Biology subjects

Mullins, E.

Publications and source records attributed to Mullins, E..

3 recordsLinked to original sources

bioRxiv2025

Detection of resistance in Phytophthora infestans to the carboxylic acid amide (CAA) fungicides using digital droplet PCR.

BackgroundPotato late blight caused by Phytophthora infestans remains the greatest biotic threat to potato production globally. In northern Europe to prevent the disease and associated yield losses fungicides are heavily relied upon, with multiple applications required during the potato growing season. Unfortunately, such intensive fungicide usage has the potential to compromise control efficacy as it puts in place immense selective pressure for the emergence and spread of fungicide resistant strains of P. infestans. In recent years this scenario has been realised, with the emergence of strains resistant to the carboxylic acid amide (CAA) fungicides. As resistance to the CAA fungicides in P. infestans has been confirmed to result from changes in the pathogens cellulose synthase A3 gene (CesA3), specifically at amino acid position 1105, it opens the possibility to develop molecular tools to rapidly monitor populations of the pathogen for the resistance allele. ResultsUsing the Stilla nacia 3-colour system a droplet digital PCR (ddPCR) was successfully developed to simultaneously detect the P. infestans CesA3 gene irrespective of its CAA sensitivity status, and either the CAA wild-type sequence for position 1105 or that conferring the resistant allele G1105S. Using a drop-off in ratio of positive droplets for either the wild-type or G1105S alleles relative to those positive for the general P. infestans CesA3 it was also possible to demonstrate that using the assay other potential alterations known to confer resistance that may occur at this position (e.g. G1105V) can be detected. The assay was validated using multiple sources of P. infestans DNA, including FTA cards. ConclusionsThe assay developed will allow for the accurate and sensitive detection of CAA resistance conferred by alterations at amino acid position 1105 in the CesA3 gene in P. infestans. The capacity to use the assay with multiple DNA sources and potential to adapt the drop-off approach to different ddPCR platforms will ensure its applicability to the wider P. infestans community in monitoring the continued use of CAA-based fungicides for P. infestans management.

microbiology↗

bioRxiv2024

Transcriptional profiling during infection of potato NLRs and Phytophthora infestans effectors using cDNA enrichment sequencing

An accurate assessment of host and pathogen gene expression during infection is critical for understanding the molecular aspects of host-pathogen interactions. Often, pathogen-derived transcripts are difficult to ascertain at early infection stages owing to the unfavourable transcript representation compared to the host genes. In this study, we compare two sequencing techniques, RNAseq and enrichment sequencing (RenSeq and PenSeq) of cDNA, to investigate gene expression patterns in the doubled monoploid potato (DM) infected with the late blight pathogen Phytophthora infestans. Our results reveal distinct advantages of cDNA RenSeq and PenSeq over traditional RNAseq in terms of target gene representation and transcriptional quantification at early infection stages. Throughout the infection time course, cDNA enrichment sequencing enables transcriptomic analyses for more targeted host and pathogen genes. For highly expressed genes that were sampled in parallel by both cDNA enrichment and RNAseq, a high level of concordance in expression profiles is observed, indicative of at least semi-quantitative gene expression representation following enrichment.

molecular biology↗

bioRxiv2019

Annual replication is essential in evaluating the response of the soil microbiome to the genetic modification of maize in different biogeographical regions

The importance of geographic location and annual variation on the detection of differences in the rhizomicrobiome caused by the genetic modification of maize (Bt-maize, event MON810) was evaluated at experimental field sites across Europe including Sweden, Denmark, Slovakia and Spain. DNA of the rhizomicrobiome was collected at the maize flowering stage in three consecutive years and analyzed for the abundance and diversity of PCR-amplified structural genes of Bacteria, Archaea and Fungi, and functional genes for bacterial nitrite reductases (nirS, nirK). The nirK genes were always more abundant than nirS. Maize MON810 did not significantly alter the abundance of any microbial genetic marker, except for sporadically detected differences at individual sites and years. In contrast, annual variation between sites was often significant and variable depending on the targeted markers. Distinct, site-specific microbial communities were detected but the sites in Denmark and Sweden were similar to each other. A significant effect of the genetic modification of the plant on the community structure in the rhizosphere was detected among the nirK denitrifiers at the Slovakian site in only one year. However, most nirK sequences with opposite response were from the same or related source organisms suggesting that the transient differences in community structure did not translate to the functional level. Our results show a lack of effect of the genetic modification of maize on the rhizosphere microbiome that would be stable and consistent over multiple years. This demonstrates the importance of considering annual variability in assessing environmental effects of genetically modified crops.

microbiology↗