Evaluation of 1021Bp, a close relative of Pseudomonas eucalypticola, for potential of plant growth promotion, fungal pathogen suppression and boxwood blight control.

Background: Pseudomonas eucalypticola, a new species of the P. fluorescens group that generates most Pseudomonas-based biocontrol agents, has not been found in any plants other than Eucalyptus dunnii leaves. Except for antagonism to the growth of a few fungi, its features in plant growth promotion and disease control have not been evaluated.

Boxwood phyllosphere fungal and bacterial communities and their differential responses to film-forming anti-desiccants.

Background: Anti-desiccant is a class of agrochemicals widely used to protect plants from water stresses, rapid temperature variations, heat and sunburn, frost and freeze damages, transplant shock, and pathogen and pest attack. Although anti-desiccants are generally considered non-toxic to organisms, it is unclear whether they may impact the phyllosphere microbial communities. In this study, three film-forming anti-desiccant products, TransFilm, Vapor Gard, and Wilt-Pruf were applied to the canopy of two boxwood cultivars 'Vardar Valley' and 'Justin Brouwers' on April 13 and August 26, 2021.

Characterization of Boxwood Shoot Bacterial Communities and Potential Impact from Fungicide Treatments.

Phyllosphere bacterial communities play important roles in plant fitness and growth. The objective of this study was to characterize the epiphytic and endophytic bacterial communities of boxwood shoots and determine how they may respond to commonly used fungicides. In early summer and early fall, shoot samples were collected immediately before and 1, 7, and 14 days after three fungicides containing chlorothalonil and/or propiconazole were applied to the canopy.

Differential Adaptation Has Resulted in Aggressiveness Variation of on Hosts , , and .

() infects (boxwood), (pachysandra), and spp. (sweet box); yet, how it adapts to its hosts has been unclear. Here, we performed serial passage experiments with the three hosts and measured changes in three aggressiveness components: infectibility, lesion size, and conidial production.

Combating an Invasive Boxwood Pathogen - - in the United States by Shifting Production to Less-Susceptible Cultivars.

Boxwood blight (BB) caused by (), an economically devastating disease affecting everyone in the supply chain from growers to gardeners, was first officially documented in the United States in 2011. This disease has taken a heavy toll on boxwood, an iconic landscape plant and the number one evergreen nursery crop. Instead of abandoning boxwood production and switching to other evergreens, growers in the United States, informed by the latest research, have elected to combat this disease.

Characterization of the Soil Bacterial Community from Selected Boxwood Gardens across the United States.

In a recent study, we observed a rapid decline of the boxwood blight pathogen () soil population in all surveyed gardens across the United States, and we speculated that these garden soils might be suppressive to . This study aimed to characterize the soil bacterial community in these boxwood gardens. Soil samples were taken from one garden in California, Illinois, South Carolina, and Virginia and two in New York in early summer and late fall of 2017 and 2018.

Multi-Year Field Plantings Evaluating Boxwood Cultivars for Susceptibility to the Blight Pathogens ( spp.) in Northern Germany.

Two multiyear field trials were conducted to evaluate boxwood cultivars for their susceptibility to the blight pathogens and in northern Germany. Fifteen cultivars were included in the first trial from 2007 to 2012, and 46 cultivars were included in the second trial from 2014 to 2017. Both trials were done in a naturally infested field that was supplemented with infected plant tissue added to the soil before planting.

Potential Distribution of Invasive Boxwood Blight Pathogen () as Predicted by Process-Based and Correlative Models.

Boxwood blight caused by is an emerging disease that has had devastating impacts on spp. in the horticultural sector, landscapes, and native ecosystems. In this study, we produced a process-based climatic suitability model in the CLIMEX program and combined outputs of four different correlative modeling algorithms to generate an ensemble correlative model.

Rapid Decline of Soil Population in Selected Gardens Across the United States.

() poses a serious threat to boxwood, an iconic landscape plant in American and European gardens. Under the mild climatic conditions of the United Kingdom, remained recoverable in infected leaf debris after being left on the soil surface or buried for 5 years. The primary objective of this study was to determine how this fungus may be affected by the warmer summers and colder winters in the United States by sampling and baiting soil with boxwood cuttings and by on-site testing with sentinel plants.

cDNA Transcriptome of Reveals Various Defense Priming Induced by a Broad-Spectrum Biocontrol Agent sp. SSG.

sp. SSG is a potent biological control agent. Even though its survival on the leaf surface declined rapidly, SSG provided extended, moderate plant protection from a broad spectrum of pathogens.

Differential Tolerance to of English Boxwood Plants Associated with the Complexity of Culturable Fungal and Bacterial Endophyte Communities.

Isolated boxwood endophytes have been demonstrated to effectively protect boxwood plants from infection by (). However, the roles of endophytes as communities in plant defense are not clear. Here, we demonstrated differential tolerance to of English boxwood ( 'Suffruticosa'), an iconic landscape plant and generally regarded as highly susceptible, and its link to endophyte complexity.

Endophytic sp. SSG as a potential biofertilizer promoting boxwood growth.

Background: sp. SSG is a bacterial endophyte isolated from boxwood leaves showing a resistant response to infection by the boxwood blight pathogen . SSG acted as a protective and curative biocontrol agent for boxwood blight and as a bio-sanitizer of disease inoculum in the field.

Complete genome sequence of a boxwood endophyte sp. SSG with broad biotechnological application potential.

sp. strain SSG is a boxwood endophyte with potent antagonistic activities against a variety of plant pathogens. Here we present its complete genome sequence that is 8.

A Potent Burkholderia Endophyte against Boxwood Blight Caused by .

() poses an increasing threat to boxwood, a major nursery crop and iconic landscape plant worldwide. Here, we report on a potent biocontrol agent that produces small sage green (SSG) colonies on potato dextrose agar. SSG is a bacterial strain recovered from Justin Brouwers boxwood leaves with unusual response to inoculation.

Indications of Susceptibility to in Some Common Groundcovers and Boxwood Companion Plants.

Knowing the host range of a pathogen is critical to developing and implementing effective disease management programs. () is known to attack a number of species, varieties, and cultivars in the genus as well as three species (, , and ) and several species, all in the Buxaceae family. The objective of this study was to evaluate non-Buxaceae groundcovers and companion plants commonly associated with boxwood plantings for their susceptibility to .

Microsclerotial Enumeration, Size, and Survival of Calonectria pseudonaviculata.

Boxwood blight caused by Calonectria pseudonaviculata (Cps) is an emerging disease in the United States. Understanding the biology and survival of microsclerotia, the resting propagules of Cps, is important to managing the disease and restoring Cps-infested sites. In this study, an image-analyzing software (OpenCFU) was adapted to enumerate microsclerotia produced in culture plates.

Host responses and impact on the boxwood blight pathogen, Calonectria pseudonaviculata.

Boxwood leaves are more susceptible to Calonectria pseudonaviculata (Cps) and better suited for Cps reproduction than those of pachysandra and sweet box. Passages through a non-boxwood host may alter Cps ability to sporulate. Calonectria pseudonaviculata (Cps) infects boxwood and its two common companion plants-pachysandra and sweet box.

Differential Usefulness of Nine Commonly Used Genetic Markers for Identifying Species.

The genus is agriculturally and ecologically important. As the number of species continues to grow, identifying isolates in this genus has become increasingly challenging even by DNA sequencing. This study evaluated nine commonly used genetic markers against 154 formally described and 17 provisionally named species.

An expanded phylogeny for the genus .

A comprehensive phylogeny representing 142 described and 43 provisionally named species is reported here for this rapidly expanding genus. This phylogeny features signature sequences of 114 ex-types and numerous authentic isolates that were designated as representative isolates by the originators of the respective species. Multiple new subclades were assigned in clades 2, 6, 7, and 9.

Diversity and community structure of cyanobacteria and other microbes in recycling irrigation reservoirs.

Recycling irrigation reservoirs (RIRs) are emerging aquatic environments of global significance to crop production, water conservation and environmental sustainability. This study characterized the diversity and population structure of cyanobacteria and other detected microbes in water samples from eight RIRs and one adjacent runoff-free stream at three ornamental crop nurseries in eastern (VA1 and VA3) and central (VA2) Virginia after cloning and sequencing the 16S rRNA gene targeting cyanobacteria and chloroplast of eukaryotic phytoplankton. VA1 and VA2 utilize a multi-reservoir recycling irrigation system with runoff channeled to a sedimentation reservoir which then overflows into transition and retention reservoirs where water was pumped for irrigation.

Soil bacteria as sources of virulence signal providers promoting plant infection by Phytophthora pathogens.

Phytophthora species are known as "plant destroyers" capable of initiating single zoospore infection in the presence of a quorum of chemical signals from the same or closely related species of oomycetes. Since the natural oomycete population is too low to reach a quorum necessary to initiate a disease epidemic, creation of the quorum is reliant on alternate sources. Here, we show that a soil bacterial isolate, Bacillus megaterium Sb5, promotes plant infection by Phytophthora species.

Pythium and Phytopythium Species in Two Pennsylvania Greenhouse Irrigation Water Tanks.

Two commercial greenhouses producing potted plants in Pennsylvania using recycled irrigation water in an ebb-and-flood system have incurred significant crop losses due to Pythium aphanidermatum. In cooperation with the greenhouses, one or more of their water tanks was monitored continuously (128 tank samplings) for Pythium spp. by baiting.