Mutation and sequencing-based cloning and functional studies of a rust resistance gene in sunflower (Helianthus annuus).

Rust, caused by the fungus Puccinia helianthi Schwein., is one of the most devastating diseases of sunflower (Helianthus annuus L.), affecting global production. The rust R gene R11 in sunflower line HA-R9 shows broad-spectrum resistance to P. helianthi virulent races and was previously mapped to an interval on sunflower chromosome 13 encompassing three candidate genes annotated in the XRQr1.0 reference genome assembly. In the current study, we combined ethyl methane sulfonate (EMS) mutagenesis with targeted region capture and PacBio long-read sequencing to clone the R11 gene. Sequencing of a 60-kb region spanning the R11 locus from the R11 -HA-R9 rust-resistant line and three EMS-induced susceptible mutants facilitated the identification of R11 and definition of induced mutations. The R11 gene is predicted to have a single 3996-bp open reading frame and encodes a protein of 1331 amino acids with CC-NBS-LRR domains typical of genes conferring plant resistance to biotrophic pathogens. Point mutations identified in the R11 rust-susceptible mutants resulted in premature stop codons, consistent with loss of function leading to rust susceptibility. Additional functional studies using comparative RNA sequencing of the resistant line R11 -HA-R9 and R11 -susceptible mutants revealed substantial differences in gene expression patterns associated with R11 -mediated resistance at 7 days post-inoculation with rust, and uncovered the potential roles of terpenoid biosynthesis and metabolism in sunflower rust resistance.

Heritable differences in abundance of bacterial rhizosphere taxa are correlated with fungal necrotrophic pathogen resistance.

Host-microbe interactions are increasingly recognized as important drivers of organismal health, growth, longevity and community-scale ecological processes. However, less is known about how genetic variation affects hosts' associated microbiomes and downstream phenotypes. We demonstrate that sunflower (Helianthus annuus) harbours substantial, heritable variation in microbial communities under field conditions. We show that microbial communities co-vary with heritable variation in resistance to root infection caused by the necrotrophic pathogen Sclerotinia sclerotiorum and that plants grown in autoclaved soil showed almost complete elimination of pathogen resistance. Association mapping suggests at least 59 genetic locations with effects on both microbial relative abundance and Sclerotinia resistance. Although the genetic architecture appears quantitative, we have elucidated previously unexplained genetic variation for resistance to this pathogen. We identify new targets for plant breeding and demonstrate the potential for heritable microbial associations to play important roles in defence in natural and human-altered environments.

Multiple Forms of Resistance to the Phomopsis Stem Canker Pathogens Diaporthe helianthi and D. gulyae in Sunflower.

Phomopsis stem canker of cultivated sunflower (Helianthus annuus L.) can be caused by multiple necrotrophic fungi in the genus Diaporthe, with Diaporthe helianthi and D. gulyae being the most common causal agents in the United States. Infection begins at the leaf margins and proceeds primarily through the vasculature, progressing from the leaf through the petiole to the stem, resulting in formation of brown stem lesions centered around the petiole. Sunflower resistance to Phomopsis stem canker is quantitative and genetically complex. Due to the intricate disease process, resistance is possible at different stages of infection, and multiple forms of defense may contribute to the overall level of quantitative resistance. In this study, sunflower lines exhibiting field resistance to Phomopsis stem canker were evaluated for stem and leaf resistance to multiple isolates of D. helianthi and D. gulyae in greenhouse experiments, and responses to the two species were compared. Additionally, selected resistant and susceptible lines were evaluated for petiole transmission resistance to D. helianthi. Lines with distinct forms of resistance were identified, and results indicated that responses to stem inoculation were strongly correlated (Spearman's coefficient 0.598, P < 0.001) for the two fungal species, while leaf responses were not (Spearman's coefficient 0.396, P = 0.076). These results provide a basis for genetic dissection of distinct forms of sunflower resistance to Phomopsis stem canker and will facilitate combining different forms of resistance to potentially achieve durable control of this disease in sunflower hybrids.

Arabidopsis GOLD36/MVP1/ERMO3 Is Required for Powdery Mildew Penetration Resistance and Proper Targeting of the PEN3 Transporter.

The Arabidopsis PENETRATION 3 (PEN3) ATP binding cassette (ABC) transporter contributes to penetration resistance against nonadapted powdery mildew fungi and is targeted to papillae deposited at sites of interaction with the fungus. Timely recruitment of PEN3 and other components of penetration resistance to the host-pathogen interface is important for successful defense against this biotrophic pathogen. A forward genetic screen was previously carried out to identify Arabidopsis mutants that mistarget the PEN3 transporter or fail to accumulate PEN3 at sites of attempted powdery mildew penetration. This study focuses on PEN3 mistargeting in the aberrant localization of PEN3 4 (alp4) mutant and identification of the causal gene. In the alp4 mutant, PEN3 accumulates within the endomembrane system in an apparently abnormal endoplasmic reticulum and is not exported into papillae at powdery mildew penetration sites. This targeting defect compromises defenses at the host-pathogen interface, resulting in increased penetration success by a nonadapted powdery mildew. Genetic mapping identified alp4 as an allele of GOLGI DEFECTS 36 (GOLD36), a gene encoding a GDSL-lipase/esterase family protein that is involved in maintaining normal morphology and organization of multiple endomembrane compartments. Genetic complementation confirmed that mutation in GOLD36 is responsible for the PEN3 targeting and powdery mildew penetration resistance defects in alp4. These results reinforce the importance of endomembrane trafficking in resistance to haustorium-forming phytopathogens such as powdery mildew fungi.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Multiple Species of Asteraceae Plants Are Susceptible to Root Infection by the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum.

The necrotrophic fungal pathogen Sclerotinia sclerotiorum can cause disease on numerous plant species, including many important crops. Most S. sclerotiorum-incited diseases of crop plants are initiated by airborne ascospores produced when fungal sclerotia germinate to form spore-bearing apothecia. However, basal stalk rot of sunflower occurs when S. sclerotiorum sclerotia germinate to form mycelia within the soil, which subsequently invade sunflower roots. To determine whether other plant species in the Asteraceae family are susceptible to root infection by S. sclerotiorum, cultivated sunflower (Helianthus annuus L.) and seven other Asteraceae species were evaluated for S. sclerotiorum root infection by inoculation with either sclerotia or mycelial inoculum. Additionally, root susceptibility of sunflower was compared with that of dry edible bean and canola, two plant species susceptible to S. sclerotiorum but not known to display root-initiated infections. Results indicated that multiple Asteraceae family plants are susceptible to S. sclerotiorum root infection after inoculation with either sclerotia or mycelium. These observations expand the range of plant hosts susceptible to S. sclerotiorum root infection, elucidate differences in root inoculation methodology, and emphasize the importance of soilborne infection to Asteraceae crop and weed species.

A Quantitative Genetic Study of Sclerotinia Head Rot Resistance Introgressed from the Wild Perennial Helianthus maximiliani into Cultivated Sunflower (Helianthus annuus L.).

Sclerotinia head rot (HR), caused by Sclerotinia sclerotiorum, is an economically important disease of sunflower with known detrimental effects on yield and quality in humid climates worldwide. The objective of this study was to gain insight into the genetic architecture of HR resistance from a sunflower line HR21 harboring HR resistance introgressed from the wild perennial Helianthus maximiliani. An F2 population derived from the cross of HA 234 (susceptible-line)/HR21 (resistant-line) was evaluated for HR resistance at two locations during 2019−2020. Highly significant genetic variations (p < 0.001) were observed for HR disease incidence (DI) and disease severity (DS) in both individual and combined analyses. Broad sense heritability (H2) estimates across environments for DI and DS were 0.51 and 0.62, respectively. A high-density genetic map of 1420.287 cM was constructed with 6315 SNP/InDel markers developed using genotype-by-sequencing technology. A total of 16 genomic regions on eight sunflower chromosomes, 1, 2, 10, 12, 13, 14, 16 and 17 were associated with HR resistance, each explaining between 3.97 to 16.67% of the phenotypic variance for HR resistance. Eleven of these QTL had resistance alleles from the HR21 parent. Molecular markers flanking the QTL will facilitate marker-assisted selection breeding for HR resistance in sunflower.

A Greenhouse Method to Evaluate Sunflower Quantitative Resistance to Basal Stalk Rot Caused by Sclerotinia sclerotiorum.

Resistance of sunflower to basal stalk rot (BSR) caused by the fungus Sclerotinia sclerotiorum is quantitative, controlled by multiple genes contributing small effects. Consequently, artificial inoculation procedures allowing sufficient throughput and resolution of resistance are needed to identify highly resistant sunflower germplasm resources and to map loci contributing to resistance. The objective of this study was to develop a greenhouse-based method for evaluating sunflower quantitative resistance to BSR that would be simple, space- and time-efficient, high throughput, high resolution, and correlated with field observations. Experiments were conducted with 5-week-old sunflower plants and Sclerotinia-infested millet seed as inoculum to assess the impact of pot size and temperature and to determine the most favorable inoculum rate and placement. Subsequently, an additional experiment was performed to assess the correlation of the greenhouse inoculation procedure with field results by using a panel of 32 sunflower genotypes with known field response to BSR previously determined in multiyear, multilocation artificially inoculated trials. Experimental observations indicated that the newly developed greenhouse inoculation procedure provided improved resolution to identify highly resistant genotypes and was strongly correlated with field observations. This method will be useful for screening of sunflower experimental and breeding materials, disease phenotyping of genetic mapping populations, and evaluation of resistance to different pathogen isolates.

PMR5, an acetylation protein at the intersection of pectin biosynthesis and defense against fungal pathogens.

Powdery mildew (Golovinomyces cichoracearum), one of the most prolific obligate biotrophic fungal pathogens worldwide, infects its host by penetrating the plant cell wall without activating the plant's innate immune system. The Arabidopsis mutant powdery mildew resistant 5 (pmr5) carries a mutation in a putative pectin acetyltransferase gene that confers enhanced resistance to powdery mildew. Here, we show that heterologously expressed PMR5 protein transfers acetyl groups from [14 C]-acetyl-CoA to oligogalacturonides. Through site-directed mutagenesis, we show that three amino acids within a highly conserved esterase domain in putative PMR5 orthologs are necessary for PMR5 function. A suppressor screen of mutagenized pmr5 seed selecting for increased powdery mildew susceptibility identified two previously characterized genes affecting the acetylation of plant cell wall polysaccharides, RWA2 and TBR. The rwa2 and tbr mutants also suppress powdery mildew disease resistance in pmr6, a mutant defective in a putative pectate lyase gene. Cell wall analysis of pmr5 and pmr6, and their rwa2 and tbr suppressor mutants, demonstrates minor shifts in cellulose and pectin composition. In direct contrast to their increased powdery mildew resistance, both pmr5 and pmr6 plants are highly susceptibile to multiple strains of the generalist necrotroph Botrytis cinerea, and have decreased camalexin production upon infection with B. cinerea. These results illustrate that cell wall composition is intimately connected to fungal disease resistance and outline a potential route for engineering powdery mildew resistance into susceptible crop species.

Determination of Virulence Phenotypes of Plasmopara halstedii in the United States.

Downy mildew, caused by Plasmopara halstedii (Farl.) Berl. and de Toni, is an economically important disease in cultivated sunflowers, Helianthus annuus L. Resistance genes incorporated into commercial hybrids are used as an effective disease management tool, but the duration of effectiveness is limited as virulence evolves in the pathogen population. A comprehensive assessment of pathogen virulence was conducted in 2014 and 2015 in the U.S. Great Plains states of North Dakota and South Dakota, where approximately 75% of the U.S. sunflower is produced annually. The virulence phenotypes (and races) of 185 isolates were determined using the U.S. standard set of nine differentials. Additionally, the virulence phenotypes of 61 to 185 isolates were determined on 13 additional lines that have been used to evaluate pathogen virulence in North America and/or internationally. Although widespread virulence was identified on several genes, new virulence was identified on the Pl8 resistance gene, and no virulence was observed on the PlArg, Pl15, Pl17 and Pl18 genes. Results of this study suggest that three additional lines should be used as differentials and agree with previous studies that six lines proposed as differentials should be used in two internationally accepted differential sets. For effective disease management using genetic resistance, it is critical that virulence data be relevant and timely. This is best accomplished when pathogen virulence is determined frequently and by using genetic lines containing resistance genes actively incorporated into commercial cultivars.

Genetic Dissection of Phomopsis Stem Canker Resistance in Cultivated Sunflower Using High Density SNP Linkage Map.

Phomopsis stem canker (PSC) caused by Diaporthe helianthi is increasingly becoming a global threat for sunflower production. In this study, the genetic basis of PSC resistance was investigated in a recombinant inbred line (RIL) population developed from a cross between HA 89 (susceptible) and HA-R3 (resistant). The RIL population was evaluated for PSC disease incidence (DI) in seven screening trials at multiple locations during 2016-2018. The distribution of PSC DI in the RIL population was continuous, confirming a polygenic inheritance of the trait. A moderately high broad-sense heritability (H2, 0.76) was estimated for the trait across environments. In the combined analysis, both the genotype and the genotype × environment interactions were highly significant. A linkage map spanning 1505.33 cM was constructed using genotyping-by-sequencing derived markers. Marker-trait association analysis identified a total of 15 quantitative trait loci (QTL) associated with PSC resistance on 11 sunflower chromosomes, each explaining between 5.24 and 17.39% of the phenotypic variation. PSC resistance QTL were detected in two genomic regions each on chromosomes 3, 5, 13, and 17, while one QTL each was detected in the remaining seven chromosomes. Tightly linked single nucleotide polymorphism (SNP) markers flanking the PSC resistance QTL will facilitate marker-assisted selection in PSC resistance sunflower breeding.

Contributions of host cellular trafficking and organization to the outcomes of plant-pathogen interactions.

In recent years it has become increasingly apparent that dynamic changes in protein localization, membrane trafficking pathways, and cellular organization play a major role in determining the outcome of interactions between plants and pathogenic microorganisms. Plants have evolved sophisticated perception systems to recognize the presence of potentially pathogenic microorganisms via the detection of non-self or modified-self elicitor molecules, pathogen virulence factors, or the activities of such virulence factors. Dynamic changes to host cellular organization and membrane trafficking pathways play pivotal roles in detection and signaling by plant immune receptors and are vital for the execution of spatially targeted defense responses to thwart invasion by potential pathogens. Conversely, from the perspective of the pathogen, the ability to manipulate plant cellular organization and trafficking processes to establish infection structures and deliver virulence factors is a major determinant of pathogen success. This review summarizes selected topics that illustrate how dynamic changes in host cellular trafficking and organization shape the outcomes of diverse plant-pathogen interactions and addresses ways in which our rapidly expanding knowledge of the cell biological processes that contribute to immunity or infection may influence efforts to improve plant disease resistance.

Sugar transporters for intercellular exchange and nutrition of pathogens.

Sugar efflux transporters are essential for the maintenance of animal blood glucose levels, plant nectar production, and plant seed and pollen development. Despite broad biological importance, the identity of sugar efflux transporters has remained elusive. Using optical glucose sensors, we identified a new class of sugar transporters, named SWEETs, and show that at least six out of seventeen Arabidopsis, two out of over twenty rice and two out of seven homologues in Caenorhabditis elegans, and the single copy human protein, mediate glucose transport. Arabidopsis SWEET8 is essential for pollen viability, and the rice homologues SWEET11 and SWEET14 are specifically exploited by bacterial pathogens for virulence by means of direct binding of a bacterial effector to the SWEET promoter. Bacterial symbionts and fungal and bacterial pathogens induce the expression of different SWEET genes, indicating that the sugar efflux function of SWEET transporters is probably targeted by pathogens and symbionts for nutritional gain. The metazoan homologues may be involved in sugar efflux from intestinal, liver, epididymis and mammary cells.

Perception of conserved pathogen elicitors at the plasma membrane leads to relocalization of the Arabidopsis PEN3 transporter.

The Arabidopsis penetration resistance 3 (PEN3) ATP binding cassette transporter participates in nonhost resistance to fungal and oomycete pathogens and is required for full penetration resistance to the barley powdery mildew Blumeria graminis f. sp. hordei. PEN3 resides in the plasma membrane and is recruited to sites of attempted penetration by invading fungal appressoria, where the transporter shows strong focal accumulation. We report that recruitment of PEN3 to sites of pathogen detection is triggered by perception of pathogen-associated molecular patterns, such as flagellin and chitin. PEN3 recruitment requires the corresponding pattern recognition receptors but does not require the BAK1 coreceptor. Pathogen- and pathogen-associated molecular pattern-induced focal accumulation of PEN3 and the penetration resistance 1 (PEN1) syntaxin show differential sensitivity to specific pharmacological inhibitors, indicating distinct mechanisms for recruitment of these defense-associated proteins to the host-pathogen interface. Focal accumulation of PEN3 requires actin but is not affected by inhibitors of microtubule polymerization, secretory trafficking, or protein synthesis, and plasmolysis experiments indicate that accumulation of PEN3 occurs outside of the plasma membrane within papillae. Our results implicate pattern recognition receptors in the recruitment of defense-related proteins to sites of pathogen detection. Additionally, the process through which PEN3 is recruited to the host-pathogen interface is independent of new protein synthesis and BFA-sensitive secretory trafficking events, suggesting that existing PEN3 is redirected through an unknown trafficking pathway to sites of pathogen detection for export into papillae.

Induction and suppression of PEN3 focal accumulation during Pseudomonas syringae pv. tomato DC3000 infection of Arabidopsis.

The pleiotropic drug resistance (PDR) proteins belong to the super-family of ATP-binding cassette (ABC) transporters. AtPDR8, also called PEN3, is required for penetration resistance of Arabidopsis to nonadapted powdery mildew fungi. During fungal infection, plasma-membrane-localized PEN3 is concentrated at fungal entry sites, as part of the plant's focal immune response. Here, we show that the pen3 mutant is compromised in resistance to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. P. syringae pv. tomato DC3000 infection or treatment with a flagellin-derived peptide, flg22, induced strong focal accumulation of PEN3-green fluorescent protein. Interestingly, after an initial induction of PEN3 accumulation, P. syringae pv. tomato DC3000 but not the type-III-secretion-deficient mutant hrcC could suppress PEN3 accumulation. Moreover, transgenic overexpression of the P. syringae pv. tomato DC3000 effector AvrPto was sufficient to suppress PEN3 focal accumulation in response to flg22. Analyses of P. syringae pv. tomato DC3000 effector deletion mutants showed that individual effectors, including AvrPto, appear to be insufficient to suppress PEN3 accumulation when delivered by bacteria, suggesting a requirement for a combined action of multiple effectors. Collectively, our results indicate that PEN3 plays a positive role in plant resistance to a bacterial pathogen and show that focal accumulation of PEN3 protein may be a useful cellular response marker for the Arabidopsis-P. syringae interaction.

Population and genome-wide association studies of Sclerotinia sclerotiorum isolates collected from diverse host plants throughout the United States.

Introduction: Sclerotinia sclerotiorum is a necrotrophic fungal pathogen causing disease and economic loss on numerous crop plants. This fungus has a broad host range and can infect over 400 plant species, including important oilseed crops such as soybean, canola, and sunflower. S. sclerotiorum isolates vary in aggressiveness of lesion formation on plant tissues. However, the genetic basis for this variation remains to be determined. The aims of this study were to evaluate a diverse collection of S. sclerotiorum isolates collected from numerous hosts and U.S. states for aggressiveness of stem lesion formation on sunflower, to evaluate the population characteristics, and to identify loci associated with isolate aggressiveness using genome-wide association mapping. Methods: A total of 219 S. sclerotiorum isolates were evaluated for stem lesion formation on two sunflower inbred lines and genotyped using genotyping-by-sequencing. DNA markers were used to assess population differentiation across hosts, regions, and climatic conditions and to perform a genome-wide association study of isolate aggressiveness. Results and discussion: We observed a broad range of aggressiveness for lesion formation on sunflower stems, and only a moderate correlation between aggressiveness on the two lines. Population genetic evaluations revealed differentiation between populations from warmer climate regions compared to cooler regions. Finally, a genome-wide association study of isolate aggressiveness identified three loci significantly associated with aggressiveness on sunflower. Functional characterization of candidate genes at these loci will likely improve our understanding of the virulence strategies used by this pathogen to cause disease on a wide array of agriculturally important host plants.

Genetic analysis of basal stalk rot resistance introgressed from wild Helianthus petiolaris into cultivated sunflower (Helianthus annuus L.) using an advanced backcross population.

Introduction: Sclerotinia sclerotiorum is a serious pathogen causing severe basal stalk rot (BSR) disease on cultivated sunflower (Helianthus annuus L.) that leads to significant yield losses due to insufficient resistance. The wild annual sunflower species H. petiolaris, commonly known as prairie sunflower is known for its resistance against this pathogen. Sunflower resistance to BSR is quantitative and determined by many genes with small effects on the resistance phenotype. The objective of this study was to identify loci governing BSR resistance derived from H. petiolaris using a quantitative trait loci (QTL) mapping approach. Methods: BSR resistance among lines of an advanced backcross population (AB-QTL) with 174 lines developed from a cross of inbred line HA 89 with H. petiolaris PI 435843 was determined in the field during 2017-2019, and in the greenhouse in 2019. AB-QTL lines and the HA 89 parent were genotyped using genotyping-by-sequencing and a genetic linkage map was developed spanning 997.51 cM and using 1,150 SNP markers mapped on 17 sunflower chromosomes. Results and discussion: Highly significant differences (p<0.001) for BSR response among AB-QTL lines were observed disease incidence (DI) in all field seasons, as well as disease rating (DR) and area under the disease progress curve (AUDPC) in the greenhouse with a moderately high broad-sense heritability (H 2) of 0.61 for the tested resistance parameters. A total of 14 QTL associated with BSR resistance were identified on nine chromosomes, each explaining a proportion of the phenotypic variation ranging from 3.5% to 28.1%. Of the 14 QTL, eight were detected for BSR resistance in the field and six were detected under greenhouse conditions. Alleles conferring increased BSR resistance were contributed by the H. petiolaris parent at 11 of the 14 QTL.

Genomic Insights Into Sclerotinia Basal Stalk Rot Resistance Introgressed From Wild Helianthus praecox Into Cultivated Sunflower (Helianthus annuus L.).

Crop wild relatives of the cultivated sunflower (Helianthus annuus L.) are a valuable resource for its sustainable production. Helianthus praecox ssp. runyonii is a wild sunflower known for its resistance against diseases caused by the fungus, Sclerotinia sclerotiorum (Lib.) de Bary, which infects over 400 broadleaf hosts including many important food crops. The objective of this research was to dissect the Sclerotinia basal stalk rot (BSR) resistance introgressed from H. praecox ssp. runyonii into cultivated sunflower. An advanced backcross quantitative trait loci (AB-QTL) mapping population was developed from the cross of a H. praecox accession with cultivated sunflower lines. The AB-QTL population was evaluated for BSR resistance in the field during the summers of 2017-2018 and in the greenhouse in the spring of 2018. Highly significant genetic variations (p < 0.001) were observed for the BSR disease in the field and greenhouse with a moderately high broad-sense heritability (H 2) ranging from 0.66 to 0.73. Genotyping-by-sequencing approach was used to genotype the parents and the progeny lines of the AB-QTL population. A genetic linkage map spanning 1,802.95 cM was constructed using 1,755 single nucleotide polymorphism (SNP) markers mapped on 17 sunflower chromosomes. A total of 19 BSR resistance QTL were detected on nine sunflower chromosomes, each explaining 2.21%-16.99% of the phenotypic variance for resistance in the AB-QTL population. Sixteen of the 19 QTL had alleles conferring increased BSR resistance derived from the H. praecox parent. SNP markers flanking the identified QTL will facilitate marker-assisted breeding to combat the disease in sunflower.

Design of a quality and performance improvement project for small primary care practices: reflections on the Center for Practice Innovation.

BACKGROUND: Small practices often lack the human, financial and technical resources to make necessary practice improvements and infrastructure investments in order to achieve sustainable change that promotes quality and efficiency. AIMS: To report on an effort to assist small primary care practices in improving quality of care and efficiency of practice management to meet the needs of patients, improve physician satisfaction and enhance the ability of these small practices to survive. METHODS: We report on an intervention design and the reflections of the implementers on what they learned and what went well or poorly during implementation. Results of the intervention are reported separately (in Quality in Primary Care). Thirty practices underwent the entire intervention. The practices were selected on the basis of practice size, diversity in patient factors, apparent dedication to making practice improvements and geographic location. The main components of the intervention were two site visits to the participating practices by Center for Practice Innovation (CPI); now known as the Centre for Practice Improvement and Innovation, team members. The CPI team provided ongoing advice and support in focus areas selected by practices after initial site visit and assessment. RESULTS: A customised session focusing on the practice report and on helping practices to think about which areas they wished to improve was more effective in engaging practices than didactic presentation. Quality and practice management improvements were observed in information posting, patient education, staff communication and patient safety practices. Having a strong physician champion and a strong office manager determined to make quality improvement changes were important elements for successful change. In addition, practices with greater stability of staff and strong finances were more likely to meet project goals. CONCLUSIONS: Small practices today are facing a range of important challenges. The CPI sought to provide successful guidance to small practices with evidence of positive change in some clinical measures, patient satisfaction and practice motivation to implement quality of care and practice management improvements.

Role of stomata in plant innate immunity and foliar bacterial diseases.

Pathogen entry into host tissue is a critical first step in causing infection. For foliar bacterial plant pathogens, natural surface openings, such as stomata, are important entry sites. Historically, these surface openings have been considered as passive portals of entry for plant pathogenic bacteria. However, recent studies have shown that stomata can play an active role in limiting bacterial invasion as part of the plant innate immune system. As a counter-defense, the plant pathogen Pseudomonas syringae pv. tomato DC3000 uses the virulence factor coronatine to actively open stomata. In nature, many foliar bacterial disease outbreaks require high humidity, rain, or storms, which could favor stomatal opening and/or bypass stomatal defense by creating wounds as alternative entry sites. Further studies on microbial and environmental regulation of stomatal closure and opening could fill gaps in our understanding of bacterial pathogenesis, disease epidemiology, and microbiology of the phyllosphere.

A simple intervention promoting patient safety improvements in small internal medicine practices.

BACKGROUND: small primary care practices may face difficulties in staying abreast of patient safety recommendations and implementing them. Some safety issues, however, may be easily and inexpensively addressed, given the necessary information on what is required. AIM: to assess changes in patient safety measures in small practices and describe simple mechanisms that appear to have facilitated change. METHODS: The design uses pre-post bivariate tests to determine the effect of a quality improvement intervention provided by the Center for Practice Innovation (CPI) of the American College of Physicians (ACP) to 34 small internal medicine practices. Compliance with safety measures was reassessed in 30 practices after the intervention. The CPI intervention involved two site visits, a practice assessment, self-selection of clinical, operational and financial focus areas for improvement and ongoing 'directed guidance' of the practices in their efforts, including weekly 'Practice tips' email alerts. Data used in this study came from the practice assessment form completed by the CPI team, which included 21 safety measures. The Wilcoxon signed-rank test and McNemar's test were used to compare the practices' safety compliance before and after the intervention. RESULTS: many safety measures had high compliance rates at the first site visit; for other safety measures, fewer than half the practices followed the recommended procedures. The intervention was associated with statistically significant positive change on over 70% of the 21 safety issues. The positive effects were most profound in safety measures regarding how a practice managed sharps, hazardous materials, medications and vaccines. CONCLUSION: this study provides insights into mechanisms that assist practices to make initial steps to improve patient safety and care quality. The study also suggests that with concrete recommendations, small practices can make significant changes in a short period of time and at relatively low cost.