DOCSLIB.ORG

Rationalization of Genes for Resistance to Bremia Lactucae in Lettuce

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Rationalization of Genes for Resistance to Bremia Lactucae in Lettuce Euphytica DOI 10.1007/s10681-016-1687-1 REVIEW Rationalization of genes for resistance to Bremia lactucae in lettuce Lorena Parra . Brigitte Maisonneuve . Ales Lebeda . Johan Schut . Marilena Christopoulou . Marieke Jeuken . Leah McHale . Maria-Jose Truco . Ian Crute . Richard Michelmore Received: 12 December 2015 / Accepted: 29 March 2016 Ó The Author(s) 2016. This article is published with open access at Springerlink.com Abstract Lettuce downy mildew caused by Bremia molecular information. This involved multiple rounds lactucae is the most important disease of lettuce of consultation with many of the original authors. This worldwide. Breeding for resistance to this disease is a paper provides the foundation for naming additional major priority for most lettuce breeding programs. genes for resistance to B. lactucae in the future as well Many genes and factors for resistance to B. lactucae as for deploying genes to provide more durable have been reported by multiple researchers over the resistance. past *50 years. Their nomenclature has not been coordinated, resulting in duplications and gaps in Keywords Lactuca spp. Á Resistance genes Á Lettuce nominations. We have reviewed the available infor- downy mildew Á Dm gene Á Quantitative trait locus Á mation and rationalized it into 51 resistance genes and Plant breeding factors and 15 quantitative trait loci along with supporting documentation as well as genetic and Abbreviations DM Downy mildew NLR Nucleotide binding-leucine rich repeat- Electronic supplementary material The online version of this article (doi:10.1007/s10681-016-1687-1) contains supple- receptor like protein mentary material, which is available to authorized users. L. Parra Á M. Christopoulou Á M.-J. Truco Á M. Jeuken R. Michelmore (&) Laboratory of Plant Breeding, Wageningen University, The Genome Center and Department of Plant Sciences, Wageningen 6700 AJ, The Netherlands University of California, Davis, CA 95616, USA e-mail: [email protected] L. McHale Department of Horticulture and Crop Science, Ohio State B. Maisonneuve University, Columbus, OH 43210, USA INRA, Ge´ne´tique et Ame´lioration des Fruits et Le´gumes, Domaine Saint Maurice, CS60094, I. Crute 84143 Montfavet Cedex, France Agriculture and Horticulture Development Board, Stoneleigh Park, Kenilworth, Warwickshire CV8 2TL, A. Lebeda UK Department of Botany, Palacky´ University, Sˇlechtitelu˚ 27, 78371 Olomouc, Czech Republic J. Schut Rijk Zwaan, De Lier 2678 ZG, The Netherlands 123 Euphytica MRC Major resistance cluster genetically (e.g. Farrara and Michelmore 1987; Bon- QTL Quantitative trait locus nier et al. 1994; Lebeda and Zinkernagel 2003; TNL NLR proteins with a Toll/interleukin Beharav et al. 2006). As more resistance genes are receptor (TIR) domain at their N-terminus characterized from these and other sources, it is likely CNL NLR proteins lacking a TIR domain often that several hundred genes with efficacy against B. with a coiled-coil (CC) N-terminal domain lactucae will be identified that will require a coordi- IBEB International Bremia Evaluation Board nated, rational nomination process. USDA United States Department of Agriculture This review compiles the knowledge of genetic DMR6 Downy mildew resistance 6 resistance against B. lactucae, summarizing what is EMS Ethyl methanesulfonate known of genes for resistance to B. lactucae that has been generated over more than 50 years of lettuce genetics and breeding (Supplemental Fig. 1). Resis- tance has been reported by multiple researchers Introduction leading to duplications in nominations as well as gaps in sequence. The extent of genetic characterization has Lettuce (Lactuca sativa) is one of the most widely varied. Genes characterized as single Mendelian loci consumed vegetable crops worldwide. It has an annual were designated Dm genes, while those that were less production of more than 3.6 billion tonnes with a value well characterized genetically were often but not of more than $2.4 billion in the U.S. (USDA-NASS always termed R-factors. For this review we have 2014). Downy mildew (DM) caused by the oomycete rationalized the nomenclature of all of the Dm genes pathogen Bremia lactucae is the most important and R-factors reported so far and provide the founda- disease of lettuce that decreases quality of the tion for future designation and use of Dm genes. marketable portion of the crop. The impact of this disease is often accentuated by postharvest losses that occur during transit and storage. DM can also increase Historical overview of breeding for resistance to B. the consequences of microbial contamination by lactucae human enteric pathogens (Simko et al. 2015a). Strategies for control of DM include the combined Breeding for resistance to B. lactucae in cultivated use of resistant cultivars and fungicides as well as lettuce has been carried out since the beginning of the agronomic practices that reduce foliar humidity. The last century. Initial breeding efforts utilized resistance use of fungicides is constrained by high costs and the identified in old lettuce cultivars (L. sativa). French development of fungicide-resistant strains (Crute traditional cultivars Gotte a` Graine Blanche de Loos 1987; Schettini et al. 1991). Moreover, increasing and Rose´e Printanie`re were the first sources of restrictive regulations aimed at reducing pesticide resistance (referenced in Crute 1992). Subsequently, applications are coming into force; in Europe several resistance was identified in several other cultivars such chemicals that are effective against B. lactucae will be as Meikoningen, May Queen, Gotte a` Forcer a` Graine redrawn from the market. The deployment of cultivars Noire, Bourguignonne Grosse Blonde d’Hiver and carrying dominant resistance genes (Dm genes) is the Blonde Lente a` Monter (Jagger and Chandler 1933; most effective method for controlling DM; however, Schultz and Ro¨der 1938; Jagger and Whitaker 1940; pathogen variability has led to the rapid defeat of Ogilvie 1944; Rodenburg et al. 1960). Later breeding individual Dm genes (e.g. Ilott et al. 1987). Conse- efforts accessed resistance from wild Lactuca species. quently, the search for new sources resistance to B. One of the first inter-specific crosses for this purpose lactucae has been a continuous, long-term priority of was between L. sativa cv. Imperial D and DM– lettuce breeding programs (Crute 1992; Lebeda et al. resistant L. serriola PI104854 (Whitaker et al. 1958). 2002, 2014). Over 50 genes for resistance have been This resistance was used in breeding programs in reported so far and genetically characterized to California during the 50’s, that led to the crisphead cv. varying extents (see below for references). In addition, Calmar (cv. Great Lakes 9 USDA 45325; Welch et al. many other sources of resistance have been identified 1965) and subsequently cv. Salinas (cv. Calmar 9 in germplasm screens but have yet to be characterized Vanguard 75; Ryder 1979a, b) that is in the pedigree of 123 Euphytica many current crisphead cultivars (Mikel 2007, 2013). Michelmore 1992). Cultivars carrying Dm6 and Dm7 Contemporary breeding efforts are focused on intro- may exhibit partial resistance associated with macro- gression of new genes from wild species. L. serriola, scopically visible hypersensitive necrosis (Crute and the likely progenitor of cultivated lettuce, and, to a Norwood 1978). Additionally, gene dosage affects the lesser extent, L. saligna have been used as donors of resistance phenotype of some Dm genes, for example resistance genes (Jagger and Whitaker 1940; Crute Dm17 under high pathogen pressure (Maisonneuve and Johnson 1976a, b; Lebeda et al. 1980; Bonnier et al. 1994). Some lettuce cultivars such as Iceberg and et al. 1994; Witsenboer et al. 1995; Maisonneuve et al. Grand Rapids exhibit resistance at the adult plant stage 1999; Jeuken and Lindhout 2002, Michelmore and in the field that cannot be attributed to Dm genes Ochoa 2006, 2008; Mc Hale et al. 2009, Zhang et al. (Milbrath 1923; Verhoeff 1960; Crute and Norwood 2009). L. virosa also possesses race-specific resistance 1981). This quantitative resistance phenotype (Nor- to B. lactucae (Lebeda and Boukema 1991; Lebeda wood and Crute 1985; Grube and Ochoa 2005) has so et al. 2002, Maisonneuve et al. 1999), but its use in far been shown to be inherited polygenically (Simko breeding programs has been restricted by infertility et al. 2013); transgressive segregation resulting in barriers between L. virosa and L. sativa (Maisonneuve elevated resistance has been observed in progeny from 2003). Transfer of resistance from L. virosa to L. cvs. Grand Rapids 9 Iceberg (Grube and Ochoa 2005; sativa has occasionally been enabled by embryo Simko et al. 2013). Some cultivars such as Green rescue (Maisonneuve 1987; Maisonneuve et al. towers and Cobham Green have no known Dm genes 1995). Other wild species such as L. aculeata are and are used as susceptible lines to grow B. lactucae potential sources of resistance that have yet to be used isolates; however, the European isolate Serr84/99 is as donors in breeding programs (Jemelkova´ et al. avirulent on Cobham Green and there is some 2015). Currently, introgression of recently identified evidence suggesting polygenic resistance in this resistance from L. serriola, L. saligna and L. virosa cultivar (Maisonneuve 2011b). Most accessions of L. through repeated backcrosses to L. sativa is being saligna are completely resistant to isolates of B. carried out by multiple public and commercial breed- lactucae derived from L. sativa; therefore, this species ing programs resulting in a large increase in the has been proposed to be a non-host for downy mildew number of resistance genes being deployed (e.g. (Bonnier et al. 1992; Petrzˇelova´ et al. 2011; van Michelmore and Ochoa 2008; Michelmore et al. Treuren et al. 2013); this complete resistance is in part 2013a). determined by several quantitative trait loci (QTLs) operating at different developmental stages (Jeuken and Lindhout 2002; Jeuken et al. 2008, Zhang et al. Genetics of resistance and nomenclature 2009; Den Boer et al. 2013). However, the mechanism of resistance genes of resistance in L.
Load more

Recommended publications
  • Report of a Working Group on Leafy Vegetables: First Meeting
    European Cooperative Programme for Plant Genetic Report of a Working Resources ECP GR Group on Leafy Vegetables First Meeting, 13-14 October 2005, Olomouc, Czech Republic L. Maggioni, A. Lebeda, I. Boukema and E. Lipman, compilers IPGRI and INIBAP operate under the name Bioversity International Supported by the CGIAR European Cooperative Programme for Plant Genetic Report of a Working Resources ECP GR Group on Leafy Vegetables First Meeting, 13-14 October 2005, Olomouc, Czech Republic L. Maggioni, A. Lebeda, I. Boukema and E. Lipman, compilers ii REPORT OF A WORKING GROUP ON LEAFY VEGETABLES: FIRST MEETING Bioversity International is an independent international scientific organization that seeks to improve the well- being of present and future generations of people by enhancing conservation and the deployment of agricultural biodiversity on farms and in forests. It is one of 15 centres supported by the Consultative Group on International Agricultural Research (CGIAR), an association of public and private members who support efforts to mobilize cutting-edge science to reduce hunger and poverty, improve human nutrition and health, and protect the environment. Bioversity has its headquarters in Maccarese, near Rome, Italy, with offices in more than 20 other countries worldwide. The Institute operates through four programmes: Diversity for Livelihoods, Understanding and Managing Biodiversity, Global Partnerships, and Commodities for Livelihoods. The international status of Bioversity is conferred under an Establishment Agreement which, by January 2008, had been signed by the Governments of Algeria, Australia, Belgium, Benin, Bolivia, Brazil, Burkina Faso, Cameroon, Chile, China, Congo, Costa Rica, Côte d’Ivoire, Cyprus, Czech Republic, Denmark, Ecuador, Egypt, Ethiopia, Ghana, Greece, Guinea, Hungary, India, Indonesia, Iran, Israel, Italy, Jordan, Kenya, Malaysia, Mali, Mauritania, Morocco, Norway, Oman, Pakistan, Panama, Peru, Poland, Portugal, Romania, Russia, Senegal, Slovakia, Sudan, Switzerland, Syria, Tunisia, Turkey, Uganda and Ukraine.
    [Show full text]
  • Effector Identification in the Lettuce Downy Mildew Bremia Lactucae By
    bs_bs_banner MOLECULAR PLANT PATHOLOGY (2012) 13(7), 719–731 DOI: 10.1111/J.1364-3703.2011.00780.X Effector identification in the lettuce downy mildew Bremia lactucae by massively parallel transcriptome sequencing JOOST H. M. STASSEN1, MICHAEL F. SEIDL2,3, PIM W. J. VERGEER1, ISAÄC J. NIJMAN4, BEREND SNEL2,3, EDWIN CUPPEN4 AND GUIDO VAN DEN ACKERVEKEN1,3,* 1Plant–Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, 3508 CH Utrecht, the Netherlands 2Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Padualaan 8, 3508 CH Utrecht, the Netherlands 3Centre for BioSystems Genomics (CBSG), Wageningen University, Binnenhaven 5, 6709 PD Wageningen, the Netherlands 4Hubrecht Institute, Developmental Biology and Stem Cell Research, KNAW and University Medical Center Utrecht, Uppsalalaan 8, Utrecht, the Netherlands agent of the Irish potato famine, and P. ramorum, which causes SUMMARY sudden oak death. The downy mildews have a narrow host range, Lettuce downy mildew (Bremia lactucae) is a rapidly adapting for instance Hyaloperonospora arabidopsidis grows only on living oomycete pathogen affecting commercial lettuce cultivation. Arabidopsis thaliana plants, Plasmopara viticola is an important Oomycetes are known to use a diverse arsenal of secreted proteins grape pathogen and Bremia lactucae is the most important patho- (effectors) to manipulate their hosts. Two classes of effector are gen of lettuce (Lactuca sativa). The control of B. lactucae is an known to be translocated by the host: the RXLRs and Crinklers. To increasingly difficult task as fungicides have been phased out gain insight into the repertoire of effectors used by B. lactucae to because of environmental concerns, and fungicide resistance is manipulate its host, we performed massively parallel sequencing becoming more widespread (Brown et al., 2004).
    [Show full text]
  • Genetic Variability and Distance Between Lactuca Serriola L
    Acta Bot. Croat. 77 (2), 172–180, 2018 CODEN: ABCRA 25 DOI: 10.2478/botcro-2018-0019 ISSN 0365-0588 eISSN 1847-8476 Genetic variability and distance between Lactuca serriola L. populations from Sweden and Slovenia assessed by SSR and AFLP markers Michaela Jemelková1, Miloslav Kitner1, Eva Křístková1, Ivana Doležalová2, Aleš Lebeda1* 1 Palacký University in Olomouc, Faculty of Science, Department of Botany, Šlechtitelů 27, 783 71 Olomouc, Czech Republic 2 Department of Genetic Resources for Vegetables, Medicinal, and Special Plants of Crop Research Institute in Olomouc, Šlechtitelů 29, 783 71 Olomouc, Czech Republic Abstract – The study involved 121 samples of the common weed, Lactuca serriola L. (prickly lettuce), represent- ing 53 populations from Sweden and Slovenia. The seed materials, originating from different habitats, were re- generated and taxonomically validated at the Department of Botany, Palacký University in Olomouc, Czech Re- public. The morphological characterizations of the collected plant materials classified all 121 samples as L. serriola f. serriola; one sample was heterogeneous, and also present was L. serriola f. integrifolia. Differences in the amount and distribution of the genetic variations between the two regions were analyzed using 257 ampli- fied fragment length polymorphism (AFLP) and 7 microsatellite (SSRs) markers. Bayesian clustering and Neigh- bor-Network were used for visualization of the differences among the samples by country. Under the Bayesian approach, the best partitioning (according to the most frequent signals) was resolved into three groups. While the absence of an admixture or low admixture was detected in the Slovenian samples, and the majority of the Swedish samples, a significant admixture was detected in the profiles of five Swedish samples collected near Malmö, which bore unique morphological features of their rosette leaves.
    [Show full text]
  • Bremia Lactucae)
    International Journal of Forestry and Horticulture (IJFH) Volume 4, Issue 2, 2018, PP 1-6 ISSN No. (Online) 2454–9487 DOI: http://dx.doi.org/10.20431/2454-9487.0402001 www.arcjournals.org Method Optimization Studies on Inoculation and Isolation of the Causal Agent of Lettuce Downy Mildew (Bremia Lactucae) Razieh Ebrahimzadeh1, F. Sara Dolar1*, Kenan Sönmez2, Ş. Şebnem Ellialtıoğlu3 1 Ankara University, Faculty of Agriculture, Department of Plant Protection, Ankara, Turkey. 2Eskişehir Osmangazi University, Faculty of Agriculture, Department of Horticulture, Eskişehir, Turkey. 3Ankara University, Faculty of Agriculture, Department of Horticulture, Ankara, Turkey. *Corresponding Author: F. Sara Dolar, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey. Abstract: Downy mildew disease caused by Bremia lactucae causes one of the most devastating diseases of lettuce worldwide. An obligat parasite, B.lactucae’s sporulation in unnatural environments and storage is more difficult than necrotrophic pathogens and some special methods are needed to be developed. For this aim, disease samples were collected during 2016 lettuce growing seasons. The all samples were stored at -20 °C and -80 °C. Small leaf parts showing symptoms from the samples were dissected and spores were scraped by various methods. The spore suspensions were obtained using three methods (keep at room illumination+room temperature, room illumination+stored in ice, darkness+room temperature). In order to determine the suitable inoculation method, seedling, and detached leaf tests (blotter, floating, waxed slide test and water agar methods) were performed. A series of petri plates and seedlings were kept at 13±1 °C in the climate chamber and another series of assay were incubated at 18-21 °C until sporulation.
    [Show full text]
  • Phylogenetic Relationships of Plasmopara, Bremia and Other
    Mycol. Res. 108 (9): 1011–1024 (September 2004). f The British Mycological Society 1011 DOI: 10.1017/S0953756204000954 Printed in the United Kingdom. Phylogenetic relationships of Plasmopara, Bremia and other genera of downy mildew pathogens with pyriform haustoria based on Bayesian analysis of partial LSU rDNA sequence data Hermann VOGLMAYR1, Alexandra RIETHMU¨LLER2, Markus GO¨KER3, Michael WEISS3 and Franz OBERWINKLER3 1 Institut fu¨r Botanik und Botanischer Garten, Universita¨t Wien, Rennweg 14, A-1030 Wien, Austria. 2 Fachgebiet O¨kologie, Fachbereich Naturwissenschaften, Universita¨t Kassel, Heinrich-Plett-Strasse 40, D-34132 Kassel, Germany. 3 Lehrstuhl fu¨r Spezielle Botanik und Mykologie, Botanisches Institut, Universita¨tTu¨bingen, Auf der Morgenstelle 1, D-72076 Tu¨bingen, Germany. E-mail : [email protected] Received 28 December 2003; accepted 1 July 2004. Bayesian and maximum parsimony phylogenetic analyses of 92 collections of the genera Basidiophora, Bremia, Paraperonospora, Phytophthora and Plasmopara were performed using nuclear large subunit ribosomal DNA sequences containing the D1 and D2 regions. In the Bayesian tree, two main clades were apparent: one clade containing Plasmopara pygmaea s. lat., Pl. sphaerosperma, Basidiophora, Bremia and Paraperonospora, and a clade containing all other Plasmopara species. Plasmopara is shown to be polyphyletic, and Pl. sphaerosperma is transferred to a new genus, Protobremia, for which also the oospore characteristics are described. Within the core Plasmopara clade, all collections originating from the same host family except from Asteraceae and Geraniaceae formed monophyletic clades; however, higher-level phylogenetic relationships lack significant branch support. A sister group relationship of Pl. sphaerosperma with Bremia lactucae is highly supported.
    [Show full text]
  • EPPO Standards 
    EPPO Standards GUIDELINES ON GOOD PLANT PROTECTION PRACTICE LETTUCE UNDER PROTECTED CULTIVATION PP 2/3(2) English oepp eppo European and Mediterranean Plant Protection Organization 1, rue Le Nôtre, 75016 Paris, France APPROVAL EPPO Standards are approved by EPPO Council. The date of approval appears in each individual standard. REVIEW EPPO Standards are subject to periodic review and amendment. The next review date for this set of EPPO Standards is decided by the EPPO Working Party on Plant Protection Products. AMENDMENT RECORD Amendments will be issued as necessary, numbered and dated. The dates of amendment appear in each individual standard (as appropriate). DISTRIBUTION EPPO Standards are distributed by the EPPO Secretariat to all EPPO Member Governments. Copies are available to any interested person under particular conditions upon request to the EPPO Secretariat. SCOPE EPPO guidelines on good plant protection practice (GPP) are intended to be used by National Plant Protection Organizations, in their capacity as authorities responsible for regulation of, and advisory services related to, the use of plant protection products. REFERENCES All EPPO guidelines on good plant protection practice refer to the following general guideline: OEPP/EPPO (1994) EPPO Standard PP 2/1(1) Guideline on good plant protection practice: principles of good plant protection practice. Bulletin OEPP/EPPO Bulletin 24, 233-240. OUTLINE OF REQUIREMENTS For each major crop of the EPPO region, EPPO guidelines on good plant protection practice (GPP) cover methods for controlling pests (including pathogens and weeds). The main pests of the crop in all parts of the EPPO region are considered. For each, details are given on biology and development, appropriate control strategies are described, and, if relevant, examples of active substances which can be used for chemical control are mentioned.
    [Show full text]
  • UC Davis UC Davis Previously Published Works
    UC Davis UC Davis Previously Published Works Title Sporulation of Bremia lactucae affected by temperature, relative humidity, and wind in controlled conditions Permalink https://escholarship.org/uc/item/9j91h7dr Journal Phytopathology, 94(4) ISSN 0031-949X Authors Su, H van Bruggen, AHC Subbarao, K V et al. Publication Date 2004-04-01 Peer reviewed eScholarship.org Powered by the California Digital Library University of California This article is from the April 2004 issue of published by The American Phytopathological Society For more information on this and other topics related to plant pathology, we invite you to visit APSnet at www.apsnet.org Ecology and Epidemiology Sporulation of Bremia lactucae Affected by Temperature, Relative Humidity, and Wind in Controlled Conditions H. Su, A. H. C. van Bruggen, K. V. Subbarao, and H. Scherm First, second, and third authors: Department of Plant Pathology, University of California, Davis 95616; and fourth author: Department of Plant Pathology, University of Georgia, Athens 30602. Current address of H. Su: Alberta Research Council, Vegreville, Alberta, Canada. Current address of A. H. C. van Bruggen: Leerstoelgroep Biologische Bedrijfssystemen, 6709 PG Wageningen, The Netherlands. Accepted for publication 4 December 2003. ABSTRACT Su, H., van Bruggen, A. H. C., Subbarao, K. V., and Scherm, H. 2004. 0.0001) affected the number of cotyledons with sporulation and the Sporulation of Bremia lactucae affected by temperature, relative humid- number of sporangia produced per cotyledon. No sporulation was ob- ity, and wind in controlled conditions. Phytopathology 94:396-401. served at wind speeds of >0.5 m s–1, regardless of RH. In still air, the number of sporangiophores produced per cotyledon increased linearly The effects of temperature (5 to 25°C), relative humidity (81 to 100%), with RH from 81 to 100% (P = 0.0001, r = 0.98).
    [Show full text]
  • Wild Lactuca Species in North America
    Horticulture Publications Horticulture 2019 Wild Lactuca Species in North America A. Lebeda Palacký University E. Křístková Palacký University I. Doležalová Medicinal and Special Plants of Crop Research Institute in Olomouc M. Kitner Palacký University Mark P. Widrlechner Iowa State University, [email protected] Follow this and additional works at: https://lib.dr.iastate.edu/hort_pubs Part of the Agricultural Science Commons, Ecology and Evolutionary Biology Commons, Horticulture Commons, Natural Resources and Conservation Commons, and the Plant Breeding and Genetics Commons The complete bibliographic information for this item can be found at https://lib.dr.iastate.edu/ hort_pubs/39. For information on how to cite this item, please visit http://lib.dr.iastate.edu/ howtocite.html. This Book Chapter is brought to you for free and open access by the Horticulture at Iowa State University Digital Repository. It has been accepted for inclusion in Horticulture Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Wild Lactuca Species in North America Abstract This chapter presents a brief history of the uses of lettuce (Lactuca sativa L.) and its wild North American relatives, and reviews the agricultural importance of lettuce and challenges in its cultivation, in relation to nutritional quality, diseases, pests, and edaphic and climatic limitations. The evolution and taxonomy of the genus Lactuca are presented, with a primary focus on the wild Lactuca species of North America, their characterization, biogeography and distribution, habitat ecology, and genepools. Specific examples of phenotypic variability, genetic diversity and disease resistance of wild Lactuca taxa from both published reports and recent evaluations conducted in our laboratory are also presented.
    [Show full text]
  • I. Albuginaceae and Peronosporaceae) !• 2
    ANNOTATED LIST OF THE PERONOSPORALES OF OHIO (I. ALBUGINACEAE AND PERONOSPORACEAE) !• 2 C. WAYNE ELLETT Department of Plant Pathology and Faculty of Botany, The Ohio State University, Columbus ABSTRACT The known Ohio species of the Albuginaceae and of the Peronosporaceae, and of the host species on which they have been collected are listed. Five species of Albugo on 35 hosts are recorded from Ohio. Nine of the hosts are first reports from the state. Thirty- four species of Peronosporaceae are recorded on 100 hosts. The species in this family re- ported from Ohio for the first time are: Basidiophora entospora, Peronospora calotheca, P. grisea, P. lamii, P. rubi, Plasmopara viburni, Pseudoperonospora humuli, and Sclerospora macrospora. New Ohio hosts reported for this family are 42. The Peronosporales are an order of fungi containing the families Albuginaceae, Peronosporaceae, and Pythiaceae, which represent the highest development of the class Oomycetes (Alexopoulous, 1962). The family Albuginaceae consists of the single genus, Albugo. There are seven genera in the Peronosporaceae and four commonly recognized genera of Pythiaceae. Most of the species of the Pythiaceae are aquatic or soil-inhabitants, and are either saprophytes or facultative parasites. Their occurrence and distribution in Ohio will be reported in another paper. The Albuginaceae include fungi which are all obligate parasites of vascular plants, causing diseases known as white blisters or white rusts. These white blisters are due to the development of numerous conidia, sometimes called sporangia, in chains under the epidermis of the host. None of the five Ohio species of Albugo cause serious diseases of cultivated plants in the state.
    [Show full text]
  • Downy Mildew of Lettuce in Florida1 Lis Rodrigues-Porto, Richard N
    HS1403 Downy Mildew of Lettuce in Florida1 Lis Rodrigues-Porto, Richard N. Raid, and Germán V. Sandoya2 The Importance of Lettuce and opportunities for foodborne pathogens, such as Escherichia coli or Salmonella enterica. Impact of Downy Mildew in Florida The United States produces 15% of the world’s lettuce (Table 1), and Florida ranks third among states, following only California and Arizona (Figure 1). In Florida, lettuce is mostly field grown, with limited production in protected structures. The majority of Florida’s field production is located on the rich organic “muck” soils of the Everglades Agricultural Area (EAA), amounting to over 10,000 acres, primarily in Palm Beach County. The state’s production values for the lettuce crop routinely exceed $80 million annually. In response to a growing demand for organically produced lettuce, production within protected structures (greenhouses) has expanded in recent years. Such facilities offer a distinct advantage in terms of greater environmental Figure 1. Percentage based on production of lettuce planted in control. A recent survey conducted and compiled with California, Arizona, and Florida in the United States according to the USDA Census of Agriculture in 2017. Source: https://www.nass.usda. responses from 240 grower operations in Florida indicated gov/ rapid growth in this type of production within the state of Credits: Lis Natali Rodrigues Porto, UF/IFAS Florida. Causal Organism Lettuce downy mildew (LDM) is the most important LDM is caused by the oomycete Bremia lactucae Regel. disease of lettuce worldwide, with losses of up to 100% Oomycetes were previously considered part of the Fungi reported in individual fields in Florida.
    [Show full text]
  • Marieke J.W. Jeuken the Genetics of Non-Host Resistance to the Lettuce
    Marieke J.W. Jeuken The genetics of non-host resistance to the lettuce pathogen Bremialactucae i n Lactucasaligna Promotor: Prof. Dr. Ir. P.Sta m Hoogleraar in deplantenveredeling , in het bijzonder de selectiemethoden en duurzame resistentie Co-promotor: Dr. P. Lindhout Universitair hoofddocent Leerstoelgroep plantenveredeling Promotiecommissie: Prof. Dr. Ir. A. H. C. van Bruggen, Wageningen Universiteit Prof. Dr. Ir. M. Koornneef, Wageningen Universiteit Dr. Ir. F.P .M . Govers, Wageningen Universiteit Dr. Ir. K.Reinink , RijkZwaan BV, De Lier ^0X201,3^03 Marieke J.W. Jeuken The genetics of non-host resistance to the lettuce pathogen Bremialactucae i n Lactucasaligna Proefschrift ter verkrijging van degraa d van doctor op gezag van derecto r magnificus van Wageningen Universiteit, Prof. Dr. Ir. L. Speelman in het openbaar te verdedigen op woensdag 22 mei 2002 om half twee 's middags in de Aula. 6u ^93? ISBN 90-5808-619-4 Keywords: plant breeding, lettuce, Lactucasativa, Lactuca saligna, Bremia lactucae, downy mildew, genetics,non-hos t resistance, QTL,quantitativ e trait locus, molecular marker, marker assisted selection STELLINGEN 1.D e oude definities van "Dm" en '7?"-genen zijn achterhaald. Het verdient voorkeur om dit onderscheid tebasere n op gekloneerde genen. 2. De extra inspanning die nodig is om AFLP merkers co-dominant te kunnen scoren wordt ruimschoots gecompenseerd door het grote gemak waarmee genetische kaarten met behulp van co-dominante merkers geconstrueerd worden. 3. De niet-waard resistentie van Lactuca saligna tegen Bremia lactucae is de meest waardevolle resistentie voor de sla-veredeling. 4. De Backcross Inbred Line karteringsstrategie kan genen onthullen die verborgen blijven in een F2karteringsbenaderin g (dit proefschrift).
    [Show full text]
  • Crop Profiles -- Washington
    Crop Profile for Lettuce in Washington Prepared: December, 2000 General Production Information ● Percent of U.S. Production: <1.0 ● Rank: #7 in U.S. acres harvested in 1997 ● Acres Harvested: 900 in 1997 (multiple crops on farms in yearly estimate) ● Yield Per Acre: 200 cwt./acre in 1997 for a total of 180,000 cwt./900 acres, with an average market price of $15.10/cwt. ● Value Per Harvested Acre: $3,020 in 1997 ● Total Value of Production: $2,718,000 in 1997 Production Regions Commercial production regions are centered in the Puget Sound area of western Washington, primarily Pierce and King counties. Other counties, such as Thurston, Whatcom, Clark, Island, Kitsap, Okanogan, Snohomish, Spokane, Stevens, and Walla Walla also reported some lettuce acreage in the 1997 Census The Crop Profile/PMSP database, including this document, is supported by USDA NIFA. of Agriculture. General Information Both head lettuce (iceberg, butterhead) and leaf lettuce (green leaf, romaine, red leaf) are grown for fresh markets, primarily located in western Washington and Alaska. The Washington lettuce industry is a niche industry, depending upon markets not utilized by the California lettuce industry. The average farm size is 50 to 60 acres, with the average lettuce field size being five acres. The majority of growers plant green leaf lettuce along with other varieties throughout the season in an effort to meet fluctuating market demands. Most farms plant three or, infrequently, four crops of lettuce per year in staggered plantings. Some growers plant lettuce followed by other vegetable crops such as Chinese cabbage, celery, or radish.
    [Show full text]