BYDV Epidemiology - merc-cerealviruses.com by yaoyufang

VIEWS: 0 PAGES: 28

									Aphid-Borne
Barley Yellow
Dwarf Luteo
Virus (BYDV)
 Viruses identified on Egyptian
       wheat and barley
1. Leafhopper-borne wheat dwarf mono-
geminivirus (WDV)
2. Seed-borne barley stripe mosaic hordeivirus
   (BSMV)
3. Leafhopper-borne maize yellow stripe
   tenuivirus-like (MYSV)
4. Aphid-borne barley yellow dwarf luteovirus
   (BYDV).
History
                History
1982, Egyptian National Campaign
  For wheat improvement has started

1984, BYDV infection has been
  recorded as sporadic single-
  infected plants in wheat fields of
  Lower Egypt (Abdel-Hak, 1984)

1991, BYDV-RMV possible causal of
  severe outbreak in Mid Egypt
  maize fields (Aboul-Ata, et al, 1996)
1992, BYDV-PAV has been
  recorded and identified using
  Koch postulates (Aboul-Ata, et al,
  1992)

1994, First record of 5 BYDV-
  serotypes (PAV, MAV, RPV, RMV
  and SGV) occurrence using DAS-
  ELISA at Purdue Univ., Indiana,
  USA (Lister, et al, 1994).
1994-2003, Egypt-ICARDA cooperation
  through Nile Valley Project funded by
  European countries. It deals with cereal
  viruses affecting wheat and barley

1994-1999, Different Wheat and barley
  germplasm were received from CIMMYT
  every year for BYDV-infection
  evaluation. Breeding program against
  BYDV has started 1994

1998,    BYDV-PAV typing was done
  at INRA, France (Mastari, et al, 1998)
   PROBLEM
IDENTIFICATION
                                  b




                a

External symptoms
caused by BYDV
a. Wheat, b. Patch of
                                      c
infection on wheat
c. Patch of infection on barley
1.


     1. Morphology of major
        aphid vectors of BYDV

     2. Virus particles of
     different BYDVs
2.
1. Barley yellow dwarf luteovirus
   (BYDV) has different serotypes
   i.e. MAV, PAV and SGV

2. Cereal yellow dwarf polerovirus
   (CYDV) has different serotypes
i.e. RPV and RMV

3. There are almost 25 aphid
species vector of both CYDV and
BYDV
Sequences of the virus specific primers used in
the multiplex RT-PCR detection method.
 Target                                                5`    Produ
 Virus               Primer          Sequence         Positi ct Size
                                                       on
BYDV-     PAVL1               5`AGAGGAGGG             2999
PAV                           CAAATCCTGT3`                     295
          PAVR2               5`ATTGTGAAGGAATTAATGT   3272     bp
                              A3`
BYDV-     MAVL1               5`CAACGCTTAACGCAGATGA    896
MAV                           A3`                              175
          MAVR2               5`AGGACTCTGCAGCACCAT    1071     bp
                              CT3`
          5`BSMV1α            5`TTGGATCCCCCCCCGTATG
                              TAAGT3`                          180
 BSMV
          3`BSMV4α            5`GCGAATTCGGAAGCTGTG             bp
                              CTAATC3`
          WSMVL2              5`CGACAATCAGCAAGAGAC    5444
                              CA3`                             193
 WSMV
          WSMVR2              5`TGAGGATCGCTGTGTTTCA   5622     bp
                              G3`
RT-PCR amplified products. M: 100 bp DNA
ladder; L1: WSMV; L2: BYDV-PAV; L3: BYDV-MAV;
L4: BSMV: L5: BYDV-MAV and BYDV-PAV.
4. BYDVs are transmitted persistently
  by aphid species and 24-48 hr is
  enough period as AAP

5. Monogenic incomplete dominant
  Yd2 and Bdv1 genes are BYDV
  resistance.

6. Resistance-breaking strains are
  mutually occurred
Cereal crop hosts of BYDV-PAV and RMV. Wild
cereal plants as sources of BYDV-PAV infection
are listed

Hosts and Reaction                                     Reference
BYDV-RMV                                               Lister et al, 1994
maize (Zea mays), sorghum (Sorghum bicolor) and
sugar cane (Saccharum officinarum)

BYDV-PAV                                               Lister et al, 1994
Bread wheat (Triticum aestivum), durum wheat (T.
durum x T. tricoscale) and barley (Hordum vulgare)

Graminaceous weeds as virus sources of                 Aboul-Ata et al,
BYDV-PAV infection:                                    1992
Avena fatua, Cyondon dactylon, Echenochloa
colonum, Paspalum distichum, Poa annua, Polypogon
monspeliensis, Leersia oryzoides and Eleusine indica
   BYDV-PAV
Etiology, Typing
and Sub-Typing
 1. BYDV-PAV was isolated using R. padi.
     Virus detection was done using TBIA
     (Aboul-Ata, et al, 1992).

2. BYDV has five serotypes: PAV, MAV,
     RMV, RPV and SGV. All of them were
     recorded in Egyptian cereals (Lister,
     et al, 1996)

3. Symptom severity range (very severe –
     very mild/serotype/crop)
4. Dominant BYDV-PAV serotype has 2
    subtype i.e. cpA and cpB. using
    Serological analysis by MAbs,
    RFLP and SSCP were used for
    differentiation .
BYDV-PAV sub-serotype (cpA and cpB) variants
BYDV-PAV Criteria BYDV-PAV Group Host
                   cpA      cpB
Isolate            EW1      EW2       wheat
Symptoms           Severe   Mild      barley
Epitop
P6                  +        +        maize
P14                 +        -        maize
Fresh weight        0.04-0.5 0.9-1. 6 barley
Tillering           No       Yes      barley
Frequency of PAV 30%         70%      barley
sub-serotype
Molecular    weight 220      396      barley
using (SSCP)
 Healthy Control = Fresh weight (1.7)
 EW1 = Egypt isolate 1, EW2 = Egypt isolate 2
Phylogenic tree of BYDV-PAV for different cpA
and cpB Sub-serotypes
BYDV Epidemiology
  And Non-insect
   Transmission
Suction Trap for aphid insect sampling
Monitoring of BYDV-vectored aphids
in the season period using DAS-ELISA
Liner relation between BYDV-vectored
aphids and BYDV infection
Non-insect inoculation




Inoculation application for sauced seeds of
wheat and maize kernels. One pin is used
for virus inoculation into wheat seeds. More
pines are used for virus inoculation into
maize seeds
Wheat breeding for
 BYDV resistance
Yield losses caused by BYDV on
commercial wheat varieties
Wheat     BYDV Infection         % Yield
Variety   Incidence   Severity   Losses
Gz164     95%         3.6        9.3

Gz167     82.5%       2.8        3.9

Sakha69   82.5%       2.5        7.5

Sids7     82.5%       3.1        0.6
Insect inoculation for BYDV resistance
1. Mass rearing of
Healthy aphid (R. padi)
2. Allow aphids to
acquire PAV-BYDV
3. Inoculation of 3-leaf
stage wheat lines using
BYDV-vectored aphids.

Genotypic response against virus
4. Spray insecticide to kill all insects used for
   Inoculation.
5. Collecting field data and virus detection 45
   days after inoculation.
THANK YOU
  ALL SO
  MUCH

								
To top