A Diketopiperazine, Cyclo-(L-Pro-L-Ile), Derived From Bacillus thuringiensis JCK-1233 Controls Pine Wilt Disease by Elicitation of Moderate Hypersensitive Reaction. - Related Documents




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1201.0000A Diketopiperazine, Cyclo-(L-Pro-L-Ile), Derived From Bacillus thuringiensis JCK-1233 Controls Pine Wilt Disease by Elicitation of Moderate Hypersensitive Reaction. Pine wilt disease (PWD) caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus is one of the devastating diseases affecting pine forests worldwide. Although effective control measurements are still missing, induction of resistance could represent a possible eco-friendly alternative. In this study, induced resistance-based in vitro and in vivo screening tests were carried out for selection of bacteria with the ability to suppress PWD. Out of 504 isolated bacteria, Bacillus thuringiensis JCK-1233 was selected for its ability to boost pathogenesis-related 1 (PR1) gene expression, a marker of systemic acquired resistance. Moreover, treatment of pine seedlings with B. thuringiensis JCK-1233 resulted in increased expression of other defense-related genes, and significantly inhibited PWD development under greenhouse conditions. However, B. thuringiensis JCK-1233 showed no direct nematicidal activity against B. xylophilus. To identify the effective compound responsible for the induction of resistance in B. thuringiensis JCK-1233, several diketopiperazines (DPKs) including cyclo-(D-Pro-L-Val), cyclo-(L-Pro-L-Ile), cyclo-(L-Pro-L-Phe), and cyclo-(L-Leu-L-Val) were isolated and tested. Foliar treatment of pine seedlings with Cyclo-(L-Pro-L-Ile) resulted in suppression of PWD severity and increased the expression of defense-related genes similarly to B. thuringiensis JCK-1233 treatment. Interestingly, treatment with B. thuringiensis JCK-1233 or cyclo-(L-Pro-L-Ile) showed moderately enhanced expression of PR-1, PR-2, PR-3, PR-4, PR-5, and PR-9 genes following inoculation with PWN compared to that in the untreated control, indicating that they mitigated the burst of hypersensitive reaction in susceptible pine seedlings. In contrast, they significantly increased the expression levels of PR-6 and PR-10 before PWN inoculation. In conclusion, foliar spraying with either B. thuringiensis JCK-1233 culture suspension or DPKs could induce resistance in pine seedlings, thereby alleviating the serious damage by PWD. Taken together, this study supports aerial spraying with eco-friendly biotic or abiotic agents as a valuable strategy that may mark an epoch for the control of PWD in pine forests.202032849672
878210.9980Antagonistic bacterium Bacillus amyloliquefaciens induces resistance and controls the bacterial wilt of tomato. BACKGROUND: Bacterial wilt caused by Ralstonia solanacearum (RS) is a serious threat for agricultural production. In this study, Bacillus amyloliquefaciens strains CM-2 and T-5 antagonistic to RS were used to create bioorganic fertilisers to control tomato wilt under greenhouse conditions. The possible mechanism of resistance inducement by the antagonistic bacteria was also evaluated. RESULTS: The application of bioorganic fertilisers significantly reduced incidences of tomato wilt (by 63-74%), promoted plant growth and significantly reduced the RS populations in rhizosphere compared with the control. Both strains CM-2 and T-5 applied with bioorganic fertilisers survived well in the tomato rhizosphere. Tomato seedlings treated with cell suspension of T-5 followed by challenge inoculation with RS increased the activities of polyphenol oxidase, phenylalanine ammonia lyase and peroxidase compared with the untreated control. Furthermore, the expressions of the marker genes responsible for synthesis of phytohormones salicylic acid, ethylene and jasmonic acid in seedlings treated with T-5 in response to inoculated pathogen were significantly higher. CONCLUSIONS: This study suggests that strains CM-2 and T-5 containing bioorganic fertilisers effectively control tomato wilt. Increased enzyme activities and expression of defence genes in plants indicated that the antagonistic bacteria induced plant resistance, which was the potential biocontrol mechanism of tomato wilt.201323519834
1320.9980Streptomyces sp. JCK-6131 Protects Plants Against Bacterial and Fungal Diseases via Two Mechanisms. Plant bacterial and fungal diseases cause significant agricultural losses and need to be controlled. Beneficial bacteria are promising candidates for controlling these diseases. In this study, Streptomyces sp. JCK-6131 exhibited broad-spectrum antagonistic activity against various phytopathogenic bacteria and fungi. In vitro assays showed that the fermentation filtrate of JCK-6131 inhibited the growth of bacteria and fungi with minimum concentration inhibitory (MIC) values of 0.31-10% and 0.31-1.25%, respectively. In the in vivo experiments, treatment with JCK-6131 effectively suppressed the development of apple fire blight, tomato bacterial wilt, and cucumber Fusarium wilt in a dose-dependent manner. RP-HPLC and ESI-MS/MS analyses indicated that JCK-6131 can produce several antimicrobial compounds, three of which were identified as streptothricin E acid, streptothricin D, and 12-carbamoyl streptothricin D. In addition, the disease control efficacy of the foliar application of JCK-6131 against tomato bacterial wilt was similar to that of the soil drench application, indicating that JCK-6131 could enhance defense resistance in plants. Molecular studies on tomato plants showed that JCK-6131 treatment induced the expression of the pathogenesis-related (PR) genes PR1, PR3, PR5, and PR12, suggesting the simultaneous activation of the salicylate (SA) and jasmonate (JA) signaling pathways. The transcription levels of PR genes increased earlier and were higher in treated plants than in untreated plants following Ralstonia solanacearum infection. These results indicate that Streptomyces sp. JCK-6131 can effectively control various plant bacterial and fungal diseases via two distinct mechanisms of antibiosis and induced resistance.202134603354
1430.9977Unraveling Pinus massoniana's Defense Mechanisms Against Bursaphelenchus xylophilus Under Aseptic Conditions: A Transcriptomic Analysis. Pine wilt disease (PWD) is caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus) and significantly impacts pine forest ecosystems globally. This study focuses on Pinus massoniana, an important timber and oleoresin resource in China, which is highly susceptible to PWN. However, the defense mechanism of pine trees in response to PWN remains unclear. Addressing the complexities of PWD, influenced by diverse factors such as bacteria, fungi, and environment, we established a reciprocal system between PWN and P. massoniana seedlings under aseptic conditions. Utilizing combined second- and third-generation sequencing technologies, we identified 3,718 differentially expressed genes post PWN infection. Transcript analysis highlighted the activation of defense mechanisms via stilbenes, salicylic acid and jasmonic acid pathways, terpene synthesis, and induction of pathogenesis-related proteins and resistance genes, predominantly at 72 h postinfection. Notably, terpene synthesis pathways, particularly the mevalonate pathway, were crucial in defense, suggesting their significance in P. massoniana's response to PWN. This comprehensive transcriptome profiling offers insights into P. massoniana's intricate defense strategies against PWN under aseptic conditions, laying a foundation for future functional analyses of key resistance genes. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.202439283201
878540.9975Mechanism of resistance to Cucumber mosaic virus elicited by inoculation with Bacillus subtilis subsp. subtilis. BACKGROUND: Systemic resistance stimulated by rhizosphere bacteria is an important strategy for the management of plant viruses. The efficacy of Bacillus subtilis subsp. subtilis was assessed for protection of cucumber and Arabidopsis against Cucumber mosaic virus (CMV). Moreover, transcriptomic analysis was carried out for A. thaliana colonized with B. subtilis subsp. subtilis and infected with CMV. RESULTS: Treatment with a cell suspension of Bacillus revealed a significant reduction of CMV severity in comparison to their control. All Arabidopsis mutants treated with B. subtilis showed a clear reduction in CMV accumulation. Disease severity data and virus concentration titer measurements correlated with gene up-regulation in microarray and reverse transcription quantitative polymerase chain reaction (RT-qPCR) experiments. Bacillus treatment increased Arabidopsis growth characteristics (fresh and dry weights and number of leaflets) under pot conditions. The molecular mechanisms by which Bacillus activated resistance to CMV were investigated. Using the microarray hybridization technique, we were able to determine the mechanism of resistance elicited by B. subtilis against CMV. The transcriptomic analysis confirmed the up-regulation of more than 250 defense-related genes in Arabidopsis expressing induced systemic resistance (ISR). RT-qPCR results validated the overexpression of defense genes (YLS9 and PR1 in Arabidopsis and PR1 and LOX in cucumber), implying their important roles in the stimulated defense response. CONCLUSION: Through the study of microarray and RT-qPCR analyses, it can be concluded that the overexpression of pathogenesis-related genes was necessary to stimulate CMV defense in cucumber and Arabidopsis by B. subtilis subsp. subtilis. © 2021 Society of Chemical Industry.202234437749
1850.9975Antivirulence effects of cell-free culture supernatant of endophytic bacteria against grapevine crown gall agent, Agrobacterium tumefaciens, and induction of defense responses in plantlets via intact bacterial cells. BACKGROUND: Crown gall disease caused by Agrobacterium tumefaciens is a very destructive affliction that affects grapevines. Endophytic bacteria have been discovered to control plant diseases via the use of several mechanisms. This research examined the potential for controlling crown gall by three endophytic bacteria that were previously isolated from healthy cultivated and wild grapevines including Pseudomonas kilonensis Ba35, Pseudomonas chlororaphis Ba47, and Serratia liquefaciens Ou55. RESULT: At various degrees, three endophytic bacteria suppressed the populations of A. tumefaciens Gh1 and greatly decreased the symptoms of crown gall. Furthermore, biofilm production and motility behaviors of A. tumefaciens Gh1were greatly inhibited by the Cell-free Culture Supernatant (CFCS) of endophytic bacteria. According to our findings, CFCS may reduce the adhesion of A. tumefaciens Gh1 cells to grapevine cv. Rashe root tissues as well as their chemotaxis motility toward the extract of the roots. When compared to the untreated control, statistical analysis showed that CFCS significantly reduced the swimming, twitching, and swarming motility of A. tumefaciens Gh1. The findings demonstrated that the endophytic bacteria effectively stimulated the production of plant defensive enzymes including superoxide dismutase (SOD), polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), and total soluble phenols at different time intervals in grapevine inoculated with A. tumefaciens Gh1. The Ba47 strain markedly increased the expression levels of defense genes associated with plant resistance. The up-regulation of PR1, PR2, VvACO1, and GAD1 genes in grapevine leaves indicates the activation of SA and JA pathways, which play a role in enhancing resistance to pathogen invasion. The results showed that treating grapevine with Ba47 increased antioxidant defense activities and defense-related gene expression, which reduced oxidative damage caused by A. tumefaciens and decreased the incidence of crown gall disease. CONCLUSION: This is the first study on how A. tumefaciens, the grapevine crown gall agent, is affected by CFCS generated by endophytic bacteria in terms of growth and virulence features. To create safer plant disease management techniques, knowledge of the biocontrol processes mediated by CFCS during microbial interactions is crucial.202438336608
2260.9974A plant growth-promoting bacteria Priestia megaterium JR48 induces plant resistance to the crucifer black rot via a salicylic acid-dependent signaling pathway. Xanthomonas campestris pv. campestris (Xcc)-induced black rot is one of the most serious diseases in cruciferous plants. Using beneficial microbes to control this disease is promising. In our preliminary work, we isolated a bacterial strain (JR48) from a vegetable field. Here, we confirmed the plant-growth-promoting (PGP) effects of JR48 in planta, and identified JR48 as a Priestia megaterium strain. We found that JR48 was able to induce plant resistance to Xcc and prime plant defense responses including hydrogen peroxide (H(2)O(2)) accumulation and callose deposition with elevated expression of defense-related genes. Further, JR48 promoted lignin biosynthesis and raised accumulation of frees salicylic acid (SA) as well as expression of pathogenesis-related (PR) genes. Finally, we confirmed that JR48-induced plant resistance and defense responses requires SA signaling pathway. Together, our results revealed that JR48 promotes plant growth and induces plant resistance to the crucifer black rot probably through reinforcing SA accumulation and response, highlighting its potential as a novel biocontrol agent in the future.202236438094
872770.9974Transcriptome Analysis of Rice Near-Isogenic Lines Inoculated with Two Strains of Xanthomonas oryzae pv. oryzae, AH28 and PXO99(A). Rice bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is a major threat to rice production and food security. Exploring new resistance genes and developing varieties with broad-spectrum and high resistance has been a key focus in rice disease resistance research. In a preliminary study, rice cultivar Fan3, exhibiting high resistance to PXO99(A) and susceptibility to AH28, was developed by enhancing the resistance of Yuehesimiao (YHSM) to BB. This study performed a transcriptome analysis on the leaves of Fan3 and YHSM following inoculation with Xoo strains AH28 and PXO99(A). The analysis revealed significant differential expression of 14,084 genes. Among the transcription factor (TF) families identified, bHLH, WRKY, and ERF were prominent, with notable differences in the expression of OsWRKY62, OsWRKY76, and OsbHLH6 across samples. Over 100 genes were directly linked to disease resistance, including nearly 30 NBS-LRR family genes. Additionally, 11 SWEET family protein genes, over 750 protein kinase genes, 63 peroxidase genes, and eight phenylalanine aminolysase genes were detected. Gene ontology (GO) analysis showed significant enrichment in pathways related to defense response to bacteria and oxidative stress response. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that differentially expressed genes (DEGs) were enriched in phenylpropanoid biosynthesis and diterpenoid biosynthesis pathways. Gene expression results from qRT-PCR were consistent with those from RNA-Seq, underscoring the reliability of the findings. Candidate genes identified in this study that may be resistant to BB, such as NBS-LRR family genes LOC_Os11g11960 and LOC_Os11g12350, SWEET family genes LOC_Os01g50460 and LOC_Os01g12130, and protein kinase-expressing genes LOC_Os01g66860 and LOC_Os02g57700, will provide a theoretical basis for further experiments. These results suggest that the immune response of rice to the two strains may be more concentrated in the early stage, and there are more up-regulated genes in the immune response of the high-resistant to PXO99A and medium-resistant to AH28, respectively, compared with the highly susceptible rice. This study offers a foundation for further research on resistance genes and the molecular mechanisms in Fan3 and YHSM.202439599338
3880.9973Alginate Oligosaccharide (AOS) induced resistance to Pst DC3000 via salicylic acid-mediated signaling pathway in Arabidopsis thaliana. Alginate Oligosaccharide (AOS) is a natural biological carbohydrate extracted from seaweed. In our study, Arabidopsis thaliana was used to evaluate the AOS-induced resistance to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Resistance was vitally enhanced at 25 mg/L in wild type (WT), showing the decreased disease index and bacteria colonies, burst of ROS and NO, high transcription expression of resistance genes PR1 and increased content of salicylic acid (SA). In SA deficient mutant (sid2), AOS-induced disease resistance dropped obviously compared to WT. The disease index was significantly higher than WT and the expression of recA and avrPtoB are two and four times lower than WT, implying that AOS induces disease resistance injecting Pst DC3000 after three days treatment by arousing the SA pathway. Our results provide a reference for the profound research and application of AOS in agriculture.201931521273
878490.9972Bacillus firmus Strain I-1582, a Nematode Antagonist by Itself and Through the Plant. Bacillus firmus I-1582 is approved in Europe for the management of Meloidogyne on vegetable crops. However, little information about its modes of action and temperature requirements is available, despite the effect of these parameters in its efficacy. The cardinal temperatures for bacterial growth and biofilm formation were determined. The bacteria was transformed with GFP to study its effect on nematode eggs and root colonization of tomato (Solanum lycopersicum) and cucumber (Cucumis sativus) by laser-scanning confocal microscopy. Induction of plant resistance was determined in split-root experiments and the dynamic regulation of genes related to jasmonic acid (JA) and salicylic acid (SA) by RT-qPCR at three different times after nematode inoculation. The bacteria was able to grow and form biofilms between 15 and 45°C; it degraded egg-shells and colonized eggs; it colonized tomato roots more extensively than cucumber roots; it induced systemic resistance in tomato, but not in cucumber; SA and JA related genes were primed at different times after nematode inoculation in tomato, but only the SA-related gene was up-regulated at 7 days after nematode inoculation in cucumber. In conclusion, B. firmus I-1582 is active at a wide range of temperatures; its optimal growth temperature is 35°C; it is able to degrade Meloidogyne eggs, and to colonize plant roots, inducing systemic resistance in a plant dependent species manner.202032765537
28100.9972Screening of rice (Oryza sativa L.) OsPR1b-interacting factors and their roles in resisting bacterial blight. PR genes, a type of genetic marker, are constitutively expressed at background levels, while being easily inducible by pathogenic bacteria. By using a yeast two-hybrid technique, four rice (Oryza sativa L.) OsPR1b-interacting factors were screened. Homozygous plants overexpressing OsPR1b were prepared by transgenic technology. We postulated that OsPR1b may participate in the resistance signaling pathway of rice. Of simultaneous treatments with hormones and pathogenic bacteria, exogenously applying JA and ET significantly increased the expression level of OsPR1b genes in seedlings. Compared with the control group that was inoculated with water, inoculation with a mixture of water and pathogenic bacteria hardly affected the expression level of OsPR1b gene, while cotreatment with SA and pathogenic bacteria slightly upregulated the expression level. However, cotreatment with JA or ET and pathogenic bacteria managed to significantly upregulate the expression level of the OsPR1b gene by 4.8 or 5.7 fold. PR genes, which are sensitive, are prone to many unknown factors during expression, and the detailed regulatory mechanisms in rice still require in-depth studies.201525867332
15110.9972Enhanced Bacterial Wilt Resistance in Potato Through Expression of Arabidopsis EFR and Introgression of Quantitative Resistance from Solanum commersonii. Bacterial wilt (BW) caused by Ralstonia solanacearum is responsible for substantial losses in cultivated potato (Solanum tuberosum) crops worldwide. Resistance genes have been identified in wild species; however, introduction of these through classical breeding has achieved only partial resistance, which has been linked to poor agronomic performance. The Arabidopsis thaliana (At) pattern recognition receptor elongation factor-Tu (EF-Tu) receptor (EFR) recognizes the bacterial pathogen-associated molecular pattern EF-Tu (and its derived peptide elf18) to confer anti-bacterial immunity. Previous work has shown that transfer of AtEFR into tomato confers increased resistance to R. solanacearum. Here, we evaluated whether the transgenic expression of AtEFR would similarly increase BW resistance in a commercial potato line (INIA Iporá), as well as in a breeding potato line (09509.6) in which quantitative resistance has been introgressed from the wild potato relative Solanum commersonii. Resistance to R. solanacearum was evaluated by damaged root inoculation under controlled conditions. Both INIA Iporá and 09509.6 potato lines expressing AtEFR showed greater resistance to R. solanacearum, with no detectable bacteria in tubers evaluated by multiplex-PCR and plate counting. Notably, AtEFR expression and the introgression of quantitative resistance from S. commersonii had a significant additive effect in 09509.6-AtEFR lines. These results show that the combination of heterologous expression of AtEFR with quantitative resistance introgressed from wild relatives is a promising strategy to develop BW resistance in potato.201729033958
30120.9972RNA-Seq analysis of Citrus reticulata in the early stages of Xylella fastidiosa infection reveals auxin-related genes as a defense response. BACKGROUND: Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is one the most important citrus diseases, and affects all varieties of sweet orange (Citrus sinensis L. Osb). On the other hand, among the Citrus genus there are different sources of resistance against X. fastidiosa. For these species identifying these defense genes could be an important step towards obtaining sweet orange resistant varieties through breeding or genetic engineering. To assess these genes we made use of mandarin (C. reticulata Blanco) that is known to be resistant to CVC and shares agronomical characteristics with sweet orange. Thus, we investigated the gene expression in Ponkan mandarin at one day after infection with X. fastidiosa, using RNA-seq. A set of genes considered key elements in the resistance was used to confirm its regulation in mandarin compared with the susceptible sweet orange. RESULTS: Gene expression analysis of mock inoculated and infected tissues of Ponkan mandarin identified 667 transcripts repressed and 724 significantly induced in the later. Among the induced transcripts, we identified genes encoding proteins similar to Pattern Recognition Receptors. Furthermore, many genes involved in secondary metabolism, biosynthesis and cell wall modification were upregulated as well as in synthesis of abscisic acid, jasmonic acid and auxin. CONCLUSIONS: This work demonstrated that the defense response to the perception of bacteria involves cell wall modification and activation of hormone pathways, which probably lead to the induction of other defense-related genes. We also hypothesized the induction of auxin-related genes indicates that resistant plants initially recognize X. fastidiosa as a necrotrophic pathogen.201324090429
8786130.9972Pattern triggered immunity (PTI) in tobacco: isolation of activated genes suggests role of the phenylpropanoid pathway in inhibition of bacterial pathogens. BACKGROUND: Pattern Triggered Immunity (PTI) or Basal Resistance (BR) is a potent, symptomless form of plant resistance. Upon inoculation of a plant with non-pathogens or pathogenicity-mutant bacteria, the induced PTI will prevent bacterial proliferation. Developed PTI is also able to protect the plant from disease or HR (Hypersensitive Response) after a challenging infection with pathogenic bacteria. Our aim was to reveal those PTI-related genes of tobacco (Nicotiana tabacum) that could possibly play a role in the protection of the plant from disease. METHODOLOGY/PRINCIPAL FINDINGS: Leaves were infiltrated with Pseudomonas syringae pv. syringae hrcC- mutant bacteria to induce PTI, and samples were taken 6 and 48 hours later. Subtraction Suppressive Hybridization (SSH) resulted in 156 PTI-activated genes. A cDNA microarray was generated from the SSH clone library. Analysis of hybridization data showed that in the early (6 hpi) phase of PTI, among others, genes of peroxidases, signalling elements, heat shock proteins and secondary metabolites were upregulated, while at the late phase (48 hpi) the group of proteolysis genes was newly activated. Microarray data were verified by real time RT-PCR analysis. Almost all members of the phenyl-propanoid pathway (PPP) possibly leading to lignin biosynthesis were activated. Specific inhibition of cinnamic-acid-4-hydroxylase (C4H), rate limiting enzyme of the PPP, decreased the strength of PTI--as shown by the HR-inhibition and electrolyte leakage tests. Quantification of cinnamate and p-coumarate by thin-layer chromatography (TLC)-densitometry supported specific changes in the levels of these metabolites upon elicitation of PTI. CONCLUSIONS/SIGNIFICANCE: We believe to provide first report on PTI-related changes in the levels of these PPP metabolites. Results implicated an actual role of the upregulation of the phenylpropanoid pathway in the inhibition of bacterial pathogenic activity during PTI.201425101956
8146140.9971The Influence of Chitosan Derivatives in Combination with Bacillus subtilis Bacteria on the Development of Systemic Resistance in Potato Plants with Viral Infection and Drought. Viral diseases of potatoes are among the main problems causing deterioration in the quality of tubers and loss of yield. The growth and development of potato plants largely depend on soil moisture. Prevention strategies require comprehensive protection against pathogens and abiotic stresses, including modeling the beneficial microbiome of agroecosystems combining microorganisms and immunostimulants. Chitosan and its derivatives have great potential for use in agricultural engineering due to their ability to induce plant immune responses. The effect of chitosan conjugate with caffeic acid (ChCA) in combination with Bacillus subtilis 47 on the transcriptional activity of PR protein genes and changes in the proteome of potato plants during potato virus Y (PVY) infection and drought was studied. The mechanisms of increasing the resistance of potato plants to PVY and lack of moisture are associated with the activation of transcription of genes encoding PR proteins: the main protective protein (PR-1), chitinase (PR-3), thaumatin-like protein (PR-5), protease inhibitor (PR-6), peroxidase (PR-9), and ribonuclease (PR-10), as well as qualitative and quantitative changes in the plant proteome. The revealed activation of the expression of marker genes of systemic acquired resistance and induced systemic resistance under the influence of combined treatment with B. subtilis and chitosan conjugate indicate that, in potato plants, the formation of resistance to viral infection in drought conditions proceeds synergistically. By two-dimensional electrophoresis of S. tuberosum leaf proteins followed by MALDI-TOF analysis, 10 proteins were identified, the content and composition of which differed depending on the experiment variant. In infected plants treated with ChCA, the synthesis of proteinaceous RNase P 1 and oxygen-evolving enhancer protein 2 was enhanced in conditions of normal humidity, and 20 kDa chaperonin and TMV resistance protein N-like was enhanced in conditions of lack of moisture. The virus coat proteins were detected, which intensively accumulated in the leaves of plants infected with potato Y-virus. ChCA treatment reduced the content of these proteins in the leaves, and in plants treated with ChCA in combination with Bacillus subtilis, viral proteins were not detected at all, both in conditions of normal humidity and lack of moisture, which suggests the promising use of chitosan derivatives in combination with B. subtilis bacteria in the regulation of plant resistance.202439204646
29150.9971Identification and Functional Analysis of Tomato TPR Gene Family. Tomato (Solanum lycopersicum) as an important vegetable grown around the world is threatened by many diseases, which seriously affects its yield. Therefore, studying the interaction between tomato and pathogenic bacteria is biologically and economically important. The TPR (Tetratricopeptide repeat) gene family is a class of genes containing TPR conserved motifs, which are widely involved in cell cycle regulation, gene expression, protein degradation and other biological processes. The functions of TPR gene in Arabidopsis and wheat plants have been well studied, but the research on TPR genes in tomato is not well studied. In this study, 26 TPR gene families were identified using bioinformatics based on tomato genome data, and they were analyzed for subcellular localization, phylogenetic evolution, conserved motifs, tissue expression, and GO (Gene Ontology) analysis. The qRT-PCR was used to detect the expression levels of each member of the tomato TPR gene family (SlTPRs) under biological stress (Botrytis cinerea) and abiotic stress such as drought and abscisic acid (ABA). The results showed that members of the tomato TPR family responded to various abiotic stresses and Botrytis cinerea stress, and the SlTPR2 and SlTPR4 genes changed significantly under different stresses. Using VIGS (Virus-induced gene silencing) technology to silence these two genes, the silenced plants showed reduced disease resistance. It was also shown that TPR4 can interact with atpA which encodes a chloroplast ATP synthase CF1 α subunit. The above results provide a theoretical basis for further exploring the molecular mechanism of TPR-mediated resistance in disease defense, and also provide a foundation for tomato disease resistance breeding.202133451131
36160.9971Bacillus amyloliquefaciens SN16-1-Induced Resistance System of the Tomato against Rhizoctonia solani. Tomato (Solanum lycopersicum), as an important economical vegetable, is often infected with Rhizoctonia solani, which results in a substantial reduction in production. Therefore, the molecular mechanism of biocontrol microorganisms assisting tomato to resist pathogens is worth exploring. Here, we use Bacillus amyloliquefaciens SN16-1 as biocontrol bacteria, and employed RNA-Seq technology to study tomato gene and defense-signaling pathways expression. Gene Ontology (GO) analyses showed that an oxidation-reduction process, peptidase regulator activity, and oxidoreductase activity were predominant. Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that phenylpropanoid biosynthesis, biosynthesis of unsaturated fatty acids, aldosterone synthesis and secretion, and phototransduction were significantly enriched. SN16-1 activated defenses in the tomato via systemic-acquired resistance (which depends on the salicylic acid signaling pathway), rather than classic induction of systemic resistance. The genes induced by SN16-1 included transcription factors, plant hormones (ethylene, auxin, abscisic acid, and gibberellin), receptor-like kinases, heat shock proteins, and defense proteins. SN16-1 rarely activated pathogenesis-related proteins, but most pathogenesis-related proteins were induced in the presence of the pathogens. In addition, the molecular mechanisms of the response of tomatoes to SN16-1 and R. solani RS520 were significantly different.202135055983
8759170.9971Genetic and transcriptomic dissection of host defense to Goss's bacterial wilt and leaf blight of maize. Goss's wilt, caused by the Gram-positive actinobacterium Clavibacter nebraskensis, is an important bacterial disease of maize. The molecular and genetic mechanisms of resistance to the bacterium, or, in general, Gram-positive bacteria causing plant diseases, remain poorly understood. Here, we examined the genetic basis of Goss's wilt through differential gene expression, standard genome-wide association mapping (GWAS), extreme phenotype (XP) GWAS using highly resistant (R) and highly susceptible (S) lines, and quantitative trait locus (QTL) mapping using 3 bi-parental populations, identifying 11 disease association loci. Three loci were validated using near-isogenic lines or recombinant inbred lines. Our analysis indicates that Goss's wilt resistance is highly complex and major resistance genes are not commonly present. RNA sequencing of samples separately pooled from R and S lines with or without bacterial inoculation was performed, enabling identification of common and differential gene responses in R and S lines. Based on expression, in both R and S lines, the photosynthesis pathway was silenced upon infection, while stress-responsive pathways and phytohormone pathways, namely, abscisic acid, auxin, ethylene, jasmonate, and gibberellin, were markedly activated. In addition, 65 genes showed differential responses (up- or down-regulated) to infection in R and S lines. Combining genetic mapping and transcriptional data, individual candidate genes conferring Goss's wilt resistance were identified. Collectively, aspects of the genetic architecture of Goss's wilt resistance were revealed, providing foundational data for mechanistic studies.202337652038
8790180.9971Bacillus circulans GN03 Alters the Microbiota, Promotes Cotton Seedling Growth and Disease Resistance, and Increases the Expression of Phytohormone Synthesis and Disease Resistance-Related Genes. Plant growth-promoting bacteria (PGPB) are components of the plant rhizosphere that promote plant growth and/or inhibit pathogen activity. To explore the cotton seedlings response to Bacillus circulans GN03 with high efficiency of plant growth promotion and disease resistance, a pot experiment was carried out, in which inoculations levels of GN03 were set at 10(4) and 10(8) cfu(⋅)mL(-1). The results showed that GN03 inoculation remarkably enhanced growth promotion as well as disease resistance of cotton seedlings. GN03 inoculation altered the microbiota in and around the plant roots, led to a significant accumulation of growth-related hormones (indole acetic acid, gibberellic acid, and brassinosteroid) and disease resistance-related hormones (salicylic acid and jasmonic acid) in cotton seedlings, as determined with ELISA, up-regulated the expression of phytohormone synthesis-related genes (EDS1, AOC1, BES1, and GA20ox), auxin transporter gene (Aux1), and disease-resistance genes (NPR1 and PR1). Comparative genomic analyses was performed between GN03 and four similar species, with regards to phenotype, biochemical characteristics, and gene function. This study provides valuable information for applying the PGPB alternative, GN03, as a plant growth and disease-resistance promoting fertilizer.202133936131
8783190.9970Characterization and potential of plant growth promoting rhizobacteria isolated from native Andean crops. Bacteria isolated from soil and rhizosphere samples collected in Peru from Andean crops were tested in vitro and in vivo to determine their potential as plant growth promoters and their ability to induce systemic resistance to Alternaria alternata in tomato plants. The isolates were identified by sequencing their 16S ribosomal RNA gene. Test for phosphate solubilization, and indolacetic acid were also carried out, together with in vitro antagonism assays in dual cultures towards the plant pathogens Fusarium solani, A. alternata and Curvularia lunata. The three most promising isolates (Pa15, Ps155, Ps168) belonged to the genus Pseudomonas. Further assays were carried out with tomato plants to assess their plant protection effect towards A. alternata and as growth promoters. Inoculation of tomato seeds with all isolates significantly enhanced seed germination, plantlets emergence and plant development. Bacterial inoculation also reduce damage level caused by A. alternata. The expression levels of three tomato genes involved in the jasmonate (AOS), ethylene responsive (ERF-2) and pathogenesis related (PR-P2) pathways were determined in plants challenged with A. alternata, alone or with each bacterial isolate, respectively. Results showed that at 24 h after infection, in absence of the pathogen, the expression level of the tested genes was very low. The presence of A. alternata alone and in combination with bacteria increased the transcripts of all genes. Data showed a potential of best performing isolate Ps168 to sustain tomato plants nutrition and activate defense-related genes for protection by pathogenic fungi.201729079927