SEED INFECTION AND TRANSMISSION OF           PLANT VIRUSES     Speaker : Somesh Jha       Advisor: Dr. B. N.            Pa...
t r an sm ission of p lan t               vir u sesIntroductionEconomic importance and significanceSeedSeed infectionW all...
INTRODUCTION
IntroductionSeed - B asic input resourceVirus transmission through seed -H ighly significant in virus preservationand spre...
SYM T S ON P   P OM     ODS AND SE DS OF COW E                      E         PA
Economic importancE        and    significancE
E con om ic im p . &     sig n ifican ce     Direct loss                                 Barrier to    to seed & crop     ...
S P YM TOM OFUL       S    CV
SOME IMPORTANT SEED BORNE VIRUSESAlfa- alfa mosaic      Medicago sativaBarley stripe mosaic    Hordeum vulgare            ...
SYMPTOM OF CABMV ON COWPEA
Contd…Citrus mosaic                  Citrus sinensisCowpea mild mottle             V. unguiculata                         ...
ULCV ON COWPEA  SYMPTOM
Contd…Soyabean mosaic        G. maxTobacco etch           Nicotiana tabacumTobacco ring spot      N. glutinosaUrdbean leaf...
ULCV ON MUNGBEANSYMPTOMS
S eedSeed              st r u ctu r e       A fragile, living organism – a miracle of life                      corn (mono...
S eed   st r u ctu r eBean   (Dicot seed)
Seed infectionVIRUS CARRIED ON THE SURFACE OF SEEDSe.g. TMV    Remains viable as contaminant            Seedling infection...
VIRUS CARRIED IN PARTS OF SEED              OUTSIDE THE EMBRYO        BYMV & CMV        Testa & Endosperm        Sugarbeet...
S eedF or m ation
EMBRYO INFECTION  Three Ways  Through introduction of virus into the embryo sac by  the male gametophyte                  ...
SYMPTOMS
Through ovule invasion by virus from the mother plant Adjacent cells                Virus    Developing of mother         ...
COLOUR DISCOLOURATION DUE TO SMV       SOYBEAN SEEDS
Through direct invasion of the embryo               Inoculation                    Infected               after           ...
Why all plant virusEs arE   not sEEd transmittEd ?               Factors preventing virus passage              through see...
Inability of virus to infect young embryo                             EmbryoVirus restricted to                           ...
Other factors    Environmental factors    Host plant and virus         Nematode trans. Virus          Seed trans.         ...
Types of viruses that are seed transmitted
Types of viruses that are   seed transmitted Certain general characteristics Most are readily sap transmissible Transmitte...
Contd…        Three points of plant reproduction which         extrapolate virus trans. through seeds A relatively long te...
Contd..           Cross-communicative interaction between  nuceller/          integument cells & the endosperm and between...
Rate of seed transmission of some plant virusesChickpea       0.1-1.0 %      0.1-2.0 %     Jones and Coutts (1995)        ...
Contd..Physalis minima           1.17 %     Rajkumar and JitenderSolanum nigrum            2.20 % LMV Mohan (1994), U.P.,N...
Seed health research activities Several IARCs in the CGIAR system are working    ICARDA         Effect of dry heat on lent...
conclusionSeed infection & transmission is related to host-pathogeninteractions. Only a minority of these interactions res...
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
Somesh jha M.Sc.(Agri.) seminar 2001
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Somesh jha M.Sc.(Agri.) seminar 2001

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AGROCONSULTANCY SERVICES
www.agroconsultants.blogspot.in
FACEBOOK/Agriculture Delhi
http://www.facebook.com/agriculturedelhigardening
1.FARM/Khet/ORCHARD/Bageecha VISITS on Call in Delhi
Agro consultancy services to farmers-Which SEEDS, FERTILIZERS, Biopesticides, PESTICIDES and PLANT GROWTH REGULATORS
2.CONSULTANCY services for Retail PESTICIDE Shop OWNERS
1.Which brands to keep and when to recommend

Somesh Jha, M.Sc.(Agri.) Plant Pathology, www.gardeningclasses.blogspot.in FACEBOOK/Agriculture Delhi 9910517789 offers Gardening Classes and Agroconsultancy Services in the sector of AGRO,RETAIL and AGRI Business with a total of experience over 10 years. Has been a former employee in companies like Vishal Retail, Reliance Retail, Aadhaar Retailing(Future Group),Godrej Agrovet Ltd., Pragya (NGO) at various managerial levels.

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Somesh jha M.Sc.(Agri.) seminar 2001

  1. 1. SEED INFECTION AND TRANSMISSION OF PLANT VIRUSES Speaker : Somesh Jha Advisor: Dr. B. N. Patel Date: 13th July,2001
  2. 2. t r an sm ission of p lan t vir u sesIntroductionEconomic importance and significanceSeedSeed infectionW all plant viruses are not seed transmitted? hyTypes of viruses that are seed transmittedSeed health research activitiesConclusion
  3. 3. INTRODUCTION
  4. 4. IntroductionSeed - B asic input resourceVirus transmission through seed -H ighly significant in virus preservationand spread.Seed transmissible viruses - adverseeffect on seed and crop health18% of known plant viruses are seedtransmitted
  5. 5. SYM T S ON P P OM ODS AND SE DS OF COW E E PA
  6. 6. Economic importancE and significancE
  7. 7. E con om ic im p . & sig n ifican ce Direct loss Barrier to to seed & crop world tradeEpidemiological Seed transmission Introduction in ofsignificance new area viruses Ecological significance Perpetuation Perennation Dissemination
  8. 8. S P YM TOM OFUL S CV
  9. 9. SOME IMPORTANT SEED BORNE VIRUSESAlfa- alfa mosaic Medicago sativaBarley stripe mosaic Hordeum vulgare Triticum aestivumBean common mosaic Phaseolus vulgaris Vigna unguiculataBean southern mosaic P. vulgarisBrinjal mosaic Solanum melongena
  10. 10. SYMPTOM OF CABMV ON COWPEA
  11. 11. Contd…Citrus mosaic Citrus sinensisCowpea mild mottle V. unguiculata Glycine maxCucumber green mottle mosaic Cucumis sativus Lagenaria sicerariaMaize dwarf mosaic Zea maysPea seed borne mosaic Pisum sativumPeanut clump Arachis hypogaeaPotato X S. tuberosum
  12. 12. ULCV ON COWPEA SYMPTOM
  13. 13. Contd…Soyabean mosaic G. maxTobacco etch Nicotiana tabacumTobacco ring spot N. glutinosaUrdbean leaf crinkle P. aureusWheat streak mosaic Zea mays
  14. 14. ULCV ON MUNGBEANSYMPTOMS
  15. 15. S eedSeed st r u ctu r e A fragile, living organism – a miracle of life corn (monocot seed)
  16. 16. S eed st r u ctu r eBean (Dicot seed)
  17. 17. Seed infectionVIRUS CARRIED ON THE SURFACE OF SEEDSe.g. TMV Remains viable as contaminant Seedling infection Mechanical transmission during handling
  18. 18. VIRUS CARRIED IN PARTS OF SEED OUTSIDE THE EMBRYO BYMV & CMV Testa & Endosperm Sugarbeet Curly Top Virus PerispermVery few of such viruses result in seed transmission Southern bean Mosaic Sobemovirus IPCV Virus present only in cotyledons and embryo Seed transmission Reddy et al., (1998)
  19. 19. S eedF or m ation
  20. 20. EMBRYO INFECTION Three Ways Through introduction of virus into the embryo sac by the male gametophyte Germination Pollen tube growsInfected pollen grain into Embryo Sac Release male gametes Union ctede with Infe met (if infected) polar Infected Union with ga nuclei embryo egg cell Infected Endosperme.g. Tobacco Rattle Virus (TRV) & Alfa-alfa Mosaic Virus (AMV)
  21. 21. SYMPTOMS
  22. 22. Through ovule invasion by virus from the mother plant Adjacent cells Virus Developing of mother Infected ovule in early plant ovule stage (Infected)e.g. Soybean Mosaic Potyvirus (SMV) route of Soybean embryo infection by invasion of the ovules Dong Hong Ping et al., (1997)
  23. 23. COLOUR DISCOLOURATION DUE TO SMV SOYBEAN SEEDS
  24. 24. Through direct invasion of the embryo Inoculation Infected after embryo floweringe.g. PSbMV Location Testa, Cotyledons Transmission Embryonic axisBCMV & Embryonicin bean & Cotyledons axis Bravo and Pineda (1996)
  25. 25. Why all plant virusEs arE not sEEd transmittEd ? Factors preventing virus passage through seed to the next generationInactivation of virus in the embryo Medium Embryo High energy Low Unfavorable Phosphates Conc No virus increaseSterility of infected gametes Direct Gametes or Infected seeds Virus lethal effects prevented embryo
  26. 26. Inability of virus to infect young embryo EmbryoVirus restricted to No embryo No vascular connection infectionVascular System Mother plantProtection of the embryo from virus infectionInterposition of No movement ofstructures between Embryo escapesthe mother plant infection virus& embryo
  27. 27. Other factors Environmental factors Host plant and virus Nematode trans. Virus Seed trans. e.g. tomato black ring virus Listler and Murant (1967) Longevity of Virus in seed Varies one month (Dodder Latent Mosaic) to >six years (Barley Stripe Mosaic) Scott (1961)
  28. 28. Types of viruses that are seed transmitted
  29. 29. Types of viruses that are seed transmitted Certain general characteristics Most are readily sap transmissible Transmitted by certain types of vectors e.g. Several non-persistent aphid transmitted viruses Nematode transmitted viruses Listler and Murant (1967)
  30. 30. Contd… Three points of plant reproduction which extrapolate virus trans. through seeds A relatively long term conductive (embryo-supportive) function is ascribed to the developing suspensorInfected Virions/ Developing suspensor embryomaternal tissue Viral RNA
  31. 31. Contd.. Cross-communicative interaction between nuceller/ integument cells & the endosperm and between the endosperm & interfacing embryo cells during embryogenesis. Integument VIRUS PASSAGE Endosperm transfer cellsCellular/biochemical factors interacting with virions or viral RNA Embryo invasion Interactive signal Viral Host-plant genome genome
  32. 32. Rate of seed transmission of some plant virusesChickpea 0.1-1.0 % 0.1-2.0 % Jones and Coutts (1995) AMV CMVLentil 0.1-5.0 % 0.1-2.0 % AustraliaSoybean 12.6 % (mild mosaic sym.) SMVKim Yul Ho et al., (1997) 14.1 % (severe mos. sym.) Korea RepublicMung bean 2.0-16.0 % Mahajan and Joi (1999) ULCVUrd bean 1.16-11.0% Rahuri, IndiaPea 1.9-32.7 % (PSbMV) Gallo and Jurik (1995)(Diff. Cult.) Slovak RepublicTomato 1.0-17.0 % (ToMV) Chitra et al., (1999)Bell Pepper 1.0-10.0 % (TMV) India
  33. 33. Contd..Physalis minima 1.17 % Rajkumar and JitenderSolanum nigrum 2.20 % LMV Mohan (1994), U.P.,Nicotiana plumbaginifolia 4.70 % IndiaCowpea 7.0-32.0 % 1.0-4.7% 1.0-3.0 % Nain et al., (1994)(V. unguiculata) BLCMV CPMV CPMMV Hissar, IndiaCowpea 3.0-25.0 % SBMV Makwana et al., (2000)Cowpea 10.0-30.0% CAbMV Sheela et al., (2001) Anand, India
  34. 34. Seed health research activities Several IARCs in the CGIAR system are working ICARDA Effect of dry heat on lentil seeds 70° C Heat treatment BBSV eliminated Further plans with PSbMV and BYMV CIP On PVT in true seedsReports HW Soybean SMV eliminated Ghufran-ul-Haque et al., (1993) seeds 70° C Pakistan DHL. siceraria CGMMV K.D. Hyun and Lee. J. Myung 75° C, 3 days seeds inactivated (2000), Korea Republic
  35. 35. conclusionSeed infection & transmission is related to host-pathogeninteractions. Only a minority of these interactions resulting ininfection also result in seed transmissionEven low rates of seed transmission in conjunction with secondaryspread by insect vectors can result in the introduction of viruses intonew area and can produce viral disease epidemicsCytoplasmic connections between the mother plant and flower andthen developing seeds may influence the seed infectionIn terms of world trade, seed-borne viruses act as barrier. Hence,detection of seed-borne viruses has to play an important role inquarantine.

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