1
|
Li S, Travadon R, Nouri MT, Trouillas FP. Determining the Main Infection Courts in Sweet Cherry Trees of the Canker Pathogens Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata. PLANT DISEASE 2024; 108:1695-1702. [PMID: 38173260 DOI: 10.1094/pdis-10-23-2154-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The major fungal canker pathogens causing branch dieback of sweet cherry trees in California include Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata. These pathogens have long been known to infect cherry trees mainly through pruning wounds. However, recent field observations revealed numerous shoots and fruiting spurs exhibiting dieback symptoms with no apparent pruning wounds or mechanical injuries. Accordingly, this study was conducted to assess the incidence of the three pathogens in symptomatic terminal shoots and dying fruiting spurs, in addition to the wood below pruning wounds in branches. Surveys were conducted in five sweet cherry orchards across three counties in California. We also investigated the possibility that leaf scars, bud scars, and wounds resulting from fruit picking could serve as infection courts for Cal. pulchella, Cyt. sorbicola, and E. lata by means of artificial inoculations in the field. Orchard surveys revealed that Cal. pulchella had the highest pathogen incidence below pruning wounds in branch samples, followed by Cyt. sorbicola and E. lata. Among terminal shoots with dieback symptoms and dying fruiting spurs, Cyt. sorbicola was the most prevalent, followed by Cal. pulchella. Results from field inoculations indicated that fruit-picking wounds could serve as important infection courts for Cal. pulchella, Cyt. sorbicola, and E. lata, with average pathogen recovery of 41.5, 63, and 36.2%, respectively. Results also indicated that leaf and bud scars could serve as an entry site for Cyt. sorbicola, although recovery was relatively low. The present study is the first to identify harvest-induced wounds on fruiting spurs of sweet cherry as an important infection court of Cal. pulchella, Cyt. sorbicola, and E. lata.
Collapse
Affiliation(s)
- Sampson Li
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Renaud Travadon
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Mohamed T Nouri
- University of California Cooperative Extension San Joaquin County, Stockton, CA 95206
| | - Florent P Trouillas
- Department of Plant Pathology, University of California, Davis, CA 95616
- Kearney Agricultural Research and Extension Center, Parlier, CA 93648
| |
Collapse
|
2
|
Rabiey M, Grace ER, Pawlos P, Bihi M, Ahmed H, Hampson GE, Al Riyami A, Alharbi L, Sanchez‐Lucas R, Korotania N, Ciusa ML, Mosley O, Hulin MT, Baxter L, Dhaouadi S, Vinchira‐Villarraga D, Jackson RW. Coevolutionary analysis of Pseudomonas syringae-phage interactions to help with rational design of phage treatments. Microb Biotechnol 2024; 17:e14489. [PMID: 38864499 PMCID: PMC11167607 DOI: 10.1111/1751-7915.14489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 05/09/2024] [Indexed: 06/13/2024] Open
Abstract
Treating plant bacterial diseases is notoriously difficult because of the lack of available antimicrobials. Pseudomonas syringae pathovar syringae (Pss) is a major pathogen of cherry (Prunus avium) causing bacterial canker of the stem, leaf and fruit, impacting productivity and leading to a loss of trees. In an attempt to find a treatment for this disease, naturally occurring bacteriophage (phage) that specifically target Pss is being investigated as a biocontrol strategy. However, before using them as a biocontrol treatment, it is important to both understand their efficacy in reducing the bacterial population and determine if the bacterial pathogens can evolve resistance to evade phage infection. To investigate this, killing curve assays of five MR phages targeting Pss showed that phage resistance rapidly emerges in vitro, even when using a cocktail of the five phages together. To gain insight to the changes occurring, Pss colonies were collected three times during a 66-h killing curve assay and separately, Pss and phage were also coevolved over 10 generations, enabling the measurement of genomic and fitness changes in bacterial populations. Pss evolved resistance to phages through modifications in lipopolysaccharide (LPS) synthesis pathways. Bacterial fitness (growth) and virulence were affected in only a few mutants. Deletion of LPS-associated genes suggested that LPS was the main target receptor for all five MR phages. Later generations of coevolved phages from the coevolution experiment were more potent at reducing the bacterial density and when used with wild-type phages could reduce the emergence of phage-resistant mutants. This study shows that understanding the genetic mechanisms of bacterial pathogen resistance to phages is important for helping to design a more effective approach to kill the bacteria while minimizing the opportunity for phage resistance to manifest.
Collapse
Affiliation(s)
- Mojgan Rabiey
- School of Life Sciences, Gibbet Hill CampusUniversity of WarwickCoventryUK
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Emily R. Grace
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Paulina Pawlos
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Muscab Bihi
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Haleem Ahmed
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Georgina E. Hampson
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Amna Al Riyami
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Leena Alharbi
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Rosa Sanchez‐Lucas
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Naina Korotania
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Maria Laura Ciusa
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Olivia Mosley
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Michelle T. Hulin
- Department of Plant Soil & Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - Laura Baxter
- Bioinformatics Research Technology PlatformUniversity of WarwickCoventryUK
| | - Sabrine Dhaouadi
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Diana Vinchira‐Villarraga
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Robert W. Jackson
- School of Biosciences and the Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| |
Collapse
|
3
|
Rubilar-Hernández C, Álvarez-Maldini C, Pizarro L, Figueroa F, Villalobos-González L, Pimentel P, Fiore N, Pinto M. Nitric Oxide Mitigates the Deleterious Effects Caused by Infection of Pseudomonas syringae pv. syringae and Modulates the Carbon Assimilation Process in Sweet Cherry under Water Stress. PLANTS (BASEL, SWITZERLAND) 2024; 13:1361. [PMID: 38794433 PMCID: PMC11125257 DOI: 10.3390/plants13101361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024]
Abstract
Bacterial canker is an important disease of sweet cherry plants mainly caused by Pseudomonas syringae pv. syringae (Pss). Water deficit profoundly impairs the yield of this crop. Nitric oxide (NO) is a molecule that plays an important role in the plant defense mechanisms. To evaluate the protection exerted by NO against Pss infection under normal or water-restricted conditions, sodium nitroprusside (SNP), a NO donor, was applied to sweet cherry plants cv. Lapins, before they were exposed to Pss infection under normal or water-restricted conditions throughout two seasons. Well-watered plants treated with exogenous NO presented a lower susceptibility to Pss. A lower susceptibility to Pss was also induced in plants by water stress and this effect was increased when water stress was accompanied by exogenous NO. The lower susceptibility to Pss induced either by exogenous NO or water stress was accompanied by a decrease in the internal bacterial population. In well-watered plants, exogenous NO increased the stomatal conductance and the net CO2 assimilation. In water-stressed plants, NO induced an increase in the leaf membranes stability and proline content, but not an increase in the CO2 assimilation or the stomatal conductance.
Collapse
Affiliation(s)
- Carlos Rubilar-Hernández
- Laboratorio de Inmunidad Vegetal, Instituto de Ciencias Agroalimentarias, Animales y Ambientales, Universidad de O’Higgins, San Fernando 3070000, Chile; (C.R.-H.); (L.P.); (F.F.)
| | - Carolina Álvarez-Maldini
- Instituto de Ciencias Agroalimentarias, Animales y Ambientales, Universidad de O’Higgins, San Fernando 3070000, Chile;
- Departamento de Silvicultura, Facultad de Ciencias Forestales, Universidad de Concepción, Concepción 4070374, Chile
| | - Lorena Pizarro
- Laboratorio de Inmunidad Vegetal, Instituto de Ciencias Agroalimentarias, Animales y Ambientales, Universidad de O’Higgins, San Fernando 3070000, Chile; (C.R.-H.); (L.P.); (F.F.)
- Centro UOH de Biología de Sistemas Para la Sanidad Vegetal, Universidad de O’Higgins, San Fernando 3070000, Chile
| | - Franco Figueroa
- Laboratorio de Inmunidad Vegetal, Instituto de Ciencias Agroalimentarias, Animales y Ambientales, Universidad de O’Higgins, San Fernando 3070000, Chile; (C.R.-H.); (L.P.); (F.F.)
| | | | - Paula Pimentel
- Centro de Estudios Avanzados en Fruticultura (CEAF), Rengo 2940000, Chile; (L.V.-G.); (P.P.)
| | - Nicola Fiore
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago 8820808, Chile;
| | - Manuel Pinto
- Instituto de Ciencias Agroalimentarias, Animales y Ambientales, Universidad de O’Higgins, San Fernando 3070000, Chile;
| |
Collapse
|
4
|
Khan A, Korban SS. Breeding and genetics of disease resistance in temperate fruit trees: challenges and new opportunities. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:3961-3985. [PMID: 35441862 DOI: 10.1007/s00122-022-04093-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Climate change, large monocultures of disease-susceptible cultivars, overuse of pesticides, and the emergence of new pathogens or pathogenic strains causing economic losses are all major threats to our environment, health, food, and nutritional supply. Temperate tree fruit crops belonging to the Rosaceae family are the most economically important and widely grown fruit crops. These long-lived crops are under attack from many different pathogens, incurring major economic losses. Multiple chemical sprays to control various diseases annually is a common practice, resulting in significant input costs, as well as environmental and health concerns. Breeding for disease resistance has been undertaken primarily in pome fruit crops (apples and pears) for a few fungal and bacterial diseases, and to a lesser extent in some stone fruit crops. These breeding efforts have taken multiple decades due to the biological constraints and complex genetics of these tree fruit crops. Over the past couple of decades, major advances have been made in genetic and physical mapping, genomics, biotechnology, genome sequencing, and phenomics, along with accumulation of large germplasm collections in repositories. These valuable resources offer opportunities to make significant advances in greatly reducing the time needed to either develop new cultivars or modify existing economic cultivars for enhanced resistance to multiple diseases. This review will cover current knowledge, challenges, and opportunities in breeding for disease resistance in temperate tree fruit crops.
Collapse
Affiliation(s)
- Awais Khan
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY, 14456, USA.
| | - Schuyler S Korban
- Department of Natural Sciences and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| |
Collapse
|
5
|
Ruinelli M, Blom J, Smits THM, Pothier JF. Comparative Genomics of Prunus-Associated Members of the Pseudomonas syringae Species Complex Reveals Traits Supporting Co-evolution and Host Adaptation. Front Microbiol 2022; 13:804681. [PMID: 35592008 PMCID: PMC9111521 DOI: 10.3389/fmicb.2022.804681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Members of the Pseudomonas syringae species complex cause symptoms that are ranging from leaf spots to cankers on a multitude of plant species, including some of the genus Prunus. To date, a total of two species of the P. syringae species complex and six different pathovars have been associated with diseases on Prunus spp., which were shown to belong to different phylogenetic units (phylogroups, PG) based on sequence similarity of housekeeping genes or whole genomes, suggesting that virulence to Prunus spp. may be the result of convergent pathoadaptation. In this study, a comparative genomics approach was used to determine genes significantly associated with strains isolated from Prunus spp. across a phylogeny of 97 strains belonging to the P. syringae species complex. Our study revealed the presence of a set of orthologous proteins which were significantly associated with strains isolated from Prunus spp. than in strains isolated from other hosts or from non-agricultural environments. Among them, the type III effector HopAY predicted to encode for a C58 cysteine protease was found to be highly associated with strains isolated from Prunus spp. and revealed patterns supporting co-evolution and host adaptation.
Collapse
Affiliation(s)
- Michela Ruinelli
- Environmental Genomics and Systems Biology Research Group, Institute for Natural Resources Sciences, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Theo H. M. Smits
- Environmental Genomics and Systems Biology Research Group, Institute for Natural Resources Sciences, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
| | - Joël F. Pothier
- Environmental Genomics and Systems Biology Research Group, Institute for Natural Resources Sciences, Zurich University of Applied Sciences (ZHAW), Wädenswil, Switzerland
| |
Collapse
|
6
|
Oksel C, Avin FA, Mirik M, Baysal-Gurel F. Identification and Genetic Characterization of Pseudomonas syringae pv. syringae from Sweet Cherry in Turkey. PLANT DISEASE 2022; 106:1253-1261. [PMID: 34818912 DOI: 10.1094/pdis-10-21-2241-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Pseudomonas syringae pv. syringae, which causes bacterial canker, is the most polyphagous bacterium in the P. syringae complex because of its broad host range. This pathogen is considered the major bacterial disease in cherry orchards. In this study, several samples were collected from infected sweet cherry (Prunus avium L.) trees in different locations of the Marmara region in Turkey between 2016 and 2018. Sixty-three isolates were identified as P. syringae pv. syringae by pathogenicity, LOPAT, GATTa, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry tests. Total genomic DNA was extracted to confirm identity, followed by PCR amplification of syrB and cfl genes. Out of 63 isolates, 12 were randomly selected for repetitive element sequence-based PCR and multilocus sequence typing analyses to gain insight into the relationships of those isolates. The cluster analysis of enterobacterial repetitive intergenic consensus-, repetitive extragenic palindromic-, and BOX-A1R-based repetitive extragenic-palindromic-PCR techniques could classify the isolates into two distinct clusters. Phylogenetic analysis was carried out to obtain the relation between isolates and the location. The multilocus sequencing typing analysis of gyrB, rpoDp, rpoDs, and gltA genes allowed a clear allocation of the isolates into two separate main clusters. The relationships among the isolates were also evaluated by constructing a genealogical median-joining network (MJN). The isolates from six locations produced 11 haplotypes that were illustrated in the MJN. The results of this study proved that location could not be an indicator for showing the genetic diversity of P. syringae pv. syringae from cherry orchards. As the genetic variability of Pseudomonads has been demonstrated, this study also showed high diversity among different isolates even within the populations. While more research is recommended, the results of this study contributed to a better understanding of the evolutionary progress of P. syringae pv. syringae and the genetic diversity of sweet cherry isolates.
Collapse
Affiliation(s)
- Cansu Oksel
- Department of Plant Protection, Tekirdag Namık Kemal University, Tekirdag 59100, Turkey
| | - Farhat A Avin
- Department of Agricultural and Environmental Sciences, Otis L. Floyd Nursery Research Center, Tennessee State University, McMinnville, TN 37110, U.S.A
| | - Mustafa Mirik
- Department of Plant Protection, Tekirdag Namık Kemal University, Tekirdag 59100, Turkey
| | - Fulya Baysal-Gurel
- Department of Agricultural and Environmental Sciences, Otis L. Floyd Nursery Research Center, Tennessee State University, McMinnville, TN 37110, U.S.A
| |
Collapse
|
7
|
Transposon Mutagenesis of Pseudomonas syringae Pathovars syringae and morsprunorum to Identify Genes Involved in Bacterial Canker Disease of Cherry. Microorganisms 2021; 9:microorganisms9061328. [PMID: 34207283 PMCID: PMC8234094 DOI: 10.3390/microorganisms9061328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 02/07/2023] Open
Abstract
Bacterial canker of Prunus, affecting economically important stone fruit crops including cherry, peach, apricot and plum, is caused by the plant pathogen Pseudomonas syringae (P.s.). Strains from two pathovars—P.s. pv. syringae (Pss) and P.s. pv. morsprunorum race 1 (PsmR1) and 2 (PsmR2)—in three phylogenetically distant clades have convergently evolved to infect Prunus. The bacteria enter woody tissues through wounds and leaf scars, causing black necrotic cankers. Symptoms are also produced on blossom, fruit and leaves. Little is known about the mechanisms P.s. uses to colonise tree hosts such as Prunus. Here, we created transposon (Tn) mutant libraries in one strain of P.s. from each of the three clades and screened the mutants on immature cherry fruit to look for changes in virulence. Mutants (242) with either reduced or enhanced virulence were detected and further characterised by in vitro screens for biofilm formation, swarming ability, and pathogenicity on leaves and cut shoots. In total, 18 genes affecting virulence were selected, and these were involved in diverse functions including motility, type III secretion, membrane transport, amino acid synthesis, DNA repair and primary metabolism. Interestingly, mutation of the effector gene, hopAU1, led to an increase in virulence of Psm R2.
Collapse
|
8
|
Rabiey M, Roy SR, Holtappels D, Franceschetti L, Quilty BJ, Creeth R, Sundin GW, Wagemans J, Lavigne R, Jackson RW. Phage biocontrol to combat Pseudomonas syringae pathogens causing disease in cherry. Microb Biotechnol 2020; 13:1428-1445. [PMID: 32383813 PMCID: PMC7415359 DOI: 10.1111/1751-7915.13585] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/13/2020] [Accepted: 04/13/2020] [Indexed: 12/14/2022] Open
Abstract
Bacterial canker is a major disease of Prunus species, such as cherry (Prunus avium). It is caused by Pseudomonas syringae pathovars, including P. syringae pv. syringae (Pss) and P. syringae pv. morsprunorum race 1 (Psm1) and race 2 (Psm2). Concerns over the environmental impact of, and the development of bacterial resistance to, traditional copper controls calls for new approaches to disease management. Bacteriophage-based biocontrol could provide a sustainable and natural alternative approach to combat bacterial pathogens. Therefore, seventy phages were isolated from soil, leaf and bark of cherry trees in six locations in the south east of England. Subsequently, their host range was assessed against strains of Pss, Psm1 and Psm2. While these phages lysed different Pss, Psm and some other P. syringae pathovar isolates, they did not infect beneficial bacteria such as Pseudomonas fluorescens. A subset of thirteen phages were further characterized by genome sequencing, revealing five distinct clades in which the phages could be clustered. No known toxins or lysogeny-associated genes could be identified. Using bioassays, selected phages could effectively reduce disease progression in vivo, both individually and in cocktails, reinforcing their potential as biocontrol agents in agriculture.
Collapse
Affiliation(s)
- Mojgan Rabiey
- School of Biological SciencesUniversity of ReadingKnight BuildingReadingRG6 6AJUK
| | - Shyamali R. Roy
- School of Biological SciencesUniversity of ReadingKnight BuildingReadingRG6 6AJUK
| | | | - Linda Franceschetti
- School of Biological SciencesUniversity of ReadingKnight BuildingReadingRG6 6AJUK
| | - Billy J. Quilty
- School of Biological SciencesUniversity of ReadingKnight BuildingReadingRG6 6AJUK
| | - Ryan Creeth
- School of Biological SciencesUniversity of ReadingKnight BuildingReadingRG6 6AJUK
| | | | - Jeroen Wagemans
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenLeuvenBelgium
| | - Rob Lavigne
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenLeuvenBelgium
| | - Robert W. Jackson
- School of Biological SciencesUniversity of ReadingKnight BuildingReadingRG6 6AJUK
- School of Biosciences and Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| |
Collapse
|
9
|
Hulin MT, Jackson RW, Harrison RJ, Mansfield JW. Cherry picking by pseudomonads: After a century of research on canker, genomics provides insights into the evolution of pathogenicity towards stone fruits. PLANT PATHOLOGY 2020; 69:962-978. [PMID: 32742023 PMCID: PMC7386918 DOI: 10.1111/ppa.13189] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/09/2020] [Accepted: 03/23/2020] [Indexed: 05/10/2023]
Abstract
Bacterial canker disease is a major limiting factor in the growing of cherry and other Prunus species worldwide. At least five distinct clades within the bacterial species complex Pseudomonas syringae are known to be causal agents of the disease. The different pathogens commonly coexist in the field. Reducing canker is a challenging prospect as the efficacy of chemical controls and host resistance may vary against each of the diverse clades involved. Genomic analysis has revealed that the pathogens use a variable repertoire of virulence factors to cause the disease. Significantly, strains of P. syringae pv. syringae possess more genes for toxin biosynthesis and fewer encoding type III effector proteins. There is also a shared pool of key effector genes present on mobile elements such as plasmids and prophages that may have roles in virulence. By contrast, there is evidence that absence or truncation of certain effector genes, such as hopAB, is characteristic of cherry pathogens. Here we highlight how recent research, underpinned by the earlier epidemiological studies, is allowing significant progress in our understanding of the canker pathogens. This fundamental knowledge, combined with emerging insights into host genetics, provides the groundwork for development of precise control measures and informed approaches to breed for disease resistance.
Collapse
Affiliation(s)
| | - Robert W. Jackson
- Birmingham Institute of Forest Research (BIFoR), University of BirminghamBirminghamUK
- School of Biosciences, University of BirminghamBirminghamUK
| | | | | |
Collapse
|
10
|
Hulin MT, Mansfield JW, Brain P, Xu X, Jackson RW, Harrison RJ. Characterization of the pathogenicity of strains of Pseudomonas syringae towards cherry and plum. PLANT PATHOLOGY 2018; 67:1177-1193. [PMID: 29937581 PMCID: PMC5993217 DOI: 10.1111/ppa.12834] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bacterial canker is a major disease of Prunus avium (cherry), Prunus domestica (plum) and other stone fruits. It is caused by pathovars within the Pseudomonas syringae species complex including P. syringae pv. morsprunorum (Psm) race 1 (R1), Psm race 2 (R2) and P. syringae pv. syringae (Pss). Psm R1 and Psm R2 were originally designated as the same pathovar; however, phylogenetic analysis revealed them to be distantly related, falling into phylogroups 3 and 1, respectively. This study characterized the pathogenicity of 18 newly genome-sequenced P. syringae strains on cherry and plum, in the field and laboratory. The field experiment confirmed that the cherry cultivar Merton Glory exhibited a broad resistance to all clades. Psm R1 contained strains with differential specificity on cherry and plum. The ability of tractable laboratory-based assays to reproduce assessments on whole trees was examined. Good correlations were achieved with assays using cut shoots or leaves, although only the cut shoot assay was able to reliably discriminate cultivar differences seen in the field. Measuring bacterial multiplication in detached leaves differentiated pathogens from nonpathogens and was therefore suitable for routine testing. In cherry leaves, symptom appearance discriminated Psm races from nonpathogens, which triggered a hypersensitive reaction. Pathogenic strains of Pss rapidly induced disease lesions in all tissues and exhibited a more necrotrophic lifestyle than hemibiotrophic Psm. This in-depth study of pathogenic interactions, identification of host resistance and optimization of laboratory assays provides a framework for future genetic dissection of host-pathogen interactions in the canker disease.
Collapse
Affiliation(s)
- M. T. Hulin
- NIAB EMRNew RoadEast MallingME19 6BJUK
- School of Biological SciencesUniversity of ReadingReadingRG6 6AJUK
| | - J. W. Mansfield
- Faculty of Natural SciencesImperial College LondonLondonSW7 2AZUK
| | - P. Brain
- NIAB EMRNew RoadEast MallingME19 6BJUK
| | - X. Xu
- NIAB EMRNew RoadEast MallingME19 6BJUK
| | - R. W. Jackson
- School of Biological SciencesUniversity of ReadingReadingRG6 6AJUK
| | | |
Collapse
|
11
|
Li B, Hulin MT, Brain P, Mansfield JW, Jackson RW, Harrison RJ. Rapid, automated detection of stem canker symptoms in woody perennials using artificial neural network analysis. PLANT METHODS 2015; 11:57. [PMID: 26705407 PMCID: PMC4690310 DOI: 10.1186/s13007-015-0100-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/09/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND Pseudomonas syringae can cause stem necrosis and canker in a wide range of woody species including cherry, plum, peach, horse chestnut and ash. The detection and quantification of lesion progression over time in woody tissues is a key trait for breeders to select upon for resistance. RESULTS In this study a general, rapid and reliable approach to lesion quantification using image recognition and an artificial neural network model was developed. This was applied to screen both the virulence of a range of P. syringae pathovars and the resistance of a set of cherry and plum accessions to bacterial canker. The method developed was more objective than scoring by eye and allowed the detection of putatively resistant plant material for further study. CONCLUSIONS Automated image analysis will facilitate rapid screening of material for resistance to bacterial and other phytopathogens, allowing more efficient selection and quantification of resistance responses.
Collapse
Affiliation(s)
- Bo Li
- />East Malling Research, New Road, East Malling, ME19 6BJ Kent, UK
| | - Michelle T. Hulin
- />East Malling Research, New Road, East Malling, ME19 6BJ Kent, UK
- />School of Biological Sciences, University of Reading, Reading, RG6 6AJ UK
| | - Philip Brain
- />East Malling Research, New Road, East Malling, ME19 6BJ Kent, UK
| | - John W. Mansfield
- />Faculty of Natural Sciences, Imperial College London, SW7 2AZ London, UK
| | - Robert W. Jackson
- />School of Biological Sciences, University of Reading, Reading, RG6 6AJ UK
| | - Richard J. Harrison
- />East Malling Research, New Road, East Malling, ME19 6BJ Kent, UK
- />School of Biological Sciences, University of Reading, Reading, RG6 6AJ UK
| |
Collapse
|