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Kuliah ke-2
SEJARAH VIROLOGI
TUMBUHAN
Tulipomania – late
th
16
century
Before it was known to be caused by a virus, tulips with color
breaking symptoms were prized and traded for large sums of
goods – this led to “tulipomania” in the late 1500’s
Traded for 1 Viceroy
tulip bulb:
4 tons of wheat
8 tons of rye
4 fat oxen
8 fat pigs
12 fat sheep
2 hogsheads of wine
4 barrels of beer
2 barrels of butter
1000 lbs of cheese
1 bed with accessories
1 full dress suit
1 silver goblet
• Adolf Mayer –1886 – showed that Tobacco
mosaic virus was transmissible, could not find
bacteria or fungi associated with disease
TMV
• Dmitri Ivanowski - 1892– showed that
Tobacco mosaic virus was not retained by
filters that retained all bacteria known at
that time
• Martinus Beijerinck - 1898–
repeated demonstration that Tobacco
mosaic virus was not retained by
filters that retained all bacteria known
at that time
 Believed results
 Did extensive dilution experiments
 Showed diffusion of infectious agent
through agar
 Named “contagium vivum fluidum”, later
virus
Wendell Stanley – 1935
• At Rockefeller Foundation in Princeton
• Crystallized TMV, thought it was only
protein
TMV
Stanley Hall, U.C. Berkeley
Bawden and Pirie - 1936
• Crystallized Tomato
bushy stunt virus
(TBSV); find that it and
TMV contain
phosphorous –
conclude that it is not
a protein, but is a
nucleoprotein
TMV
TBSV
Markham and Smith - 1949
• Two classes of particles in
purified Turnip yellow
mosaic virus preparations:
– light ones containing only
protein, which were not
infectious
– heavy ones containing
protein+nucleic acid, which
were infectious
empty
full
Myron Brakke - 1951
• Development of density
gradient centrifugation
– Isopycnic: particles reach
position of equal density in
gradient
– Rate-zonal: Particles sediment
differentially through medium
as a function of size, shape, and
density
– Equilibrium zonal: Combination
of the above
Fraenkel-Conrat
1955-1956
• Complete, infectious TMV
particles can be
reconstituted in vitro from
the RNA and protein
components
• RNA alone is infectious
• RNA can be
“transcapsidated” in protein
from closely related virus;
resulting virus has
properties of RNA strain
Virus Aa:
RNA A
capsid a
protein
RNA
reconstitute
in vitro
inoculate plants
symptoms (A)
extract virus
virus Aa
Crick and Watson – 1956
• TMV virions are
composed of one
nucleic acid and many
identical protein
subunits: RNA does not
have the coding
capacity to make many
different subunits
Casper and Klug – 1962
• Structure of Tomato bushy stunt
virus solved by X-ray
crystallography, the first icosahedral
virus so determined
Heinz Sanger – 1978
• Complete sequence of
Potato spindle tuber
viroid
– First pathogen sequence
to be determined
– Yielded relatively little
information that was
immediately useful
1 cggaactaaa ctcgtggttc ctgtggttca cacctgacct
cctgagcaaa aaagaaaaaa gataggcggc
tcggaggagc gcttcaggga tccccgggga
aacctggagc gaactggcaa aaaaggacgg
tggggagtgc ccagcggccg acaggagtaa
ttcccgccga aacagggttt tcacccttcc tttcttcggg
tgtccttcct cgcgcccgca ggaccacccc tcgccccctt
tgcgctgtcg cttcggctac tacccggtgg aaacaactga
agctcccgag aaccgctttt tctctatctt cttgcttccg
gggcgagggt gtttagccct tggaaccgca gttggttcct
Paul Ahlquist – 1984
• Infectious viral RNA
transcribed in vitro from
cDNA clones
– Done with Brome mosaic
virus – with 3 RNAs
– Brought reverse genetics to
RNA viruses
RNA
RNA
cDNA
Inoculate
plants
Roger Beachy – 1986
• Transgenic plants
expressing TMV coat
protein are resistant to
virus infection
• First example of
“pathogen-mediated
resistance”
Bill Dougherty – 1991
• RNA was critical component in
resistance in pathogenmediated resistance
• All of the hallmarks that later
came to be associated with
PTGS and RNAi were first
observed with Tobacco etch
virus (TEV) (1993 Lindbo et al.,
Plant Cell 5:1749-1759)