉酸诱导蛋白,茉莉酸信号转导途径及其与脱落酸信号转导之间的关系。     

茉莉酸及其甲酯与植物诱导抗病性

介绍了茉莉酸 (JA)及其甲酯 (MeJA)在植物抗病中的作用及其诱导植物抗病的机制 ,并概述了目前这一领域需要进一步研究解决的若干问题     

植物的环境信号分子茉莉酸及其生物学功能

茉莉酸信号分子参与植物生长发育众多生理过程的调控,尤其是作为环境信号分子能有效地介导植物对生物及非生物胁迫的防御反应。迄今已知具有信号分子生理功能的至少包括茉莉酸(jasmonic acid,JA)以及茉莉酸甲酯(methyl jasmonate,Me JA)和茉莉酸-异亮氨酸复合物(jasmonoyl-isoleucine,JA-Ile)等茉莉酸衍生物,统称为茉莉酸类化合物(jasmonates,JAs)。从环境信号分子角度介绍了茉莉酸信号的启动(环境信号感知与转导、茉莉酸类化合物合成)、传递(局部传递、维管束传输、空气传播)和生物学功能(茉莉酸信号受体、调控的转录因子、参与的生物学过程)。     

在伤信号传导中茉莉酸与水杨酸的关系

近年来,发现茉莉酸和水杨酸都是植物体对外界伤害作出反应,表达抗性基因的信号分子。水杨酸可抑制茉莉酸类的合成及其所诱导的蛋白基因的表达;茉莉酸能阻止病原侵染后所产缮乃钏岬脑黾印＼岳蛩嵝藕抛纪揪逗退钏嵝藕抛纪揪洞嬖谧沤徊妫。牵裕薪岷蛋白和细胞分裂素可能起着信号开关的作用。     

在伤信号传导中茉莉酸与水杨酸的关系

近年来,发现茉莉酸和水杨酸都是植物体对外界伤害作出反应,表达抗性基因的信号分子。水杨酸可抑制茉莉酸类的合成及其所诱导的蛋白基因的表达;茉莉酸能阻止病原侵染后所产生的水杨酸的增加。茉莉酸信号转导途径和水杨酸信号转导途径存在着交叉,小GTP结合蛋白和细胞分裂素可能起着信号开关的作用。     

茉莉酸在植物抗逆性中的研究进展

茉莉酸(jasmonic acid, JA)是一种植物内源合成的脂类激素，在植物响应胁迫的调控中发挥着重要作用。本文概括了JA的生物合成与代谢途径及其调控机制；总结了JA信号的传导通路；系统归纳了JA在植物响应生物和非生物胁迫应答中的作用机制和调控网络，重点关注了最新的研究进展。此外，本文梳理了JA与其他植物激素在植物抗逆性调节过程中的信号交流。最后讨论了JA信号通路介导的植物抗逆性研究中亟待解决的问题，并展望了新的分子生物学技术在调控JA信号通路增强作物抗性中的应用前景，以期为植物的抗逆性研究和改良提供参考。     

茉莉酸及其信号传导研究进展

茉莉酸及其衍生物茉莉酸甲酯等统称为茉莉酸盐,是广泛存在于植物中的一种生长调节物质,在植物细胞中起着非常重要的作用.茉莉酸作为信号分子广泛参与调节植物的生长发育和胁迫响应过程.本文主要就茉莉酸的生物合成、茉莉酸的信号传导途径和调控机制、茉莉酸的信号传导途径与乙烯、脱落酸、水杨酸和一氧化氮信号传导途径的相互关系进行了综述.     

Identification of Jasmonic Acid in Three Species of Higher Plants and Its Biological Activities

(–)-Jasmonic acid (JA) was isolated and characterizedfrom immature seeds of Phaseolus vulgaris L. as a growth inhibitoragainst rice seedlings. The presence of JA was also confirmedin both fresh leaves and insect galls of Castanea crenata Sieb.et Zucc. and immature seeds of Dolichos lablab L. by combinedgas chromatography-mass spectrometry analyses. The biologicalactivities of JA were evaluated in several bioassay systems,and it was shown that JA is a new type of plant growth regulator. (Received February 9, 1981; Accepted March 27, 1981)     

Possible Involvement of Jasmonic Acid in Tuberization of Yam Plants

Jasmonic acid (JA) was isolated from yam leaves (Dioscorea batatas),with the guidance of assay for tuber-inducing activity whichwas carried out by cultures of single-node segments of potatostems in vitro, and identified by HPLC and mass spectrometry.The level of endogenous JA in the leaves of the plants, whichbeing 5 ? 10^–7 M at the first harvest, increased continuouslywith the growth of the plants. The effect of exogenous JA onthe tuberization of yam plants was examined in vitro, and itwas found to have strong tuber-inducing activity. The thresholdconcentration of JA for induction of yam tuberization was ca.10^–7M. These results suggest that tuberization of yamplants is controlled by JA. (Received February 25, 1991; Accepted April 15, 1991)     

Interplay Between Abscisic Acid and Jasmonic Acid and its Role in Water-oxidative Stress in Wild-type, ABA-deficient, JA-deficient, and Ascorbate-deficient Arabidopsis Plants

The interplay between jasmonic acid (JA) and abscisic acid (ABA) in plant responses to water stress and in water-stress-enhanced oxidative stress was investigated in Arabidopsis thaliana plants subjected to water stress by water deprivation. For this purpose a drought assay was conducted using Arabidopsis mutants impaired in ABA (aba2), JA (aos), and ascorbate (vtc1) biosynthesis. Our results show an interaction between ABA and JA during their biosynthesis. Moreover, the coordinated action of ABA and JA protected wild-type, aba2, and aos plants from the effects of stress. However, this effect was not observed in the vtc1 mutant, which showed a distinct decrease in the F _v/F _m ratio, concomitant with a marked fall in relative water content (RWC), despite high endogenous concentrations of JA and ABA. This finding indicates the relevance of ascorbate metabolism in plant acclimation to stress. Despite the interaction between the two phytohormones, drought-associated stomatal closure is regulated mainly by ABA and weakly by JA, whereas JA plays a role in the formation of antioxidants regulating ascorbate and glutathione metabolism. A time course analysis revealed the relevance of plant age and stress duration in the responses of the mutants compared to wild-type plants. Here we discuss the relationship between ABA, JA, ascorbate, and glutathione in plants under water stress.     

Qualitative and Quantitative Analysis of Endogenous Jasmonic Acid in Bulbing and Non-Bulbing Onion Plants

Bulb development in onion plants (Allium cepa L.) is consideredto be regulated by bulbing and anti-bulbing hormones. Sincebulbing involves the disruption of microtubules, both jasmonicacid (JA) and methyl jasmonate (JAMe) are candidates for thebulbing hormone because of their microtubule-disrupting activitiesand wide distribution in higher plants. To survey JA and JAMein onion plants, we developed a radioimmunoassay (RIA) for JAMethat is sensitive enough to detect femtomole amounts of JAMe.Using this RIA, we detected JA in leaf blades, leaf sheathsand roots of onion plants, but no JAMe was detected in any tissue.The endogenous levels of JA in leaf blades, leaf sheaths androots of 4-week-old bulbing and non-bulbing onion plants weredetermined by gas chromatography/selected ion monitoring with[²H₂]JA as an internal standard. The amount of JA per plantin leaf sheaths of bulbing onion plants was about three timeshigher than that of non-bulbing onion plants, although the differencein levels of JA in leaf blades between bulbing and non-bulbingonion plants was quite small, and the level of JA in roots ofbulbing onion plants was lower than that of non-bulbing onionplants. However, the relationship between endogenous JA andthe development of onion bulbs remains to be clarified. (Received June 3, 1992; Accepted October 1, 1992)     

Sexual Reproduction in Higher Plants Ⅰ: Fertilization and the Initiation of Zygotic Program

Sexual plant reproduction is a critical developmental step in the life cycle of higher plants, to allow maternal and paternal genes to be transmitted in a highly regulated manner to the next generation. During evolution, a whole set of signal transduction machinery is developed by plants to ensure an error-free recognition between male and female gametes and initiation of zygotic program. In the past few years, the molecular machineries underlying this biological process have been elucidated, particularly on the importance of synergid cells in pollen tube guidance, the Ca spike as the immediate response of fertilization and the epigenetic regulation of parental gene expressions in early zygotic embryogenesis. This review outlines the most recent development in this area.     

Double Fertilization in Gnetum gnemon: The Relationship between the Cell Cycle and Sexual Reproduction

Gnetum gnemon, a nonflowering seed plant and member of the Gnetales, expresses a rudimentary pattern of double fertilization that results in the formation of two zygotes per pollen tube. The process of double fertilization in G. gnemon was examined with light and fluorescence microscopy, and the DNA content of various nuclei involved in sexual reproduction was quantified with 4[prime],6-diamidino-2-phenylindole microspectrofluorometry.Male and female gamete nuclei pass through the synthesis phase of the cell cycle and increase their DNA content from 1C to 2C before fertilization. Each of the two zygotes found in association with a pollen tube is diploid and contains the 4C quantity of DNA at inception. Based on these results as well as previous studies of nuclear DNA content in plant sperm, eggs, and zygotes, three fundamental and distinct patterns of gamete karyogamy among seed plants can be circumscribed: (1) G1 karyogamy, in which male and female gametes contain the 1C quantity of DNA throughout karyogamy and the zygote undergoes DNA replication; (2) S-phase karyogamy, in which gamete nuclei initiate fusion at 1C but pass through the S phase of the cell cycle before completely fusing; and (3) G2 karyogamy, in which male and female gamete nuclei pass through the S phase of the cell cycle before the onset of fertilization. Our results show definitively a pattern of G2 karyogamy in G. gnemon.     

中国亚麻酸资源植物分布格局及其与气候和地理因子的关系

据资料统计,中国种子植物中具有开发利用价值的亚麻酸资源植物共计116科、446属、816种。该研究以大尺度的植物物种分布信息为基础,通过对中国亚麻酸资源植物及其地理、环境、气候等因子的统计分析,探讨中国亚麻酸资源植物的分布格局及其影响因子。结果表明:(1)唇形科、大戟科、豆科、蔷薇科、十字花科、葫芦科等类群中亚麻酸资源植物较为丰富且分布较广,是中国最重要的亚麻酸资源植物类群。(2)西南地区亚麻酸资源植物丰富度最高,并以此为中心向四周降低。(3)亚麻酸资源植物丰富度随着海拔的升高先增加后降低,在900m左右最丰富。(4)气候因子对亚麻酸资源植物分布影响较大,其中相对湿度、年平均温度、年降雨量是导致中国亚麻酸资源植物分布格局的主要原因,且与亚麻酸资源植物丰富度成正相关关系,而纬度、年辐射量、平均海拔等因子成负相关关系;地形因子是一个独立因子。(5)聚类分析结果将中国亚麻酸资源植物分布地划分为十类地区,一定程度上揭示了亚麻酸植物在中国的分布特点。