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1.
Microb Ecol ; 87(1): 119, 2024 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-39340548

RESUMO

Microbiota associated with host-parasite relationships offer an opportunity to explore interactions among plants, parasites, and microbes, thereby contributing to the overall complexity of community structures. The dynamics of ecological interactions between parasitic plants and their hosts in arid environments remain largely understudied, especially in Africa. This study aimed to examine the bacterial communities of Cuscuta epithymum L. (clover dodder), an epiphytic parasitic plant, and its host, Ziziphus lotus L. (jujuba), in an arid environment. Our goal was to uncover the ecological complexities of microbial communities within the framework of plant-plant interactions. We conducted a comprehensive analysis of the bacterial composition and diversity within populations of the C. epithymum parasite, the infected- and non-infected jujuba host, and their interface at the shoots of the host. This involved amplicon sequencing, targeting the V5-V6 regions of the 16S rRNA gene. A total of 5680 amplicon sequence variants (ASVs) were identified, with Pseudomonadota, Bacillota, and Actinobacteriota being prevalent phyla. Among the bacterial communities, three genera were dominant: Cutibacterium, Staphylococcus, and Acinetobacter. Interestingly, analyses of alpha-diversity (p = 0.3 for Shannon index and p = 0.5 for Simplon index) and beta-diversity (PERMANOVA, with p-values of 0.6 and 0.3) revealed no significant differences between Cuscuta-infected and non-infected jujube shrubs, suggesting a shared shoot endophytic bacteriome. This finding advances our comprehension of microbial communities linked to plant-parasite interactions in the arid environments of Africa. Further research on various hosts is required to confirm plant-to-plant bacterial transmission through Cuscuta infection. Additionally, studies on functional diversity, cytology, ecophysiology and the mechanisms by which bacterial communities transferred between host and parasite are necessary.


Assuntos
Bactérias , Cuscuta , Endófitos , Microbiota , RNA Ribossômico 16S , Ziziphus , Cuscuta/fisiologia , Cuscuta/microbiologia , Cuscuta/genética , Ziziphus/microbiologia , RNA Ribossômico 16S/genética , Endófitos/genética , Endófitos/fisiologia , Endófitos/classificação , Endófitos/isolamento & purificação , Bactérias/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Interações Hospedeiro-Parasita , DNA Bacteriano/genética
2.
Mycorrhiza ; 25(7): 573-85, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25720736

RESUMO

Seedlings of parasitic Cuscuta species are autotrophic but can survive only a short period of time, during which they must locate and attach to a suitable host. They have an ephemeral root-like organ considered not a "true" root by most studies. In the present study, two species with contrasting ecology were examined: Cuscuta gronovii, a North American riparian species, and Cuscuta campestris, an invasive dodder that thrives in disturbed habitats. The morphology, structure, and absorptive capability of their root-like organ were compared, their potential for colonization by two species of arbuscular mycorrhizal fungi (AMF) was assessed, and the effect of the AMF on seedling growth and survival was determined. The root of both species absorbed water and interacted with AMF, but the two species exhibited dissimilar growth and survival patterns depending on the colonization level of their seedlings. The extensively colonized seedlings of C. gronovii grew more and survived longer than non-colonized seedlings. In contrast, the scarce colonization of C. campestris seedlings did not increase their growth or longevity. The differential growth responses of the AMF-colonized and non-colonized Cuscuta species suggest a mycorrhizal relationship and reflect their ecology. While C. gronovii roots have retained a higher ability to interact with AMF and are likely to take advantage of fungal communities in riparian habitats, the invasive C. campestris has largely lost this ability possibly as an adaptation to disturbed ecosystems. These results indicate that dodders have a true root, even if much reduced and ephemeral, that can interact with AMF.


Assuntos
Cuscuta/crescimento & desenvolvimento , Cuscuta/microbiologia , Micorrizas/fisiologia , Cuscuta/anatomia & histologia , Cuscuta/metabolismo , Ecossistema , Plântula/anatomia & histologia , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Plântula/microbiologia , Especificidade da Espécie
3.
Mol Plant Microbe Interact ; 24(4): 458-68, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21190436

RESUMO

Huanglongbing (HLB), also known as citrus greening, is a lethal disease of citrus caused by several species of 'Candidatus Liberibacter', a psyllid-transmitted, phloem-limited, alpha proteobacteria. 'Ca. Liberibacter asiaticus' is widespread in Florida citrus. The recently published 'Ca. L. asiaticus' psy62 genome, derived from a psyllid, revealed a prophage-like region of DNA in the genome, but phage have not been associated with 'Ca. L. asiaticus' to date. In the present study, shotgun sequencing and a fosmid DNA library of curated 'Ca. L. asiaticus' UF506, originally derived from citrus symptomatic for HLB, revealed two largely homologous, circular phage genomes, SC1 and SC2. SC2 encoded putative adhesin and peroxidase genes that had not previously been identified in 'Ca. L. asiaticus' and which may be involved in lysogenic conversion. SC2 also appeared to lack lytic cycle genes and replicated as a prophage excision plasmid, in addition to being found integrated in tandem with SC1 in the UF506 chromosome. By contrast, SC1 carried suspected lytic cycle genes and was found in nonintegrated, lytic cycle forms only in planta. Phage particles associated with 'Ca. L. asiaticus' were found in the phloem of infected periwinkles by transmission electron microscopy. In psyllids, both SC1 and SC2 were found only as prophage.


Assuntos
Bacteriófagos/genética , Bacteriófagos/fisiologia , Doenças das Plantas/microbiologia , Prófagos/genética , Rhizobiaceae/virologia , Animais , Bacteriófagos/classificação , Bacteriófagos/ultraestrutura , Cromossomos Bacterianos/virologia , Citrus/microbiologia , Cuscuta/microbiologia , DNA Bacteriano/genética , DNA Circular , DNA Viral , Florida , Genoma Viral , Hemípteros/microbiologia , Microscopia Eletrônica de Transmissão , Anotação de Sequência Molecular , Floema/microbiologia , Floema/ultraestrutura , Doenças das Plantas/genética , Plasmídeos , Prófagos/classificação , Prófagos/isolamento & purificação , Prófagos/fisiologia , Origem de Replicação , Rhizobiaceae/genética , Rhizobiaceae/isolamento & purificação , Rhizobiaceae/patogenicidade , Análise de Sequência de DNA , Vinca/microbiologia , Vinca/ultraestrutura , Ativação Viral , Integração Viral , Replicação Viral
4.
Phytopathology ; 100(8): 756-62, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20626279

RESUMO

Huanglongbing, or citrus greening, threatens the global citrus industry. The presumptive pathogens, 'Candidatus Liberibacter asiaticus' and 'Ca. L. americanus' can be transferred from citrus to more easily studied experimental hosts by using holoparasitic dodder plants. However, the interaction between 'Candidatus Liberibacter' spp. and the dodder has not been studied. We combined quantitative polymerase chain reaction with electron microscopy to show that only 65% of tendrils of Cuscuta indecora grown on 'Ca. Liberibacter' spp.-infected host plants had detectable levels of the pathogen. Among tendrils that were colonized by Liberibacter in at least one 2 cm segment, most were not colonized in all segments. Furthermore, the estimated population levels of the pathogen present in serial 2 cm segments of dodder tendrils varied widely and without any consistent pattern. Thus, there was generally not a concentration gradient of the pathogen from the source plant towards the recipient and populations of the pathogen were sometimes found in the distal segments of the dodder plant but not in the proximal or middle segments. Populations of the pathogens ranged from 2 x 10(2) to 3.0 x 10(8) cells per 2 cm segment. On a fresh weight basis, populations as high as 1.4 x 10(10) cells per g of tissue were observed demonstrating that 'Ca. Liberibacter' spp. multiplies well in Cuscuta indecora. However, 55% of individual stem segments did not contain detectable levels of the pathogen, consistent with a pattern of nonuniform colonization similar to that observed in the much more anatomically complex citrus tree. Colonization of dodder by the pathogen is also nonuniform at the ultrastructural level, with adjacent phloem vessel elements being completely full of the pathogen or free of the pathogen. We also observed bacteria in the phloem vessels that belonged to two distinct size classes based on the diameters of cross sections of cells. In other sections from the same tendrils we observed single bacterial cells that were apparently in the process of differentiating between the large and round forms to the long and thin forms (or vice versa). The process controlling this morphological differentiation of the pathogen is not known. The highly reduced and simplified anatomy of the dodder plant as well as its rapid growth rate compared with citrus, and the ability of the plant to support multiplication of the pathogen to high levels, makes it an interesting host plant for further studies of host-pathogen interactions.


Assuntos
Citrus/microbiologia , Cuscuta/microbiologia , Interações Hospedeiro-Patógeno , Rhizobiaceae/fisiologia , Citrus/parasitologia , Cuscuta/fisiologia , Floema/microbiologia , Doenças das Plantas/microbiologia , Rhizobiaceae/ultraestrutura
5.
Methods Mol Biol ; 938: 41-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22987404

RESUMO

Transmission of phytoplasmas from naturally infected plant host species using the parasitic plant Cuscuta spp. (dodder) to Catharanthus roseus (Madagascar periwinkle) is an effective way to maintain a wide range of phytoplasmas for further research. Here, we describe transmission via dodder from an infected medicinal plant Rehmannia glutinosa var. purpurea and from a symptomatic redcurrant plant (Ribes spp.) to C. roseus indicator plants using a "stable bridges" method. In both cases, typical symptoms of phytoplasma disease on periwinkle plants were obtained: virescent flowers with an increased number of axillary shoots and smaller leaves after transmission from R. glutinosa, and greening petals (virescence) after transmission from Ribes spp. Phytoplasmas could be detected in donor and recipient plants by electron microscopy and by polymerase chain reaction (PCR) assays using universal phytoplasma primer pairs. Restriction fragment length polymorphism analyses of PCR fragments can also be used to confirm the identity of the phytoplasmas from donor and recipient plants.


Assuntos
Catharanthus/microbiologia , Cuscuta/microbiologia , Phytoplasma , Doenças das Plantas/microbiologia , Catharanthus/crescimento & desenvolvimento , Cuscuta/crescimento & desenvolvimento
6.
PLoS One ; 8(11): e81389, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24312295

RESUMO

Dodders are among the most important parasitic plants that cause serious yield losses in crop plants. In this report, we sought to unveil the genetic basis of dodder parasitism by profiling the trancriptomes of Cuscuta pentagona and C. suaveolens, two of the most common dodder species using a next-generation RNA sequencing platform. De novo assembly of the sequence reads resulted in more than 46,000 isotigs and contigs (collectively referred to as expressed sequence tags or ESTs) for each species, with more than half of them predicted to encode proteins that share significant sequence similarities with known proteins of non-parasitic plants. Comparing our datasets with transcriptomes of 12 other fully sequenced plant species confirmed a close evolutionary relationship between dodder and tomato. Using a rigorous set of filtering parameters, we were able to identify seven pairs of ESTs that appear to be shared exclusively by parasitic plants, thus providing targets for tailored management approaches. In addition, we also discovered ESTs with sequences similarities to known plant viruses, including cryptic viruses, in the dodder sequence assemblies. Together this study represents the first comprehensive transcriptome profiling of parasitic plants in the Cuscuta genus, and is expected to contribute to our understanding of the molecular mechanisms of parasitic plant-host plant interactions.


Assuntos
Produtos Agrícolas/parasitologia , Cuscuta/genética , Perfilação da Expressão Gênica , Cuscuta/microbiologia , Cuscuta/fisiologia , Genes de Plantas/genética , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Análise de Sequência de RNA , Especificidade da Espécie
7.
Fungal Biol ; 116(4): 465-77, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22483045

RESUMO

In this study, fungal viruses (mycoviruses) of plant-associated fungi were used to test the general assertion that communities of parasitic and mutualistic symbionts may be more species-diverse than communities of their hosts. Mycoviruses are poorly studied in general, but can affect the fitness and ecology of the fungi and plants with which they associate. To date, mycovirus incidence and diversity in natural communities remain largely unaddressed. Here, we compared the incidence and diversity of fungi associated with tallgrass prairie plants to the diversity and incidence of mycoviruses within those fungi. Specifically, we sampled viruses from fungi associated with a parasitic plant (Cuscuta cuspidata) and its most frequent host plant (Ambrosia psilostachya) in a tallgrass prairie habitat in Oklahoma. For each plant sample we cultured fungal endophytes from surface-sterilized above-ground tissues. From the cultured fungi we extracted DNA to identify fungi, and extracted double-stranded RNA (dsRNA) to detect mycoviruses. Mycoviruses were further characterized using reverse transcription-PCR and sequence analyses. We found at least 25 fungal taxa associated with the two plants, and 10 % of these fungi contained readily detectable viruses. Several mycovirus types were shared among fungal taxa, indicating that mycoviruses may be less specialized than originally thought. Although the virus community was not as diverse as the fungal endophyte community (16 taxa), species accumulation rates of mycoviruses (inferred from rescaled rarefaction curves) may be higher than those of their associated fungal hosts. Thus, mycoviruses represent a further layer of undocumented biodiversity in ecological communities.


Assuntos
Ambrosia/microbiologia , Biodiversidade , Cuscuta/microbiologia , Fungos/classificação , Fungos/virologia , Vírus de RNA/classificação , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Endófitos/classificação , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/virologia , Proteínas Fúngicas/genética , Fungos/genética , Fungos/isolamento & purificação , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/genética , Dados de Sequência Molecular , Oklahoma , Filogenia , Vírus de RNA/genética , Vírus de RNA/isolamento & purificação , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Simbiose
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