Jasmonic acid‐inducible TSA1 facilitates ER body formation

Members of the Brassicales contain an organelle, the endoplasmic reticulum (ER) body, which is derived from the ER. Recent studies have shed light on the biogenesis of the ER body and its physiological role in plants. However, formation of the ER body and its physiological role are not fully understood. Here, we investigated the physiological role of TSK‐associating protein 1 (TSA1), a close homolog of NAI2 that is involved in ER body formation, and provide evidence that it is involved in ER body biogenesis under wound‐related stress conditions. TSA1 is N‐glycosylated and localizes to the ER body as a luminal protein. TSA1 was highly induced by the plant hormone, methyl jasmonate (MeJA). Ectopic expression of TSA1:GFP induced ER body formation in root tissues of transgenic Arabidopsis thaliana and in leaf tissues of Nicotiana benthamiana. TSA1 and NAI2 formed a heterocomplex and showed an additive effect on ER body formation in N. benthamiana. MeJA treatment induced ER body formation in leaf tissues of nai2 and tsa1 plants, but not nai2/tsa1 double‐mutant plants. However, constitutive ER body formation was altered in young seedlings of nai2 plants but not tsa1 plants. Based on these results, we propose that TSA1 plays a critical role in MeJA‐induced ER body formation in plants.     

Soybean Resistance to Phakopsora pachyrhizi as Affected by Acibenzolar‐S‐Methyl,Jasmonic Acid and Silicon

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, is one of the most important diseases on soybean. At the moment, ASR is managed mainly with fungicides due to the absence of commercial cultivars with resistance to this disease. This study evaluated the effects of acibenzolar‐Smethyl (ASM), jasmonic acid (JA), potassium silicate (PS) and calcium silicate (CS) on soybean resistance to ASR. The ASM, JA and PS were sprayed to leaves 24 h prior to inoculation with P. pachyrhizi. The CS was amended to the soil. The incubation period (time from the inoculation until symptoms development) was longer for plants growing in soil amended with CS or sprayed with ASM in comparison with plants sprayed with water (control). Plants sprayed with ASM had longer latent period (time from the inoculation until signs appearance) in comparison with the control plants. Plants sprayed with PS showed fewer uredia per cm² of leaf in relation to the control plants. The ASM and PS were the most effective treatments in reducing the ASR symptoms in contrast to the JA and CS treatments. The JA served as an inducer of susceptibility to ASR.     

Jasmonic acid carboxyl methyltransferase regulates development and herbivory‐induced defense response in rice

Jasmonic acid(JA) and related metabolites play a key role in plant defense and growth. JA carboxyl methyltransferase(JMT) may be involved in plant defense and development by methylating JA to methyl jasmonate(Me JA) and thus influencing the concentrations of JA and related metabolites. However, no JMT gene has been well characterized in monocotyledon defense and development at the molecular level. After we cloned a rice JMT gene,Os JMT1, whose encoding protein was localized in the cytosol, we found that the recombinant Os JMT1 protein catalyzed JA to Me JA. Os JMT1 is up-regulated in response to infestation with the brown planthopper(BPH; Nilaparvata lugens). Plants in which Os JMT1 had been overexpressed(oeJMT plants) showed reduced height and yield. These oe-JMT plants also exhibited increased Me JA levels but reduced levels of herbivore-induced JA and jasmonoyl-isoleucine(JAIle). The oe-JMT plants were more attractive to BPH female adults but showed increased resistance to BPH nymphs,probably owing to the different responses of BPH female adults and nymphs to the changes in levels of H_2O_2 and Me JA in oe-JMT plants. These results indicate that Os JMT1,by altering levels of JA and related metabolites, plays a role in regulating plant development and herbivore-induced defense responses in rice.     

茉莉酸生物合成的调控及其信号通路

茉莉酸类化合物作为一种细胞信号分子,在植物的生长发育、机械损伤、代谢调节及诱导防御相关基因表达等方面起着重要的作用。本文概述了茉莉酸的生物合成调控以及人们目前对茉莉酸信号通路的认识,并对该研究领域存在的问题及今后可能的研究方向进行展望。     

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.     

Jasmonic acid promotes germination and lipase activity in non‐stratified apple embryos

The effects of (−)jasmonic acid (JA) on germination of embryos isolated from dormant seeds of apple ( Malus domestica Borb. cv. Antonówka) cultured in darkness or at 12‐h photoperiod were studied, as well as its effects on the activity of alkaline lipase (AlkL, EC 3.1.1.3) in these embryos. The maximum sensitivity of germination to JA occurred on days 3 and 4 of embryo culture. Both germination and enzyme activity were stimulated by JA, its effect being additive to that of light. Inhibitors of lipoxygenase inhibited embryo germination and AlkL activity, both effects being partially reversed by JA treatment. We suggest that (1) JA is implicated in an endogenous complex controlling apple seed germination, and that (2) it acts independently of the mechanism triggered by light.     

茉莉酸信号转导突变体ber15 的分离和基因克隆表明油菜素内酯的合成影响茉莉酸信号转导

bestatin是一种氨肽酶抑制剂, 能够激活茉莉酸信号转导途径而诱导抗性相关基因的表达, 从而为用化学遗传学手段解析茉莉酸途径提供了一个有效的工具。ber15是我们鉴定到的一个对bestatin不敏感的拟南芥突变体, 随后的研究表明该突变体对外源茉莉酸的敏感性也明显降低, 表明相应的野生型基因BER15在茉莉酸信号转导中起重要作用。图位克隆结果表明BER15编码一个细胞色素P450单加氧酶, 是植物激素油菜素内酯合成途径中的一个关键酶。对BER15基因功能的深入研究将会为了解油菜素内酯的合成与茉莉酸信号途径间的互作关系提供证据。     

茉莉酸信号转导突变体ber15的分离和基因克隆表明油菜素内酯的合成影响茉莉酸信号转导

bestatin是一种氨肽酶抑制剂,能够激活茉莉酸信号转导途径而诱导抗性相关基因的表达,从而为用化学遗传学手段解析茉莉酸途径提供了一个有效的工具。ber15是我们鉴定到的一个对bestatin不敏感的拟南芥突变体,随后的研究表明该突变体对外源茉莉酸的敏感性也明显降低,表明相应的野生型基因BER15在茉莉酸信号转导中起重要作用。图位克隆结果表明BER15编码一个细胞色素P450单加氧酶,是植物激素油菜素内酯合成途径中的一个关键酶。对BER15基因功能的深入研究将会为了解油菜素内酯的合成与茉莉酸信号途径间的互作关系提供证据。     

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].     

Jasmonic acid in wound signal transduction pathways

Wounding induces expression of genes encoding defense-related proteins involved in wound healing. An intensive survey has been carried out to clarify the initial signal transduction pathways that mediate this stress to expression of genes. In this context, signal molecules that intermediate in the wound signal to cellular response have been actively searched for. Jasmonic acid (JA) has been considered to be a key signal molecule in this pathway. Systemin, ABA, ethylene, and electrical current have been suggested to function by transmitting the wound signal to JA. A mitogen-activated protein kinase has been shown to respond rapidly to wounding, and proposed to function as one of the key enzymes involved in JA biosynthesis. Transgenic plants overexpressing a gene encoding a Rab-type, small GTP-binding protein contained 6-fold higher levels of cytokinins than wild-type plants, and responded to wounding by rapidly producing JA and, uncommonly, accumulating salicylic acid (SA), a pathogenic signal. These phenomena observed in the transgenic plants were reproduced when wild-type plants were wounded in the presence of the synthetic cytokinin, benzylaminopurine, suggesting that cytokinins are indispensable in the control of endogenous levels of JA and SA.     

Exogenous Jasmonic Acid Inhibits Cotton Fiber Elongation

Jasmonic acid (JA) is a well-characterized phytohormone that acts in various ways to influence plant development. Its role in cotton fiber development, however, has not yet been thoroughly explored. In this study, JA was proven to be an inhibitor of ovule and fiber development in vitro. Continuous exogenous JA application inhibited fiber elongation. This effect was dependent on development stage and dosage. Fibers and ovules at three different stages of development and different JA dosages were compared. The most serious suppression was detected when ovules 1?day before anthesis (–1?DPA) were cultured in medium with 2.5?μM JA. Genes related to trichome and fiber development responded differently to JA treatment between –1?DPA and 1?day post anthesis (1 DPA). JAs (JA and JA-Ile) quantification showed that JAs content was sharply decreased from –1?DPA to 5?DPA ovules, which indicated that JA was negatively associated with fiber elongation in vivo. In addition, gene expression analysis showed the same trend. Our results demonstrate that there was a negative relationship of JA with fiber elongation in vitro and in vivo. These results are meaningful for uncovering the mechanism of fiber elongation in cotton.     

Jasmonic acid signaling modulates ozone-induced hypersensitive cell death

Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.     

Kaolin and Jasmonic acid improved cotton productivity under water stress conditions

Drought is one of the most emerging threat that causes a severe reduction in cotton plant growth and development. Being cotton is a major cash crop has great threat to prevailing drought events in Pakistan. A field experiment was conducted in Kharif season 2018 at Research Area of MNS-University of Agriculture, Multan, Pakistan to assess the role of foliar applied kaolin and jasmonic acid on vegetative growth, gas exchange and reproductive traits of cotton under normal irrigated and artificial water deficit conditions. The experiment was laid -out in a factorial randomized complete block design with split – split plot arrangement. Main plots were allocated for irrigation levels, sub-plots for two -cotton genotypes viz. NIAB − 878 and SLH − 19 while sub – sub plots for treatments of kaolin and Jasmonic acid. Water deficit stress was created by skipping irrigation at flowering for 21 days. Foliar sprays of Kaolin (5%, w/v) and Jasmonic acid (100 μM) were applied alone or in combination at 60 days after planntinon both to normal irrigated and water-stresse skip irrigation while irrigation water alone was sprayed in control plots. Both cotton genotypes responded variably to normal irrigated and skip conditions. Skipping irrigation for up to 21 days at flowering caused a significant decrease in leaf relative water content, SPAD values, net photosynthetic rate and seed cotton yield in both the genotypes. Seed cotton yield showed an overall decline of 24.7% in skip over Normal irrigated crop. The genotype NIAB − 878 produced maximum seed cotton yield of 3.304 Mg ha⁻¹ in normal that dropped to 2.579 Mg ha⁻¹ in skip, thus showing an average decline of 21.9 %. Similarly, SLH − 19 produced 2.537 Mg ha⁻¹ seed cotton under normal that dropped to 1.822 Mg ha⁻¹ in skip, showing an average decline of 28.2%. The Application of Kaolin and JA Jasmonic acid, either applied individually or in combination, improved vegetative and reproductive development of both cotton varieties in normal and skip regimes. However, combined kaolin and Jasmonic Acid application proved to be more beneficial in terms of seed cotton production and other parameters studied.     

Jasmonic acid stimulates shoot and bulb formation of garlic in vitro

Although much information is available concerning the involvement of jasmonates in the regulation of plant development, few reports are devoted to their effects in tissue culture. In the present study, the influence of jasmonic acid (JA) on shoot and bulb formation in tissue culture of garlic (Allium sativum cv. Ptuj) was studied. Isolated basal plates were placed onto Gamborg's B5 medium. JA significantly enhanced the shoot and bulb development in concentrations from 1–10 M. When the combination of 10 M JA and 5 M 2-iP was used in the initiation media, the average number of shoots was 30 after 6 weeks of culture. The bulbs formed on approximately 50% of shoots. Results described in this article show that JA might play an important role in the formation of storage organs in plants, in this case on garlic bulbs.     

Jasmonic acid affects dormancy and sugar catabolism in germinating apple embryos

Embryos isolated from dormant seeds of apple (Malus domestica Borb., cv. Antonówka) were cultured in darkness in the presence of jasmonic acid (JA, 20 μM) for 7 d in parallel to control non-treated ones. Soluble sugars were quantified and some sugar-catabolysing enzyme activities were determined in axes and in cotyledons of the embryos during the culture. JA treatment stimulated growth of the axis and sucrose hydrolysis in this organ. In contrast, JA inhibited the growth of isolated cotyledons. In intact embryos, JA treatment inhibited the growth of the lower cotyledon (being in contact with wet medium) thus alleviating the growth asymmetry of cotyledons. In both cotyledons JA stimulated hydrolysis of sucrose during the period preceding growth. The effect persisted in the upper cotyledon for the whole experimental period, whereas in the lower one the treatment provoked a sharp rise in soluble sugar levels observed relatively late during the experiment. The later effect correlated with the stimulation of isocitrate lyase activity in the lower cotyledon by JA. The results suggest the induction of the gluconeogenetic pathway by JA in the lower cotyledon of cultured dormant apple embryos. They also provide evidence for the site of JA action in the regulatory complex controlling embryonic dormancy in apple.     

茉莉酸在植物诱导防御中的作用

茉莉酸(JA)和茉莉酸甲酯(MeJA)作为与损伤相关的植物激素和信号分子,广泛地存在于植物体中,外源应用能够激发防御植物基因的表达,诱导植物的化学防御,产生与机械损伤和昆虫取食相似的效果。大量研究表明,用茉莉酸类化合物处理植物可系统诱导蛋白酶抑制剂(PI)和多酚氧化酶(PPO),从而影响植食动物对营养物质的吸收,还能增加过氧化物酶、壳聚糖酶和脂氧合酶等防御蛋白的活性水平,导致生物碱和酚酸类次生物质的积累,增加并改变挥发性信号化合物的释放,甚至形成防御结构,如毛状体和树脂导管。经茉莉酸处理的植物提高了植食动物的死亡率,变得更加吸引捕食性和寄生性天敌。挥发性化合物——茉莉酸甲酯可以从植物的气孔进入植物体内,在细胞质中被酯酶水解为茉莉酸,实现长距离的信号传导和植物间的交流,诱导邻近植物产生诱导防御反应。茉莉酸和茉莉酸甲酯分别具有4种立体异构,其中具有活性的是顺式结构,但顺式结构不稳定,会差向异构化为反式结构。茉莉酸的代谢物(Z)-茉莉酮(cis-Jasmone)具电生理活性,在植物诱导防御中起作用,并且在防御信号的作用上不同于茉莉酸和茉莉酸甲酯。