pigeon pea sterility mosaic virus

2. EMARA VIRUS
Pigeonpea
Sterility Mosaic
Virus

3. TAXONOMY:-
 It belongs to group 5 in Baltimore classification system , which is
given by David Baltimore in 1971.
It is having negative sense ssRNA as genetic material.
Phylum :- Negarnavaricota
Sub-phylum :- Polylovaricotina
Class :- Ellioviricetes
Order :- Bunyavirales
family :- Fimoviridae
Genus :- Emara virus

4. This genus is consisting of 6 species…
Type species :- European Mountain Ash Ringspot Associated Virus
(EMARA Virus)
Other species are :-
1. Fig Mosaic Virus (FMV)
2. Pigeonpea Sterility Mosaic Virus (PPMV)
3. Raspberry Leaf Blotch Virus (RLBV)
4. Rose Rosette Virus (RRV)
5. Maize Red Stripe Virus (MRSV)
MRSV is previously called as high plain virus because infection at high
plains.

5. EMARA FMV RRV
RLBV MRSV

6. NEW EMARA LIKE
VIRUS INFECTED
COFFEE,IN HAWAII.
Symptoms:- Chlorotic spots.
Most probable Vector :- Mite.
Before, this virus was never
reported across globe.
But in February 2014, a
farmer in Hawaii island found
this symptoms.
Its identity was confirmed by
Dr. Micheal Meizer in March
2014.

7. PIGEONPEA STERILITY MOSAIC
VIRUS :-
It is causal agent of sterility mosaic disease (SMD) of Redgram(
cajanus cajan) which is called as Green plague as the infected
plants remain in vegetative phase without production of
flowering .
The Etiology of SMD is remained as mystery for over 70 years
and it was resolved with the discovery of PPSMV in 2000 and its
complete genome sequence in 2014.

9. MORPHOLOGY:-
• Virus is an Isometric ( Spherical)
and Double membrane
enveloped virus.
• Particle is 80-100nm dia.
with Ribonucleocapsid envelop .
• Helical symmetry.
• DMBs:- Double Membrane
Bodies
• These DMBs found in almost all
cell types of leaf except in
phloem and bundle sheath
parenchyma cells ( no or few

10. GENETIC MATERIAL:-
The genetic material is negative sense ssRNA , which is
enveloped in ribonucleocapsid enveloped of 80-100nm
diameter particles
Recently scientists discovered that SMD is caused by 2 kind of
particles i.e
PPSMV-1, PPSMV-2 which consists of 4 segmented & 5 or 6
segmented –ve sense ssRNA particles respectively.
The RNA ends are fully conserved in a stretch of 13 nucleotides
and 5’&3’ ends of each RNA is almost fully complementary over
a sequence between 19 and 23 nucleotides.

11. PPSMV-2 PARTICLE

12. A. PPSMV-1; B.PPSMV-2

13. GENOME ORGANIZATION :-
RNA-1:-
RNA-1 of PPSMV-1 consists of 7009nucleotides & PPSMV-2
consists of 7022nucleotides with both having 45nts at 5’ end and
79nts at 3’ end.
RNA-2:- Both particles consisting of 2296nucleotides .
RNA-3:- Both particles consisting of 1362nucleotides.
RNA-4:- Both particles consisting of 1493nucleotides.
RNA-5:- PPSMV-2 consists of 1840nucleotides.
 RNA-6:- PPSMV-2 consisting of 1191nucleotides.
Each RNA encodes for single Open Reading Frame(ORF) that
encodes proteins.

15. REPLICATION:-
Nucleic Acid Nucleotides Encodes for Encoding of
Protein having
Aminoacids
RNA-1 7009
(PPSMV-1)
7022(PPSMV-
2)
Encodes for 266.22kDa protein
(P1)
2294 A.a
RNA-2 2296 74.41kDa protein (P2) identified as
Glycoprotein precursor.
649 A.a
RNA-3 1362 35kDa protein (P3) i.e
Nucleocapsid protein (NCP)
314 A.a
RNA-4 1493 40.7kDa protein (P4) 361 A.a
RNA-5 1840 55.1kDa protein (P5) 474 A.a

16. RNA-1:- encodes for RdRp (RNA dependent RNA polymerase).
RNA-2:- encodes for GP (Glycoprotein precursor).
RNA-3:- encodes for NCP (Nucleocapsid Protein).
RNA-4:- encodes for Movement Protein.
RNA-5:-
RNA-6:- with Unknown function.

17. TRANSMISSION:-
PPSMV is transmitted by Eriophid mite (Aceria cajani) in semi
persistent manner.
Virus doesn’t Replicate in host & vector stays infectious for 6-
13hrs.
Inoculation Access Period :- atleast 90mins.
Acquisition Access period :- atleast 15mins.
Due to short stylet of Eriophid mite, it may reach to
epidermal cells or adjacent layers of mesophyll.

18. Mechanical transmission is found to be difficult.
But PPSMV can transmit mechanically to Tobacco plants
Nicotiana clevelandii & Nicotiana benthamiana.
Seed borne but only on coat not on cotyledons.

19. OTHER HOSTS:-
PPSMV can infect several genotypes of cultivated and wild
relatives of pigeonpea.
Experimental hosts include N. benthamiana, N. clevelandii,
P. vulgaris and Chrozophora rottleri.
However, pigeon pea alone and a few wild species of Cajanus
were found to support the vector A. cajani.

20. SIMILARITY WITH OTHER TAXA:-
The genus Emaravirus shares some similarities with viruses belonging
to the family Bunyaviridae and the floating genus Tenuivirus.
 The segmented genome of emaraviruses is of negative polarity.
Based on a comparison of the amino acid sequences of the conserved
RdRp motifs, highest similarity can be found with the plant-infecting
genus Tospovirus and the orthobunyaviruses within the
family Bunyaviridae.
The 3′ and 5′ ends of the genomic RNAs are complementary and their
conserved sequence resembles that of the
genera Orthobunyavirus and Hantavirus (Bunyaviridae).
However, the number of genome segments (at least four)
distinguishes the genus Emaravirus from bunyaviruses and sequence
analyses do not allow classification within either the
family Bunyaviridae or the genus Tenuivirus