Salicylic Acid Levels Research Articles

Reduced γ-glutamyl hydrolase activity likely contributes to high folate levels in Periyakulam-1 tomato.

Tomato cultivars show wide variation in nutraceutical folate in ripe fruits, yet the loci regulating folate levels in fruits remain unexplored. To decipher regulatory points, we compared two contrasting tomato cultivars: Periyakulam-1 (PKM-1) with high folate and Arka Vikas (AV) with low folate. The progression of ripening in PKM-1 was nearly similar to AV but had substantially lower ethylene emission. In parallel, the levels of phytohormones salicylic acid, ABA, and jasmonic acid were substantially lower than AV. The fruits of PKM-1 were metabolically distinct from AV, with upregulation of several amino acids. Consistent with higher °Brix, the red ripe fruits also showed upregulation of sugars and sugar-derived metabolites. In parallel with higher folate, PKM-1 fruits also had higher carotenoid levels, especially lycopene and β-carotene. The proteome analysis showed upregulation of carotenoid sequestration and folate metabolism-related proteins in PKM-1. The deglutamylation pathway mediated by γ-glutamyl hydrolase (GGH) was substantially reduced in PKM-1 at the red-ripe stage. The red-ripe fruits had reduced transcript levels of GGHs and lower GGH activity than AV. Conversely, the percent polyglutamylation of folate was much higher in PKM-1. Our analysis indicates the regulation of GGH activity as a potential target to elevate folate levels in tomato fruits.

Identification of key gene networks related to the freezing resistance of apricot kernel pistils by integrating hormone phenotypes and transcriptome profiles

BackgroundApricot kernel, a woody oil tree species, is known for the high oil content of its almond that can be used as an ideal feedstock for biodiesel production. However, apricot kernel is vulnerable to spring frost, resulting in reduced or even no yield. There are no effective countermeasures in production, and the molecular mechanisms underlying freezing resistance are not well understood.ResultsWe used transcriptome and hormone profiles to investigate differentially responsive hormones and their associated co-expression patterns of gene networks in the pistils of two apricot kernel cultivars with different cold resistances under freezing stress. The levels of auxin (IAA and ICA), cytokinin (IP and tZ), salicylic acid (SA) and jasmonic acid (JA and ILE-JA) were regulated differently, especially IAA between two cultivars, and external application of an IAA inhibitor and SA increased the spring frost resistance of the pistils of apricot kernels. We identified one gene network containing 65 hub genes highly correlated with IAA. Among these genes, three genes in auxin signaling pathway and three genes in brassinosteroid biosynthesis were identified. Moreover, some hub genes in this network showed a strong correlation such as protein kinases (PKs)-hormone related genes (HRGs), HRGs-HRGs and PKs-Ca2+ related genes.ConclusionsCa2+, brassinosteroid and some regulators (such as PKs) may be involved in an auxin-mediated freezing response of apricot kernels. These findings add to our knowledge of the freezing response of apricot kernels and may provide new ideas for frost prevention measures and high cold–resistant apricot breeding.

Revealing Differential Expression of Phytohormones in Sorghum in Response to Aphid Attack Using the Metabolomics Approach.

Sorghum (Sorghum bicolor) is an important multipurpose crop grown worldwide, but like many other crops, it is often threatened by insect pests. Sugarcane aphid (SCA, Melanaphis sacchari Zehntner), for example, is one of the most severe pests in sorghum, which causes plant damage and yield loss. The main objective of this study was to assess the effect of phytohormones on host plant resistance to aphid attack. Two sorghum genotypes, BTx623 (susceptible) and Tx2783 (resistant), were selected for a comparative analysis of differential expression of a group of phytohormones in response to aphid infestation. The quantification of phytohormones through LC-MS demonstrated higher levels of jasmonic acid (JA), salicylic acid (SA), abscisic acid (ABA), and auxins in the resistant genotype infested with SCA. The PCA plot supports the strong differential responses between resistant and susceptible genotypes, indicating a positive correlation between JA and ABA and a negative correlation between SA and auxins. Similarly, RT-PCR results of the phytohormones-related marker genes showed higher expression in the resistant genotype compared to the susceptible one. Furthermore, to corroborate the role of phytohormones in plant defense, the susceptible genotype was treated with SA, JA, and ABA. The exogenous application of SA and JA + ABA significantly reduced plant mortality, aphid number, and damage in the susceptible genotype, suggesting a strong correlation between phytohormones and plant survival. Our findings indicate that phytohormones play positive roles in plant defense against aphids and provide new insights into the molecular mechanisms operating in plants for self-protection. These findings could also stimulate further research into the mystery about the regulation of phytohormone production during plant interaction with aphids.

Effects of Chilling Treatment on Baicalin, Baicalein, and Wogonin Biosynthesis in Scutellaria baicalensis Plantlets.

When plants are exposed to stressful conditions, they modulate their nutrient balance by regulating their primary and secondary metabolisms to adapt. In this study, changes in primary and secondary metabolites elicited by chilling stress treatment and the effects of treatment duration were examined in roots of Scutellaria baicalensis (S. baicalensis) plantlets. The concentrations of most sugars (maltose, glucose, sucrose, and fructose) and of several amino acids (proline and GABA), which are crucial regarding plant defense mechanisms, increased with increasing duration of chilling stress. Furthermore, salicylic acid levels increased after two-day chilling treatments, which may enhance plant tolerance to cold temperatures. The concentrations of flavones (baicalin, baicalein, and wogonin) increased during chilling stress, and those of phenolic acids (ferulic acid and sinapic acid) increased after two-day chilling treatments. The concentrations of these flavones were positively correlated with sucrose levels which acted as energy sources.

MusaNAC29-like transcription factor improves stress tolerance through modulation of phytohormone content and expression of stress responsive genes

Understanding the molecular mechanisms governed by genes and cross-talks among stress signaling pathways is vital for generating a broad view on stress responses in plants. Here, we analysed the effects of MusaNAC29-like transcription factor of banana on stress responses and report the quantitative modulation of phytohormone and flavonoid content and analysed the growth parameters and yield trait in transgenic banana plants. Expression of MusaNAC29-like transcription factor was strongly altered in responses to stress conditions and application of signaling molecules. Under control conditions, PMusaNAC29-like-GUS is activated in cells bordering xylem vessel elements and is strongly triggered in other cells types after influence of salicylic acid and abscisic acid. Transgenic banana plants of cultivar Rasthali and Grand Naine overexpressing MusaNAC29-like transcription factor displayed superior tolerance towards drought and salinity stress. LC-MS analysis indicated elevated levels of jasmonic acid and salicylic acid while content of zeatin was significantly reduced in leaves of transgenic banana lines. Transgenic banana lines displayed increased levels of gallic acid, coumaric acid, naringenin, chlorogenic acid while levels of vanillic acid and piperine were significantly reduced. Expression of stress related genes coding for antioxidants, thiol peptidase proteins, cold-regulated proteins, late embryogenesis abundant proteins, ethylene-responsive transcription factors, bHLH proteins, jasmonate-zim-domain proteins and WRKY transcription factors were significantly induced in transgenic banana lines. Though MusaNAC29-like transcription factor improved stress tolerance, its overexpression resulted in retarded growth of transgenic lines resulting in reduced yield of banana fruits.

Enolase2 regulates seed fatty acid accumulation via mediating carbon partitioning in Arabidopsis thaliana.

In many higher plants, fatty acid (FA) biosynthesis is coordinately regulated at multiple levels by intricate regulatory networks. However, the factors and their regulatory mechanisms underlying seed oil accumulation are still limited. Here, we identified that loss of glycolytic metalloenzyme enolase2 (AtENO2) activity increased the contents of total FAs and salicylic acid (SA) but reduced the accumulation of flavonoids and mucilage by regulating the expression of key genes involved in their biosynthesis pathway in Arabidopsis thaliana seeds. AtENO2 physically interacts with the transcription factor AtTGA5, which may participate in the regulation of SA levels. Non-targeted metabolomics analysis of eno2- and WT also showed that the levels of three flavonoids, quercetin-3-galactoside, quercitrin, and epicatechin, were significantly decreased in eno2- , and the flavonoid biosynthesis pathway was also enriched in the KEGG analysis. Meanwhile, the mutation of AtENO2 delayed silique ripening, thereby prolonging silique photosynthesis time, allowing siliques to generate more photosynthesis products for FA biosynthesis. These results reveal a molecular mechanism by AtENO2 to regulate seed oil accumulation in A. thaliana, providing potential targets for improving crop seed oil quality.

Biochars as culture medium additives influence organogenic potential of plant explants through changes in endogenous phytohormone and carbohydrate contents in Daphne species

Biochar applicability as culture medium amendment is rarely investigated due to its uncovered impact on in vitro cultured plants. This study assessed the feasibility of several biochars as alternatives to activated charcoal, for micropropagation of two ornamental Daphne species (Thymelaeaceae). We distinguished metabolic responses that were specific for: a) medium supplementation with any type of charcoal; b) biochar addition; c) biochar activation; d) the process of charcoal activation itself. We compared impacts of industrially produced biochar and three different biochars made in small-scale stoves (from residues of Gliricidia sepium) on organogenic capacity and physiological status in Daphne sp. shoots. Metabolite profiling revealed that biochars differently modulated accumulation of endogenous phytohormones and osmolytes in the shoots. Biochars reduced accumulation of proline, betaines and stress-related phytohormones (ABA, jasmonates), and impacted carbohydrate profile. For D. jasminea the most impactful was biochar activation, which increased micropropagation efficiency by elevating cytokinin and soluble sugars content. For D. tangutica charcoal/biochar activation, and application of biochar reduced accumulation of ABA and jasmonic acid, increased level of gibberellins, salicylic and benzoic acid, and altered carbohydrate composition. The study revealed that tested biochars can be used as a sustainable medium supplements without negative impact on production of new microshoots. Based on studied species we showed that biochar supplements could stimulate plantlet formation (D. jasminea,) ameliorate stress response (D. tangutica), and constitute a way of undesired biomass utilization (invasive species G. sepium).

The Effects of High CO2 and Strigolactones on Shoot Branching and Aphid-Plant Compatibility Control in Pea.

Elevated atmospheric CO2 concentrations (eCO2) regulate plant architecture and susceptibility to insects. We explored the mechanisms underpinning these responses in wild type (WT) peas and mutants defective in either strigolactone (SL) synthesis or signaling. All genotypes had increased shoot height and branching, dry weights and carbohydrate levels under eCO2, demonstrating that SLs are not required for shoot acclimation to eCO2. Since shoot levels of jasmonic acid (JA) and salicylic acid (SA) tended to be lower in SL signaling mutants than the WT under ambient conditions, we compared pea aphid performance on these lines under both CO2 conditions. Aphid fecundity was increased in the SL mutants compared to the WT under both ambient and eCO2 conditions. Aphid infestation significantly decreased levels of JA, isopentenyladenine, trans-zeatin and gibberellin A4 and increased ethylene precursor ACC, gibberellin A1, gibberellic acid (GA3) and SA accumulation in all lines. However, GA3 levels were increased less in the SL signaling mutants than the WT. These studies provide new insights into phytohormone responses in this specific aphid/host interaction and suggest that SLs and gibberellins are part of the network of phytohormones that participate in host susceptibility.

Three rhizobacteria differentially change endogenous hormones and yield in four rice cultivars

Four Thai rice cultivars Pathum Thani 1, RD41, RD57, and RD85 were investigated to observe their responses to Plant Growth Promoting Bacteria Bacillus sp. N7 (N7), Lysinibacillus sp. N5 (N5), and Bacillus thuringiensis B20 (B20). A pot experiment with 5 plants pot−1 and four replicates was used. This study reported that the combination of plant growth promoting bacteria and optimized fertilization play role in crop yield enhancement by modulating endogenous levels of indole-3-acetic acid, salicylic acid, and tryptophan. Endogenous levels of indole-3-acetic acid, salicylic acid, tryptophan, and grain-yield-related components and grain yield of four Thai rice cultivars Pathum Thani 1, RD41, RD57, and RD85 were measured. Significant (p < 0.05) increase in grain yield observed at PTT1, RD41, and RD85 (40.13–51.18 g pot−1, 43.33–54.05 g pot−1, 47.80–69.08 g pot−1, respectively), but no significant (p > 0.05) grain yield increase in RD57 (48.75–51.75 g pot−1) when compared to uninoculated conditions. Significant (p < 0.05) endogenous indole-3-acetic acid, salicylic acid, and tryptophan level changes compared to the uninoculated control were observed across four Thai rice cultivars. Consortia development to enhance the plant growth promoting bacteria capability and larger field trials will be performed in the future to further investigate the efficacy of the bacteria in the real-field application.

Salicylic acid treatment inhibits ethylene synthesis and starch-sugar conversion to maintain apple fruit quality during shelf life

Starch and sugars are widely acknowledged as taste determinants, energy substances, and signal molecules in fruits. Salicylic acid (SA) regulates many physiological and biochemical processes during fruit ripening. In this work, we investigated the effects of SA treatment on physiological parameters and SA synthesis, ethylene production, and starch-sugar metabolism of apples during shelf life. Results showed that SA maintained fruit firmness, reduced weight loss, and inhibited starch to sugar conversion during shelf life. The endogenous SA level was increased in SA-treated fruits, mediated by MdPAL, MdICS2, and MdNPR1, thus decreasing MdACS1 and MdACO1 expressions and inhibiting ethylene biosynthesis. Furthermore, the expression of starch and sugar-related genes, MdAMY, MdBam5, MdBam8, MdSPS, MdSUSY, MdNINV, and MdAINV, were inhibited by SA treatment during shelf life. It was inferred that exogenous SA could inhibit ethylene synthesis and starch-sugar conversion, maintain the quality, and prolong the shelf life of apples

Physiological, biochemical and phytohormone responses of Elymus nutans to α-pinene-induced allelopathy.

The α-pinene is the main allelochemical of many weeds that inhibit the growth of Elymus nutans, an important forage and ecological restoration herbage. However, the response changes of α-pinene-induced allelopathy to E. nutans is still unclear. Here, we investigated the physiological, biochemical and phytohormone changes of E. nutans exposed to different α-pinene concentrations. The α-pinene-stress had no significant effect on height and fresh weight (FW) of seedlings. The water-soluble proteins, the soluble sugars and proline (Pro) strengthened seedlings immunity at 5 and 10 µL L−1 α-pinene. Superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased at 5 µL L−1 α-pinene to resist stress. APX reduced the membrane lipid peroxidation quickly at 10 µL L−1 α-pinene. The high-activity of peroxidase (POD), APX along with the high level of GSH contributed to the cellular redox equilibrium at 15 µL L−1 α-pinene. The POD, glutathione reductase (GR) activity and glutathione (GSH) level remained stable at 20 µL L−1 α-pinene. The changes in antioxidant enzymes and antioxidants indicated that E. nutans was effective in counteracting the harmful effects generated by hydrogen peroxide (H2O2). The α-pinene caused severe phytotoxic effects in E. nutans seedlings at 15 and 20 µL L−1. Endogenous signal nitric oxide (NO) and cell membrane damage product Pro accumulated in leaves of E. nutans seedlings at 15 and 20 µL L−1 α-pinene, while lipid peroxidation product malondialdehyde (MDA) accumulated. The chlorophylls (Chls), chlorophyll a (Chl a), chlorophyll b (Chl b) content decreased, and biomass of seedlings was severely inhibited at 20 µL L−1 α-pinene. The α-pinene caused phytotoxic effects on E. nutans seedlings mainly through breaking the balance of the membrane system rather than with reactive oxygen species (ROS) productionat 15 and 20 µL L−1 α-pinene. Additionally, phytohormone levels were altered by α-pinene-stress. Abscisic acid (ABA) and indole acetic acid (IAA) of E. nutans seedlings were sensitive to α-pinene. As for the degree of α-pinene stress, salicylic acid (SA) and jasmonic acid (JA) played an important role in resisting allelopathic effects at 15 µL L−1 α-pinene. The ABA, Zeatin, SA, gibberellin 7 (GA7), JA and IAA levels increased at 20 µL L−1 α-pinene. The α-pinene had a greatest impact on ABA and IAA levels. Collectively, our results suggest that E. nutans seedlings were effective in counteracting the harmful effects at 5 and 10 µL L−1 α-pinene, and they were severely stressed at 15 and 20 µL L−1 α-pinene. Our findings provided references for understanding the allelopathic mechanism about allelochemicals to plants.

Foliar application of thiourea, salicylic acid, and kinetin alleviate salinity stress in maize grown under etiolated and de-etiolated conditions

Salinity stress and the absence of light negatively impact growth and development of the plants. Morpho-physiological and biochemical attributes of maize (Zea mays L.) get severely affected by salt stress and subdue light. Therefore, a pot experiment was conducted under the prevailing environmental conditions of Turbat, Balochistan, to explore etiolation and the de-etiolation response of maize hybrid (SP-17S23) to salinity stress under exogenous application of plant growth regulators (PGRs). Maize seedlings in three sets, i.e., non-etiolated, etiolated, de-etiolated, subjected to salinity stress (120 mM NaCl) after 15 days of seed germination. After a week, the seedlings were sprayed with optimized levels of different PGRs, including thiourea (TU; 10 mM), salicylic acid (SA; 250 µM), and kinetin (KIN; 3 µM). Salinity stress hampered plant growth and affected morpho-physiological attributes. However, PGRs foliar treatment proved effective, thus ameliorating the impact of salinity and etiolation on maize seedlings. Growth attributes (root/shoot length, leaf area, root/shoot fresh and dry weight), photosynthetic pigments (Chl a, b and carotenoids) were significantly enhanced under the foliar treatment of PGRs, especially under TU and KIN treatments. However, the oxidative damage parameters, i.e., malondialdehyde (MDA) and hydrogen peroxide (H2O2), decreased under the treatment of PGRs, thereby protecting seedlings under salinity and etiolated conditions. Overall, PGRs enhanced tolerance potential of plants under salinity stress with the consideration of light variations remain the key concern for developing healthy and vigor seedling strands.

The Genes Associated with Jasmonic Acid and Salicylic Acid Are Induced in Tropical Chili Pepper against Ralstonia solanacearum by Applying Arbuscular Mycorrhizal Fungi

Controlling soil-borne pathogens is a significant problem in agriculture. Arbuscular mycorrhizae have a potential role in controlling soil-borne pathogens by increasing plant phytohormone contents. However, the mechanism of resistance by mycorrhizae has not been fully elucidated, particularly against bacterial wilt disease in Solanaceae. This study examined the role of mycorrhizae in expressing genes involved in the signaling pathways mediated by jasmonic acid (JA) and salicylic acid (SA) in tropical chili pepper against the bacterium Ralstonia solanacearum. Seedlings from ten genotypes of chili pepper were inoculated with a consortium of five mycorrhizal species and/or inoculated with a mixture of nine isolates of R. solanacearum. The leaves of 10-week-old plants after the treatment were sampled for real-time polymerase chain reaction analysis. The results showed that the mycorrhizae strengthened the immune system of tropical chili pepper by increasing the relative gene expression levels of JA and SA in genotypes with high and low responsiveness to the mycorrhizae. The relative gene expression level of JA was related to the percentage colonization of mycorrhizae and the resistance of the tropical chili pepper genotypes to R. solanacearum. The relative gene expression level of SA was associated with the resistance of tropical chili pepper to R. solanacearum.

(Z)-3-hexenol primes callose deposition against whitefly-mediated begomovirus infection in tomato.

Rapid callose accumulation has been shown to mediate defense in certain plant-virus interactions. Exposure to the green leaf volatile (Z)-3-hexenol (Z-3-HOL) can prime tomato (Solanum lycopersicum) for an enhanced defense against subsequent infection by whitefly-transmitted Tomato yellow leaf curl virus (TYLCV). However, the molecular mechanisms affecting Z-3-HOL-induced resistance are poorly understood. Here, we explored the mechanisms underlying Z-3-HOL-induced resistance against whitefly-transmitted TYLCV infection and the role of callose accumulation during this process. Tomato plants pre-treated with Z-3-HOL displayed callose priming upon whitefly infestation. The callose inhibitor 2-deoxy-d-glucose abolished Z-3-HOL-induced resistance, confirming the importance of callose in this induced resistance. We also found that Z-3-HOL pre-treatment enhanced salicylic acid levels and activated sugar signaling in tomato upon whitefly infestation, which increased the expression of the cell wall invertase gene Lin6 to trigger augmented callose deposition against TYLCV infection resulting from whitefly transmission. Using virus-induced gene silencing, we demonstrated the Lin6 expression is relevant for sugar accumulation mediated callose priming in restricting whitefly-transmitted TYLCV infection in plants that have been pre-treated with Z-3-HOL. Moreover, Lin6 induced the expression of the callose synthase gene Cals12, which is also required for Z-3-HOL-induced resistance of tomato against whitefly-transmitted TYLCV infection. These findings highlight the importance of sugar signaling in the priming of callose as a defense mechanism in Z-3-HOL-induced resistance of tomato against whitefly-transmitted TYLCV infection. The results will also increase our understanding of defense priming can be useful for the biological control of viral diseases.

Physiological and biochemical responses of Brassica napus L. cultivars exposed to Cd stress

Four different rapeseed (Brassica napus L.) cultivars CZL, Benefit, Iwas and ZhongZhuang9, were used to analyse physiological responses to higher doses of cadmium (Cd) and their ability of Cd accumulation. Plants were exposed for 30 days to different Cd dosages (0, 50, 100, and 150 mg Cd/kg) in soil under greenhouse conditions. Cadmium was accumulated more in roots than in shoots of all tested cultivars, with the highest Cd in ZhongZhuang9. After the lowest Cd dose, the highest translocation factor was for CZL (0.8) and Benefit (0.6). The content of both K and Ca varied between treatments and cultivars. The chlorophyll fluorescence parameters and relative chlorophyll content were affected minimally. High constant levels of salicylic acid and a sharp increase in proline content were found mostly in Iwas; therefore, it may be considered as a more tolerant cultivar.

Rice β-Glucosidase 4 (Os1βGlu4) Regulates the Hull Pigmentation via Accumulation of Salicylic Acid.

Salicylic acid (SA) is a stress hormone synthesized in phenylalanine ammonia-lyase (PAL) and the branching acid pathway. SA has two interconvertible forms in plants: SAG (SA O-β-glucoside) and SA (free form). The molecular mechanism of conversion of SA to SAG had been reported previously. However, which genes regulate SAG to SA remained unknown. Here, we report a cytoplasmic β-glucosidase (β-Glu) which participates in the SA pathway and is involved in the brown hull pigmentation in rice grain. In the current study, an EMS-generated mutant brown hull 1 (bh1) displayed decreased contents of SA in hulls, a lower photosynthesis rate, and high-temperature sensitivity compared to the wild type (WT). A plaque-like phenotype (brown pigmentation) was present on the hulls of bh1, which causes a significant decrease in the seed setting rate. Genetic analysis revealed a mutation in LOC_Os01g67220, which encodes a cytoplasmic Os1βGlu4. The knock-out lines displayed the phenotype of brown pigmentation on hulls and decreased seed setting rate comparable with bh1. Overexpression and complementation lines of Os1βGlu4 restored the phenotype of hulls and normal seed setting rate comparable with WT. Subcellular localization revealed that the protein of Os1βGlu4 was localized in the cytoplasm. In contrast to WT, bh1 could not hydrolyze SAG into SA in vivo. Together, our results revealed the novel role of Os1βGlu4 in the accumulation of flavonoids in hulls by regulating the level of free SA in the cellular pool.

Jasmonic Acid and Salicylic Acid Levels in Defense Response of Azalea (Rhododendron simsii Hybrid) to Broad Mite (Polyphagotarsonemus latus)

The broad mite (Polyphagotarsonemus latus (Banks)) is an important pest in many crops, including azalea (Rhododendron simsii Planch. hybrid). Broad mites cause the malformation of shoot tips, leaves and flowers in azalea. It is known that the jasmonic acid (JA)- and salicylic acid (SA)-dependent signaling pathways are related to the presence of herbivorous mites. Here, we describe the levels of the two main plant defense-related hormones, SA and JA, in mite-infested plants. The plant hormones were analyzed using liquid chromatography combined with tandem mass spectrometry (LC-MS/MS). We studied both short-term hormonal responses under controlled conditions with artificial inoculation, and long-term responses under culture conditions with natural infestation. The long-term development of broad mite populations and hormone response were studied during two subsequent growing seasons on 3 and 18 different cultivars, respectively. During the experiments on 18 azalea cultivars under natural infestation, the presence of different species of tarsonemid mites was also examined. JA concentrations only showed variation in the early phase of infestation. Subsequently, the SA levels increased significantly for all the cultivars where broad mites were detected. Based on the observed timing of the defense responses, we suggest that the interaction of the JA and SA pathways as a defense response for pot azalea against P. latus involves a primary plant response through the JA pathway. In the presence of the mites, the production of SA increased in the plants in a later phase as the P. latus population grew. Our results also show that the hormone response depends on type of mite. Changes in hormone levels were found upon infestation with P. latus, but not in the presence of another frequently occurring tarsonemid mite, Tarsonemus confusus Ewing.

Volatile Dimethyl Disulfide from Guava Plants Regulate Developmental Performance of Asian Citrus Psyllid through Activation of Defense Responses in Neighboring Orange Plants.

Intercropping with guava (Psidium guajava L.) can assist with the management of Asian citrus psyllid (ACP, Diaphorina citri Kuwayama), the insect vector of the huanglongbing pathogen, in citrus orchards. Sulfur volatiles have a repellent activity and physiological effects, as well as being important components of guava volatiles. In this study, we tested whether the sulfur volatiles emitted by guava plants play a role in plant–plant communications and trigger anti-herbivore activities against ACP in sweet orange plants (Citrus sinensis L. Osbeck). Real-time determination using a proton-transfer-reaction mass spectrometer (PTR-MS) showed that guava plants continuously release methanethiol, dimethyl sulfide (DMS), and dimethyl disulfide (DMDS), and the contents increased rapidly after mechanical damage. The exposure of orange plants to DMDS resulted in the suppression of the developmental performance of ACP. The differential elevation of salicylic acid (SA) levels; the expression of phenylalanine ammonia lyase (PAL), salicylate-O-methyl transferase (SMT), and pathogenesis-related (PR1) genes; the activities of defense-related enzymes PAL, polyphenol oxidase (PPO), and peroxidase (POD); and the total polyphenol content were observed in DMDS-exposed orange plants. The emission of volatiles including myrcene, nonanal, decanal, and methyl salicylate (MeSA) was increased. In addition, phenylpropanoid and flavonoid biosynthesis, and aromatic amino acid (such as phenylalanine, tyrosine, and tryptophan) metabolic pathways were induced. Altogether, our results indicated that DMDS from guava plants can activate defense responses in eavesdropping orange plants and boost their herbivore resistance to ACP, which suggests the possibility of using DMDS as a novel approach for the management of ACP in citrus orchards.

Successful Treatment of Recalcitrant Non-genital Warts (Verruca vulgaris) with a Topical Solution Containing Two Antivirals and a Low Concentration of Salicylic Acid

Aims: Commercial formulas for the treatment of warts use salicylic acid in concentrations above 100 mg/ml, which causes skin irritation, and the results are often unsatisfactory. To address this problem, we developed a new formula with a low concentration of salicylic acid (20 mg/ml) and with the addition of virucidal compounds (metallic iodine and benzoic acid) and compared it to a formula currently on the market (Verrux®) containing 165 mg salicylic acid (0.165 g) and 145.2 mg lactic acid (0.145 g) per ml collodion.&#x0D; Study Design: A randomized double-blind study was conducted.&#x0D; Location and Duration of Study: Department of Biotechnology, UNINCOR, Chácara das Rosas, Três Corações, MG, Brazil; School of Pharmacy, Universidade Federal do Amapá - Campus Universitário Marco Zero do Equador, Rod. Juscelino Kubitschek, KM-02, Jardim Marco Zero, Macapá, AP, Brazil and School of Medicine, Universidad Politécnica y Artística del Paraguay (UPAP), Km 10, Ciudad del Este, Paraguay, between December 2004 and October 2016.&#x0D; Methodology: 95 patients were treated with the formula with salicylic acid (20mg), benzoic acid (20mg) and metallic iodine (2.5mg) per ml (group A) and 95 received treatment with Verrux® (salicylic acid 165mg, lactic acid 145.2mg per ml collodion) (group B).&#x0D; Results: All patients in Group A (100%) reported complete resolution of signs and symptoms after 13 weeks of treatment. In contrast, 67 subjects (70.5%) in group B reported regression of symptoms during the same period.&#x0D; Conclusion: There was a statistically significant difference between the groups studied here (P&lt; 0.05). This new formulation with a low level of salicylic acid and two virucidal agents promotes healing of recalcitrant cutaneous warts without significant side effects. The price of the two formulas is virtually the same (about $8 to $10 each bottle).

Cellular differentiation, hormonal gradient, and molecular alternation between the division zone and the elongation zone of bamboo internodes.

Bamboo differentiates a cell division zone (DZ) and a cell elongation zone (EZ) to promote internode elongation during rapid growth. However, the biological mechanisms underlying this sectioned growth behavior are still unknown. Using histological, physiological, and genomic data, we found that the cell wall and other subcellular organelles such as chloroplasts are more developed in the EZ. Abundant hydrogen peroxide accumulated in the pith cells of the EZ, and stomata formed completely in the EZ. In contrast, most cells in the DZ were in an undifferentiated state with wrinkled cell walls and dense cytoplasm. Hormone detection revealed that the levels of gibberellin, auxin, cytokinin, and brassinosteroid were higher in the DZ than in the EZ. However, the levels of salicylic acid and jasmonic acid were higher in the EZ than in the DZ. Transcriptome analysis with qRT-PCR quantification revealed that the transcripts for cell division and primary metabolism had higher expression in the DZ, whereas the genes for photosynthesis, cell wall growth, and secondary metabolism were dramatically upregulated in the EZ. Overexpression of a MYB transcription factor, BmMYB83, promotes cell wall lignification in transgenic plants. BmMYB83 is specifically expressed in cells that may have lignin deposits, such as protoxylem vessels and fiber cells. Our results indicate that hormone gradient and transcriptome reprogramming, as well as specific expression of key genes such as BmMYB83, may lead to differentiation of cell growth in the bamboo internode.