ET Signaling Research Articles

Identification and Characterization of High-Molecular-Weight Proteins Secreted by Plasmodiophora brassicae That Suppress Plant Immunity.

Plasmodiophora brassicae is an obligate intracellular parasitic protist that causes clubroot disease on cruciferous plants. So far, some low-molecular-weight secreted proteins from P. brassicae have been reported to play an important role in plant immunity regulation, but there are few reports on its high-molecular-weight secreted proteins. In this study, 35 putative high-molecular-weight secreted proteins (>300 amino acids) of P. brassicae (PbHMWSP) genes that are highly expressed during the infection stage were identified using transcriptome analysis and bioinformatics prediction. Then, the secretory activity of 30 putative PbHMWSPs was confirmed using the yeast signal sequence trap system. Furthermore, the genes encoding 24 PbHMWSPs were successfully cloned and their functions in plant immunity were studied. The results showed that ten PbHMWSPs could inhibit flg22-induced reactive oxygen burst, and ten PbHMWSPs significantly inhibited the expression of the SA signaling pathway marker gene PR1a. In addition, nine PbHMWSPs could inhibit the expression of a marker gene of the JA signaling pathway. Therefore, a total of 19 of the 24 tested PbHMWSPs played roles in suppressing the immune response of plants. Of these, it is worth noting that PbHMWSP34 can inhibit the expression of JA, ET, and several SA signaling pathway marker genes. The present study is the first to report the function of the high-molecular-weight secreted proteins of P. brassicae in plant immunity, which will enrich the theory of interaction mechanisms between the pathogens and plants.

Endothelin-1 Correlates with Blood Pressure and Pulse Pressure in Females with Lupus Associated Hypertension

Systemic Lupus Erythematosus (SLE) is a common autoimmune disease that is classified by IgG complex deposition in end organs including the kidney, heart, and vasculature. SLE disproportionally affects women to men (9:1 ratio), with a high prevalence in African American women. Importantly, patients with an SLE diagnosis have common cardiovascular complications including hypertension. Importantly, numerous studies have reported that plasma and urinary endothelin-1 (ET-1) levels are elevated in patients with SLE or hypertension. However, few studies have investigated the role of the synergistic effects of SLE and hypertension on ET-1. Therefore, we hypothesized that women with SLE and hypertension would have elevated plasma ET-1 levels compared to SLE or hypertension alone. To investigate this, we recruited non-SLE non-HTN controls (n=8), non-SLE HTN (n=7), SLE non-HTN (n=5), and SLE-HTN (n=6) female human subjects and analyzed clinical and demographic characteristics, plasma ET-1, c-reactive protein (CRP), soluble vascular adhesion molecule-1 (sVCAM-1), and anti-Smith autoantibodies. We found that plasma ET-1 levels are significantly higher in African American compared to European American patients independent of SLE or blood pressure status (p=0.0182). When plasma ET-1 levels were correlated with age and body mass index (BMI), ET-1 had a positive association with age (r=0.4861;p=0.0118), but no correlation with BMI (r=0.2137;p=0.2945). When subjects we characterized by SLE diagnosis, we found that female subjects with SLE had elevated plasma ET-1 levels compared to non-SLE controls (p=0.0141). Next, we stratified subjects by blood pressure status and found that only SLE-HTN subjects had significantly elevated plasma ET-1 levels compared to non-SLE non-HTN controls (p=0.0005), and a trend for elevated ET-1 levels over SLE non-HTN (p=0.0799). Lastly, we correlated plasma ET-1 levels to offce systolic blood pressure, diastolic blood pressure and calculated pulse pressure. We found that plasma ET-1 positively associated with systolic blood pressure (r=0.5621;p=0.0035) and pulse pressure (r=0.5810;p=0.0023) but not diastolic blood pressure (r=0.3177;p=0.1217). These data demonstrate that plasma ET-1 levels associate with SLE diagnosis and blood pressure status in our cohort of female SLE human subjects. Further investigation of ET signaling should be done in SLE and SLE-HTN human subjects. Veterans Affairs Biomedical Laboratory Research & Development Career Development Award (CDA-2) 1IK2BX005605-01 to J.P.V.B, Medical University of South Carolina College of Medicine Program Project Grant to J.C.O and J.P.V.B., and Medical University of South Carolina Core Centers for Clinical Research Project Award P30AR072582 to M.A.C and J.P.V.B. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Tomato CYP94C1 inactivates bioactive JA-Ile to attenuate jasmonate-mediated defense during fruit ripening

As the master regulators of the ET signaling pathway, EIL transcription factors directly activate the expression of CYP94C1 to inactivate bioactive JA-Ile, thereby attenuating JA-mediated defense during fruit ripening. Knockout of CYP94C1 improves tomato fruit resistance to necrotrophs without compromising fruit quality.

Comparative transcriptome analysis highlights resistance regulatory networks of maize in response to Exserohilum turcicum infection at the early stage.

Northern corn leaf blight, caused by Exserohilum turcicum (E. turcicum), is one of the most destructive diseases in maize, leading to serious yield losses. However, the underlying molecular mechanisms of E. turcicum infection response in maize remain unclear. In this study, we performed comparative transcriptome analysis in resistant maize inbred line J9D207 (R) and susceptible maize inbred line PH4CV (S) after infecting with E. turcicum at 0 h, 24 h and 72 h, respectively. Compared with 0 h, 9656 (24 h) and 8748 (72 h) differentially expressed genes (DEGs) were identified in J9D207, and 7915 (24 h) and 7865 (72 h) DEGs were identified in PH4CV. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that alpha-linolenic acid metabolism, benzoxazinoid biosynthesis, flavonoid biosynthesis and phenylpropanoid biosynthesis might be involved in maize defense reactions. Some DEGs coded for transcription factors, such as MYB-related, ERF, NAC, bZIP, bHLH and WRKY families, which indicated that they may participate in resistance against E. turcicum. In addition, DEGs involved in SA, JA, ABA and ET signaling pathways were revealed. Moreover, 75 SOD activity-related genes and 421 POD activity-related genes were identified through weighted gene co-expression network analysis (WGCNA), respectively. These results provide a novel insight into the resistance mechanism of maize in response to E. turcicum inoculation.

Abstract C006: Identifying aggressive prostate cancer variants toward reducing cancer disparities

Abstract Background: Prostate cancer (PrCa) has a more detrimental impact on Black men than on men from other races, owing to factors such as limited screening, inadequate treatment received, low involvement in clinical research, and a history of unfair treatment in the healthcare system, among others. Patients with PrCa have a dismal prognosis and are often detected using biomarkers like the prostate-specific antigen (PSA) test and tumor staging. In localized PrCa, there are not enough biomarkers for diagnosis and prognosis. Genomic databases, such as the cBioPortal, may be utilized to conduct studies, evaluate information, discuss findings, and forecast next-generation solutions for effectively combating the increasing prevalence and mortality rates of PrCa. Method: The cBioPortal, containing around 10,366 samples from 22 studies, was explored to identify genomic alterations in genes. We filtered through the datasets and chose prostate adenocarcinoma (MSK, Clin Cancer Res. 2022) and race differences in prostate cancer (MSK, 2021). A total of 3,486 PrCa patients were included in our study but used 1,809 patients. Whereas 1,677 patients were eliminated due to sample types ("not available” NA), race (only black (n= 152) and white (n= 1,657) were included), and sex (males). Primary prostate cancers (n = 994) and metastatic prostate cancers (n = 815) were the two categories of PrCa samples studied. After merging the query results from the two datasets, we identified and estimated the numbers and percentages of overall gene alterations and individual categories of gene alterations. Results: We calculated the prevalence of reported alterations (i.e., mutations, copy number alterations (CNAs), and structural variants) in 10 genes: FOXA1 (AR pathway), TP53, ERG, TMPRSS2 (ETS signaling), PTEN (PI3K-AKT-mTOR signaling), CDK12, KMT2C and BRCA2 (DNA damage repair), SPOP, and MYC (down-regulated by androgen). MYC, FOXA1, SPOP, CDK12, KMT2C, and AR exhibit higher overexpression frequencies in black males than in white men in the profiled samples (P < 0.05). MYC overexpression was observed to be more prevalent in PrCa samples from black patients than samples from white patients, and statistical significance was achieved (9.2% vs 5.6%, p < 0.05). Similarly, black patients had higher levels of PTEN expression than white patients, albeit statistical significance was not achieved (24.0% vs 14.5%, p = 0.08). FOXA1 overexpression is higher in blacks than whites (17.7% vs 15.5%, p = 0.27). CDK12 and KMT2C genomic alterations are more prevalent in black patients than in white patients (60.8% vs 29.8%; 9.9% vs 5.7%, p < 0.05). Using the chi-square (for the racial category and smoking status) and Wilcoxon (for age at diagnosis) statistical tests, clinical factors varied significantly (p<0.001). Conclusion: It is important to understand the genetic underpinnings of disparities in prostate cancer. Our findings support a modest association between genomic alterations in PrCa genes and differential expression by race. Citation Format: Olumide Arigbede, Opeyemi Ogungbola, Sarah Buxbaum, Sara Falzarano, Suhn Rhie. Identifying aggressive prostate cancer variants toward reducing cancer disparities [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C006.

Abstract P125: Tissue Specific Regulation Of The Cardiac And Renal Endothelin System In A Lupus-prone Mouse Model

Systemic Lupus Erythematosus (SLE), the most common form of lupus autoimmune disease, disproportionally affects women (9:1) with high prevalence in African Americans. Numerous studies report elevated endothelin-1 (ET-1) in the plasma of patients with lupus and demonstrate increased ET-1 contribution to various pathological cardiovascular complications including hypertension, cardiac hypertrophy, and heart failure in lupus patients. However, few studies explored the relative roles and regulation of the cardiac and renal ET systems in lupus-associated cardiovascular complications. We hypothesized that immune modulation and acceleration of lupus by a toll-like receptor 7/8 agonist, Resiquimod, would lead to tissue-specific regulation of the ET system in both the kidney and heart in lupus-prone mice. To investigate this, female lupus-prone B6.Nba2 mice were subjected to bi-weekly treatment with the Resiquimod (R848; 100ug/30ul; n=4) or vehicle control (Acetone; n=5) for one month and subsequently studied for 12 weeks. At 16 weeks post-treatment (30 weeks old), heart and kidneys were collected, and the ET system was analyzed by RT-PCR, immunoblotting, and immunohistochemistry. R848 treatment significantly increased cardiac but not kidney expression of ET-1 (19.90 ± 1.36 vs. 7.65 ± 0.54 pg/mg; p=0.02 compared to controls (6.10 ± 1.64 vs. 4.95 ± 0.55 pg/mg; p>0.05). Furthermore, R848 treated mice had no significant effect on cardiac endothelin receptor A (ET A ) nor endothelin receptor B (ET B ) expression at both the RNA and protein levels (p>0.05 for all). Interestingly, renal ET B RNA expression was reduced (0.08 vs. 1.62; p <0.05), while ET A expression was unchanged (p > 0.05) with R848. The same trend was observed at the protein level by immunoblotting and immunohistochemistry (p>0.05) Our results provide evidence that lupus acceleration with TLR7/8 activation in B6.Nba2 mice differentially regulates tissue-specific ET systems in the heart and kidney, potentially contributing to the tissue specific dysfunction found in lupus. These findings suggest that our model offers an opportunity to identify cardiac and renal contributions to lupus complications, and specifically determine the cell-specific regulation of ET biosynthesis and signaling.

Ethylene enhanced waterlogging tolerance by changing root architecture and inducing aerenchyma formation in maize seedlings

Waterlogging negatively affects maize growth and yield. In this study, we found that ethylene played a vital role in plant adaptation to waterlogging. ET promotes better growth in seedlings under waterlogging conditions by altering root architecture and increasing lateral root formation by 42.1%. What's more, plants with high endogenous ethylene levels exhibited reduced sensitivity to waterlogging stress. ET also induced the formation of aerenchyma, a specialized tissue that facilitates gas exchange, in a different pattern compared to aerenchyma formed under waterlogging. Aerenchyma induced by ET was mainly located in the medial cortex of the roots and was not prone to decay. ethylene inhibited root elongation under normal conditions, but this inhibition was not alleviated under waterlogging stress. Upon activation of the ET signaling pathway, the transcription factor EREB90 promoted aerenchyma formation by enhancing the programmed cell death process. Overexpression of EREB90 resulted in increased waterlogging tolerance compared to wild type plants. Our findings suggest that pre-treatment of maize seedlings with ET before waterlogging stress can trigger the programmed cell death process and induce aerenchyma formation, thus improving waterlogging resistance.

Comparative transcriptome analysis reveals key genes and pathways in response to Alternaria alternata apple pathotype infection

Apple leaf spot, caused by the Alternaria alternata apple pathotype (AAAP), is an important fungal disease of apple. To understand the molecular basis of resistance and pathogenesis in apple leaf spot, the transcriptomes of two apple cultivars ‘Hanfu’ (HF) (resistant) and ‘Golden Delicious’(GD) (susceptible) were analyzed at 0, 6, 18, 24 and 48 h after AAAP inoculation by RNA-Seq. At each time point, a large number of significantly differentially expressed genes (DEGs) were screened between AAAP-inoculated and uninoculated apple leaves. Analysis of the common DEGs at four time points revealed significant differences in the resistance of ‘HF’ and ‘GD’ apple to AAAP infection. RLP, RNL, and JA signal-related genes were upregulated in both cultivars to restrict AAAP development. However, genes encoding CNLs, TNLs, WRKYs, and AP2s were only activated in ‘HF’ as part of the resistance response, of which, some play major roles in the regulation of ET and SA signal transduction. Further analysis showed that many DEGs with opposite expression trends in the two hosts may play important regulatory roles in response to AAAP infection. Transient expression of one such gene MdERF110 in ‘GD’ apple leaves improved AAAP resistance. Collectively, this study highlights the reasons for differential resistance to AAAP infection between ‘HF’ and ‘GD’ apples which can theoretically assist the molecular breeding of disease-resistant apple crops.

Transcriptomic and physiological analysis reveals the possible mechanism of ultrasound inhibiting strawberry (Fragaria × ananassa Duch.) postharvest softening.

Ultrasound effectively inhibited strawberry softening but the mechanism was not clear. In this study, physical data including firmness, soluble pectin (SP) contents, pectin esterase (PE), polygalacturonase (PG) activity and transcriptome sequencing data were analyzed to explore the mechanism of strawberry response to ultrasonic treatment. After 24 days storage, the firmness reduction rate and soluble contents (SP) increased rate of the strawberry treated with ultrasound (25 kHz, 0.15 W/cm2) for 3 min decreased 41.70 and 63.12% compared with the control, respectively. While the PG and PE enzyme activities of ultrasound-treated strawberries were significantly lower than control after storage for 18 days. A total of 1,905 diferentially expressed genes (DEGs) were identified between ultrasound-treated and control, with 714 genes upregulated and 1,254 genes downregulated, including 56 genes in reactive oxygen species (ROS), auxin (AUX), ethylene (ETH) and jasmonic acid (JA) signaling pathways. At 0 h, 15 genes including LOX, JMT, ARP, SKP, SAUR, IAA, ARF, and LAX were significantly upregulated compared with the control group, which means reactive oxygen specie, auxin, ethylene and jasmonic acid-mediated signaling pathway respond to ultrasound immediately. ERF109, ERF110, and ACS1_2_6 downregulated before 2 days storage indicated ethylene signaling pathway was inhibited, while after 2 days, 9 genes including ERF027, ERF109, and ERF110 were significantly upregulated indicating that the response of the ethylene signaling pathway was lagging. Therefore, in strawberry ultrasound enhanced ROS scavenging and activated JA biosynthesis, which acts as a signal for delaying the activation of ET signaling pathway, thus suppressing the activity of pectin-degrading enzymes PE and PG, and ultimately inhibiting postharvest softening.

Coordinately regulated transcription factors EIN3/EIL1 and MYCs in ethylene and jasmonate signaling interact with the same domain of MED25.

Ethylene (ET) and jasmonate (JA) are plant hormones that act synergistically to regulate plant development and defense against necrotrophic fungi infections, and antagonistically in response to wounds and apical hook formation. Previous studies revealed that the coordination of these responses is due to dynamic protein-protein interactions (PPI) between their master transcription factors (TFs) EIN3/EIL1 and MYC in ET and JA signaling, respectively. In addition, both TFs are activated via interactions with the same transcriptional mediator MED25, which upregulates downstream gene expression. Herein, we analyzed the PPI between EIN3/EIL1 and MED25, and as with the PPI between MYC3 and MED25, found that the short binding domain of MED25 (CMIDM) is also responsible for the interaction with EIN3/EIL1-a finding which suggests that both TFs compete for binding with MED25. These results further inform our understanding of the coordination between the ET and JA regulatory systems.

Immunomodulatory Molecular Mechanisms of Luffa cylindrica for Downy Mildews Resistance Induced by Growth-Promoting Endophytic Fungi.

Downy mildew (DM), caused by P. cubensis, is harmful to cucurbits including luffa, with increased shortcomings associated with its control through cultural practices, chemical fungicides, and resistant cultivars; there is a prompt need for an effective, eco-friendly, economical, and safe biocontrol approach. Current research is therefore dealt with the biocontrol of luffa DM1 through the endophytic fungi (EF) consortium. Results revealed that T. harzianum (ThM9) and T. virens (TvA1) showed pathogen-dependent inducible metabolic production of squalene and gliotoxins by higher gene expression induction of SQS1/ERG9 (squalene synthase) and GliP (non-ribosomal peptide synthetase). Gene expression of lytic enzymes of EF was also induced with subsequently higher enzyme activities upon confrontation with P. cubensis. EF-inoculated luffa seeds showed efficient germination with enhanced growth potential and vigor of seedlings. EF-inoculated plants showed an increased level of growth-promoting hormone GA with higher gene expression of GA2OX8. EF-pre-inoculated seedlings were resistant to DM and showed an increased GSH content and antioxidant enzyme activities (SOD, CAT, POD). The level of MDA, H2O2, REL, and disease severity was reduced by EF. ACC, JA, ABA, and SA were overproduced along with higher gene expression of LOX, ERF, NCED2, and PAL. Expression of defense-marker genes (PPO, CAT2, SOD, APX, PER5, LOX, NBS-LRR, PSY, CAS, Ubi, MLP43) was also modulated in EF-inoculated infected plants. Current research supported the use of EF inoculation to effectively escalate the systemic immunity against DM corresponding to the significant promotion of induced systemic resistance (ISR) and systemic acquired resistance (SAR) responses through initiating the defense mechanism by SA, ABA, ET, and JA biosynthesis and signaling pathways in luffa.

Arabinogalactan Protein-Like Proteins From Ulva lactuca Activate Immune Responses and Plant Resistance in an Oilseed Crop.

Natural compounds isolated from macroalgae are promising, ecofriendly, and multifunctional bioinoculants, which have been tested and used in agriculture. Ulvans, for instance, one of the major polysaccharides present in Ulva spp. cell walls, have been tested for their plant growth-promoting properties as well as their ability to activate plant immune defense, on a large variety of crops. Recently, we have characterized for the first time an arabinogalactan protein-like (AGP-like) from Ulva lactuca, which exhibits several features associated to land plant AGPs. In land plant, AGPs were shown to play a role in several plant biological functions, including cell morphogenesis, reproduction, and plant-microbe interactions. Thus, isolated AGP-like proteins may be good candidates for either the plant growth-promoting properties or the activation of plant immune defense. Here, we have isolated an AGP-like enriched fraction from Ulva lactuca and we have evaluated its ability to (i) protect oilseed rape (Brassica napus) cotyledons against Leptosphaeria maculans, and (ii) its ability to activate immune responses. Preventive application of the Ulva AGP-like enriched fraction on oilseed rape, followed by cotyledon inoculation with the fungal hemibiotroph L. maculans, resulted in a major reduction of infection propagation. The noticed reduction correlated with an accumulation of H2O2 in treated cotyledons and with the activation of SA and ET signaling pathways in oilseed rape cotyledons. In parallel, an ulvan was also isolated from Ulva lactuca. Preventive application of ulvan also enhanced plant resistance against L. maculans. Surprisingly, reduction of infection severity was only observed at high concentration of ulvan. Here, no such significant changes in gene expression and H2O2 production were observed. Together, this study indicates that U. lactuca AGP-like glycoproteins exhibit promising elicitor activity and that plant eliciting properties of Ulva extract, might result not only from an ulvan-originated eliciting activities, but also AGP-like originated.

Identification and expression analysis of arabinogalactan protein genes in cotton reveal the function of GhAGP15 in Verticillium dahliae resistance

Verticillium wilt, primarily caused by the fungal pathogen Verticillium dahliae, is a serious disease in cotton. Arabinogalactan proteins (AGPs), a class of hydroxyproline-rich glycoproteins, have been widely implicated in plant growth and environmental adaptation. The purpose of this study is to identify and characterize AGP members in cotton plants and explore their roles in responding to environmental stressors. In total, 65 GhAGP members were identified in upland cotton (Gossypium hirsutum), along with 43, 35, and 37 AGP members that were also identified in G. barbadense, G. arboreum, and G. raimondii, respectively. According to gene structure and protein domains analysis, GhAGP genes in upland cotton are highly conserved. Meanwhile, tandem duplication events have occurred frequently throughout cotton’s evolutionary history. Expression analysis showed that GhAGP genes were widely expressed during growth and development and in response to abiotic stressors. Many cis-elements related to hormonal responses and environmental stressors were detected in GhAGP promoter regions. GhAGP genes participate in responding to cold, drought, and salt stress, and were sensitive to ET signaling. Furthermore, the expression level of GhAGP15 was elevated during V. dahliae infection and resistance against V. dahliae in upland cotton was significantly weakened by silencing GhAGP15 using a virus-induced gene silencing (VIGS) approach. Our results further suggest that the function of GhAGP15 in V. dahliae resistance might be involved in regulation of the JA, SA, and reactive oxygen species (ROS) pathways. The comprehensive analysis of AGP genes in cotton performed in this study provides a basic framework for further functional research of these genes.

Wheat transcriptome profiling reveals abscisic and gibberellic acid treatments regulate early-stage phytohormone defense signaling, cell wall fortification, and metabolic switches following Fusarium graminearum-challenge

BackgroundTreatment of wheat with the phytohormones abscisic acid (ABA) and gibberellic acid (GA) has been shown to affect Fusarium head blight (FHB) disease severity. However, the molecular mechanisms underlying the elicited phenotypes remain unclear. Toward addressing this gap in our knowledge, global transcriptomic profiling was applied to the FHB-susceptible wheat cultivar ‘Fielder’ to map the regulatory responses effected upon treatment with ABA, an ABA receptor antagonist (AS6), or GA in the presence or absence of Fusarium graminearum (Fg) challenge.ResultsSpike treatments resulted in a total of 30,876 differentially expressed genes (DEGs) identified in ‘Fielder’ (26,004) and the Fg (4872) pathogen. Topology overlap and correlation analyses defined 9689 wheat DEGs as Fg-related across the treatments. Further enrichment analyses demonstrated that these included expression changes within ‘Fielder’ defense responses, cell structural metabolism, molecular transport, and membrane/lipid metabolism. Dysregulation of ABA and GA crosstalk arising from repression of ‘Fielder’ FUS3 was noted. As well, expression of a putative Fg ABA-biosynthetic cytochrome P450 was detected. The co-applied condition of Fg + ABA elicited further up-regulation of phytohormone biosynthesis, as well as SA and ET signaling pathways and cell wall/polyphenolic metabolism. In contrast, co-applied Fg + GA mainly suppressed phytohormone biosynthesis and signaling, while modulating primary and secondary metabolism and flowering. Unexpectedly, co-applied Fg + AS6 did not affect ABA biosynthesis or signaling, but rather elicited antagonistic responses tied to stress, phytohormone transport, and FHB disease-related genes.ConclusionsObserved exacerbation (misregulation) of classical defense mechanisms and cell wall fortifications upon ABA treatment are consistent with its ability to promote FHB severity and its proposed role as a fungal effector. In contrast, GA was found to modulate primary and secondary metabolism, suggesting a general metabolic shift underlying its reduction in FHB severity. While AS6 did not antagonize traditional ABA pathways, its impact on host defense and Fg responses imply potential for future investigation. Overall, by comparing these findings to those previously reported for four additional plant genotypes, an additive model of the wheat-Fg interaction is proposed in the context of phytohormone responses.

Overexpression of PsoRPM3, an NBS-LRR gene isolated from myrobalan plum, confers resistance to Meloidogyne incognita in tobacco.

We reported an NBS-LRR gene, PsoRPM3, is highly expressed following RKN infection, initiating an HR response that promotes plant resistance. Meloidogyne spp. are root-knot nematodes (RKNs) that cause substantial economic losses worldwide. Screening for resistant tree resources and identifying plant resistance genes is currently the most effective way to prevent RKN infestations. Here, we cloned a novel TIR-NB-LRR-type resistance gene, PsoRPM3, from Xinjiang wild myrobalan plum (Prunus sogdiana Vassilcz.) and demonstrated that its protein product localized to the nucleus. In response to Meloidogyne incognita infection, PsoRPM3 gene expression levels were significantly higher in resistant myrobalan plum plants compared to susceptible plants. We investigated this difference, discovering that the - 309 to - 19bp region of the susceptible PsoRPM3 promoter was highly methylated. Indeed, heterologous expression of PsoRPM3 significantly enhanced the resistance of susceptible tobacco plants to M. incognita. Moreover, transient expression of PsoRPM3 induced a hypersensitive response in tobacco, whereas RNAi-mediated silencing of PsoRPM3 in transgenic tobacco reduced this hypersensitive response. Several hypersensitive response marker genes were considerably up-regulated in resistant myrobalan plum plants when compared with susceptible counterparts inoculated with M. incognita. PsoPR1a (a SA marker gene), PsoPR2 (a JA marker gene), and PsoACS6 (an ET signaling marker gene) were all more highly expressed in resistant than in susceptible plants. Together, these results support a model in which PsoRPM3 is highly expressed following RKN infection, initiating an HR response that promotes plant resistance through activated salicylic acid, jasmonic acid, and ethylene signaling pathways.

Redox Status, JA and ET Signaling Pathway Regulating Responses to Botrytis cinerea Infection Between the Resistant Cucumber Genotype and Its Susceptible Mutant.

Botrytis cinerea is an important necrotrophic fungal pathogen with a broad host range and the ability to causing great economic losses in cucumber. However, the resistance mechanism against this pathogen in cucumber was not well understood. In this study, the microscopic observation of the spore growth, redox status measurements and transcriptome analysis were carried out after Botrytis cinerea infection in the resistant genotype No.26 and its susceptible mutant 26M. Results revealed shorter hypha, lower rate of spore germination, less acceleration of H2O2, O2 -, and lower total glutathione content (GSH+GSSG) in No.26 than that in 26M, which were identified by the staining result of DAB and NBT. Transcriptome data showed that after pathogen infection, a total of 3901 and 789 different expression genes (DEGs) were identified in No.26 and 26M respectively. These DEGs were highly enriched in redox regulation pathway, hormone signaling pathway and plant-pathogen interaction pathway. The glutathione S-transferase genes, putative peroxidase gene, and NADPH oxidase were up-regulated in No.26 whereas these genes changed little in 26M after Botrytis cinerea infection. Jasmonic acid and ethylene biosynthesis and signaling pathways were distinctively activated in No.26 comparing with 26M upon infection. Much more plant defense related genes including mitogen-activated protein kinases, calmodulin, calmodulin-like protein, calcium-dependent protein kinase, and WRKY transcription factor were induced in No.26 than 26M after pathogen infection. Finally, a model was established which elucidated the resistance difference between resistant cucumber genotype and susceptible mutant after B. cinerea infection.

A transcriptional response atlas of Chrysanthemum morifolium to dodder invasion

Chrysanthemum (Chrysanthemum morifolium), as one of the most commercially important ornamental crops, is threatened by dodder (Cuscuta spp.) during cultivation. When chrysanthemum was parasitized by dodder, growth of chrysanthemum slowed down and the leaves became dry and yellow. In the study, RNA sequencing assays were used for elucidating the immune response of chrysanthemum after dodder invasion and a total of 20,789 genes were differentially expressed. KEGG enrichment analysis revealed that these differentially expressed genes were involved in multiple pathways, “plant hormone signal transduction”, “cutin, suberine and wax biosynthesis”, and “plant-pathogen interaction”, etc. Combined with weighted gene co-expression network analysis (hereafter named WGCNA), we found that when the vascular connections were formed through haustoria, chrysanthemum recognized and fended off pathogens by the two stages of plant immune systems (PTI and ETI). Membrane bound receptors RLKs and the intracellular NLR proteins perceived pathogen-derived proteins and delivered the defense signals to trigger a series of defense responses in chrysanthemum. Reactive oxygen species (ROS), calcium, and MAPK-related pathways were triggered and a series of defense genes were up‐regulated. Besides, in stems of chrysanthemum, ET and SA signal transduction pathways played vital roles and had strong regulatory relationship with each other in response to dodder invasion. Our study provides an understanding of how chrysanthemum responds to dodder’s invasion, which could lay the basis for further revealing the interaction mechanism between chrysanthemum and dodder.

First SETI Observations with China’s Five-hundred-meter Aperture Spherical Radio Telescope (FAST)

Abstract The Search for Extraterrestrial Intelligence (SETI) attempts to address the possibility of the presence of technological civilizations beyond the Earth. Benefiting from high sensitivity, large sky coverage, and an innovative feed cabin for China’s Five-hundred-meter Aperture Spherical radio Telescope (FAST), we performed SETI’s first observations with FAST’s newly commissioned 19 beam receiver; we report preliminary results in this paper. Using the data stream produced by the SERENDIP VI real-time multibeam SETI spectrometer installed at FAST, as well as its off-line data processing pipelines, we identify and remove four kinds of radio frequency interference (RFI): zone, broadband, multibeam, and drifting, utilizing the Nebula SETI software pipeline combined with machine-learning algorithms. After RFI mitigation, the Nebula pipeline identifies and ranks interesting narrowband candidate ET signals, scoring candidates by the number of times candidate signals have been seen at roughly the same sky position and same frequency, signal strength, proximity to a nearby star or object of interest, along with several other scoring criteria. We show four example candidate groups that demonstrate this RFI mitigation and candidate selection. This preliminary testing on FAST data helps to validate our SETI instrumentation techniques as well as our data processing pipeline.

Identification of the targets of HbEIN3/EILs in genomic wide in Hevea brasiliensis.

EIN3/EILs are key regulators in ET signaling pathway. In this work, 4 members of EIN3/EILs of Hevea brasiliensis (HbEIN3/EILs) showed interaction with two F box proteins, HbEBF1 and HbEBF2. HbEIN3 located in nucleus and exhibited strong transcriptional activity. HbEIN3 was induced by ET treatment in C-serum, but not in B-serum of latex. HbEIN3/EILs bound to G-box cis-element. To globally search the potential targets of HbEIN3/EILs, genomic sequences of H. brasiliensis was re-annotated and an HCES (Hevea Cis-Elements Scanning) program was developed ( www.h-brasiliensis.com ). HCES scanning results showed that ET- and JA- responsive cis-elements distribute overlapping in gene promoters. 3146 genes containing G-box in promoters are potential targets of HbEIN3, including 41 genes involved in biosynthesis and drainage of latex, of which 7 rate-limiting genes of latex production were regulated by both ET and JA, suggesting that ET and JA signaling pathways coordinated the latex biosynthesis and drainage in H. brasiliensis. Abbreviations: ABRE: ABA responsive elements; bHLH: basic helix-loop-helix; COG: Orthologous Groups; DRE: dehydration response element; ERE: ethylene responsive element; ET: Ethylene; GO: Gene Ontology; HCES: Hevea Cis-Elements Scanning; JA: jasmonates; JRE: Jasmonate-responsive element; KEGG: Kyoto Encyclopedia of Genes and Genomes; NR: non-redundant database; PLACE: Plant Cis-acting Regulatory DNA Elements; qRT-PCR: quantitative real-time RT-PCR.

Androgen upregulates NR4A1 via the TFAP2A and ETS signaling networks.

Hyperandrogenism is one of the clinical and biochemical characteristics of polycystic ovary syndrome (PCOS). Our previous studies confirmed that nuclear receptor subfamily 4 group A member 1 (NR4A1), as a differentially expressed gene in the ovaries of PCOS patients, was upregulated by increased androgen. However, the potential mechanism of NR4A1 upregulation remains unknown. To elucidate the molecular mechanisms involved in NR4A1 regulation, we cloned and characterized the promoter regions of the NR4A1 gene using a series of truncated promoter plasmids in luciferase reporter assays. We identified two unique core promoters of NR4A1 located within the +1055/+1251 and +3183/+3233 regions relative to the transcription start site. TFAP2A downregulated NR4A1 expression, while five ETS transcription factors, ETS1, ELK1, ERG, FLI1 and SPI1, could upregulate NR4A1 promoter activity in HeLa cells. Of these transcription factors, ETS1 and ELK1 were the most effective ones. Moreover, all six transcription factors were confirmed to interact directly with the NR4A1 promoter. In conclusion, this study presents the first description that TFAP2A and ETS family signaling networks are involved in the androgen-mediated transcriptional regulation of NR4A1, which contributes to the understanding of the molecular mechanisms involved in the TFAP2A-NR4A1 and ETS-NR4A1 signaling networks in PCOS.