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1.
Plant Biotechnol J ; 22(7): 1929-1941, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38366355

RESUMEN

Plants have evolved a sophisticated immunity system for specific detection of pathogens and rapid induction of measured defences. Over- or constitutive activation of defences would negatively affect plant growth and development. Hence, the plant immune system is under tight positive and negative regulation. MAP kinase phosphatase1 (MKP1) has been identified as a negative regulator of plant immunity in model plant Arabidopsis. However, the molecular mechanisms by which MKP1 regulates immune signalling in wheat (Triticum aestivum) are poorly understood. In this study, we investigated the role of TaMKP1 in wheat defence against two devastating fungal pathogens and determined its subcellular localization. We demonstrated that knock-down of TaMKP1 by CRISPR/Cas9 in wheat resulted in enhanced resistance to rust caused by Puccinia striiformis f. sp. tritici (Pst) and powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt), indicating that TaMKP1 negatively regulates disease resistance in wheat. Unexpectedly, while Tamkp1 mutant plants showed increased resistance to the two tested fungal pathogens they also had higher yield compared with wild-type control plants without infection. Our results suggested that TaMKP1 interacts directly with dephosphorylated and activated TaMPK3/4/6, and TaMPK4 interacts directly with TaPAL. Taken together, we demonstrated TaMKP1 exert negative modulating roles in the activation of TaMPK3/4/6, which are required for MAPK-mediated defence signalling. This facilitates our understanding of the important roles of MAP kinase phosphatases and MAPK cascades in plant immunity and production, and provides germplasm resources for breeding for high resistance and high yield.


Asunto(s)
Sistemas CRISPR-Cas , Resistencia a la Enfermedad , Enfermedades de las Plantas , Inmunidad de la Planta , Triticum , Triticum/genética , Triticum/microbiología , Triticum/inmunología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/genética , Inmunidad de la Planta/genética , Resistencia a la Enfermedad/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ascomicetos/fisiología , Mutagénesis , Fosfatasa 1 de Especificidad Dual/genética , Fosfatasa 1 de Especificidad Dual/metabolismo , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/genética , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/metabolismo , Puccinia/fisiología , Plantas Modificadas Genéticamente
2.
New Phytol ; 242(4): 1630-1644, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38105548

RESUMEN

Nonmycorrhizal cluster root-forming species enhance the phosphorus (P) acquisition of mycorrhizal neighbours in P-impoverished megadiverse systems. However, whether mycorrhizal plants facilitate the defence of nonmycorrhizal plants against soil-borne pathogens, in return and via their symbiosis, remains unknown. We characterised growth and defence-related compounds in Banksia menziesii (nonmycorrhizal) and Eucalyptus todtiana (ectomycorrhizal, ECM) seedlings grown either in monoculture or mixture in a multifactorial glasshouse experiment involving ECM fungi and native oomycete pathogens. Roots of B. menziesii had higher levels of phytohormones (salicylic and jasmonic acids, jasmonoyl-isoleucine and 12-oxo-phytodienoic acid) than E. todtiana which further activated a salicylic acid-mediated defence response in roots of B. menziesii, but only in the presence of ECM fungi. We also found that B. menziesii induced a shift in the defence strategy of E. todtiana, from defence-related secondary metabolites (phenolic and flavonoid) towards induced phytohormone response pathways. We conclude that ECM fungi play a vital role in the interactions between mycorrhizal and nonmycorrhizal plants in a severely P-impoverished environment, by introducing a competitive component within the facilitation interaction between the two plant species with contrasting nutrient-acquisition strategies. This study sheds light on the interplay between beneficial and detrimental soil microbes that shape plant-plant interaction in severely nutrient-impoverished ecosystems.


Asunto(s)
Micorrizas , Oomicetos , Fósforo , Micorrizas/fisiología , Fósforo/metabolismo , Oomicetos/fisiología , Oomicetos/patogenicidad , Eucalyptus/microbiología , Eucalyptus/fisiología , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Plantones/microbiología , Simbiosis/fisiología , Especificidad de la Especie , Ambiente
3.
J Exp Bot ; 75(5): 1493-1509, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-37952109

RESUMEN

Herbivore-associated elicitors (HAEs) are active molecules produced by herbivorous insects. Recognition of HAEs by plants induces defence that resist herbivore attacks. We previously demonstrated that the tomato red spider mite Tetranychus evansi triggered defence in Nicotiana benthamiana. However, our knowledge of HAEs from T. evansi remains limited. Here, we characterize a novel HAE, Te16, from T. evansi and dissect its function in mite-plant interactions. We investigate the effects of Te16 on spider mites and plants by heterologous expression, virus-induced gene silencing assay, and RNA interference. Te16 induces cell death, reactive oxygen species (ROS) accumulation, callose deposition, and jasmonate (JA)-related responses in N. benthamiana leaves. Te16-mediated cell death requires a calcium signalling pathway, cytoplasmic localization, the plant co-receptor BAK1, and the signalling components SGT1 and HSP90. The active region of Te16-induced cell death is located at amino acids 114-293. Moreover, silencing Te16 gene in T. evansi reduces spider mite survival and hatchability, but expressing Te16 in N. benthamiana leaves enhances plant resistance to herbivores. Finally, Te16 gene is specific to Tetranychidae species and is highly conserved in activating plant immunity. Our findings reveal a novel salivary protein produced by spider mites that elicits plant defence and resistance to insects, providing valuable clues for pest management.


Asunto(s)
Solanum lycopersicum , Tetranychidae , Animales , Herbivoria , Tetranychidae/fisiología , Nicotiana/genética , Solanum lycopersicum/genética , Hojas de la Planta
4.
Plant Cell Environ ; 46(8): 2575-2589, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37264560

RESUMEN

The novel protein elicitor GP1pro is the protein component of glycoprotein GP-1 isolated and identified from Streptomyces kanasensis ZX01. GP1pro induces the production of reactive oxygen species (ROS) and a hypersensitive response (HR), along with the accumulation of resistance-related genes and secondary metabolites. It ultimately regulates plant defence responses. Further analysis revealed that GP1pro interacts with the PIP2-family aquaporin protein NbPIP2;4 on the plant plasma membrane (PM) in Nicotiana benthamiana. PM localization is necessary for inducing GP1pro resistance. These results demonstrate that NbPIP2;4 acts as a H2 O2 transporter to positively regulate plant immunity and ROS accumulation. In summary, this study elucidates a conserved and novel pathway caused by GP1pro to initiate host cellular defences by targeting the plant aquaporin protein NbPIP2;4 and transporting apoplast-to-cytoplast H2 O2 to regulate plant immunity.


Asunto(s)
Acuaporinas , Inmunidad de la Planta , Especies Reactivas de Oxígeno/metabolismo , Proteínas de Plantas/metabolismo , Nicotiana/metabolismo , Acuaporinas/metabolismo , Enfermedades de las Plantas
5.
BMC Plant Biol ; 22(1): 480, 2022 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-36209051

RESUMEN

BACKGROUND AND OBJECTIVES: Phytophthora ramorum severely affects both European larch (EL) and Japanese larch (JL) trees as indicated by high levels of mortality particularly in the UK. Field observations suggested that EL is less severely affected and so may be less susceptible to P. ramorum than JL; however, controlled inoculations have produced inconsistent or non-statistically significant differences. The present study aimed to compare RNA transcript accumulation profiles in EL and JL in response to inoculation with P. ramorum to improve our understanding of their defence responses. METHODOLOGY: RNA-sequencing was carried out on bark tissues following the inoculation with P. ramorum of potted saplings in both EL and JL carried out under controlled environment conditions, with sampling at 1, 3, 10, and 25 days post inoculation in infected and control plants. RESULTS: All of the inoculated trees rapidly developed lesions but no statistically significant differences were found in lesion lengths between EL and JL. RNA-Sequencing comparing control and inoculate saplings identified key differences in differentially expressed genes (DEGs) between the two larch species. European larch had rapid induction of defence genes within 24 hours of infection followed by sustained expression until 25 days after inoculation. Results in JL were more varied; upregulation was stronger but more transient and represented fewer defence pathways. Gene enrichment analyses highlighted differences in jasmonate signalling and regulation including NPR1 upregulation in EL only, and specific aspects of secondary metabolism. Some DEGs were represented by multiple responsive copies including lipoxygenase, chalcone synthase and nucleotide-binding, leucine-rich-repeat genes. CONCLUSION: The variations between EL and JL in responsive DEGs of interest as potentially related to differences seen in the field and should be considered in the selection of trees for planting and future breeding.


Asunto(s)
Larix , Phytophthora , Japón , Larix/genética , Leucina/genética , Lipooxigenasas/genética , Nucleótidos , Phytophthora/fisiología , Fitomejoramiento , Enfermedades de las Plantas/genética , ARN , Transcriptoma , Árboles/genética
6.
Plant Biotechnol J ; 20(11): 2187-2201, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35984895

RESUMEN

Aphids secrete diverse repertoires of salivary effectors into host plant cells to promote infestation by modulating plant defence. The greenbug Schizaphis graminum is an important cereal aphid worldwide. However, the secreted effectors of S. graminum are still uncharacterized. Here, 76 salivary proteins were identified from the watery saliva of S. graminum using transcriptome and proteome analyses. Among them, a putative salivary effector Sg2204 was significantly up-regulated during aphid feeding stages, and transient overexpression of Sg2204 in Nicotiana benthamiana inhibited cell death induced by BAX or INF1. Delivering Sg2204 into wheat via the type III secretion system of Pseudomonas fluorescens EtAnH suppressed pattern-triggered immunity (PTI)-associated callose deposition. The transcript levels of jasmonic acid (JA)- and salicylic acid (SA)-associated defence genes of wheat were significantly down-regulated, and the contents of both JA and SA were also significantly decreased after delivery of Sg2204 into wheat leaves. Additionally, feeding on wheat expressing Sg2204 significantly increased the weight and fecundity of S. graminum and promoted aphid phloem feeding. Sg2204 was efficiently silenced via spray-based application of the nanocarrier-mediated transdermal dsRNA delivery system. Moreover, Sg2204-silenced aphids induced a stronger wheat defence response and resulted in negative impacts on aphid feeding behaviour, survival and fecundity. Silencing of Sg2204 homologues from four aphid species using nanocarrier-delivered dsRNA also significantly reduced aphid performance on host plants. Thus, our study characterized the salivary effector Sg2204 of S. graminum involved in promoting host susceptibility by suppressing wheat defence, which can also be regarded as a promising RNAi target for aphid control.


Asunto(s)
Áfidos , Animales , Áfidos/genética , Triticum/metabolismo , Proteínas y Péptidos Salivales/metabolismo , Oxilipinas/metabolismo , Ácido Salicílico/metabolismo
7.
BMC Genomics ; 21(1): 339, 2020 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-32366323

RESUMEN

BACKGROUND: Schizaphis graminum is one of the most important and devastating cereal aphids worldwide, and its feeding can cause chlorosis and necrosis in wheat. However, little information is available on the wheat defence responses triggered by S. graminum feeding at the molecular level. RESULTS: Here, we collected and analysed transcriptome sequencing data from leaf tissues of wheat infested with S. graminum at 2, 6, 12, 24 and 48 hpi (hours post infestation). A total of 44,835 genes were either up- or downregulated and differed significantly in response to aphid feeding. The expression levels of a number of genes (9761 genes) were significantly altered within 2 hpi and continued to change during the entire 48 h experiment. Gene Ontology analysis showed that the downregulated DEGs were mainly enriched in photosynthesis and light harvesting, and the total chlorophyll content in wheat leaves was also significantly reduced after S. graminum infestation at 24 and 48 hpi. However, a number of related genes of the salicylic acid (SA)-mediated defence signalling pathway and MAPK-WRKY pathway were significantly upregulated at early feeding time points (2 and 6 hpi). In addition, the gene expression and activity of antioxidant enzymes, such as peroxidase and superoxide dismutase, were rapidly increased at 2, 6 and 12 hpi. DAB staining results showed that S. graminum feeding induced hydrogen peroxide (H2O2) accumulation at the feeding sites at 2 hpi, and increased H2O2 production was detected with the increases in aphid feeding time. Pretreatment with diphenylene iodonium, an NADPH oxidase inhibitor, repressed the H2O2 accumulation and expression levels of SA-associated defence genes in wheat. CONCLUSIONS: Our transcriptomic analysis revealed that defence-related pathways and oxidative stress in wheat were rapidly induced within hours after the initiation of aphid feeding. Additionally, NADPH oxidase plays an important role in aphid-induced defence responses and H2O2 accumulation in wheat. These results provide valuable insight into the dynamic transcriptomic responses of wheat leaves to phytotoxic aphid feeding and the molecular mechanisms of aphid-plant interactions.


Asunto(s)
Áfidos/fisiología , Inmunidad de la Planta/genética , Triticum/inmunología , Animales , Vías Biosintéticas/genética , Clorofila/genética , Clorofila/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Interacciones Huésped-Parásitos , Peróxido de Hidrógeno/metabolismo , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/parasitología , Hojas de la Planta/genética , Hojas de la Planta/inmunología , Hojas de la Planta/parasitología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transducción de Señal/genética , Triticum/genética , Triticum/parasitología
8.
Pestic Biochem Physiol ; 170: 104681, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32980063

RESUMEN

Chitosan oligosaccharides (COS) can elicit plant immunity and defence responses in rice plants, but exactly how this promotes plant growth remains largely unknown. Herein, we explored the effects of 0.5 mg/L COS on plant growth promotion in rice seedlings by measuring root and stem length, investigating biochemical factors in whole plants via proteomic analysis, and confirming upregulated and downregulated genes by real-time quantitative PCR. Pathway enrichment results showed that COS promoted root and stem growth, and stimulated metabolic (biosynthetic and catabolic processes) and photosynthesis in rice plants during the seedling stage. Expression levels of genes related to chlorophyll a-b binding, RNA binding, catabolic processes and calcium ion binding were upregulated following COS treatment. Furthermore, comparative analysis indicated that numerous proteins involved in the biosynthesis, metabolic (catabolic) processes and photosynthesis pathways were upregulated. The findings indicate that COS may upregulate calcium ion binding, photosynthesis, RNA binding, and catabolism proteins associated with plant growth during the rice seedling stage.


Asunto(s)
Quitosano , Oryza/genética , Clorofila A , Regulación de la Expresión Génica de las Plantas , Oligosacáridos , Proteínas de Plantas/genética , Proteómica , Plantones/genética
10.
Semin Cell Dev Biol ; 56: 174-189, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27312082

RESUMEN

Plant hormones are essential regulators of plant growth and immunity. In the last few decades, a vast amount of information has been obtained detailing the role of different plant hormones in immunity, and how they work together to ultimately shape the outcomes of plant pathogen interactions. Here we provide an overview on the roles of the main classes of plant hormones in the regulation of plant immunity, highlighting their metabolic and signaling pathways and how plants and pathogens utilize these pathways to activate or suppress defence.


Asunto(s)
Reguladores del Crecimiento de las Plantas/farmacología , Plantas/microbiología , Plantas/parasitología , Modelos Biológicos , Inmunidad de la Planta/efectos de los fármacos , Plantas/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos
11.
New Phytol ; 220(4): 1296-1308, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-29424928

RESUMEN

Several studies have investigated soil microbial biodiversity, but understanding of the mechanisms underlying plant responses to soil microbiota remains in its infancy. Here, we focused on tomato (Solanum lycopersicum), testing the hypothesis that plants grown on native soils display different responses to soil microbiotas. Using transcriptomics, proteomics, and biochemistry, we describe the responses of two tomato genotypes (susceptible or resistant to Fusarium oxysporum f. sp. lycopersici) grown on an artificial growth substrate and two native soils (conducive and suppressive to Fusarium). Native soils affected tomato responses by modulating pathways involved in responses to oxidative stress, phenol biosynthesis, lignin deposition, and innate immunity, particularly in the suppressive soil. In tomato plants grown on steam-disinfected soils, total phenols and lignin decreased significantly. The inoculation of a mycorrhizal fungus partly rescued this response locally and systemically. Plants inoculated with the fungal pathogen showed reduced disease symptoms in the resistant genotype in both soils, but the susceptible genotype was partially protected from the pathogen only when grown on the suppressive soil. The 'state of alert' detected in tomatoes reveals novel mechanisms operating in plants in native soils and the soil microbiota appears to be one of the drivers of these plant responses.


Asunto(s)
Microbiota , Microbiología del Suelo , Suelo , Solanum lycopersicum/microbiología , Regulación de la Expresión Génica de las Plantas , Ontología de Genes , Lignina/metabolismo , Solanum lycopersicum/genética , Solanum lycopersicum/inmunología , Microbiota/genética , Modelos Biológicos , Inmunidad de la Planta/genética , Raíces de Plantas/genética , Raíces de Plantas/microbiología , Propanoles/metabolismo , Proteoma/metabolismo , Estrés Fisiológico/genética , Transcriptoma/genética
12.
Molecules ; 23(9)2018 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-30208652

RESUMEN

The present review discusses the impact of heavy metals on the growth of plants at different concentrations, paying particular attention to the hormesis effect. Within the past decade, study of the hormesis phenomenon has generated considerable interest because it was considered not only in the framework of plant growth stimulation but also as an adaptive response of plants to a low level of stress which in turn can play an important role in their responses to other stress factors. In this review, we focused on the defence mechanisms of plants as a response to different metal ion doses and during the crosstalk between metal ions and biotic stressors such as insects and pathogenic fungi. Issues relating to metal ion acquisition and ion homeostasis that may be essential for the survival of plants, pathogens and herbivores competing in the same environment were highlighted. Besides, the influence of heavy metals on insects, especially aphids and pathogenic fungi, was shown. Our intention was also to shed light on the relationship between heavy metals deposition in the environment and ecological communities formed under a strong selective pressure.


Asunto(s)
Metales Pesados/farmacología , Desarrollo de la Planta/efectos de los fármacos , Animales , Áfidos/efectos de los fármacos , Hongos/efectos de los fármacos , Plantas/microbiología , Plantas/parasitología , Estrés Fisiológico/efectos de los fármacos
13.
Plant Cell Environ ; 40(4): 491-508, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26662183

RESUMEN

Cdc48, a molecular chaperone conserved in different kingdoms, is a member of the AAA+ family contributing to numerous processes in mammals including proteins quality control and degradation, vesicular trafficking, autophagy and immunity. The functions of Cdc48 plant orthologues are less understood. We previously reported that Cdc48 is regulated by S-nitrosylation in tobacco cells undergoing an immune response triggered by cryptogein, an elicitin produced by the oomycete Phytophthora cryptogea. Here, we inv estigated the function of NtCdc48 in cryptogein signalling and induced hypersensitive-like cell death. NtCdc48 was found to accumulate in elicited cells at both the protein and transcript levels. Interestingly, only a small proportion of the overall NtCdc48 population appeared to be S-nitrosylated. Using gel filtration in native conditions, we confirmed that NtCdc48 was present in its hexameric active form. An immunoprecipitation-based strategy following my mass spectrometry analysis led to the identification of about a hundred NtCdc48 partners and underlined its contribution in cellular processes including targeting of ubiquitylated proteins for proteasome-dependent degradation, subcellular trafficking and redox regulation. Finally, the analysis of cryptogein-induced events in NtCdc48-overexpressing cells highlighted a correlation between NtCdc48 expression and hypersensitive cell death. Altogether, this study identified NtCdc48 as a component of cryptogein signalling and plant immunity.


Asunto(s)
Proteínas Fúngicas/farmacología , Nicotiana/inmunología , Nicotiana/metabolismo , Proteínas de Plantas/metabolismo , Proteína que Contiene Valosina/metabolismo , Muerte Celular/efectos de los fármacos , Cromatografía en Gel , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Nitrosación , Células Vegetales/efectos de los fármacos , Células Vegetales/metabolismo , Unión Proteica/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Nicotiana/genética
14.
New Phytol ; 207(3): 778-89, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25825039

RESUMEN

Heterodera schachtii, a plant-parasitic cyst nematode, invades host roots and induces a specific syncytial feeding structure, from which it withdraws all required nutrients, causing severe yield losses. The system H. schachtii-Arabidopsis is an excellent research model for investigating plant defence mechanisms. Such responses are suppressed in well-established syncytia, whereas they are induced during early parasitism. However, the mechanisms by which the defence responses are modulated and the role of phytohormones are largely unknown. The aim of this study was to elucidate the role of hormone-based defence responses at the onset of nematode infection. First, concentrations of main phytohormones were quantified and the expression of several hormone-related genes was analysed using quantitative real-time (qRT)-PCR or GeneChip. Further, the effects of individual hormones were evaluated via nematode attraction and infection assays using plants with altered endogenous hormone concentrations. Our results suggest a pivotal and positive role for ethylene during nematode attraction, whereas jasmonic acid triggers early defence responses against H. schachtii. Salicylic acid seems to be a negative regulator during later syncytium and female development. We conclude that nematodes are able to impose specific changes in hormone pools, thus modulating hormone-based defence and signal transduction in strict dependence on their parasitism stage.


Asunto(s)
Arabidopsis/fisiología , Arabidopsis/parasitología , Reguladores del Crecimiento de las Plantas/metabolismo , Inmunidad de la Planta , Estrés Fisiológico , Tylenchoidea/fisiología , Animales , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Bioensayo , Cromatografía Líquida de Alta Presión , Ciclopentanos/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Espectrometría de Masas , Oxilipinas/farmacología , Parásitos/fisiología , Enfermedades de las Plantas/parasitología , Inmunidad de la Planta/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/parasitología , Ácido Salicílico/farmacología , Estrés Fisiológico/efectos de los fármacos , Estrés Fisiológico/genética , Transcripción Genética/efectos de los fármacos , Tylenchoidea/efectos de los fármacos
15.
Plant Cell Environ ; 38(2): 331-48, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24506708

RESUMEN

Nitric oxide (NO) has many functions in plants. Here, we investigated its interplays with reactive oxygen species (ROS) in the defence responses triggered by the elicitin cryptogein. The production of NO induced by cryptogein in tobacco cells was partly regulated through a ROS-dependent pathway involving the NADPH oxidase NtRBOHD. In turn, NO down-regulated the level of H2O2. Both NO and ROS synthesis appeared to be under the control of type-2 histone deacetylases acting as negative regulators of cell death. Occurrence of an interplay between NO and ROS was further supported by the finding that cryptogein triggered a production of peroxynitrite (ONOO(-)). Next, we showed that ROS, but not NO, negatively regulate the intensity of activity of the cryptogein-induced protein kinase NtOSAK. Furthermore, using a DNA microarray approach, we identified 15 genes early induced by cryptogein via NO. A part of these genes was also modulated by ROS and encoded proteins showing sequence identity to ubiquitin ligases. Their expression appeared to be negatively regulated by ONOO(-), suggesting that ONOO(-) mitigates the effects of NO and ROS. Finally, we provided evidence that NO required NtRBOHD activity for inducing cell death, thus confirming previous assumption that ROS channel NO through cell death pathways.


Asunto(s)
Proteínas Fúngicas/metabolismo , Óxido Nítrico/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Proteínas Fúngicas/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Peróxido de Hidrógeno/metabolismo , Modelos Biológicos , Ácido Peroxinitroso/metabolismo , Proteínas de Plantas/metabolismo , Transducción de Señal/efectos de los fármacos , Suspensiones , Nicotiana/citología , Nicotiana/efectos de los fármacos
16.
J Exp Bot ; 66(3): 973-87, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25399020

RESUMEN

Plant leaf senescence and defence responses are important biological processes, but the molecular mechanisms involved are not well understood. This study identified a new rice mutant, spotted leaf 29 (spl29). The SPL29 gene was identified by map-based cloning, and SPL29 was confirmed as UDP-N-acetylglucosamine pyrophosphorylase 1 (UAP1) by enzymatic analysis. The mutant spl29 lacks UAP activity. The biological phenotypes for which UAP is responsible have not previously been reported in plants. The spl29 mutant displayed early leaf senescence, confirmed by chlorophyll loss and photosystem II decline as physiological indicators, chloroplast degradation as a cellular characteristic, and both upregulation of senescence transcription factors and senescence-associated genes, and downregulation of photosynthesis-related genes, as molecular evidence. Defence responses were induced in the spl29 mutant, shown by enhanced resistance to bacterial blight inoculation and upregulation of defence response genes. Reactive oxygen species, including O2 (-) and H2O2, accumulated in spl29 plants; there was also increased malondialdehyde content. Enhanced superoxide dismutase activity combined with normal catalase activity in spl29 could be responsible for H2O2 accumulation. The plant hormones jasmonic acid and abscisic acid also accumulated in spl29 plants. ROS and plant hormones probably play important roles in early leaf senescence and defence responses in the spl29 mutant. Based on these findings, it is suggested that UAP1 is involved in regulating leaf senescence and defence responses in rice.


Asunto(s)
Nucleotidiltransferasas/genética , Oryza/genética , Inmunidad de la Planta , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/genética , Mutación , Nucleotidiltransferasas/metabolismo , Oryza/enzimología , Oryza/inmunología , Oryza/metabolismo , Filogenia , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo
17.
J Exp Bot ; 65(12): 3081-95, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24723397

RESUMEN

Light-grown Arabidopsis thaliana cell suspension culture (ACSC) were subjected to mild photooxidative damage with Rose Bengal (RB) with the aim of gaining a better understanding of singlet oxygen-mediated defence responses in plants. Additionally, ACSC were treated with H2O2 at concentrations that induced comparable levels of protein oxidation damage. Under low to medium light conditions, both RB and H2O2 treatments activated transcriptional defence responses and inhibited photosynthetic activity, but they differed in that programmed cell death (PCD) was only observed in cells treated with RB. When dark-grown ACSC were subjected to RB in the light, PCD was suppressed, indicating that the singlet oxygen-mediated signalling pathway in ACSC requires functional chloroplasts. Analysis of up-regulated transcripts in light-grown ACSC, treated with RB in the light, showed that both singlet oxygen-responsive transcripts and transcripts with a key role in hormone-activated PCD (i.e. ethylene and jasmonic acid) were present. A co-regulation analysis proved that ACSC treated with RB exhibited higher correlation with the conditional fluorescence (flu) mutant than with other singlet oxygen-producing mutants or wild-type plants subjected to high light. However, there was no evidence for the up-regulation of EDS1, suggesting that activation of PCD was not associated with the EXECUTER- and EDS1-dependent signalling pathway described in the flu mutant. Indigo Carmine and Methylene Violet, two photosensitizers unable to enter chloroplasts, did not activate transcriptional defence responses in ACSC; however, whether this was due to their location or to their inherently low singlet oxygen quantum efficiencies was not determined.


Asunto(s)
Apoptosis , Arabidopsis/fisiología , Cloroplastos/metabolismo , Rosa Bengala/metabolismo , Arabidopsis/genética , Células Cultivadas , Regulación de la Expresión Génica de las Plantas , Peróxido de Hidrógeno/metabolismo , Luz , Datos de Secuencia Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análisis por Matrices de Proteínas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Transducción de Señal , Oxígeno Singlete/metabolismo , Regulación hacia Arriba
18.
J Appl Microbiol ; 116(3): 654-66, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24279777

RESUMEN

AIMS: To investigate the efficacy of Trichoderma harzianum NBRI-1055 (denoted as 'T-1055') in suppression of seedling blight of sunflower caused by Rhizoctonia solani Kühn and their impact on host defence responses. METHODS AND RESULTS: T-1055 was applied as seed treatment, soil application and combined application (seed treatment + soil application). Higher protection afforded by combined application of T-1055 was associated with the marked induction of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (PO) and cinnamyl alcohol dehydrogenase (CAD) activities. The activities of PAL and PPO reached maximum at 10 days after sowing (DAS), while PO and CAD levels reached maximum at 12 DAS. This was further supported by the accumulation of total phenolic content that showed an increase up to threefold at 14 DAS. In addition, HPLC analysis revealed that the contents of ferulic and p-coumaric acids increased by 6·3 and 4·6 times, respectively, at 14 DAS. Amount of gallic acid was also little more than double. Lignin deposition in sunflower root increased by 2·7, 3·4 and 3·7 times through combined application of T-1055 at 16, 18 and 20 DAS, respectively. Combined application also increased the accumulation of PR-2 and PR-3 proteins by 3·3 and 3·9 times, respectively, at 12 DAS in followed by seed treatment alone. CONCLUSIONS: The combined application of T-1055 triggered defence responses in an enhanced level in sunflower than the soil and seed alone and provided better protection against Rhizoctonia seedling blight. SIGNIFICANCE AND IMPACT OF THE STUDY: Rhizospheric fungal bioagent 'T-1055' can enhance protection in sunflower against the R. solani pathogen through augmented elicitation of host defence responses.


Asunto(s)
Agentes de Control Biológico , Resistencia a la Enfermedad , Helianthus/microbiología , Enfermedades de las Plantas/prevención & control , Rhizoctonia , Trichoderma/fisiología , Oxidorreductasas de Alcohol/metabolismo , Catecol Oxidasa/metabolismo , Helianthus/enzimología , Helianthus/crecimiento & desarrollo , Fenilanina Amoníaco-Liasa/metabolismo , Enfermedades de las Plantas/microbiología , Raíces de Plantas/microbiología , Plantones/microbiología , Semillas/microbiología
19.
Mol Plant Pathol ; 25(5): e13461, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38695657

RESUMEN

Mitogen-activated protein kinase (MPK) cascades play central signalling roles in plant immunity and stress response. The soybean orthologue of MPK kinase2 (GmMKK2) was recently identified as a potential signalling node whose expression is upregulated in the feeding site induced by soybean cyst nematode (SCN, Heterodera glycines). To investigate the role of GmMKK2 in soybean-SCN interactions, we overexpressed a catabolically inactive variant referred to as kinase-dead variant (KD-GmMKK2) using transgenic hairy roots. KD-GmMKK2 overexpression caused significant reduction in soybean susceptibility to SCN, while overexpression of the wild-type variant (WT-GmMKK2) exhibited no effect on susceptibility. Transcriptome analysis indicated that KD-GmMKK2 overexpressing plants are primed for SCN resistance via constitutive activation of defence signalling, particularly those related to chitin, respiratory burst, hydrogen peroxide and salicylic acid. Phosphoproteomic profiling of the WT-GmMKK2 and KD-GmMKK2 root samples upon SCN infection resulted in the identification of 391 potential targets of GmMKK2. These targets are involved in a broad range of biological processes, including defence signalling, vesicle fusion, chromatin remodelling and nuclear organization among others. Furthermore, GmMKK2 mediates phosphorylation of numerous transcriptional and translational regulators, pointing to the presence of signalling shortcuts besides the canonical MAPK cascades to initiate downstream signalling that eventually regulates gene expression and translation initiation. Finally, the functional requirement of specific phosphorylation sites for soybean response to SCN infection was validated by overexpressing phospho-mimic and phospho-dead variants of two differentially phosphorylated proteins SUN1 and IDD4. Together, our analyses identify GmMKK2 impacts on signalling modules that regulate soybean response to SCN infection.


Asunto(s)
Glycine max , Enfermedades de las Plantas , Transducción de Señal , Tylenchoidea , Glycine max/parasitología , Glycine max/genética , Animales , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/genética , Tylenchoidea/fisiología , Tylenchoidea/patogenicidad , Regulación de la Expresión Génica de las Plantas , Plantas Modificadas Genéticamente , Raíces de Plantas/parasitología , Raíces de Plantas/metabolismo , Raíces de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Resistencia a la Enfermedad/genética
20.
Data Brief ; 54: 110301, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38524842

RESUMEN

Grapevines encounter many different pathogens throughout their lifespans, including the bacterial pathogen Xylella fastidiosa, which causes Pierce's disease that results in vascular occlusion and eventual plant host death, the fungal pathogen Neofusicoccum parvum, which causes stem cankers that kill individual vines and reduce fruit yields, and the root knot nematode Meloidogyne incognita, which destroys root tissues that impacts host vigour. To date, little research has been conducted to examine how one infection could impact subsequent infections by the same or different pathogens despite this is important to ensure healthy vineyards. Therefore, grapevines initially infected with either X. fastidiosa, N. parvum, or M. incognita were subsequently infected with N. parvum eight weeks later to observe developing lesion lengths, which were assessed to determine grapevine resistance to infections. Collected data shows that when prior infections were present, the N. parvum lesions lengths were smaller. This suggests grapevines had induced resistance to combat infections. Further, defence-associated phenolics were measured by high-performance liquid chromatography to determine roles in observed resistance to the secondary N. parvum infections. Data shows that of the different phenolics examined, only stilbenoids were different due to infections, with lowered levels observed in plants that were infected compared with non-infected controls. These data provide insight into how infections by different pathogens could impact grapevine host resistance to new, subsequent pathogen infections.

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