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1.
Arch Virol ; 166(2): 651-654, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33387023

RESUMEN

A novel lytic bacteriophage, Ralstonia phage RP13, was isolated from tomato fields in Pang Nga, Thailand. Electron microscopic observation showed it to have the features of a myovirus with a novel triangulation number (T = 21, dextro). The RP13 DNA appeared to be heavily modified. By applying RNA sequencing and RNA-sequence-mediated DNA sequencing, the whole genome of RP31 was determined to be 170,942 bp in length with a mean G+C content of 39.2%. A total of 277 ORFs were identified as structural, functional, or hypothetical genes in addition to four tRNA genes. Phylogenetic analysis suggested that RP13 is not closely related to any other known phages. Thus, we concluded that the RP13 is a novel phage infecting R. solanacearum strains and will be a useful biocontrol agent against bacterial wilt disease.


Asunto(s)
Bacteriófagos/genética , Genoma Viral/genética , Enfermedades de las Plantas/microbiología , Ralstonia solanacearum/virología , Composición de Base/genética , Genómica/métodos , Especificidad del Huésped/genética , Lycopersicon esculentum/microbiología , Sistemas de Lectura Abierta/genética , Filogenia , ARN de Transferencia/genética , Tailandia
2.
Ecotoxicol Environ Saf ; 208: 111688, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396020

RESUMEN

Elemental defense hypothesis suggests that toxic metals accumulated in plant tissues could enhance plant defense against herbivores and pathogens. Since over-accumulation of metals in plant organs will pose negative effects on plant health, it is necessary to find a way to alleviate metal-induced toxicity in plants while keeping or even improving plant resistance. Exogenous nitrogen (N) application was reported to have such alleviation effect while stimulating metal accumulation in plant tissues. In this study, we examined whether soil N addition in three different doses to a poplar species under cadmium (Cd) stress can simultaneously improve plant growth and resistance to four herbivorous insects and a leaf pathogen. The results showed that N application to Cd-amended soil prominently enhanced plant growth and leaf Cd accumulation. While N addition in three doses all remarkably reduced herbivore growth than control plants, only the highest N dose exerted stronger inhibition than the sole Cd-treated plants. In the paired-choice experiment, plants supplied with the highest N dose showed an enhanced deterrent effect on herbivore preference than plants exposed to sole Cd. Furthermore, plant resistance to the leaf pathogen infection was strongly enhanced as the levels of N addition increased. Leaf sugar and three main defensive chemicals were not affected by N application implied that such enhanced effect of N on plant resistance was due to increased leaf Cd accumulation. Our results suggested that the application of exogenous N over a certain amount could enhance the resistance of Cd-treated plants to leaf herbivory and pathogen infection.


Asunto(s)
Cadmio/toxicidad , Nitrógeno/farmacología , Hojas de la Planta/efectos de los fármacos , Populus/efectos de los fármacos , Contaminantes del Suelo/toxicidad , Animales , Cadmio/metabolismo , Herbivoria/efectos de los fármacos , Lepidópteros/efectos de los fármacos , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/microbiología , Populus/crecimiento & desarrollo , Populus/microbiología , Suelo/química , Contaminantes del Suelo/metabolismo
3.
BMC Plant Biol ; 21(1): 67, 2021 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-33514310

RESUMEN

BACKGROUND: Most plant viruses rely on vectors for their transmission and spread. One of the outstanding biological questions concerning the vector-pathogen-symbiont multi-trophic interactions is the potential involvement of vector symbionts in the virus transmission process. Here, we used a multi-factorial system containing a non-persistent plant virus, cucumber mosaic virus (CMV), its primary vector, green peach aphid, Myzus persicae, and the obligate endosymbiont, Buchnera aphidicola to explore this uncharted territory. RESULTS: Based on our preliminary research, we hypothesized that aphid endosymbiont B. aphidicola can facilitate CMV transmission by modulating plant volatile profiles. Gene expression analyses demonstrated that CMV infection reduced B. aphidicola abundance in M. persicae, in which lower abundance of B. aphidicola was associated with a preference shift in aphids from infected to healthy plants. Volatile profile analyses confirmed that feeding by aphids with lower B. aphidicola titers reduced the production of attractants, while increased the emission of deterrents. As a result, M. persicae changed their feeding preference from infected to healthy plants. CONCLUSIONS: We conclude that CMV infection reduces the B. aphidicola abundance in M. persicae. When viruliferous aphids feed on host plants, dynamic changes in obligate symbionts lead to a shift in plant volatiles from attraction to avoidance, thereby switching insect vector's feeding preference from infected to healthy plants.


Asunto(s)
Áfidos/virología , Buchnera/fisiología , Capsicum/virología , Cucumovirus/fisiología , Enfermedades de las Plantas/virología , Simbiosis , Animales , Áfidos/efectos de los fármacos , Áfidos/microbiología , Áfidos/fisiología , Capsicum/microbiología , Capsicum/parasitología , Conducta Alimentaria , Interacciones Huésped-Parásitos , Insectos Vectores/fisiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/parasitología , Rifampin/farmacología , Compuestos Orgánicos Volátiles/metabolismo
4.
Artículo en Inglés | MEDLINE | ID: mdl-33464199

RESUMEN

Wheat blue dwarf (WBD) is one of the most economically damaging cereal crop diseases in northwestern PR China. The agent associated with the WBD disease is a phytoplasma affiliated with the aster yellows (AY) group, subgroup C (16SrI-C). Since phytoplasma strains within the AY group are ecologically and genetically diverse, it has been conceived that the AY phytoplasma group may consist of more than one species. This communication presents evidence to demonstrate that, while each of the two 16 rRNA genes of the WBD phytoplasma shares >97.5 % sequence similarity with that of the 'Candidatus Phytoplasma asteris' reference strain, the WBD phytoplasma clearly represents an ecologically separated lineage: the WBD phytoplasma not only has its unique transmitting vector (Psammotettix striatus) but also elicits a distinctive symptom in its predominant plant host (wheat). In addition, the WBD phytoplasma possesses molecular characteristics that further manifest its significant divergence from 'Ca. P. asteris'. Such molecular characteristics include lineage-specific antigenic membrane proteins and a lower than 95 % genome-wide average nucleotide identity score with 'Ca. P. asteris'. These ecological, molecular and genomic evidences justify the recognition of the WBD phytoplasma as a novel taxon, 'Candidatus Phytoplasma tritici'.


Asunto(s)
Filogenia , Phytoplasma/clasificación , Enfermedades de las Plantas/microbiología , Triticum/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Phytoplasma/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
5.
Nat Commun ; 12(1): 705, 2021 01 29.
Artículo en Inglés | MEDLINE | ID: mdl-33514716

RESUMEN

Plant genomes encode hundreds of receptor kinases and peptides, but the number of known plant receptor-ligand pairs is limited. We report that the Arabidopsis leucine-rich repeat receptor kinase LRR-RK MALE DISCOVERER 1-INTERACTING RECEPTOR LIKE KINASE 2 (MIK2) is the receptor for the SERINE RICH ENDOGENOUS PEPTIDE (SCOOP) phytocytokines. MIK2 is necessary and sufficient for immune responses triggered by multiple SCOOP peptides, suggesting that MIK2 is the receptor for this divergent family of peptides. Accordingly, the SCOOP12 peptide directly binds MIK2 and triggers complex formation between MIK2 and the BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1) co-receptor. MIK2 is required for resistance to the important root pathogen Fusarium oxysporum. Notably, we reveal that Fusarium proteomes encode SCOOP-like sequences, and corresponding synthetic peptides induce MIK2-dependent immune responses. These results suggest that MIK2 may recognise Fusarium-derived SCOOP-like sequences to induce immunity against Fusarium. The definition of SCOOPs as MIK2 ligands will help to unravel the multiple roles played by MIK2 during plant growth, development and stress responses.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/inmunología , Proteínas Fúngicas/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Enfermedades de las Plantas/inmunología , Proteínas Quinasas/metabolismo , Receptores de Superficie Celular/metabolismo , Arabidopsis/metabolismo , Arabidopsis/microbiología , Proteínas de Arabidopsis/inmunología , Clonación Molecular , Resistencia a la Enfermedad/inmunología , Proteínas Fúngicas/inmunología , Fusarium/inmunología , Fusarium/metabolismo , Fusarium/patogenicidad , Péptidos y Proteínas de Señalización Intercelular/inmunología , Ligandos , Enfermedades de las Plantas/microbiología , Raíces de Plantas/inmunología , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Plantas Modificadas Genéticamente , Proteínas Quinasas/inmunología , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores de Superficie Celular/inmunología , Transducción de Señal/inmunología , Tabaco/genética , Tabaco/inmunología
6.
Arch Virol ; 166(3): 973-976, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33427965

RESUMEN

In this study, a new double-stranded RNA (dsRNA) virus, Alternaria tenuissima partitivirus 1 (AttPV1), was isolated from Alternaria tenuissima strain XJ-BZ-2-6, a phytopathogenic fungus infecting cotton in China. The genome of AttPV1 comprised three dsRNAs of 1,785 nt (dsRNA1), 1,545 nt (dsRNA2), and 1,537 nt (dsRNA3) in length, the nucleotide sequence of which was determined using reverse transcription polymerase chain reaction, random-primed clones, and RNA-ligase-mediated rapid amplification of cDNA ends. dsRNA1 had a single open reading frame encoding a putative 61.54-kDa RNA-dependent RNA polymerase (RdRp). dsRNA2 and dsRNA3 were predicted to encode putative coat proteins (CPs) of 47.90 kDa and 46.25 kDa, respectively. The RdRp domain shared 63.54-73.17% amino acid sequence identity with members of the genus Gammapartitivirus. Phylogenetic trees based on RdRp or CP sequences showed that AttPV1 clustered with members of the genus Gammapartitivirus. Hence, these results indicate that AttPV1 is a new gammapartitivirus from A. tenuissima.


Asunto(s)
Alternaria/virología , Virus Fúngicos/genética , Genoma Viral/genética , Virus ARN/genética , ARN Viral/genética , Secuencia de Aminoácidos , Secuencia de Bases , Proteínas de la Cápside/genética , China , Virus Fúngicos/clasificación , Virus Fúngicos/aislamiento & purificación , Gossypium/microbiología , Sistemas de Lectura Abierta/genética , Enfermedades de las Plantas/microbiología , Virus ARN/clasificación , Virus ARN/aislamiento & purificación , ARN Bicatenario/genética , Alineación de Secuencia , Proteínas Virales/genética
7.
Food Chem ; 339: 127858, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32829246

RESUMEN

Olive anthracnose is caused by fungal species within the Colletotrichum acutatum, C. gloeosporioides and C. boninense complexes. Anthracnose causes severe pre- and post-harvest olive drupe fall. This study aimed to design a species-specific qPCR assay, based on klap1 gene, suitable for C. acutatum s.s. quantification in cv. Galega Vulgar fruit samples. The developed qPCR assay presented a detection limit of 10.14 fg/reaction, and a linear cycle threshold of R2 = 0.996. C. acutatum inoculum was detected in pulverized olive fruits, and in early infection stages, before symptom appearance, 16 h after inoculation (Ct values = 28.29 ± 1.1). In olive samples, the derived melting curve was specific presenting a single dissociation peak (Tmelting = 88.7 °C). The designed assay was effectively applied in C. acutatum detection and quantification using infected olive samples, with a LOD of 0.59 ng and a LOQ of 1.8 ng, allowing its application to orchard management.


Asunto(s)
Colletotrichum/genética , Colletotrichum/aislamiento & purificación , Frutas/microbiología , Olea/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Enfermedades de las Plantas/microbiología , Especificidad de la Especie
8.
Ecotoxicol Environ Saf ; 209: 111749, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33348258

RESUMEN

Elucidation of the inhibitory effects of humic substances (HSs) on phytopathogenic fungi and the underlying molecular mechanisms are highly important for improved biocontrol. In this study, we investigated the growth suppression, morphological characteristics, transcriptomic sequence, and radical signals of Rhizoctonia solani following HS addition (50 mg/L). Through mycelial cultured experiment, mycelia growth of R. solani had been suppressed with HS addition, and the inhibition rate was 24.88 ± 0.11% compared to the control. Field emission-scanning electron microscopy showed increased and superimposed branching mycelial growth, with a shriveled appearance. RNA samples of R. solani cultured with or without HSs were both extracted to examine the sequence on molecular level by Illumina HiSeq sequencing platform. RNA sequencing analysis revealed 175 differentially expressed genes (DEGs; 111 upregulated and 64 downregulated) between the HSs treatment and control. The upregulated unigenes were annotated and significantly enriched to three molecular processes: vitamin B6 metabolism, ABC transporters, and glutathione metabolism, while the downregulated unigenes were annotated to carbohydrate metabolism, but not significantly enriched. Real time-quantitative polymerase chain reaction analysis showed that the unigenes related to hexokinase, glucose-6-phosphate isomerase, glutathione synthase, and glutathione reductase were significantly decreased (by 60.03%, 70.70%, 60.33%, and 57.59%, respectively), while those related to glutathione S-transferase were significantly increased (2.66-fold). The electron paramagnetic resonance spectra showed that HSs induced increased the intensity of radical signals of R. solani in a cultured system increased by 59.56% compared to CK (without HSs addition). Network analysis based on DEGs expression and the chemical structure of HSs revealed that the carbonyl moiety in HSs formed the most links with nodes of the DEGs (sum of the links of positive and negative effects = 70), implicating this structure as the active fraction responsible for the inhibitory effect. This study provides molecular and chemical evidence of the biofungicidal activity of HSs with the potential for practical application.


Asunto(s)
Sustancias Húmicas , Rhizoctonia/fisiología , Micelio , Enfermedades de las Plantas/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Rhizoctonia/efectos de los fármacos , Rhizoctonia/genética , Rhizoctonia/crecimiento & desarrollo , Transcriptoma
9.
Ecotoxicol Environ Saf ; 209: 111813, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33360212

RESUMEN

Phytophthora capsici causes a severe soil-borne disease in a wide variety of vegetables; to date, no effective strategies to control P. capsici have been developed. Liquiritin (LQ) is a natural flavonoid found in licorice (Glycyrrhiza spp.) root, and it is used in pharmaceuticals. However, the antifungal activity of LQ against P. capsici remains unknown. In the present study, we demonstrated that LQ inhibits P. capsici mycelial growth and sporangial development. In addition, the EC50 of LQ was 658.4 mg/L and LQ caused P. capsici sporangia to shrink and collapse. Next, LQ severely damaged the cell membrane integrity, leading to a 2.0-2.5-fold increase in relative electrical conductivity and malondialdehyde concentration, and a 65-70% decrease in sugar content. Additionally, the H2O2 content was increased about 2.0-2.5 fold, but the total antioxidant activity, catalase activity and laccase activity were attenuated by 40-45%, 30-35% and 70-75%. LQ also induced autophagy, apoptosis, and reduction of intracellular Ca2+ content. Furthermore, LQ inhibited P. capsici pathogenicity by reducing the expression of virulence genes PcCRN4 and Pc76RTF, and stimulating the plant defense (including the activated transcriptional expression of defense-related genes CaPR1, CaDEF1, and CaSAR82, and the increased antioxidant enzyme activity). Our results not only elucidate the antifungal mechanism of LQ but also suggest a promising alternative to commercial fungicides or a key compound in the development of new fungicides for the control of the Phytophthora disease.


Asunto(s)
Antifúngicos/farmacología , Capsicum/fisiología , Flavanonas/farmacología , Fungicidas Industriales/farmacología , Glucósidos/farmacología , Phytophthora/efectos de los fármacos , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Capsicum/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Enfermedades de las Plantas/microbiología , Plantas/efectos de los fármacos , Suelo , Verduras/efectos de los fármacos , Virulencia/efectos de los fármacos
10.
Food Chem ; 337: 127772, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32777571

RESUMEN

Chitosan can function a key role in plant resistant against Botrytis cinerea infection, while its mechanism is unclear in ripened fruits. In this study, we investigated the chitosan effect on two type of ripened fruits including strawberry and grapes (Kyoho and Shine-Muscat) when were infected with B. cinerea. Results showed that chitosan inhibited B. cinerea growth, increased phenolic compounds and cell wall composition, modulated oxidative stress and induced jasmonic acid (JA) production in ripened fruits. Data-independent acquisition (DIA) showed that 224 and 171 proteins were upregulated 1.5-fold by chitosan in Kyoho and Shine-Muscat grape, respectively. Topless-related protein 3 (TPR3) were identified and interacted with histone deacetylase 19 (HDAC19) and negatively regulated by JA and chitosan. Meanwhile, overexpression of VvTPR3 and VvHDAC19 reduced the stability of cell wall against B. cinerea in strawberry. Taken together, chitosan induces defense related genes and protect the fruit quality against Botrytis infection through JA signaling.


Asunto(s)
Botrytis/efectos de los fármacos , Quitosano/farmacología , Ciclopentanos/metabolismo , Fragaria/metabolismo , Oxilipinas/metabolismo , Vitis/metabolismo , Botrytis/fisiología , Pared Celular/metabolismo , Fragaria/microbiología , Frutas/metabolismo , Frutas/microbiología , Histona Desacetilasas/genética , Histona Desacetilasas/metabolismo , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/antagonistas & inhibidores , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Interferencia de ARN , Esporas Fúngicas/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Vitis/microbiología
11.
Gene ; 764: 145078, 2021 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-32858175

RESUMEN

In maize, eat rot and stalk rot caused by Fusarium verticillioides and Fusarium graminearum lead to contamination of moldy grains to produce mycotoxins. Identification of resistance genes against these pathogens for maize breeding is an effective way for disease control. Several 2-oxoglutarate-dependent dioxygenase (2OGD) proteins have been found to confer resistance to different pathogens in diverse plant species. However, little is known about the 2OGD superfamily in maize. Here, we identified 103 putative 2OGD genes in maize from a genome-wide analysis, and divided them into three classes - DOXA, DOXB, and DOXC. We further comprehensively investigated their gene structure, chromosome distribution, phylogenetic tree, gene-function enrichment, and expression profiles among different tissues. The genes encoding three 2OGD proteins, ACO, F3H, and NCS involved in ethylene biosynthesis, flavonoids biosynthesis, and alkaloids biosynthesis pathways, respectively, were identified to be induced by F. verticillioides and F. graminearum. The promoters of the three genes contain the binding sites for the transcription factor ZmDOF and ZmHSF, which are also induced by the two pathogens. The results imply that the three 2OGDs and the two transcription factors might be involved in the resistance to the two pathogens. This study provided a comprehensive understanding of the 2OGD superfamily in maize and laid the foundation for the further functional analysis of their roles in maize resistance to eat rot and stalk rot.


Asunto(s)
Dioxigenasas/genética , Fusarium/inmunología , Proteínas de Plantas/genética , Zea mays/fisiología , Secuencia de Bases/genética , Sitios de Unión/genética , Cromosomas de las Plantas/genética , Coenzimas/metabolismo , Secuencia Conservada/genética , Dioxigenasas/inmunología , Dioxigenasas/metabolismo , Resistencia a la Enfermedad/genética , Evolución Molecular , Fusarium/patogenicidad , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas/fisiología , Estudio de Asociación del Genoma Completo , Ácidos Cetoglutáricos/metabolismo , Filogenia , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/inmunología , Proteínas de Plantas/metabolismo , Tallos de la Planta/enzimología , Tallos de la Planta/crecimiento & desarrollo , Tallos de la Planta/microbiología , Regiones Promotoras Genéticas/genética , RNA-Seq , Factores de Transcripción/metabolismo , Zea mays/microbiología
12.
Gene ; 764: 145081, 2021 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-32860897

RESUMEN

Metalaxyl is one of the main fungicides used to control pepper blight caused by Phytophthora capsici. Metalaxyl resistance of P. capsici, caused by the long-term intense use of this fungicide, has become one of the most serious challenges facing pest management. In this study, a conserved domain RPOLA-N of the RPA190 gene of P. capsici (RPA190-pc) was identified from the P. capsici SD1-9 strain. The role of the RPA190-pc underlying the metalaxyl resistance of P. capsici was investigated. Three P. capsici mutants, two with downregulated RPA190-pc (SD1-9C-3 and C-4) expression and one showing upregulation (OESD1-9-1), were obtained by Polyethylene Glycol (PEG) mediated protoplast transformations of P. capsici SD1-9. Quantitative real-time reverse transcription PCR results showed that RPA190-pc was downregulated by more than 60% in SD1-9C-3/C-4 and upregulated 3-fold in OESD1-9-1 compared with that of the control strain SD1-9. Evaluation of the metalaxyl resistance of these three transformants showed that the EC50 values of metalaxyl against SD1-9C-3, SD1-9C-4, and OESD1-9-1 were 120.0 µg·mL-1, 24.4 µg·mL-1, and 15573.0 µg·mL-1, respectively, corresponding to 63.3% decrease, 92.5% decrease, and 47.7-fold increase relative to the EC50 value in SD1-9. Compared with SD1-9, the mycelia of transformants SD1-9C-3, SD1-9C-4, and OESD1-9-1 showed more branches and shorter branches; and the transformants had different pathogenicity to different hosts plants. The expression of the candidate gene RPA190-pc during 10 life-history stages was further studied, the results showed that expression level reached a maximum at the zoospores stage, and it gradually increased with the increase of SD1 and SD1-9 infection time of pepper leaves, indicated that RPA190-pc may be related to the growth and pathogenicity of P. capsici. These results indicate that the expression of RPA190-pc is involved in the regulation of P. capsici resistance to metalaxyl.


Asunto(s)
Farmacorresistencia Fúngica/genética , Proteínas Fúngicas/genética , Fungicidas Industriales/farmacología , Phytophthora/genética , ARN Polimerasa I/genética , Alanina/análogos & derivados , Alanina/farmacología , Capsicum/microbiología , Regulación del Desarrollo de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Genes Fúngicos , Estadios del Ciclo de Vida/genética , Mutación , Micelio/genética , Micelio/crecimiento & desarrollo , Phytophthora/efectos de los fármacos , Phytophthora/crecimiento & desarrollo , Phytophthora/patogenicidad , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Hojas de la Planta/microbiología , Dominios Proteicos/genética , Esporangios/genética , Esporangios/crecimiento & desarrollo , Virulencia/genética
13.
Food Chem ; 337: 127992, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32920270

RESUMEN

Mechanical wounding causes significant economic losses of fresh produce due to accelerated senescence and spoilage as well as loss of nutritional value. Here, pre-application of oligogalacturonides (OGs) enzymatically hydrolyzed from apple pectin effectively reduced the healing times of mechanical wounds from>24 h in mock groups to 12 h, and the Botrytis cinerea infection rate was reduced from 37.5% to 12.5%. OGs accordingly increased callose deposition; SlPR1, SlPAL and SlHCT gene expression; and phenylalanine ammonia-lyase (PAL) activity around the wounds. Inhibition of Ca2+ signaling using the inhibitor Ruthenium Red markedly inhibited OG accelerated healing of mechanical wounding on fruit. SlPG2, SlEXP1, and SlCEL2 mRNAs accumulation was reduced in OG-elicited tomato fruit compared to water-treated fruit with subsequent retardation of the fruit softening during ripening. These results indicated that apple pectin OGs accelerate wound healing and inhibit fruit softening by activating calcium signaling in tomato fruits during postharvest storage.


Asunto(s)
Lycopersicon esculentum/efectos de los fármacos , Lycopersicon esculentum/fisiología , Oligosacáridos/farmacología , Botrytis/patogenicidad , Calcio/metabolismo , Frutas/efectos de los fármacos , Frutas/metabolismo , Frutas/microbiología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Glucanos/metabolismo , Hidrólisis , Lycopersicon esculentum/microbiología , Malus/química , Oligosacáridos/química , Pectinas/química , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
14.
PLoS One ; 15(12): e0232648, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33378350

RESUMEN

Verticillium wilt, caused by the soil-borne fungus Verticillium dahliae, is one of the most harmful diseases in Mediterranean olive-growing areas. Although, the effects of both soil temperature and moisture on V. dahliae are well known, there is scant knowledge about what climatic drivers affect the occurrence of the pathogen on a large scale. Here, we investigate what climatic drivers determine V. dahliae occurrence in olive-growing areas in southern Spain. In order to bridge this gap in knowledge, a large-scale field survey was carried out to collect data on the occurrence of V. dahliae in 779 olive groves in Granada province. Forty models based on competing combinations of climatic variables were fitted and evaluated using information-theoretic methods. A model that included a multiplicative combination of seasonal and extreme climatic variables was found to be the most viable one. Isothermality and the seasonal distribution of precipitation were the most important variables influencing the occurrence of the pathogen. The isothermal effect was in turn modulated by the seasonality of rainfall, and this became less negative as seasonality increases. Thus, V. dahliae occurs more frequently in olive-growing areas where the day-night temperature oscillation is lower than the summer-winter one. We also found that irrigation reduced the influence of isothermality on occurrence. Our results demonstrate that long-term compound climatic factors rather than "primary" variables, such as annual trends, can better explain the spatial patterns of V. dahliae occurrence in Mediterranean, southern Spain. One important implication of our study is that appropriate irrigation management, when temperature oscillation approaches optimal conditions for V. dahliae to thrive, may reduce the appearance of symptoms in olive trees.


Asunto(s)
Ascomicetos , Clima , Olea/microbiología , Enfermedades de las Plantas/microbiología , Raíces de Plantas/microbiología , Estaciones del Año , España , Temperatura
15.
Proc Biol Sci ; 287(1941): 20202723, 2020 12 23.
Artículo en Inglés | MEDLINE | ID: mdl-33352079

RESUMEN

Natural plant populations encounter strong pathogen pressure and defence-associated genes are known to be under selection dependent on the pressure by the pathogens. Here, we use populations of the wild tomato Solanum chilense to investigate natural resistance against Cladosporium fulvum, a well-known ascomycete pathogen of domesticated tomatoes. Host populations used are from distinct geographical origins and share a defined evolutionary history. We show that distinct populations of S. chilense differ in resistance against the pathogen. Screening for major resistance gene-mediated pathogen recognition throughout the whole species showed clear geographical differences between populations and complete loss of pathogen recognition in the south of the species range. In addition, we observed high complexity in a homologues of Cladosporium resistance (Hcr) locus, underlying the recognition of C. fulvum, in central and northern populations. Our findings show that major gene-mediated recognition specificity is diverse in a natural plant-pathosystem. We place major gene resistance in a geographical context that also defined the evolutionary history of that species. Data suggest that the underlying loci are more complex than previously anticipated, with small-scale gene recombination being possibly responsible for maintaining balanced polymorphisms in the populations that experience pathogen pressure.


Asunto(s)
Ascomicetos , Lycopersicon esculentum/fisiología , Enfermedades de las Plantas/microbiología , Cladosporium , Resistencia a la Enfermedad , Genes de Plantas , Lycopersicon esculentum/microbiología , Solanum
16.
PLoS One ; 15(12): e0243445, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33338052

RESUMEN

Pierce's disease (PD) caused by the bacterium Xylella fastidiosa is a deadly disease of grapevines. This study used 20 SSR markers to genotype 326 accessions of grape species collected from the southeastern and southwestern United States, Mexico and Costa Rica. Two hundred sixty-six of these accessions, and an additional 12 PD resistant hybrid cultivars developed from southeastern US grape species, were evaluated for PD resistance. Disease resistance was evaluated by quantifying the level of bacteria in stems and measuring PD symptoms on the canes and leaves. Both Bayesian clustering and principal coordinate analyses identified two groups with an east-west divide: group 1 consisted of grape species from the southeastern US and Mexico, and group 2 consisted of accessions collected from the southwestern US and Mexico. The Sierra Madre Oriental mountain range appeared to be a phylogeographic barrier. The state of Texas was identified as a potential hybridization zone. The hierarchal STRUCTURE analysis on each group showed clustering of unique grape species. An east-west divide was also observed for PD resistance. With the exception of Vitis candicans and V. cinerea accessions collected from Mexico, all other grape species as well as the resistant southeastern hybrid cultivars were susceptible to the disease. Southwestern US grape accessions from drier desert regions showed stronger resistance to the disease. Strong PD resistance was observed within three distinct genetic clusters of V. arizonica which is adapted to drier environments and hybridizes freely with other species across its wide range.


Asunto(s)
Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/microbiología , Vitis/crecimiento & desarrollo , Xylella/patogenicidad , Costa Rica , Genotipo , Humanos , Hibridación Genética/genética , México , Enfermedades de las Plantas/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/microbiología , Sudoeste de Estados Unidos , Texas , Vitis/genética , Vitis/microbiología
17.
BMC Plant Biol ; 20(1): 563, 2020 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-33317452

RESUMEN

BACKGROUND: Bacterial blight, which is caused by Xanthomonas oryzae pv. oryzae (Xoo), is a devastating rice disease worldwide. Rice introgression line H471, derived from the recurrent parent Huang-Hua-Zhan (HHZ) and the donor parent PSBRC28, exhibits broad-spectrum resistance to Xoo, including to the highly virulent Xoo strain PXO99A, whereas its parents are susceptible to PXO99A. To characterize the responses to Xoo, we compared the proteome profiles of the host and pathogen in the incompatible interaction (H471 inoculated with PXO99A) and the compatible interaction (HHZ inoculated with PXO99A). RESULTS: In this study, a total of 374 rice differentially abundant proteins (DAPs) and 117 Xoo DAPs were detected in the comparison between H471 + PXO99A and HHZ + PXO99A. Most of the Xoo DAPs related to pathogen virulence, including the outer member proteins, type III secretion system proteins, TonB-dependent receptors, and transcription activator-like effectors, were less abundant in the incompatible interaction than in the compatible interaction. The rice DAPs were mainly involved in secondary metabolic processes, including phenylalanine metabolism and the biosynthesis of flavonoids and phenylpropanoids. Additionally, some DAPs involved in the phenolic phytoalexin and salicylic acid (SA) biosynthetic pathways accumulated much more in H471 than in HHZ after the inoculation with PXO99A, suggesting that phytoalexin and SA productions were induced faster in H471 than in HHZ. Further analyses revealed that the SA content increased much more rapidly in H471 than in HHZ after the inoculation, suggesting that the SA signaling pathway was activated faster in the incompatible interaction than in the compatible interaction. CONCLUSIONS: Overall, our results indicate that during an incompatible interaction between H471 and PXO99A, rice plants prevent pathogen invasion and also initiate multi-component defense responses that inhibit disease development.


Asunto(s)
Oryza/metabolismo , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/metabolismo , Proteoma , Xanthomonas/fisiología , Oryza/microbiología , Proteómica
18.
Nat Commun ; 11(1): 5802, 2020 11 16.
Artículo en Inglés | MEDLINE | ID: mdl-33199718

RESUMEN

A major bottleneck in identifying therapies to control citrus greening and other devastating plant diseases caused by fastidious pathogens is our inability to culture the pathogens in defined media or axenic cultures. As such, conventional approaches for antimicrobial evaluation (genetic or chemical) rely on time-consuming, low-throughput and inherently variable whole-plant assays. Here, we report that plant hairy roots support the growth of fastidious pathogens like Candidatus Liberibacter spp., the presumptive causal agents of citrus greening, potato zebra chip and tomato vein greening diseases. Importantly, we leverage the microbial hairy roots for rapid, reproducible efficacy screening of multiple therapies. We identify six antimicrobial peptides, two plant immune regulators and eight chemicals which inhibit Candidatus Liberibacter spp. in plant tissues. The antimicrobials, either singly or in combination, can be used as near- and long-term therapies to control citrus greening, potato zebra chip and tomato vein greening diseases.


Asunto(s)
Antiinfecciosos/farmacología , Ensayos Analíticos de Alto Rendimiento , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Rhizobiaceae/fisiología , Secuencia de Bases , Citrus/efectos de los fármacos , Citrus/microbiología , Edición Génica , Lycopersicon esculentum/efectos de los fármacos , Lycopersicon esculentum/microbiología , Enfermedades de las Plantas/microbiología , Raíces de Plantas/genética , Rhizobiaceae/efectos de los fármacos , Solanum tuberosum/efectos de los fármacos , Solanum tuberosum/microbiología , Transgenes
19.
Vet Clin North Am Food Anim Pract ; 36(3): 745-774, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33032704

RESUMEN

This review focuses on factors associated with mold production in feedstuffs and major mycotoxins affecting ruminants in North America. Ruminants are often considered less sensitive to mycotoxins owing to rumen microflora metabolism to less toxic compounds. However, ruminants occupy wide agricultural niches that expose animals to diverse toxins under widely different environmental and nutritional conditions. Often the moldy and potentially highly contaminated feeds end up at feedlots. Less than optimal feedstuffs creating suboptimal rumen microbial flora could result in decreased ruminal capacity to detoxify certain mycotoxins and adverse effects. Numerous mycotoxins and clinical effects in ruminants are discussed.


Asunto(s)
Productos Agrícolas/microbiología , Micotoxicosis/veterinaria , Micotoxinas/envenenamiento , Enfermedades de las Plantas/microbiología , Rumiantes , Alimentación Animal/análisis , Alimentación Animal/microbiología , Animales , Micotoxicosis/metabolismo , América del Norte
20.
Nat Commun ; 11(1): 5264, 2020 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-33067433

RESUMEN

Soil-inhabiting fungal pathogens use chemical signals released by roots to direct hyphal growth towards the host plant. Whether other soil microorganisms exploit this capacity for their own benefit is currently unknown. Here we show that the endophytic rhizobacterium Rahnella aquatilis locates hyphae of the root-infecting fungal pathogen Fusarium oxysporum through pH-mediated chemotaxis and uses them as highways to efficiently access and colonize plant roots. Secretion of gluconic acid (GlcA) by R. aquatilis in the rhizosphere leads to acidification and counteracts F. oxysporum-induced alkalinisation, a known virulence mechanism, thereby preventing fungal infection. Genetic abrogation or biochemical inhibition of GlcA-mediated acidification abolished biocontrol activity of R. aquatilis and restored fungal infection. These findings reveal a new way by which bacterial endophytes hijack hyphae of a fungal pathogen in the soil to gain preferential access to plant roots, thereby protecting the host from infection.


Asunto(s)
Endófitos/fisiología , Fusarium/fisiología , Rahnella/fisiología , Quimiotaxis , Endófitos/genética , Fusarium/genética , Hifa , Lycopersicon esculentum/microbiología , Enfermedades de las Plantas/microbiología , Raíces de Plantas/microbiología , Plantas , Rahnella/genética
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