Web application and smartphone-supported disease management in strawberry fields

Botrytis cinerea and Monilinia fructicola, the causal agents of gray mold and brown rot diseases, are one of the most important plant-pathogenic fungi affecting strawberry and peach, respectively. During the last decade, control of both diseases in the southeastern United States has largely been dependent on the use of at-risk fungicides with single-site modes of action. The appearance of gray mold and brown rot, despite applications of fungicides, have been reported by strawberry and peach growers in several states, especially during highly favorable conditions, enhancing concerns about the presence of fungicide-resistant isolates of B. cinerea and M. fructicola in the region. A regional resistance-monitoring program was implemented to help growers determine location-specific resistance profiles. They were originally used to serve South Carolina and Georgia growers, but the service soon became so popular among specialists and growers that, in 2014, growers from 10 states, including Maryland, Pennsylvania, Virginia, West Virginia, North Carolina, South Carolina, Florida, Georgia, Arkansas, and Connecticut used the service. The service provides precise information that has not been available before and enables producers to adjust spray programs before fungicide resistance causes crop loss.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Fitness and Competitive Ability of Alternaria alternata Field Isolates with Resistance to SDHI Fungicides and resistance to QoI and MBC fungicides

Alternaria rot, caused by Alternaria alternata, was observed in well managed, commercial peach orchards in South Carolina. In total, 64 isolates were collected in 2012 and 2013 from symptomatic fruit of problem orchards. Most isolates were resistant to boscalid, pyraclostrobin, and thiophanate-methyl. Resistance to SDHIs was due to point mutations in the SDH subunits, resistance to pyraclostrobin was due to the G143A mutation in the cytb gene, and resistance to thiophanate-methyl was due to 167Y in the β-tubulin gene. The four most commonly found genotypes based on mutations in the SDH subunits (H277Y in SDHB, H134R in SDHC, D123E in SDHD) were selected for fitness evaluations. Genotypes H277Y and H134R didn’t suffer fitness penalties based on mycelia growth on PDA, spore production in vitro, osmotic sensitivity, oxidative sensitivity, germination ability, and ability to cause disease. Hypersensitivity to oxidative stress and weak sporulation capacity was only observed in genotype D123E. No competitive advantage was detected for sensitive isolates over the course of five generations when mixed with genotypes H277Y or H134R. The results suggest that in the absence of fungicide pressure, isolates of the H277Y and H134R genotypes may effectively compete with the wildtype population

Increased resistance of plants to pathogens from multiple higher-order phylogenetic lineages

Transgenic plants, plant tissue, and propagation materials are disclosed that exhibit or convey increased resistance to pathogens of multiple higher-order phylogenetic lineages. The disclosed transgenic plants and plant tissues include plant cells containing a DNA construct encoding Gastrodia Anti-Fungal Protein (GAFP), also known as gastrodianin, an anti-fungal gene naturally occurring in a Chinese orchid, Gastrodia elata. Transgenic plants disclosed include herbaceous plants as well as woody plants, including fruit trees. Disclosed transgenic plants can also be beneficially utilized as rootstock, for instance rootstock for stone fruit crops such as peach, thereby conferring enhanced disease resistance to the rootstock without genetically altering the scion

Novel gene-sequence markers for isolate tracking within \u3ci\u3eMonilinia fructicola\u3c/i\u3e lesions

Background: Monilinia fructicola is a diverse pathogen of pome and stone fruits that causes severe economic losses each year. However, little is known about inoculum flow within or between orchards and pathogen establishment in an orchard, because few methods exist for detecting diversity or tracking isolates over time. SSR loci are an effective option, but may be confounded by a high degree of mutability and potential sensitivity to abiotic stress. Results: Through transcriptome analysis, we identified novel markers mrr1, DHFR and MfCYP01 and validated stability of these markers under fungicide stress in natural infection sites. Nucleotide variation within mrr1, DHFR and MfCYP01 sequences differentiated isolates at all spatial scales: within the same infection site, between trees and between two farms. Sequenced regions were also effective for matching isolates collected from blossoms at the beginning of the season to progeny in cankers obtained at the end of the season. Conclusions: Collectively, results show that mrr1, DHFR and MfCYP01 are able to accurately differentiate M. fructicola isolates at the population level, can be used to track isolates over time, and are more stable than SSRs under external stresses. Either by themselves or combined with SSR markers, these gene-encoding regions are a much-needed tool for better understanding M. fructicola population dynamics. Includes supplemental materials

Studies on Sensitivity Reduction in Solo and Mixture Treatments and Fungicide-Induced Mutagenesis in \u3ci\u3eMonilinia fructicola\u3c/i\u3e

Three fungicide-sensitive Monilinia fructicola isolates were exposed in weekly transfers of mycelia to a dose gradient of a DMI and a QoI fungicide (azoxystrobin) in solo or mixture treatments and fungicide sensitivity as well as genetic changes were assessed. Isolates showed a faster reduction in sensitivity (higher resistance factors) to azoxystrobin than to SYP-Z048; this process was slower in the mixture treatment. The decrease of fungicide sensitivity was not a heritable trait. Genomic mutagenesis at 8 of 15 microsatellite loci was evidenced in one of three isolates tested after exposure to azoxystrobin. These non-coding regions of the genome either showed single repeat additions or deletions, or large insertions or deletions, suggesting sublethal exposure to azoxystrobin may increase the rate of genomic mutagenesis. Mutagenesis was only observed after exposure to azoxystrobin, which may be dependent on the mode of action of this fungicide, however, more rigorous experimentation is needed before such conclusions can be drawn from these results

Fungicide-induced transposon movement in Monilinia fructicola

Repeated applications of fungicides with a single mode of action are believed to select for pre-existing resistant strains in a pathogen population, while the impact of sub-lethal doses of such fungicides on sensitive members of the population is unknown. In this study, in vitro evidence is presented that continuous exposure of Monilinia fructicola mycelium to some fungicides can induce genetic change in form of transposon transposition. Three fungicide-sensitive M. fructicola isolates were exposed in 12 weekly transfers of mycelia to a dose gradient of demethylation inhibitor fungicide (DMI) SYP-Z048 and quinone outside inhibitor fungicide (QoI) azoxystrobin in solo or mixture treatments. Evidence of mutagenesis was assessed by monitoring Mftc1, a multicopy transposable element of M. fructicola, by PCR and Southern blot analysis. Movement of Mftc1 was observed following azoxystrobin and azoxystrobin plus SYPZ048 treatments in two of the three isolates, but not in the non-fungicide-treated controls. Interestingly, the upstream promoter region of MfCYP51 was a prime target for Mftc1 transposition in these isolates. Transposition of Mftc1 was verified by Southern blot in two of three isolates from another, similar experiment following prolonged, sublethal azoxystrobin exposure, although in these isolates movement of Mftc1 in the upstream MfCYP51 promoter region was not observed. More research is warranted to determine whether fungicide-induced mutagenesis may also happen under field conditions

Fungicide-induced transposon movement in Monilinia fructicola

Repeated applications of fungicides with a single mode of action are believed to select for pre-existing resistant strains in a pathogen population, while the impact of sub-lethal doses of such fungicides on sensitive members of the population is unknown. In this study, in vitro evidence is presented that continuous exposure of Monilinia fructicola mycelium to some fungicides can induce genetic change in form of transposon transposition. Three fungicide-sensitive M. fructicola isolates were exposed in 12 weekly transfers of mycelia to a dose gradient of demethylation inhibitor fungicide (DMI) SYP-Z048 and quinone outside inhibitor fungicide (QoI) azoxystrobin in solo or mixture treatments. Evidence of mutagenesis was assessed by monitoring Mftc1, a multicopy transposable element of M. fructicola, by PCR and Southern blot analysis. Movement of Mftc1 was observed following azoxystrobin and azoxystrobin plus SYPZ048 treatments in two of the three isolates, but not in the non-fungicide-treated controls. Interestingly, the upstream promoter region of MfCYP51 was a prime target for Mftc1 transposition in these isolates. Transposition of Mftc1 was verified by Southern blot in two of three isolates from another, similar experiment following prolonged, sublethal azoxystrobin exposure, although in these isolates movement of Mftc1 in the upstream MfCYP51 promoter region was not observed. More research is warranted to determine whether fungicide-induced mutagenesis may also happen under field conditions

Male silver eels mature by swimming

<p>Abstract</p> <p>Background</p> <p>If European silver eels are prevented from reproductive migration, they remain in a prepubertal stage by dopaminergic inhibition of pituitary activity. Because this inhibition is likely a requirement for an extended female growth stage, we tested if it is sex-specific by subjecting both sexes to stimulation by GnRHa (Gonadotropin-Releasing Hormone agonist) – injection or 3-months swimming in seawater.</p> <p>Results</p> <p>In contrast to females, males showed a two- to three-fold higher LHβ (luteinising hormone β subunit) – expression, a three- to five-fold higher GSI (Gonadosomatic index) and induced spermatogenesis when compared with the untreated control group.</p> <p>Conclusion</p> <p>Dopaminergic inhibition is thus not effective in males and swimming results in natural maturation, probably via GnRH-release.</p

Transcriptomics reveal the genetic coordination of early defense to Armillaria root rot (ARR) in Prunus spp

Armillaria root rot (ARR) poses a significant threat to the long-term productivity of stone-fruit and nut crops in the predominant production area of the United States. To mitigate this issue, the development of ARR-resistant and horticulturally-acceptable rootstocks is a crucial step towards the maintenance of production sustainability. To date, genetic resistance to ARR has been found in exotic plum germplasm and a peach/plum hybrid rootstock, ’MP-29‘. However, the widely-used peach rootstock Guardian® is susceptible to the pathogen. To understand the molecular defense mechanisms involved in ARR resistance in Prunus rootstocks, transcriptomic analyses of one susceptible and two resistant Prunus spp. were performed using two causal agents of ARR, including Armillaria mellea and Desarmillaria tabescens. The results of in vitro co-culture experiments revealed that the two resistant genotypes showed different temporal response dynamics and fungus-specific responses, as seen in the genetic response. Gene expression analysis over time indicated an enrichment of defense-related ontologies, including glucosyltransferase activity, monooxygenase activity, glutathione transferase activity, and peroxidase activity. Differential gene expression and co-expression network analysis highlighted key hub genes involved in the sensing and enzymatic degradation of chitin, GSTs, oxidoreductases, transcription factors, and biochemical pathways likely involved in Armillaria resistance. These data provide valuable resources for the improvement of ARR resistance in Prunus rootstocks through breeding

Proposal for a unified nomenclature for target site mutations associated with resistance to fungicides

Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino-acid substitutions is to cite the wild type amino acid, the codon number and the new amino acid, using the one letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers. These differences in numbering arise from the different lengths of the proteins in each species. The purpose of the current paper is to propose a system for unifying the labelling of amino acids in fungicide target proteins. To do this we have produced alignments between fungicide target proteins of relevant species fitted to a well-studied “archetype” species. Orthologous amino acids in all species are then assigned numerical “labels” based on the position of the amino acid in the archetype protein