菌根共生体中植物信号物质的产生及其作用机制

菌根是丛枝菌根真菌与宿主植物形成的互利共生体,在共生的不同阶段,植物产生一系列的信号物质如独脚金内酯、溶血磷脂酰胆碱、茉莉酸和水杨酸等.这些信号物质在植物与丛枝菌根真菌间相互识别、菌根形成、营养物质交换,以及植物防御反应诱导等方面发挥重要作用.文中探讨植物信号物质在丛枝菌根共生系统形成前后和病原体侵害的3个阶段可能的生理效应和作用机制,旨在为研究丛枝菌根真菌与植物信号物质的相互作用及其在农业生产和环境保护方面的应用提供依据.     

HPLC-MS/MS同时测定植物6种內源激素含量方法的优化

植物激素在植物的胚胎发育、种子萌发、生长发育、开花结果等生理过程中相互调节对生物合成起着至关重要的作用.针对植物激素在植物体内含量极低且不稳定的特征,采用高效液相色谱与质谱(HPLC-MS/MS)联用的方法检测拟南芥(Arabidopsis thaliana)不同部位中的生长素(IAA)、赤霉素(GA_3和GA_4)、脱落酸(ABA)、茉莉酸(JA)和水杨酸(SA)6种激素的含量,同时对玉米(Zea mays)内源激素合成突变体及野生型材料的内源GA_3和GA_4含量进行了定量的研究.通过不断实验,优化了植物材料的前期处理方法及提取技术,提高了植物内源激素的提取和检测效率,形成了一套较为完整高效的植物内源激素检测方法.     

不同信号传导物质对玉米防御酶活性的诱导作用

茉莉酸（甲酯）和水杨酸（甲酯）已证实是植物体内信号传导物质，与植物防御物质的产生有密切关系。本文研究了信号传导物质（水杨酸、茉莉酸甲酯以及水杨酸甲酯）对玉米品种粤农9号玉米幼苗防御性酶的诱导作用。     

诱导子对蜀葵悬浮细胞、不定根培养的影响

为探究诱导子对蜀葵(Alcea rosea)细胞次生代谢产物的影响,分别使用茉莉酸甲酯、水杨酸、酵母提取物3种诱导子处理快速生长期后期的蜀葵悬浮细胞.结果表明:茉莉酸甲酯和水杨酸均会抑制悬浮细胞和不定根的生长,而低浓度的酵母提取物则会促进其生长;茉莉酸甲酯对于悬浮细胞和不定根中的糖醛酸含量没有影响,而水杨酸和酵母提取物均对其糖醛酸含量有促进作用,且酵母提取物效果更好;3种诱导子均能有效提高悬浮细胞和不定根中的总黄酮含量,其中以茉莉酸甲酯效果最好,水杨酸次之.这些结果表明,3种诱导子对蜀葵悬浮细胞和不定根培养物都能产生影响,但综合考虑酵母提取物的效果最为明显,水杨酸次之.     

植物抗病反应及其信号分子(综述)

介绍了植物抗病反应及信号分子包括水杨酸 (SA)、乙烯、茉莉酸及其甲酯 (JA和Me -JA)、活性氧(Aos)及钙离子流等在植物抗病反应中的主要作用。     

水稻中一个与COI1同源的基因克隆及其表达分析

利用同源序列分析,在水稻基因数据库中检索到了几条与拟南芥中的COI1基因具有高度同源性的EST(expression sequence tag)片段和相应的基因组序列．根据EST拼接和基因组比较结果设计引物,利用RT—PCR在水稻中得到与COI1高度同源的cDNA,并在基因组中推断出相应的基因,命名为RCOI1．RCOI1与COI1在氨基酸水平有74％的同源性．与COI1相似,RCOI1蛋白也具有典型的F—box和LRRs结构域．半定量RT—PCR显示该基因的表达受茉莉酸甲酯(MeJA)的诱导,说明这个基因可能参与水稻茉莉酸应答反应．该基因的发现对于探索单子叶植物的茉莉酸信号转导途径,以及研究该途径在农作物中的抗虫抗病和抵抗恶劣环境等方面的作用都有重要意义．     

雄全异株桂花不同花期光合和内源激素的变化

【目的】桂花(Osmanthus fragrans)同时拥有雄株和两性株,具有极为罕见的雄全异株繁育系统。对桂花不同花期的光合特性及花部组织的内源激素含量进行测定,比较雄性和两性桂花在不同花期的光合及内源激素含量的变化规律,为评价雄性和两性桂花生长适应性及后续生理生态学研究提供参考。【方法】利用Li-6400XT光合作用测量系统对雄性和两性桂花不同花期的光合特性进行测量,并利用酶联免疫吸附分析法对生长素(IAA)、茉莉酸(JA)、脱落酸(ABA)、赤霉素(GA₃)和玉米素核苷(ZRs)5种植物激素含量进行测定。【结果】雄性桂花的气孔导度和净光合速率在不同花期均低于两性桂花的;测定的5种激素中,平均激素含量最高的为脱落酸;茉莉酸含量在雄花的花期内持续增加,玉米素核苷含量在两性花的花期内不断升高。【结论】气孔导度是影响桂花净光合速率的一个关键因子,与净光合速率呈正相关;脱落酸和茉莉酸的不断积累可能导致了雄性桂花花瓣的大量脱落;玉米素核苷在两性桂花花期的积累对果实的发育有促进作用。研究结果可为雄全异株桂花不同花期阶段提供基础生理数据,为后续探索雄花花瓣脱落及果实发育提供参考。     

茉莉酸类物质的生物合成及其信号转导研究进展

茉莉酸（JA）是脂类起源的并在植物界广泛存在的一种重要的信号分子,在植物防御生物和非生物胁迫反应及植物的生长和发育过程中起着重要作用．文中介绍了茉莉酸生物合成,钙离子在茉莉酸信号传导中的作用及其钙离子的来源,环核苷酸门控的离子通道可能参与JA诱导的质外体钙离子动员等,并对该领域今后的研究进行展望．     

基于UPLC-MS/MS分析刺梨种子萌发过程中几种内源激素含量变化

种子休眠与萌发受到内源激素的调控,利用超高效液相色谱串联质谱(UPLC-MS/MS)建立了同时测定刺梨种子胚中脱落酸ABA、生长素类IAA和Me-IAA、茉莉酸类JA、JA-Ile和H_2JA、水杨酸SA含量的分析方法.通过测定刺梨种子萌发30 d内几种激素含量变化,以期了解种子休眠萌发的激素调控机制.结果表明,在30℃恒温条件下培养30 d后,ABA含量从91.50 ng/g下降至54.70 ng/g; IAA含量从111.40 ng/g下降至73.46 ng/g; Me-IAA含量从3.95 ng/g上升至9.43 ng/g; H_2JA含量从2.03 ng/g上升至4.80 ng/g; SA/JA的比值从19.795 4下降至17.073 7.SA、JA和JA-Ile含量无显著性变化,IAA/ABA、SA/ABA的比值无显著性变化.因此,刺梨种子的萌发是ABA、IAA、Me-IAA、JA、JA-Ile、H_2JA、SA等多种激素共同作用的结果,仍需进一步研究各激素调控刺梨种子萌发的分子机制.     

茉莉酸甲酯对蓝莓果实生理生化变化的影响

研究茉莉酸甲酯对蓝莓果实生理生化变化的影响。以未经过处理的蓝莓果实为对照样品,探讨了不同浓度的茉莉酸甲酯处理对蓝莓果实采后贮藏期间乙烯释放量、腐烂率、失重率、总花色苷含量、维生素C含量和可溶性固形物含量的影响。实验结果表明,与对照相比,茉莉酸甲酯处理能有效抑制蓝莓乙烯释放量、腐烂率和失重率的上升,提高总花色苷含量并维持可溶性固形物含量,其中,50μmol/L茉莉酸甲酯对蓝莓果实的保鲜效果更显著。由此可见,不同浓度茉莉酸甲酯处理能不同程度地延缓蓝莓的后熟与衰老进程,并提高了蓝莓果实的贮藏期品质和商品价值,显著延长蓝莓果实的货架期。     

Analysis of Salicylic Acid Induced Proteins in Rice

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β-Glucosidase treatment and infestation by the rice brown planthopper Nilaparvata lugens elicit similar signaling pathways in rice plants

β-Glucosidase has been reported to induce the production of herbivore-induced plant volatiles. However, how it works remains unclear. Here, we investigated the levels of salicylic acid （SA）, jasmonic acid （JA）, ethylene, and H2O2, all of which are known signaling molecules that play important roles in induced plant defense in rice plants treated with β-glucosidase, and compared these to levels in plants infested by the rice brown planthopper Nilaparvata lugens （Stal）. Results showed that wounding and treatment by β-glucosidase increased the levels of SA, ethylene, and H2O2, but not JA, in all plants compared to control plants. The signaling pathways activated by β-glucosidase treatment are similar to those activated by an infestation by N. lugens, although the magnitude and timing of the signals elicited by the two treatments are different. This may explain why both treatments have similar volatile profiles and are equally attractive to the parasitoid Anagrus nilaparvatae Pang et Wang.     

Salicylic acid and ethylene signaling pathways are involved in production of rice trypsin proteinase inhibitors induced by the leaf folder Cnaphalocrocis medinalis （Guenee）

The roles of signaling pathways in the production of trypsin proteinase inhibitors (TrypPIs) in rice infested by the leaf folder (LF) Cnaphalocrocis medinalis were studied. Infestation by LF increased TrypPI levels in the leaves of rice plants at the tillering, booting and flowering stages but decreased TrypPI levels at the ripening stage; TrypPI levels in rice stems did not increase at any developmental stage. Infestation by LF at the tillering stage systemically increased TrypPI levels in leaves but not in stems; it also enhanced salicylic acid (SA) levels in leaves and stems, and the ethylene level released from plants. However, LF infestation did not increase JA concentrations. Exogenous application of SA or ethylene enhanced TrypPI levels in the leaves and stems of plants at the tillering stage, whereas treatment with both SA and ethylene induced lower levels of TrypPIs than treatment with SA or ethylene alone, suggesting an antagonistic effect of SA and ethylene on TrypPIs induction. The results suggest that both SA and ethylene signaling pathways are involved in the production of TrypPIs in rice induced by LF; moreover, the antagonistic effect of SA and ethylene may explain the changes in TrypPI levels seen at different plant developmental stages and in different organs.     

水稻组蛋白单泛素化连接酶基因(OsHUB1)的克隆及其表达分析

对模式植物拟南芥的研究发现,AtHUB1基因参与调控植物对灰霉病的抗性.为了研究水稻的抗病机理,笔者利用同源搜索从水稻数据库中获得了目标基因的序列,并通过RT-PCR技术从水稻中克隆了组蛋白单泛素化连接酶基因,命名为OsHUB1.该片段包含1个2 655 bp的开放阅读框,编码了1个885氨基酸的多肽.与NCBI数据库的比对结果表明:OsHUB1的氨基酸序列与短柄草(Brachypodium distachyon)、葡萄(Vitis vinifera)、杨树(Populus tomentosa)、大豆(Glycine max)和拟南芥(Arabidopsis thaliana)的泛素E3连接酶的同源性分别为78%,68%,68%,67%和62%.这些不同来源的组蛋白单泛素化连接酶都含有一个高度保守的RING指结构域.半定量表达分析结果表明:OsHUB1基因能够被水杨酸(SA)和茉莉酸(JA)诱导表达,说明OsHUB1基因可能通过SA和JA介导的信号转导途径参与水稻的抗病反应.     

热锻炼与外源水杨酸对葡萄叶肉细胞膜脂过氧化的影响

以1年生赤霞珠葡萄（Vitis vinifera L．CV．Cabernet Sauviqnon）扦插苗为试材，研究了外源水杨酸和热锻炼对葡萄幼苗叶肉细胞膜脂过氧化的影响。结果表明，热锻炼和外施水杨酸都能显著降低膜脂过氧化水平。热锻炼和喷施100μmol／L水杨酸后，葡萄叶肉细胞的丙二醛和O2^-含量显著降低，质膜相对透性明显减小，保护酶系SOD、CAT活性都明显升高。从而说明外施水杨酸和热锻炼有相似的提高抗热性的机制，可能通过提高葡萄叶肉细胞对膜脂过氧化的抗性来诱导其对胁迫的抗性。     

Nitric oxide:A potential key point of the signaling network leading to plant secondary metabolite biosynthesis

The endogenous signaling network of plants plays important roles in mediating the exogenous factor-induced biosynthesis of secondary metabolites. Nitric oxide (NO) has emerged as a key signaling molecule in plants recently. Numerous studies demonstrated that the main signaling molecules such as salicylic acid (SA), jasmonic acid (JA), reactive oxygen species (ROS), and NO were not only involved in regulating plant secondary metabolite biosynthesis but also interacted to form a complex signaling network by mutual inhibition and/or synergy. The recent progress in the signal network of plant secondary metabolite biosynthesis has been discussed in this paper. Furthermore, we propose a hypothetical model to show that NO might act as a potential molecular switch in the signaling network leading to plant secondary metabolite biosynthesis.     

Nitric oxide: A potential key point of the signaling network leading to plant secondary metabolite biosynthesis

The endogenous signaling network of plants plays important roles in mediating the exogenous factor-induced biosynthesis of secondary metabolites. Nitric oxide (NO) has emerged as a key signaling molecule in plants recently. Numerous studies demonstrated that the main signaling molecules such as salicylic acid (SA), jasmonic acid (JA), reactive oxygen species (ROS), and NO were not only involved in regulating plant secondary metabolite biosynthesis but also interacted to form a complex signaling network by mutual inhibition and/or synergy. The recent progress in the signal network of plant secondary metabolite biosynthesis has been discussed in this paper. Furthermore, we propose a hypothetical model to show that NO might act as a potential molecular switch in the signaling network leading to plant secondary metabolite biosynthesis.     

低温下水杨酸对粳型巨胚稻幼苗生长的影响

本文以粳型巨胚稻西巨胚1号为试验材料,研究了6℃低温处理前用0．25mmol．L-1和0．5mmol．L-1水杨酸进行预处理（叶面喷施和灌根处理）对幼苗生长的影响。结果表明,水杨酸预处理可使巨胚稻幼苗叶片在低温处理下叶绿素和可溶性糖含量增加,提高幼苗的抗寒性,减轻低温伤害,对幼苗地上部分和根系生长具有一定的促进作用。从对提高巨胚稻幼苗抗寒性的效果来看,0．5mmol．L-1浓度水杨酸处理效果较0．5mmol．L-1浓度好,灌根处理效果较叶面喷施好。     

Systemic defense signaling in tomato

The wound-inducible expression of proteinase inhibitors （PIs） genes in tomato provides a powerful model system to elucidate the signal transduction pathway of systemic defense response. An increasing body of evidence indicates that systemin and jasmonic acid （JA） work in the same signaling pathway to activate the expression of Pls and other defense-related genes. However, little is known about how systemin and JA interact to regulate cell to cell communication over long distances. Genetic analysis of the systemin/JA signaling pathway in tomato plants provides a unique opportunity to dissect the mechanism by which peptide and oxylipin signals interact to coordinate systemic expression of defense-related genes. Previously, it has been proposed that systemin is the long-distance mobile signal for systemic expression of defense related genes. However, recent genetic approach provided new evidence that jasmonic acid, rather than systemin, functions as the systemic wound signal, and that the peptide systemin works to regulate the biosynthesis of JA.