Influence Of Jasmonic Acid Research Articles

Magnaporthe oryzae infection triggers rice resistance to brown planthopper through the influence of jasmonic acid on the flavonoid biosynthesis pathway.

In agroecosystems, plants are constantly exposed to attack from diverse herbivorous insects and microbes, and infestation with one species may change the plant defense response to other species. In our investigation of the relationships among rice plants, the brown planthopper Nilaparvata lugens (Stål) and the rice blast fungus Magnaporthe oryzae, we observed a significant increase in the resistance of rice treated with rice blast to N.lugens, as evidenced by improved plant survival rates in a small population resistance study. Subsequent transcriptome data analysis revealed that the rice blast fungus can induce the expression of genes in the jasmonic acid (JA) and flavonoid pathways. Similar to the flavonoid pathway, the JA pathway also contains 2 types of genes that exhibit similar and opposite trends in response to N.lugens and rice blast. Among these genes, the osjaz1 mutant and the osmyc2 mutant were phenotypically confirmed to positively and negatively regulate rice resistance to N.lugens and rice blast, respectively. Subsequent mass spectrometry and quantification experiments showed that the exogenous application of methyl jasmonate (MeJA) can induce the accumulation of eriodictyol, naringenin and quercetin, as well as the expression of OsF3H, Os4CL5 and OsCHI in the flavonoid pathway. This suggests a close connection between the JA pathway and the flavonoid pathway. However, OsF3'H, which negatively regulates rice resistance to N.lugens and rice blast, did not show increased expression. Phenotypic and molecular experiments confirmed that OsMYC2 can bind to and inhibit the expression of OsF3'H, thus revealing the mechanism of rice resistance to N.lugens after treatment with rice blast. These findings will deepen our understanding of the interactions among rice, N.lugens and rice blast.

Influence of Jasmonic Acid and Chlorpropham Treatments on Sprouting, Quality and Storability of Potato Tubers during Cold Storage

The present investigation was carried out on Diamant potato tubers (Solanum tuberosum L.), harvested at theircommercial maturity stage (May, 2017) in a private farm at Kom Hamada Behira Governorate, Egypt. The selection oftubers was based on size, absence of physical injuries, mechanical damage and disease infection. Tubers were packed innet plastic boxes (15 kg/ box), and were surface-disinfected by dipping in 2% sodium hypochlorite for 2-4 mins, thenrinsed with tap water and air-dried. Potato tubers were immersed in solutions containing chlorpropham (CIPC) at 0, 50, 75and 100 ppm and jasmonic acid (JA) at 0, 0.001, 0.01 and 0.1 mM/L, either alone or in combinations for 20 minutes andthen were cured in the dark for one week at 20°C and 75% RH. After curing, the tubers were placed in the dark coldstorage room for long-term storage (140 days) at 10±1°C and 85±5% relative humidity (RH). Treatments were distributedin design with three replicates for each treatment (one replicate = one box of 15 kg tubers).Tuber’s firmness, dry matter, starch, acidity and ascorbic acid increased, while SSC and total sugars decreased withincreasing concentration of CIPC. Chlorpropham at the concentration of 75 ppm of decreased the weight loss, decay andsprouting percent during cold storage or after removal from cold storage and kept at ambient temperature as comparedwith 50 or 100 ppm and control. Furthermore, the storability and shelf life of potato tubers have been extendedsignificantly with 75 ppm in both the storage temperature conditions. Likewise, applied of jasmonic acid at rate of 0.01mM JA/L caused noticeable increase in tubers firmness, dry matter, starch, acidity and ascorbic acid contents. Meanwhile,soluble solids content, total sugars, weight loss, decay and sprouting percent decreased during storage as compared withthe other concentrations of jasmonic acid (0.001 or 0.1 mM JA/L) and the untreated tubers. Additionally, the storage andshelf life of tubers have been extended significantly with 0.01 mM JA/L dips during cold storage or ambient temperatureat 25±2°C and 75-80 % RH.

Differential induction of two different cystatin genes during pathogenesis of Karnal bunt (Tilletia indica) in wheat under the influence of jasmonic acid

In the present study, expression patterns of two different wheat cystatins (WCs) were studied under the influence of jasmonate signaling in triggering resistance against Karnal bunt (KB). Cystatins are cysteine proteinase inhibitors (CPI) constituting a multigene family which regulate the activity of endo- and/or exogenous cysteine proteinases (CP). Two wheat varieties HD-29 (resistant, R) and WH-542 (susceptible, S) were pre-conditioned with jasmonate and then artificially inoculated with sporidial suspension of Tilletia indica to study its influence in inducing defense by regulating cystatin genes. On the transcriptional level, WC4 and WC5 gave different temporal expression patterns. Expression of WC4 was higher in boot emergence stage which is most susceptible to KB and then slowly declined in both varieties. Expression of WC5 showed an entirely reverse pattern of expression, which kept on rising as the grains matured. Cystatin activity determination by inhibitor assay gave higher activity in resistant variety and under JA treatment. Estimation of specific activity of total cystatin at different days after inoculation (DAI) showed that JA positively induced cystatin expression in both varieties but R variety always registered a greater cystatin expression than the susceptible one (P<0.05). In plants inoculated with pathogen, initially there was a rise in cystatin activity which gradually decreased 7 DAI when compared with the un-inoculated plants. Based on these findings it is clearly demonstrated that jasmonate acts as a potential activator of induced resistance by up-regulating cystatin expression and provides the conditioning effect prior to infection through the maintenance of critical balance of CP/CPI interaction. However, different cystatin genes show different temporal expression patterns and may play different roles at various developmental stages of the grain.

Influence of jasmonic acid as potential activator of induced resistance against Karnal bunt in developing spikes of wheat

Induction of defense response against Karnal bunt (KB)by suppressing the pathogenesis was observed upon exogenous application of jasmonic acid (JA)as evident from decrease in the coefficient of infection and overall response value in both susceptible and resistant varieties of wheat. The ultra-structural changes during disease progression showed the signs of programmed cell death (PCD). However, JA strengthened the defense barrier by enhancing the lignifications of cell walls as observed in spikes of both varieties by histochemical analysis. Compared to the plants inoculated with pathogen alone, plants of resistant line (RJP) first treated with JA followed by inoculation with pathogen showed more lignifications and extracellular deposition of other metabolites on cells, which is supposed to prevent mycelial invasions. Contrary to this, susceptible (SJP)lines also showed lignifications but the invasion was more compared to resistant line. Induction of protease activity was higher in resistant variety than its corresponding susceptible variety. The protease activity induced during the colonization of the pathogen and its proliferation inside the host system gets inhibited by JA treatment as demonstrated by the quantitative and in-gel protease assay. The results indicate the role of JA signalling in inhibiting the proteases due to expression of certain protease inhibitor genes. SDS-PAGE analysis shows differential gene expression through induction and/or suppression of different proteins in wheat spikes of resistant and susceptible varieties under the influence of JA. Thus, exogenously applied JA provides the conditioning effect prior to the challenge of infection and induces defense against KB probably by maintaining a critical balance between proteases and protease inhibitors and/or coordinating induction of different families of new proteins.

Estimating the plasma membrane permeability of Taxus x media cells with the spin probe TEMPOL by EPR

Production of paclitaxel and other taxanes by cell suspension cultures of Taxus species is an alternative to their extraction from yew tree bark or shoots. Little is known about the mechanism of taxane transport in Taxus cells, in either cell cultures or plants. In our study we measured the influence of jasmonic acid (JA), an elicitor of taxane production, on plasma membrane permeability in cell suspensions of Taxus x media. TEMPOL spin probe was added to the suspension of cells grown in the presence of JA and to control cells. Reduction of TEMPOL in the cell interior was measured by electron paramagnetic resonance (EPR). Plasma membrane permeability was derived from the kinetics of reduction. JA was shown to decrease the membrane permeability of Taxus x media cells. The observed inhibition of the spin probe permeability by JA can be ascribed to modification of the membrane structure and lipid composition or, at least, to changes in the lipid lateral domain structures, thus affecting the transport of TEMPOL. The changed permeability to small uncharged molecules could influence the primary cellular metabolism and possibly also the transport of taxanes.

The influence of jasmonic acid on the amount and the distribution of cysteine proteinase PLCP-2 in healthy and PVY&lt;sup&gt;NTN&lt;/sup&gt; infected potato plants (Solanum tuberosum L.)

The localization of cysteine proteinase PLCP-2 was investigated in potato plants (Solanum tuberosum L.) cultivar Désirée by electron microscopy. Healthy and PVY&lt;sup&gt;NTN&lt;/sup&gt; infected potato plants were grown in vitro on media with or without a supplement of jasmonic acid. We had already shown that PLCP-2 is present in leaves, stems, tips of shoots and tips of roots of healthy and PVY&lt;sup&gt;NTN&lt;/sup&gt; infected plants. It was detected in various cell types in protein bodies in vacuoles, in cytoplasm and in cell walls. There were significantly larger amounts of PLCP-2 in plants grown on medium with a supplement of jasmonic acid in both healthy and virus infected plants. More protein bodies in vacuoles were found in plants grown on medium with addition of jasmonic acid.

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 μM. When the combination of 10 μM JA and 5 μM 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.

The influence of jasmonic acid on biophysical properties of potato leaf protoplasts and roots

Jasmonic acid (JA) and its derivatives are a novel group of plant endogenous growth regulators. In our experiments some new data about the physiological effects of JA were obtained using electron paramagnetic resonance spectroscopy. Experiments were performed on potato plants (Solanum tuberosum L. cv. Vesna) grown in vitro. Different quantities of JA (0.1-10 μM) were added to the growth medium. Root samples of plants grown on media supplemented with JA showed a more rapid spin probe N-oxyl-2,2,6,6-tetramethyl piperidine reduction than the control plants, which is a possible indicator of altered root permeability. Samples of leaf protoplasts were probed with methyl ester of 5-doxyl-haxadecanoic acid. We observed a membrane fluidity decrease in protoplasts isolated from plants grown on higher concentrations of JA (1 and 10 μM).

Regulation of potato meristem development by jasmonic acid in vitro

The influence of jasmonic acid (JA) on differentiation of meristems of the potato,Solanum tuberosum cv. Vesna, was investigated in vitro. Meristems were grown on Murashige and Skoog (MS) medium supplemented with indole-3-acetic acid (IAA) (10 μM), kinetin (10 μM), gibberellic acid (3 μM), as modified by Bang. Addition of JA in concentrations of 0.5–10 μM increased the number of meristems that developed into buds, particularly in meristems isolated from shoots grown from tubers in the dark. JA had no noticeable effect on meristems from germs grown in light. All added concentrations of JA retarded callus and root formation. The inhibitory effect on rhizogenesis disappeared immediately after transfer of the developed buds to medium without JA.