DOCSLIB.ORG

Host Effects on Natural Spread of Citrus Tristeza Virus in Florida

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Host Effects on Natural Spread of Citrus Tristeza Virus in Florida Host Effects on Natural Spread of Citrus Tristeza Virus in Florida R. K. Yokomi and S. M. Garnsey ABSTRACT. Aphid transmission and natural spread of citrus tristeza virus (CTV) in different citrus receptor hosts were studied under field and laboratory conditions. After 10 years of field exposure, natural infection of 12 citrus cultivars segregated into three groups: 1) highly susceptible varieties (89-100%) which included Alemow, Volkamer lemon, Ridge Pineapple, Orlando tangelo, and rough lemon; 2) varieties with low susceptibility (27-53%) which included Rangpur lime, Cleopatra mandarin, sour orange, and Palestine sweet lime; and 3) resistant varieties (0%) which included Swingle citrumelo, trifoliate orange, and Carrizo citrange. In greenhouse tests, Alemow and Mexican lime seedlings were the best receptor plants for transmission of the T-67 isolate of CTV by Aphis gossypii Glover with infection rates of 38 and 31%, respectively, whereas infection rates in Pineapple and Hamlin sweet oranges and Duncan grapefruit were 19, 17, and 11%, respectively. No transmis- sion was obtained to sour orange or Carrizo citrange. Citms hystrix DC, sweet orange varieties, Temple, and grapefruit were good hosts for nymph survival and production of A. gossypii and Aphis citricola van der Goot in laboratory tests with detached leaves. In comparison, Mexican lime was a poor host while Alemow was a nonhost. Carrizo citrange and Swingle citrumelo were also nonhosts of the aphids. These observations indicated that many varieties susceptible to CTV were good hosts for citrus aphids under test conditions, but vector transmission to different receptor plants was not necessarily correlated to aphid host suitability. Index words. Citrus rootstocks, aphid vectors, resistance, epidemiology, transmission, host range. Citrus varieties differ in suscepti- METHODS AND MATERIALS bility to citrus tristeza virus (CTV). The mechanism of these differences is Trees and plot. A 13-row citrus complex and not well understood. plot was planted in a commercial cit- Garnsey et al. (4) have described dif- rus grove in 1976 in Indiantown, ferences in virus titer of different Florida. Ten rows were planted with CTV isolates in different cultivars. Valencia orange trees infected with Some varieties such as trifoliate T-26, a mild CTV isolate, on different orange, Swingle citrumelo, and Car- rootstocks. Greenhouse-grown, 1- rizo citrange are highly resistant to year-old seedlings or rooted cuttings CTV infection, even by graft trans- of 12 cultivars (Table 1) were planted mission, whereas sweet orange vari- as tristeza-free trees in rows 1,8, and eties support high titers of virus. 13 in this plot. These trees were Natural spread of CTV is by aphid rootstock varieties and were planted vectors. The variety of the acquisition in a randomized complete block de- host and the variety of the receptor sign with six replications and three affected CTV transmission under ex- trees per replication. The entire plot perimental conditions (2, 7,9). Hence, area covered 1.4 ha with 80 trees per natural spread of CTV depends on a row and a tree spacing of 5.2 x 7.6 m. complex of factors which includes sus- The primary purpose of this plot test ceptibility to inoculation, virus repli- was to monitor citrus blight incidence cation, vector feeding behavior, vec- in grafted and nongrafted trees. Since tor reproduction, and vector move- other commercial plantings near this ment. The purpose of this study was plot were infected with CTV, a sur- to gain further insight into these in- vey was conducted of all rootstocks teractions by comparing field spread trees in the plot after 10 years of field of CTV into different cultivars with exposure. These trees provided an some laboratory tests of vector trans- opportunity to measure CTV spread mission, and to measure aphid repro- in the field under replicated condi- duction on different citrus varieties. tions. Tenth IOCV Conference CTV assay. Fully expanded cal analysis was conducted by SAS young leaves or twigs were harvested (Raleigh, NC). from two sides of each field tree in the spring of 1985 and 1986. Bark and/ RESULTS or leaf midribs were excised from Field spread. After 10 years of these samples and assayed for CTV field exposure to endemic and field infection by double antibody sandwich sources of CTV and natural popula- enzyme-linked immunosorbent assay tions of aphid vectors, sufficient field (1) using antisera to whole, unfixed spread had occurred to segregate the virus particles of CTV isolate T-4 (3). citrus varieties into three categories Vector transmission. Seedlings based on number or percentage of of nine citrus varieties were grown in trees infected (Table 1). The first the greenhouse. These plants were group was highly susceptible to CTV used as receptor plants when they with infection percentages ranging were ca. 10-20 cm tall. highly trans- from 89 to 100%. This group included missible CTV isolate, T-67, was prop- Ridge Pineapple (loo%), Alemow agated in Madam Vinous sweet (loo%), Volkamer lemon (loo%), Or- orange as the inoculum source for lando tangelo (94%), and rough lemon virus acquisition by Aphis gossypii (89%). The second group was rather Glover (9). Twenty aphids (late in- poorly susceptible to CTV with infec- stars and adults) were transferred to tion ranging from 27 to 53%. This each receptor plant. The virus acquis- group included Rangpur lime (53%), ition access and the inoculation Cleopatra mandarin (50%), sour periods were each 24 h. Donor and re- orange (52%), and Palestine sweet ceptor plants were maintained in an lime (27%). The last group, which in- air-cooled, partly shaded glasshouse. cluded Carrizo citrange, remained Daily diurnal temperatures fluctuated free of CTV. between 20-32 C. Aphid host range. Laboratory colonies of the melon aphid were TABLE 1 reared on okra, Hibiscus esculentum NATURAL INFECTION BY CITRUS L. var. Clemson spineless, while the TRISTEZA VIRUS OF CITRUS CUL- spirea aphid, Aphis citricola van der TIVARS ATER 10 YEARS IN A COMMER- Goot, was reared on C. hystrix DC. CIAL GROVE IN INDIANTOWN, Both aphids were reared in environ- FLORIDAz mental chambers at 25 C with a rela- No. tive humidity of 80 + 10% and a 16 h infectedY % photoperiod at 5000 foot candles. Two Cultivar no. tested Infected reproductively mature apterous Alemow 18/18 100 aphids were transferred from the col- Volkamer lemon 17/17 100 ony to detached leaves of each cul- Ridge Pineapple 212 100 tivar on 1% water agar, as described Orlando tangelo 17/18 94 by Yokomi and Gottwald (10). There Rough lemon 16/18 89 Rangpur lime 8/15 53 were 10 replications and the test was Cleopatra mandarin 9/18 50 repeated twice. Host suitability was Sour orange 9/17 52 evaluated by counting the number of Palestine sweet lime 4/15 27 live nymphs on each detached leaf at Swingle citrumelo 0118 0 Trifoliate orange 0118 0 day 7. This value was called the re- Canizo citrange 0117 0 productive rate. Because host precon- ditioning was not included prior to the "Trees were planted in November 1976, with a test, the early reproductive rate was row spacing of 5.2 x 7.6 m. often influenced by the colony host. YCTVinfection was determined by double anti- body sandwich enzyme-linked immunosorbent After 7 days, however, the number assay. Total treeslvariety was 18. Tree deaths of live nymphs was indicative of the due to freezes or Phytophthora foot rot ac- host suitability of the aphid. Statisti- counted for tree counts less than 18lvariety. Tristeza and Related Diseases Vector transmission tests. Influ- TABLE 3 ence of host receptor variety on A. REPRODUCTION OF APHIDS ON DE- TACHED LEAVES OF DIFFERENT CIT- gossypii transmission of T-67 was de- RUS CULTIVARSz termined under laboratory condi- tions. Infection rates in Mexican lime Avg. no. and Alemow were the highest at 31% nymphslaphidY and 38%, respectively (Table 2). Li- Aphis Aphis mited tests with pummel0 and rough Host gossypii citrieola lemon receptors resulted in transmis- Hystrix sion rates of 30 and 20%, respectively. Valencia Rates for Pineapple and Hamlin Temple sweet oranges were 19 and 17%, re- Marsh spectively. Infection in grapefruit Pineapple Navel was 11%, whereas no transmission to Mexican lime sour orange or Carrizo citrange was Orlando tangelo detected. Four hosts were common to Trifoliate orange the field test described above. Volkamer lemon Rangpur lime Aphid reproduction. Nymph pro- Cleopatra mandarin duction of A. gossypii under test con- Rough lemon ditions was generally lower than that Palestine sweet lime of A. citricola on comparable hosts. Carrizo citrange Sour orange C. hystrix was the best host for the Alemow melon aphid with 37.3 nymphs per Swingle citrumelo adult (P < .05), whereas Valencia and Temple were the next best hosts at "Leaves incubated on 1% water agar for 7 days 15.9 and 15.7 nymphs per adult, re- in environmental chamber set for 25 C and 16 h photoperiod at 5000 foot candles (10). spectively (Table 3). Some reproduc- Two reproductively mature adult aphids were tion (4-5 nymphs) occurred on Pineap- placed on each detached leaf on day 0. The data ple and navel oranges, and on Mexi- represent the averages of two separate tests can lime, but this group was not per aphid host after 7 days. Each test had 10 statistically different from nonhosts replications. "Means associated with the same letter are not (0 to 1.5 nymphs). For spirea aphid, statistically different (P < .05) by Duncan's the highest reproduction was 25.6 multiple range test. TABLE 2 nymphs on Valencia followed by C. APHID TRANSMISSION OF CTV TO DIF- FERENT RECEPTOR CULTIVARS OF hystrix, navel, and Temple with 20.9, CITRUS IN THE GREENHOUSEz 18.5, and 16.9 nymphs, respectively.
Load more

Recommended publications
  • Field Diagnosis of Citrus Tristeza Virus1 Stephen H
    HS996 Field Diagnosis of Citrus Tristeza Virus1 Stephen H. Futch and Ronald H. Brlansky2 Citrus tristeza virus (CTV) is one of the most important roots, the roots use up stored starch and begin to decline, pathogens affecting citrus worldwide. Tristeza was first leading to the ultimate death of the tree. Decline-inducing reported in Florida in the 1950s. By the 1980s, it produced strains of the virus may be present in trees on resistant serious losses due to tree decline and death on sour orange rootstocks and may provide a reservoir of virus that aphids and Citrus macrophylla rootstocks. Tree decline continues can spread to susceptible rootstocks. to be a consideration today in groves that have trees grown on sour orange rootstock trees remaining. Citrus tristeza virus strains or isolates may vary from mild to severe, causing little damage to severe decline, especially on trees grafted on sour orange rootstock. In cases of infection with mild isolates in trees grown on susceptible rootstocks, trees may be reduced in size, vigor, and fruit yields. Trees with a severe strain may quickly decline and die, with the first symptoms being leaf wilt (Figure 1) and ultimate tree death in several weeks. Additionally, other strains may cause stem-pitting in limes, grapefruit, and sweet orange. Fortunately, stem pitting strains are not currently a problem in Florida. Figure 1. Citrus tree declining due to citrus tristeza virus. When trees are propagated on susceptible rootstocks and are infected with CTV decline strains, typical symptoms CTV is transmitted by several aphid species with the most include: decline, wilting, dieback, “quick decline,” leaf effective being the brown citrus aphid (Toxoptera citricida), chlorosis and curling, heavy fruit set, honeycombing, bud which was introduced to Florida in the 1990s.
    [Show full text]
  • Exotic Diseases of Citrus M.M
    PP264 Exotic Diseases of Citrus M.M. Dewdney, J.D. Yates, M.E. Rogers, T.M. Spann CITRUS VARIEGATED LEprosis Sweet ORAnge CHLOROSIS (CVC) Scab (SOS) Leprosis (early symptoms) Leprosis ( advanced symptoms) CVC (upper side of leaf) Sweet Orange Scab Citrus TristezA Leprosis on fruit Leprosis on mature fruit Leprosis bark scaling CVC (underside of leaf) Citrus Black Spot CVC (small, hard fruit) Healthy fruit Citrus Black Spot (hard spot) Citrus Black Spot Citrus Black Spot (virulent spot) (false melanose) Citrus Tristeza Virus Stem-Pitting For more information, contact the University of Florida / IFAS Citrus Research and Education Center 863-956-1151, www.crec.ifas.ufl.edu, or your local county citrus extension agent: at http://citrusagents.ifas.ufl.edu/citrus_agents_home_page/citrus_agents_home.html 1. This document is PP264, one of a series of the Department of Plant Pathology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: April 2009. Revised December 2009. 2. Megan M. Dewdney, assistant professor, Department of Plant Pathology, Jamie D. Yates, coordinator for canker and greening extension education, Michael E. Rogers, assistant professor, Department of Entomology, Timothy M. Spann, assistant professor, Department of Horticulture, Citrus REC, Lake Alfred, Florida; Cooperative Extension Service, Institute of Food and Agricultural Sciences; University of Florida; Gainesville, FL 32611. Photo Credits: J.D. Yates, M.M. Dewdney, M.E. Rogers, N.A. Peres, L.W. Timmer,
    [Show full text]
  • 101R to Release Genetically Engineered Citrus Tristeza Virus
    Southern Gardens Citrus Nursery, LLC Permit 17-044- 101r to Release Genetically Engineered Citrus tristeza virus Preliminary Pest Risk Assessment May 2018 Agency Contact Cindy Eck Biotechnology Regulatory Services 4700 River Road USDA, APHIS Riverdale, MD 20737 Fax: (301) 851-3892 The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’S TARGET Center at (202) 720–2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326–W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250–9410 or call (202) 720–5964 (voice and TDD). USDA is an equal opportunity provider and employer. Mention of companies or commercial products in this report does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned. USDA neither guarantees nor warrants the standard of any product mentioned. Product names are mentioned solely to report factually on available data and to provide specific information. This publication reports research involving pesticides. All uses of pesticides must be registered by appropriate State and/or Federal agencies before they
    [Show full text]
  • Citrus Industry Biosecurity Plan 2015
    Industry Biosecurity Plan for the Citrus Industry Version 3.0 July 2015 PLANT HEALTH AUSTRALIA | Citrus Industry Biosecurity Plan 2015 Location: Level 1 1 Phipps Close DEAKIN ACT 2600 Phone: +61 2 6215 7700 Fax: +61 2 6260 4321 E-mail: biosecurity@phau.com.au Visit our web site: www.planthealthaustralia.com.au An electronic copy of this plan is available through the email address listed above. © Plant Health Australia Limited 2004 Copyright in this publication is owned by Plant Health Australia Limited, except when content has been provided by other contributors, in which case copyright may be owned by another person. With the exception of any material protected by a trade mark, this publication is licensed under a Creative Commons Attribution-No Derivs 3.0 Australia licence. Any use of this publication, other than as authorised under this licence or copyright law, is prohibited. http://creativecommons.org/licenses/by-nd/3.0/ - This details the relevant licence conditions, including the full legal code. This licence allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to Plant Health Australia (as below). In referencing this document, the preferred citation is: Plant Health Australia Ltd (2004) Industry Biosecurity Plan for the Citrus Industry (Version 3.0 – July 2015). Plant Health Australia, Canberra, ACT. Disclaimer: The material contained in this publication is produced for general information only. It is not intended as professional advice on any particular matter. No person should act or fail to act on the basis of any material contained in this publication without first obtaining specific and independent professional advice.
    [Show full text]
  • Cross Protection Against Citrus Tristeza Virus - a Review
    UC Riverside International Organization of Citrus Virologists Conference Proceedings (1957-2010) Title Cross Protection Against Citrus tristeza virus - a Review Permalink https://escholarship.org/uc/item/73v0t59c Journal International Organization of Citrus Virologists Conference Proceedings (1957-2010), 17(17) ISSN 2313-5123 Authors Roistacher, C. N. da Graça, J. V. Müller, G. W. Publication Date 2010 DOI 10.5070/C573v0t59c Peer reviewed eScholarship.org Powered by the California Digital Library University of California Proceedings, 17th Conference, 2010 – Citrus Tristeza Virus Cross Protection Against Citrus tristeza virus - a Review C. N. Roistacher1, J. V. da Graça2 and G. W. Müller3 1Department of Plant Pathology, University of California, Riverside CA 92521, USA 2Texas A & M University-Kingsville Citrus Center, Weslaco TX 78596, USA 3Rua Firmino Costa No 250 CEP 13076-625, Campinas, SP, Brazil ABSTRACT. Tristeza, caused by Citrus tristeza virus (CTV) is now in its second century as one of the most destructive and most researched diseases of citrus. This review encompasses the early history of tristeza and its relationship to the 19th century Phytophthora epidemic which caused worldwide destruction of citrus then grown primarily as seedlings. The sour orange then evolved as a highly regarded and popular Phytophthora-tolerant rootstock. However, this combination of sweet orange, mandarin or grapefruit on the sour orange rootstock was susceptible to a new highly destructive vector-transmitted disease aptly named tristeza. There are two primary vectors for CTV: Aphis gossypii and the more efficient Toxoptera citricida. When tristeza enters a country, sour orange ultimately will disappear as the primary rootstock. All attempts at cross protection to salvage sour orange as a rootstock have failed.
    [Show full text]
  • 2020–2021 Florida Citrus Production Guide: Tristeza Decline1 Ozgur Batuman, Amit Levy, Mark E
    PP-181 2020–2021 Florida Citrus Production Guide: Tristeza Decline1 Ozgur Batuman, Amit Levy, Mark E. Hilf, Peggy J. Sieburth, William O. Dawson, and Ronald H. Brlansky2 Citrus tristeza virus (CTV) is a major cause of the decline Citrus tristeza virus is transmitted by aphids. They acquire and eventual death of trees on sour orange rootstocks. it within minutes of feeding on an infected plant and Initially, affected trees have small leaves and twig dieback. transmit it to healthy plants within minutes of picking up Diseased trees often produce very small fruit, and the the virus. The brown citrus aphid (Toxoptera citricida), yield declines. Eventually, large limbs die back and the tree which first appeared in Florida in 1995, is considered the gradually declines. In extreme cases, trees may suffer from most efficient vector of the virus. The cotton or melon quick decline and wilt, dying in a matter of weeks. On sour aphid (Aphis gossypii) is a less efficient but still effective orange rootstock, some isolates of CTV cause an incompat- vector, whereas the green citrus or spirea aphid (Aphis ibility at the bud union, which results in the loss of fibrous spiraecola) and the black citrus aphid (Toxoptera aurantii) roots and reduced ability for water uptake. Bark flaps cut are considered to be less efficient vectors of CTV in Florida. from across the graft union of declining trees often show The establishment of T. citricida in Florida is believed to pitting consisting of small holes (honeycombing) on the have resulted in a more rapid spread of decline-inducing inside face of the bark flap from the rootstock side of the isolates of tristeza.
    [Show full text]
  • Citrus Bacterial Canker Disease and Huanglongbing (Citrus Greening)
    PUBLICATION 8218 Citrus Bacterial Canker Disease and Huanglongbing (Citrus Greening) MARYLOU POLEK, Program Manager and Plant Pathologist, Citrus Tristeza Virus Program, California Department of Food and Agriculture, Tulare; GEORGIOS VIDALAKIS, Director, Citrus Clonal Protection Program (CCPP), Department of Plant Pathology, University of UNIVERSITY OF California, Riverside; and KRIS GODFREY, Senior Environmental Research Scientist, CALIFORNIA Biological Control Program, California Department of Food and Agriculture, Sacramento Division of Agriculture and Natural Resources INTroduCTioN http://anrcatalog.ucdavis.edu Compared with the rest of the world, the California citrus industry is relatively free of diseases that can impact growers’ profits. Unfortunately, exotic plant pathogens may become well established before they are recognized as such. This is primarily because some of the initial symptoms mimic other diseases, mineral deficiencies, or toxicities. In addition, development of disease symptoms caused by some plant pathogenic organisms occurs a long time after initial infection. This long latent period results in significantly delayed disease diagnosis and pathogen detection. Citrus canker (CC) and huanglong- bing (HLB, or citrus greening) are two very serious diseases of citrus that occur in many other areas of the world but are not known to occur in California. However, if the patho- gens causing these diseases are introduced into California, they will create serious prob- lems for the state’s citrus production and nursery industries. CiTrus BACTerial CaNker Disease Citrus bacterial canker disease (CC) is caused by pathotypes or variants of the bacterium Xanthomonas axonopodis (formerly campestris) pv. citri (Xac). This bacterium is a quar- antine pest for many citrus-growing countries and is strictly regulated by international phytosanitary programs.
    [Show full text]
  • The Response of Star Ruby Grapefruit to Different Citrus Tristeza Virus Isolates
    Sixteenth IOCV Conference, 2005—Citrus Tristeza Virus The Response of Star Ruby Grapefruit to Different Citrus tristeza virus Isolates S. P. van Vuuren1 and B. Q. Manicom2 1Citrus Research International, P.O. Box 28, Nelspruit 1200, South Africa; 2ARC–Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa ABSTRACT. The failure of GFMS 12 (Nartia) as a cross-protecting Citrus tristeza virus (CTV) isolate for Star Ruby grapefruit in South Africa necessitated the use of GFMS 35 as a substitute for the interim. Seven new CTV isolates derived from Star Ruby and Rosé grapefruit trees were evalu- ated and compared to GFMS 12, GFMS 35, to two isolates from mother trees at the Citrus Founda- tion Block that were pre-immunized with GFMS 12, two severe isolates (GFSS 1and GFSS 5), and to trees that were planted virus-free. Trees pre-immunized with isolates GFMS 35 and GFMS 78 had the best production over a 5-yr period. These trees produced significantly better than trees that were planted virus-free, trees with mild isolates GFMS 12, GFMS 67, and those with the two severe isolates. The crop value (fruit size coupled with market prices) of trees with GFMS 35 was 5% better than that of trees with GFMS 78. Trees with GFMS 12a were third best and were 16% lower than those with GFMS 35. The latter isolate was collected from a good parent tree at the Cit- rus Foundation Block that was pre-immunized with GFMS 12. The results show that CTV isolate GFMS 35, which is the present pre-immunizing isolate for red grapefruit, together with isolate GFMS 78, are superior to the other isolates.
    [Show full text]
  • Distribution of Citrus Tristeza Virus in Grapefruit and Sweet Orange in Florida and South Africa*, ** R
    Distribution of Citrus Tristeza Virus in Grapefruit and Sweet Orange in Florida and South Africa*, ** R. F. Lee, S. M. Garnsey, L. J. Marais, J. N. Moll, and C. 0. Youtsey ABSTRACT. The distribution of citrus tristeza virus (CTV) in field trees was determined by enzyme-linked immunosorbent assay on individual flushes collected from citrus trees in Florida and South Africa. In Florida, most CTV isolates were unevenly distributed in grapefruit trees, especially in late summer. However, one mild isolate with some cross-protecting ability (T26) was consistently distributed throughout the trees regardless of season. Citrus tristeza virus was more evenly distri- buted in sweet orange trees in Florida, but occasionally very young flush tissue was found CTV-free. In South Africa, CTV was found evenly distributed throughout both grapefruit and sweet orange trees. South African isolates were highly invasive in recently inoculated plants. The even distribution of CTV within trees is a trait which may be important for effective cross protection by mild CTV strains. Index words. ELISA, cross protection, stem pitting. Citrus tristeza virus (CTV), a of effective cross protection. Selection member of the closterovirus group, is of cross-protecting CTV strains has the most economically important cit- thus far been an empirical process. rus virus worldwide (1). There are The distribution of the mild strain of many strains of CTV which differ in virus within the plant host may play their biological activity (1, 3). Quick an important role in its ability to cross decline of trees on sour orange protect the host against subsequent rootstock induced by CTV has killed challenge by severe isolates (9).
    [Show full text]
  • Amplification of Citrus Tristeza Virus from a Cdna Clone and Infection of Citrus Trees
    Virology 280, 87–96 (2001) doi:10.1006/viro.2000.0759, available online at http://www.idealibrary.com on View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Amplification of Citrus Tristeza Virus from a cDNA Clone and Infection of Citrus Trees T. Satyanarayana,*,1 M. Bar-Joseph,†,1 M. Mawassi,* M. R. Albiach-Martı´,* M. A. Ayllo´n,* S. Gowda,* M. E. Hilf,‡ P. Moreno,§ S. M. Garnsey,* and W. O. Dawson*,2 *Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, Florida 33850; †The Volcani Institute, Bet-Dagan 50250, Israel; ‡USDA-ARS, 2001 South Rock Road, Fort Pierce, Florida 34945; and §Instituto Valenciano de Investigaciones Agrarias, 46113 Moncada, Valencia, Spain Received October 26, 2000; returned to author for revision November 13, 2000; accepted November 22, 2000 Isolates of the Closterovirus, Citrus tristeza virus (CTV), are populations of disparate genotypes and defective RNAs developed during long periods of vegetative propagation of citrus trees. Because it has not been possible to obtain pure cultures of the virus, it is not known what components of the population are primarily responsible for induction of diseases. We previously developed an infectious cDNA clone from which in vitro-produced RNA transcripts could infect protoplasts (Satyanarayana et al., 1999, Proc. Natl. Acad. Sci. USA 96, 7433–7438). However, neither the RNA transcripts nor virions from transcript-infected protoplasts were competent for infection of citrus trees. Using a green fluorescent protein-marked virus as inoculum, we found that the ϳ20-kb RNA from virions or transcripts of cDNA infected only a small percentage of protoplasts (ϳ0.01%), but virions could infect more than 80% of the protoplasts.
    [Show full text]
  • Citrus Tristeza Virus Reminder CTV Virion: • Long Flexuous Particles, 2Μm Long × 10–12 Nm in Width
    Citrus Tristeza Virus Reminder CTV Virion: • long flexuous particles, 2µm long × 10–12 nm in width. • The virions have helical symmetry with about 8-9 capsids per helix turn, and a central hole of 3-4 nm. Gold-labeled CP antiserum Gold-labeled CPm antiserum From: Tian et al. J. Gen. Virol.80:1111 (1999) Phloem CP Antibody associated cells Brief History: • CTV existed in Asia for centuries, with growers adapting tolerant varieties • Out of Asia, citrus got heavily infected with Phytophthora sp., which was managed by adapting the more tolerant sour orange rootstock. • The result- citrus production in many areas was almost entirely based that single rootstock. • This decision had grave effects when CTV pandemics swept throughout the world, causing ‘quick decline’ (death) of trees on this rootstock. • Since the 1930's that the extent of this deadly disease problem manifested itself first in Argentina and shortly later in Brazil and California, with the death of millions of trees • Switching to non-sour orange rootstock eliminated the danger from CTV decline. • But now, with HLB, growers are switching back… Citrus Tristeza Virus (CTV) – Decline CTV decline is associated with death of phloem near the bud union, resulting in a girdling effect that may cause the overgrowth of the scion at the bud union, loss of feeder roots and thus drought sensitivity, stunting, yellowing of leaves, reduced fruit size, poor growth, dieback, wilting, and death. Roots of declining tree – no feeder roots Citrus tristeza virus (CTV) – decline •Transmission and Epidemiology
    [Show full text]
  • Diseases of Citrus in Arizona Mary Olsen, Mike Matheron, Mike Mcclure and Zhongguo Xiong
    ARIZONA COOPERATIVE E TENSION AZ1154 Revised 08/11 Diseases of Citrus in Arizona Mary Olsen, Mike Matheron, Mike McClure and Zhongguo Xiong Introduction Although citrus is indigenous to southeast Asia, oranges were first planted commercially in central Arizona in the late 1800s. Today commercial production is centered in several warm and low-frost-risk areas of central and southwestern Arizona. A great number of citrus varieties are also widely planted in home gardens. Many diseases of citrus have been described world wide and have colorful and descriptive names such as: blue mold, green mold, gray mold, pink mold, pink nose, brown rot, black spot, black rot, black pit, yellow vein, yellow spot, rubbery wood, lumpy rind, curly leaf, corky bark, slow decline, spreading decline, and stubborn. Other names are rooted in the many international languages of citrus such as: Italian (impietratura and mal secco), Portuguese (tristeza), or Greek and Latin (cachexia, psorosis, exocortis, xyloporosis, cristacortis, and leprosis). Fortunately, most of the more serious, widespread diseases do not occur or are of little importance in Arizona. Diseases of importance here include several caused by fungi or Figure 1. Non-specific symptoms in citrus of general tree decline with tip die fungal-like organisms: foot rot gummosis (Phytophthora root back and sparse foliage. This condition could be caused by several factors rot) caused by Phytophthora nicotianae (syn. Phytophthora including Phytophthora crown and root rot, citrus nematode, or nutrient parasitica) and P. citrophthora, Hendersonula branch wilt deficiencies or excesses. (caused by Hendersonula toruloidea), brown heartwood rot of lemons caused by species of Antrodia and Coniophora, and Many serious and widespread diseases in citrus grown in black rot of fruit caused by Alternaria sp.
    [Show full text]