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1. Tolerance and Biological Removal of Fungicides by Trichoderma Species Isolated From the Endosphere of Wild Rubiaceae Plants

   https://doi.org/10.3389/fagro.2021.772170  

   Escudero-Leyva, Efraín; Alfaro-Vargas, Pamela; Muñoz-Arrieta, Rodrigo; Charpentier-Alfaro, Camila; Granados-Montero, María del; Valverde-Madrigal, Katherine S.; Pérez-Villanueva, Marta; Méndez-Rivera, Michael; Rodríguez-Rodríguez, Carlos E.; Chaverri, Priscila; et al (February 2022, Frontiers in Agronomy)

   The transition from conventional to organic agriculture is often challenged by the adaptation of biological control agents to environments heavily exposed to agrochemical pollutants. We studied Trichoderma species isolated from living leaf tissues of wild Rubiacaeae (coffee family) plants to determine their fungicide tolerance and potential for bioremoval. First, we assessed the in vitro tolerance to fungicides of four Trichoderma isolates ( Trichoderma rifaii T1, T . aff. crassum T2, T . aff. atroviride T3, and T . aff. strigosellum T4) by placing mycelial plugs onto solid media supplemented with seven different systemic and non-systemic fungicides. After a week, most of the fungicides did not significantly inhibit the growth of the isolates, except in the case of cyproconazole, where the only isolate able to grow was T1; however, the colony morphology was affected by the presence of fungicides. Second, biological removal potential was established for selected isolates. For this experiment, the isolates T1, T2, and T4 were independently inoculated into liquid media with the fungicides azoxystrobin, chlorothalonil, cyproconazole, and trifloxystrobin. After 14 days of incubation, a removal of up to 89% was achieved for chlorothalonil, 46.4% for cyproconazole, and 33.1% for trifloxystrobin using viable biomass. In the case of azoxystrobin, the highest removal (82.2%) occurred by adsorption to fungal biomass. Ecotoxicological tests in Daphnia magna revealed that T1 has the highest removal potential, achieving significant elimination of every fungicide, while simultaneously detoxifying the aqueous matrix (except in the case of cyproconazole). Isolate T4 also exhibited an intermediate efficiency, while isolate T2 was unable to detoxify the matrix in most cases. The removal and detoxification of cyproconazole failed with all the isolates. These findings suggest that endosphere of wild plants could be an attractive guild to find new Trichoderma species with promising bioremediation capabilities. In addition, the results demonstrate that attention should be placed when combining certain types of agrochemicals with antagonistic fungi in Integrated Pest and Disease Management strategies or when transitioning to organic agriculture. 

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2. Genomic characterization of Pseudomonas syringae pv. syringae from Callery pear and the efficiency of associated phages in disease protection

   https://doi.org/10.1128/spectrum.02833-23  

   Holtappels, D; Abelson, S A; Nouth, S C; Rickus, G_E J; Amare, S Z; Giller, J P; Jian, D Z; Koskella, B (March 2024, Microbiology Spectrum)

   Zeng, Quan (Ed.)

   ABSTRACT ThePseudomonas syringaespecies complex is a heterogeneous group of plant pathogenic bacteria associated with a wide distribution of plant species. Advances in genomics are revealing the complex evolutionary history of this species complex and the wide array of genetic adaptations underpinning their diverse lifestyles. Here, we genomically characterize twoP. syringaeisolates collected from diseased Callery pears (Pyrus calleryana) in Berkeley, California in 2019 and 2022. We also isolated a lytic bacteriophage, which we characterized and evaluated for biocontrol efficiency. Using a multilocus sequence analysis and core genome alignment, we classified theP. syringaeisolates as members of phylogroup 2, related to other strains previously isolated fromPyrusandPrunus. An analysis of effector proteins demonstrated an evolutionary conservation of effectoromes across isolates classified in PG2 and yet uncovered unique effector profiles for each, including the two newly identified isolates. Whole-genome sequencing of the associated phage uncovered a novel phage genus related toPseudomonas syringaepv.actinidiaephage PHB09 and theFlaumdravirusgenus. Finally, usingin plantainfection assays, we demonstrate that the phage was equally useful in symptom mitigation of immature pear fruit regardless of the Pss strain tested. Overall, this study demonstrates the diversity ofP. syringaeand their viruses associated with ornamental pear trees, posing spill-over risks to commercial pear trees and the possibility of using phages as biocontrol agents to reduce the impact of disease.IMPORTANCEGlobal change exacerbates the spread and impact of pathogens, especially in agricultural settings. There is a clear need to better monitor the spread and diversity of plant pathogens, including in potential spillover hosts, and for the development of novel and sustainable control strategies. In this study, we characterize the first described strains ofPseudomonas syringaepv.syringaeisolated from Callery pear in Berkeley, California from diseased tissues in an urban environment. We show that these strains have divergent virulence profiles from previously described strains and that they can cause disease in commercial pears. Additionally, we describe a novel bacteriophage that is associated with these strains and explore its potential to act as a biocontrol agent. Together, the data presented here demonstrate that ornamental pear trees harbor novelP. syringaepv.syringaeisolates that potentially pose a risk to local fruit production, or vice versa—but also provide us with novel associated phages, effective in disease mitigation. 

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3. Floral Microbes Suppress Growth of Monilinia laxa with Minimal Effects on Honey Bee Feeding

   https://doi.org/10.1094/PDIS-03-21-0549-RE  

   Crowley-Gall, Amber; Trouillas, Florent P.; Niño, Elina L.; Schaeffer, Robert N.; Nouri, Mohamed T.; Crespo, Maria; Vannette, Rachel L. (February 2022, Plant Disease)

   Management of Monilinia laxa, the causal agent of brown rot blossom blight in almond (Prunus dulcis), relies heavily on the use of chemical fungicides during bloom. However, chemical fungicides can have nontarget effects on beneficial arthropods, including pollinators, and select for resistance in the pathogen of concern. Almond yield is heavily reliant on successful pollination by healthy honey bees (Apis mellifera); thus, identifying sustainable, effective, and pollinator-friendly control methods for blossom blight during bloom is desirable. Flower-inhabiting microbes could provide a natural, sustainable form of biocontrol for M. laxa, while potentially minimizing costly nontarget effects on almond pollinators and the services they provide. As pollinators are sensitive to floral microbes and their associated taste and scent cues, assessing effects of prospective biocontrol species on pollinator attraction is also necessary. Here, our objective was to isolate and identify potential biocontrol microbes from an array of agricultural and natural flowering hosts and test their efficacy in suppressing M. laxa growth in culture. Out of an initial 287 bacterial and fungal isolates identified, 56 were screened using a dual culture plate assay. Most strains reduced M. laxa growth in vitro. Ten particularly effective candidate microbes were further screened for their effect on honey bee feeding. Of the 10, nine were found to both strongly suppress M. laxa growth in culture and not reduce honey bee feeding. These promising results suggest a number of strong candidates for augmentative microbial biocontrol of brown rot blossom blight in almond with potentially minimal effects on honey bee pollination. 

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4. A new family of liquid and solid guanidine-based n-type dopants for solution-processed perovskite solar cells

   https://doi.org/10.1039/D0QM00437E  

   Nakayama, Hidenori; Schneider, Julia A.; Faust, Mina; Wang, Hengbin; Read de Alaniz, Javier; Chabinyc, Michael L. (January 2020, Materials Chemistry Frontiers)

   We present a series of new dopants based on a bicyclcic guanidine-type structure, 1,5,7-triazabicyclo[4.4.0]dec-5-ene ( TBD ), for organic semiconductors. A series of TBD derivatives that were alkylated at the 7-position were synthesized and their physical properties were determined. These stable dopants were shown to be effective n-type dopants for [6,6]-phenyl- C 61 -butyric acid methyl ester (PC 61 BM), poly{[ N , N ′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt -5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2)) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3- d :2′,3′- d ′]- s -indaceno[1,2- b :5,6- b ′]dithiophene (ITIC). Films of PC 61 BM doped with 10 mol% of a dimeric derivative of TBD had electrical conductivities of 0.065 S cm −1 . The utility of the dopants was further shown by doping electron transport layers of PC 61 BM with 2TBD-C10 for methyl ammonium lead iodide (MAPbI 3 ) solar cells leading to improved fill factors and PCEs relative to undoped ETLs. 

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5. Stratifying risk of Alzheimer’s disease in healthy middle-aged individuals with machine learning

   https://doi.org/10.1093/braincomms/fcaf121  

   Tandon, Raghav; Zhao, Liping; Watson, Caroline M; Sarkar, Neel; Elmor, Morgan; Heilman, Craig; Sanders, Katherine; Hales, Chadwick M; Yang, Huiying; Loring, David W; et al (January 2025, Brain Communications)

   Alzheimer’s disease has a prolonged asymptomatic phase during which pathological changes accumulate before clinical symptoms emerge. This study aimed to stratify the risk of clinical disease to inform future disease-modifying treatments. Cerebrospinal fluid analysis from participants in the Emory Healthy Brain Study was used to classify individuals based on amyloid beta 42 (Aβ42), total tau (tTau) and phosphorylated tau (pTau) levels. Cognitively normal (CN), biomarker-positive (CN)/BM+individuals were identified using a tTau: Aβ42 ratio > 0.24, determined by Gaussian mixture models. CN/BM+ individuals (n = 134) were classified as having asymptomatic Alzheimer’s disease (AsymAD), while CN, biomarker-negative (CN/BM−) individuals served as controls (n = 134). Cognitively symptomatic, biomarker-positive individuals with an Alzheimer’s disease diagnosis confirmed by the Emory Cognitive Neurology Clinic were labelled as Alzheimer’s disease (n = 134). Study groups were matched for age, sex, race and education. Cerebrospinal fluid samples from these matched Emory Healthy Brain Study groups were analysed using targeted proteomics via selected reaction monitoring mass spectrometry. The targeted cerebrospinal fluid panel included 75 peptides from 58 unique proteins. Machine learning approaches identified a subset of eight peptides (ADQDTIR, AQALEQAK, ELQAAQAR, EPVAGDAVPGPK, IASNTQSR, LGADMEDVCGR, VVSSIEQK, YDNSLK) that distinguished between CN/BM− and symptomatic Alzheimer’s disease samples with a binary classifier area under the curve performance of 0.98. Using these eight peptides, Emory Healthy Brain Study AsymAD cases were further stratified into ‘Control-like’ and ‘Alzheimer’s disease-like’ subgroups, representing varying levels of risk for developing clinical disease. The eight peptides were evaluated in an independent dataset from the Alzheimer’s Disease Neuroimaging Initiative, effectively distinguishing CN/BM− from symptomatic Alzheimer’s disease cases (area under the curve = 0.89) and stratifying AsymAD individuals into control-like and Alzheimer’s disease-like subgroups (area under the curve = 0.89). In the absence of matched longitudinal data, an established cross-sectional event-based disease progression model was employed to assess the generalizability of these peptides for risk stratification. In summary, results from two independent modelling methods and datasets demonstrate that the identified eight peptides effectively stratify the risk of progression from asymptomatic to symptomatic Alzheimer’s disease. 

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