Tom Peters Seminar2001 Rollercoaster Days: Learning to … Rock & Roll! Phoenix 06.11.01.
somesh pg seminar2001
-
Upload
agricultured -
Category
Documents
-
view
219 -
download
0
Transcript of somesh pg seminar2001
-
8/7/2019 somesh pg seminar2001
1/43
-
8/7/2019 somesh pg seminar2001
2/43
-
8/7/2019 somesh pg seminar2001
3/43
SEED INFECTION AND TRANSMISSION OF
PLANT VIRUSES
Speaker : Somesh Jha
Guide: Dr. B. N. Patel
Date: 13th
July,2001
-
8/7/2019 somesh pg seminar2001
4/43
Seed infection and transmission
of plant viruses
Introduction
Economic importance and significance
SeedSeed infection
Why all plant viruses are not seed transmitted?
Types of viruses that are seed transmittedSeed health research activities
Conclusion
-
8/7/2019 somesh pg seminar2001
5/43
INTRODUCTION
-
8/7/2019 somesh pg seminar2001
6/43
Seed - Basic input resource
Virus transmission through seed - Highly
significant in virus preservation andspread.
Seed transmissible viruses - adverse effecton seed and crop health
18% of known plant viruses are seedtransmitted
-
8/7/2019 somesh pg seminar2001
7/43
SYMPTOMS ON PODS AND SEEDS OF COWPEA
-
8/7/2019 somesh pg seminar2001
8/43
Economic importanceand
significance
-
8/7/2019 somesh pg seminar2001
9/43
Seed transmissionof
viruses
Epidemiologicalsignificance
Introduction in
new area
Ecological significance
Perpetuation Perennation Dissemination
Barrier to
world tradeDirect loss
to seed & crop
Economic imp. &
significance
-
8/7/2019 somesh pg seminar2001
10/43
SYMPTOMS OF ULCV
-
8/7/2019 somesh pg seminar2001
11/43
-
8/7/2019 somesh pg seminar2001
12/43
SYMPTOM OF CABMV ON COWPEA
-
8/7/2019 somesh pg seminar2001
13/43
Citrus mosaic Citrus sinensis
Cowpea mild mottle V. unguiculata
Glycine max
Cucumber green mottle mosaic Cucumis sativus
Lagenaria siceraria
Maize dwarf mosaic Zea mays
Pea seed borne mosaic Pisum sativum
Peanut clump Arachis hypogaea
Potato X S. tuberosum
Contd
-
8/7/2019 somesh pg seminar2001
14/43
ULCV ON COWPEA
SYMPTOM
-
8/7/2019 somesh pg seminar2001
15/43
Soyabean mosaic G. max
Tobacco etch Nicotiana tabacum
Tobacco ring spot N. glutinosa
Urdbean leaf crinkle P. aureus
Wheat streak mosaic Zea mays
Contd
-
8/7/2019 somesh pg seminar2001
16/43
ULCV ON MUNGBEAN
S
Y
MPT
O
MS
-
8/7/2019 somesh pg seminar2001
17/43
-
8/7/2019 somesh pg seminar2001
18/43
-
8/7/2019 somesh pg seminar2001
19/43
Seed structure
Bean (Dicot seed)
-
8/7/2019 somesh pg seminar2001
20/43
-
8/7/2019 somesh pg seminar2001
21/43
VIRUS CARRIED ON THE SURFACE OF SEEDS
e.g. TMV Remains viable as contaminant
Seedling infection
Mechanical transmission during handling
-
8/7/2019 somesh pg seminar2001
22/43
VIRUS CARRIED IN PARTS OF SEED
OUTSIDE THE EMBRYO
BYMV & CMV Testa & Endosperm
Sugarbeet Curly Top Virus Perisperm
Very few of such viruses result in seed transmission
Southern bean Mosaic Sobemovirus
IPCV Virus present only in cotyledons andembryo Seed transmission
-
8/7/2019 somesh pg seminar2001
23/43
Seed Formation
-
8/7/2019 somesh pg seminar2001
24/43
SYMPTOMS
-
8/7/2019 somesh pg seminar2001
25/43
SYMPTOMS
-
8/7/2019 somesh pg seminar2001
26/43
Adjacent cells
of mother
plant(Infected)
Virus Developing
ovule in early
stage
Infected
ovule
e.g. Soybean Mosaic Potyvirus (SMV) route of Soybean
embryo infection by invasion of the ovulesDong Hong Ping et al., (1997)
-
8/7/2019 somesh pg seminar2001
27/43
COLOUR DISCOLOURATION DUE TO SMV
SOYBEAN SEEDS
-
8/7/2019 somesh pg seminar2001
28/43
e.g. PSbMV
Testa, Cotyledons Embryonic axis
& Cotyledons
Location
& Embryonic
axis
TransmissionBCMVin bean
Bravo and Pineda (1996)
-
8/7/2019 somesh pg seminar2001
29/43
Why all plant viruses are not seed
-
8/7/2019 somesh pg seminar2001
30/43
Why all plant viruses are not seed
transmitted ?Factors preventing virus passage
through seed to the next generation
Inactivation of virus in the embryo
Embryo High energy
Phosphates Conc
Medium
Unfavorable
No virus increase
Sterility of infected gametes
VirusDirect
lethal effectsGametes or
embryo
Infected seeds
prevented
Low
-
8/7/2019 somesh pg seminar2001
31/43
Inability of virus to infect young embryo
Virus restricted to
Vascular System
Embryo
Mother plant
No vascular connectionNo embryo
infection
Protection of the embryo from virus infection
Interposition of
structures between
the mother plant
& embryo
Embryo escapes
infection
No movement of
virus
-
8/7/2019 somesh pg seminar2001
32/43
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)
-
8/7/2019 somesh pg seminar2001
33/43
-
8/7/2019 somesh pg seminar2001
34/43
-
8/7/2019 somesh pg seminar2001
35/43
Three points of plant reproduction which
extrapolate virus trans. through seeds
A relatively long term conductive (embryo-supportive)
function is ascribed to the developing suspensor
Infected
maternal tissue
Virions/
Viral RNA
suspensorDeveloping
embryo
Contd
C td
-
8/7/2019 somesh pg seminar2001
36/43
Cross-communicative interaction betweennuceller/integument cells & the endosperm and between
the endosperm & interfacing embryo cells during
embryogenesis.
Integument
transfer cellsEndosperm
Cellular/biochemical factors interacting with virions or viral RNA
Viral
genome
Interactive signal
Embryoinvasion
Host-plant
genome
VIRUS PASSAGE
Contd..
-
8/7/2019 somesh pg seminar2001
37/43
Chickpea 0.1-1.0 % 0.1-2.0 %
Lentil 0.1-5.0 % 0.1-2.0 %AMV CMV
Jones and Coutts (1995)
Australia
Soybean 12.6 % (mild mosaic sym.) Kim Yul Ho et al.,(1997)Korea Republic
Mung bean 2.0-16.0 %
Urd bean 1.16-11.0%ULCV
Mahajan and Joi (1999)
Rahuri, India
14.1 % (severe mos. sym.) SMV
Pea 1.9-32.7 % (PSbMV) Gallo and Jurik (1995)
Slovak Republic
Tomato 1.0-17.0 % (ToMV)
(Diff. Cult.)
Bell Pepper 1.0-10.0 %(TMV) Chitra et al., (1999)India
-
8/7/2019 somesh pg seminar2001
38/43
Physalis minima 1.17 %Solanum nigrum 2.20 %
Nicotiana plumbaginifolia 4.70 %LMV
Rajkumar and Jitender
Mohan (1994), U.P.,
India
Cowpea 7.0-32.0 % 1.0-4.7% 1.0-3.0 %(V. unguiculata) BLCMV CPMV CPMMV
Nain et al., (1994)Hissar, India
Cowpea 3.0-25.0 % SBMV
Cowpea 10.0-30.0% CAbMV
Makwana et al., (2000)
Sheela et al., (2001)
Anand, India
Contd..
-
8/7/2019 somesh pg seminar2001
39/43
Seed health research activities
-
8/7/2019 somesh pg seminar2001
40/43
Seed health research activities
Several IARCs in the CGIAR system are working
ICARDA Effect of dry heat on lentil seeds
Heat treatment BBSV eliminated
Further plans with PSbMV and BYMV
CIP On PVT in true seeds
Reports
Soybean SMV eliminated Ghufran-ul-Haque et al., (1993)Pakistanseeds
L. siceraria CGMMV K.D. Hyun and Lee. J. Myung
seeds inactivated
(2000), Korea Republic
70 C
HW70 C
DH
75 C, 3 days
-
8/7/2019 somesh pg seminar2001
41/43
-
8/7/2019 somesh pg seminar2001
42/43
conclusion
Seed infection & transmission is related to host-pathogeninteractions. Only a minority of these interactions resulting ininfection also result in seed transmission
Even low rates of seed transmission in conjunction with secondaryspread by insect vectors can result in the introduction of viruses into
new area and can produce viral disease epidemics
Cytoplasmic connections between the mother plant and flower and
then developing seeds may influence the seed infection
In terms of world trade, seed-borne viruses act as barrier. Hence,
detection of seed-borne viruses has to play an important role in
quarantine.
-
8/7/2019 somesh pg seminar2001
43/43