Microbial community of cultivated and uncultivated citrus rhizosphere microbiota in Brazil.

The rhizosphere microbiome is known to contain beneficial microorganisms that promote plant growth and increase tolerance to abiotic and biotic stresses. Understanding citrus microbiome diversity and the percentage of diversity that can be recovered in the laboratory is essential for developing innovative approaches to improve plant health and promote sustainable agricultural practices. However, information about the citrus root microbiome, especially in the context of exploring commercial citrus growing areas to identify beneficial plant growth-promoting rhizobacteria (PGPR), is scarce.

A transcription factor and a phosphatase regulate temperature-dependent morphogenesis in the fungal plant pathogen Zymoseptoria tritici.

Naturally fluctuating temperatures provide a constant environmental stress that requires adaptation. Some fungal pathogens respond to heat stress by producing new morphotypes that maximize their overall fitness. The fungal wheat pathogen Zymoseptoria tritici responds to heat stress by switching from its yeast-like blastospore form to hyphae or chlamydospores.

Probing the Application of OmpA-Derived Peptides to Disrupt the Acquisition of ' Liberibacter asiaticus' by .

Huanglongbing (HLB) is currently the most devastating disease of citrus worldwide. Both bacteria ' Liberibacter asiaticus' (CLas) and ' Liberibacter americanus' (CLam) are associated with HLB in Brazil but with a strong prevalence of CLas over CLam. Conventionally, HLB management focuses on controlling the insect vector population (; also known as Asian citrus psyllid [ACP]) by spraying insecticides, an approach demonstrated to be mostly ineffective.

Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments.

The adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs.

The role of vegetative cell fusions in the development and asexual reproduction of the wheat fungal pathogen Zymoseptoria tritici.

Background: The ability of fungal cells to undergo cell-to-cell communication and anastomosis, the process of vegetative hyphal fusion, allows them to maximize their overall fitness. Previous studies in a number of fungal species have identified the requirement of several signaling pathways for anastomosis, including the so far best characterized soft (So) gene, and the MAPK pathway components MAK-1 and MAK-2 of Neurospora crassa. Despite the observations of hyphal fusions' involvement in pathogenicity and host adhesion, the connection between cell fusion and fungal lifestyles is still unclear.

Stress-Driven Transposable Element De-repression Dynamics and Virulence Evolution in a Fungal Pathogen.

Transposable elements (TEs) are drivers of genome evolution and affect the expression landscape of the host genome. Stress is a major factor inducing TE activity; however, the regulatory mechanisms underlying de-repression are poorly understood. Plant pathogens are excellent models to dissect the impact of stress on TEs.

Morphological changes in response to environmental stresses in the fungal plant pathogen Zymoseptoria tritici.

During their life cycles, pathogens have to adapt to many biotic and abiotic environmental stresses to maximize their overall fitness. Morphological transitions are one of the least understood of the many strategies employed by fungal plant pathogens to adapt to constantly changing environments, even though different morphotypes may play important biological roles. Here, we first show that blastospores (the "yeast-like" form of the pathogen typically known only under laboratory conditions) can form from germinated pycnidiospores (asexual spores) on the surface of wheat leaves, suggesting that this morphotype can play an important role in the natural history of Z.

Distribution and Genetic Diversity of Xylella fastidiosa subsp. pauca Associated with Olive Quick Syndrome Symptoms in Southeastern Brazil.

In Brazil, the host expansion of Xylella fastidiosa subsp. pauca was recently demonstrated with the report of diseased olive trees (Olea europaea), whose symptoms were associated with olive quick decline syndrome previously described in southern Italy. We employed both polymerase chain reaction-based techniques and culture medium isolation to investigate the geographic distribution of X.

Comparative Transcriptome Analyses in Zymoseptoria tritici Reveal Significant Differences in Gene Expression Among Strains During Plant Infection.

Zymoseptoria tritici is an ascomycete fungus that causes Septoria tritici blotch, a globally distributed foliar disease on wheat. Z. tritici populations are highly polymorphic and exhibit significant quantitative variation for virulence.

Spatial Genetic Structure of Coffee-Associated Xylella fastidiosa Populations Indicates that Cross Infection Does Not Occur with Sympatric Citrus Orchards.

Xylella fastidiosa, an economically important plant-pathogenic bacterium, infects both coffee and citrus trees in Brazil. Although X. fastidiosa in citrus is well studied, knowledge about the population structure of this bacterium infecting coffee remains unknown.

Homologous Recombination and Xylella fastidiosa Host-Pathogen Associations in South America.

Homologous recombination affects the evolution of bacteria such as Xylella fastidiosa, a naturally competent plant pathogen that requires insect vectors for dispersal. This bacterial species is taxonomically divided into subspecies, with phylogenetic clusters within subspecies that are host specific. One subspecies, pauca, is primarily limited to South America, with the exception of recently reported strains in Europe and Costa Rica.

Temporal and spatial scaling of the genetic structure of a vector-borne plant pathogen.

The ecology of plant pathogens of perennial crops is affected by the long-lived nature of their immobile hosts. In addition, changes to the genetic structure of pathogen populations may affect disease epidemiology and management practices; examples include local adaptation of more fit genotypes or introduction of novel genotypes from geographically distant areas via human movement of infected plant material or insect vectors. We studied the genetic structure of Xylella fastidiosa populations causing disease in sweet orange plants in Brazil at multiple scales using fast-evolving molecular markers (simple-sequence DNA repeats).

Candidatus Liberibacter americanus induces significant reprogramming of the transcriptome of the susceptible citrus genotype.

Background: Citrus huanglongbing (HLB) disease is caused by endogenous, phloem-restricted, Gram negative, uncultured bacteria named Candidatus Liberibacter africanus (CaLaf), Ca. L. asiaticus (CaLas), and Ca.