African fan palm (Borassus aethiopum) and oil palm (Elaeis guineensis) are alternate hosts of coconut lethal yellowing phytoplasma in Mozambique

In this study, potential alternate hosts of the phytoplasma causing coconut lethal yellowing disease (CLYD) in Mozambique were investigated based on 16S rRNA and secA genes. The results reveal that the naturalized palm species, Elaeis guineensis and Borassus aethiopum are alternate hosts of CLYD phytoplasma in Mozambique. Based on the iPhyClassifier online software, the phytoplasma detected in B. aethiopum belongs to the 16Sr group XXII-A, which include ‘Candidatus Phytoplasma palmicola’ and ‘Candidatus Phytoplasma cocosnigeriae’. This is the first report associating ‘Candidatus Phytoplasma palmicola’ with wild naturalized palm species in the world. Key words: Alternate hosts, Borassus aethiopum, „Candidatus Phytoplasma palmicola‟, Elaeis guineensis, Mozambique, palm lethal phytoplasma phylogeny

Analyses of expressed sequence tags in Neurospora reveal rapid evolution of genes associated with the early stages of sexual reproduction in fungi

Background: The broadly accepted pattern of rapid evolution of reproductive genes is primarily based on studies of animal systems, although several examples of rapidly evolving genes involved in reproduction are found in diverse additional taxa. In fungi, genes involved in mate recognition have been found to evolve rapidly. However, the examples are too few to draw conclusions on a genome scale. Results: In this study, we performed microarray hybridizations between RNA from sexual and vegetative tissues of two strains of the heterothallic (self-sterile) filamentous ascomycete Neurospora intermedia, to identify a set of sex-associated genes in this species. We aligned Expressed Sequence Tags (ESTs) from sexual and vegetative tissue of N. intermedia to orthologs from three closely related species: N. crassa, N. discreta and N. tetrasperma. The resulting four-species alignments provided a dataset for molecular evolutionary analyses. Our results confirm a general pattern of rapid evolution of fungal sex-associated genes, compared to control genes with constitutive expression or a high relative expression during vegetative growth. Among the rapidly evolving sex-associated genes, we identified candidates that could be of importance for mating or fruiting-body development. Analyses of five of these candidate genes from additional species of heterothallic Neurospora revealed that three of them evolve under positive selection. Conclusions: Taken together, our study represents a novel finding of a genome-wide pattern of rapid evolution of sex-associated genes in the fungal kingdom, and provides a list of candidate genes important for reproductive isolation in Neurospora. © 2012 Nygren et al.; licensee BioMed Central Ltd

\u2018Candidatus Phytoplasma palmicola\u2019 and Tanzanian lethal decline phytoplasma detection in the Derbidae Diastrombus mukurangai in Mozambique

revealed that Diastrombus mukurungai is a potential vector of the coconut phytoplasmas in Mozambique. Furthermore, the results revealed that Diastrombus mukurungai was harbouring two different phytoplasmas types: \u2018Candidatus Phytoplasma palmicola\u2019 (16SrXXII-A), and and a strain that was previously isolated in Tanzania. The results also confirm the occurrence of \u2018Ca. Phytoplasma cocostanzaniae\u2019 in Mozambique. This is the first report associating D. mukurungai with \u2018Ca. Phytoplasma palmicola\u2019 in the world. Moreover the results also revealed slightly higher diversity of phytoplasmas species associated with Diastrombus mukurungai in Mozambique than previously found. Further research is underway to increase our knowledge about the vectors of the CLYD phytoplasmas in Mozambique

Sex-linked transcriptional divergence in the hermaphrodite fungus Neurospora tetrasperma

In the filamentous ascomycete Neurospora tetrasperma, a large (approx. 7 Mbp) region of suppressed recombination surrounds the mating-type (mat) locus. While the remainder of the genome is largely homoallelic, this region of recombinational suppression, extending over 1500 genes, is associated with sequence divergence. Here, we used microarrays to examine how the molecular phenotype of gene expression level is linked to this divergent region, and thus to the mating type. Culturing N. tetrasperma on agar media that induce sexual/female or vegetative/male tissue, we found 196 genes significantly differentially expressed between mat A and mat a mating types. Our data show that the genes exhibiting mat-linked expression are enriched in the region genetically linked to mating type, and sequence and expression divergence are positively correlated. Our results indicate that the phenotype of mat A strains is optimized for traits promoting sexual/female development and the phenotype of mat a strains for vegetative/male development. This discovery of differentially expressed genes associated with mating type provides a link between genotypic and phenotypic divergence in this taxon and illustrates a fungal analogue to sexual dimorphism found among animals and plants

New alternate hosts for Cronartium

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<scp>DMI</scp> fungicide resistance in <scp><i>Zymoseptoria tritici</i></scp> is unlinked to geographical origin and genetic background: a case study in Europe

Background: The hemibiotrophic fungus Zymoseptoria tritici causing Septoria tritici blotch (STB), is a devastating foliar pathogen of wheat worldwide. A common group of fungicides used to control STB are the demethylation inhibitors (DMIs). DMI fungicides restrict fungal growth by inhibiting the sterol 14-α-demethylase, a protein encoded by CYP51 gene and essential for maintaining fungal cell permeability. However, the adaptation of Z. tritici populations in response to intensive and prolonged DMI usage has resulted in a gradual shift towards reduced sensitivity to this group of fungicides. In this study, 311 isolates were collected pre-treatment from nine wheat-growing regions in Europe in 2019. These isolates were analysed by high-throughput amplicon-based sequencing of nine housekeeping genes and the CYP51 gene. Results: Analyses based on housekeeping genes and the CYP51 gene revealed a lack of population structure in Z. tritici samples irrespective of geographical origin. Minimum spanning network (MSN) analysis showed clustering of multilocus genotypes (MLGs) based on CYP51 haplotypes, indicating an effect of selection due to DMI fungicide use. The majority of the haplotypes identified in this study have been reported previously. The diversity and frequencies of mutations varied across regions. Conclusion: Using a high-throughput amplicon-sequencing approach, we found several mutations in the CYP51 gene combined in different haplotypes that are likely to cause fungicide resistance. These mutations occurred irrespective of genetic background or geographical origin. Overall, these results contribute to the development of effective and sustainable risk monitoring for DMI fungicide resistance. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry