A detailed history of plant pathology is mentioned, covered various important contributions with diagrammatic representations of scientists and depth include of subject matter has been updated

1. History of plant
pathology
N. H. SHANKAR REDDY
1st , Ph.D Plant Pathology
Annamalai University

2. The history of plant pathology is divided into different five eras:
• Ancient era : Ancient to 5th century (476 A.D.)
• Dark era : 5th to 16th century (476 A.D. to 1600)
• Pre modern era: 17th century to 1853 (1600 to 1853)
• Modern era : 1853 to 1906
• Present era : 1906 onwards.

3. Ancient era :Ancient to 5th century (476A.D. )
Archives in India
• Rigveda, Atharveda (1500- 500 B.C.) ,
• Artha Shastra of Kautilya (321 – 186 B.C.)
• Sushruta samhitan (200 – 500 A.D.)
• Vishnu Puran (500 A.D.)
• Agnipuran (500 – 700 A.D.)
• Vishnu dharmottara (500-700 A.D.)
• Raghuvamsha of Kalidas.

4. Theophrastus (370-286 B.C.)
• Considered as ‘Father of Botany’
• books 'Enquiry into Plants'
‘The Nature of Plants’ and
‘Reasons of
Vegetable Growth’
• He told that ‘Plant diseases as the
wrath/ punishment of gods’ for wrongs
and sins they had committed.
Theophrastus

5. Democritus (470 B.C.) - He recommended controlling plant blights by
sprinkling leaf extract of olive oil.
Homer (1000 B.C.) – Mentioned therapeutic properties of sulphur on
plant diseases.

6. • Robigalia – Praise the god to prevent the
crop from destruction, the religious ceremony
was initiated by the King Numa Pompilus
and incorporated into the Christian calendar
as St. Mark’s Day or Rogation on April 25
and the peoples accept the spontaneous
generation, Rubi - Red

7. Albert magnus (1200 A.D.) –
• Recognised the first plant pathogen in the
world – Mistletoe
• Recommended cultural methods (Pruning)
for control of Mistletoe
• Common mistletoe and leafy mistletoe
• Europe – Viscum
• North America – Phoradendron
• Dwarft mistletoes – Arceuthobium (affected
conifers)
Nicander (185 B. C) – Called mushroom, the
evil ferments of the earth

8. 1670 – Thoullier (French Physician) – Ergotism or Holy Fire

9. ❑Ergot – argot(French) – means “spur” – Claviceps purpurea
❑Symptoms caused to humans – reddening and blistering, excruciating pain in the
lower abdomen, muscle spasms, trembling, shaking, convulsions, hallucinations,
permanent insanity, gangrene, loss of fingers and limbs and cause death
❑“ Devil’s curse”, “Fire”, “Holy fire” , “St. Anthony’s fire”
❑Ergot alkaloids – LSD (Lysergic acid diethylamide)
❑1960 – young turkey birds affected by the disease by fully mold feed – Turkey X
disease
❑1978 – gangrenous ergotism occurred in Ethiopia

10. 1601 - Clusius –
• Water colour drawings of mushrooms
• His book was “ Raroium Plantarum
Historica”
1665 - Robert hook [1635 -1703]
• Drawn sporangia of Mucor and
Telispores of Phrgmidium disciflorum ,
phragmidium mucronatum and first
observed under Microscope.
• Wrote a book “Micrographia” in 1665.
• Invented the double-lensed (compound)
microscope with which he examined thin
slices of cork and called its units “cells”.

11. Carolus van Linnaeus – Sweden - (1707 -1778) –
• Introduced “Binomial System of Nomenclature”
• ‘A scandal of art’ (Ordering of fungi)
• Published his main work ‘Systema Natura’ in 1735
• His Book “Species Plantarum” published in 1753
• Students are C. H. Persoon and E. M. Fries

12. 1729 -Pier Antonio Micheli (Italy)-
• “Founder and Father of mycology”
• He wrote a book called “Nova Plantarum
genera” in 1729
• Proved that disease is caused by spores
• Described 900 fungi
• He also proved that if these spores are
placed on a piece of fruits (melons and
pears)
• they grow into a new thallus of the fungus

13. 1761-1836 - C. H. Persoon (France)-
• “Founding Father of systemic mycology”,
• “Founding father of modern taxonomy of
mushrooms”(Taxonomy of mushroom)
• based on spore colour and arrangement of the
Hymenophore)
• Article of fungi (1973), introduced his
classification system (1794) ,
• Published “Synopsis methodica fungorum”
(1801) a chief starting point for the naming of
fungi
• Sold his herbarium to Dutch government in
1825 due to his poverty

14. ❑ 1859 – Charles Darwin (Englishman) – showed species of all organism
❑ Book – The origin of species by means of Natural selection

15. E.M. Fries (Sweden) -
• Linneaus of mycology, Father of systemic mycology
• Wrote a book called “Systema mycologicum” in 1821 (starting point in
nomenclature of fungi)
• Regarded the Rust and Smut fungi as products of diseased plants
• Basidiomycota is dominated with “Friesian approach”

16. Matheiu Du Tillet , 1755
Great Grandfather of PhytoPathology. Bunt of
wheat is a contagious disease (external transmission
of bunt) and he showed that bunt affected seeds
treated with water containing salt and lime
produced a lower percentage of diseases plants.

17. 1840 - Tulsane Brothers (Paris)-
• L. R. Tulsane is Considered as “Reconstructor of
mycology”
• Recognised the five spore stages of Autoecious
(single) rust fungus in 1854
• Book “ Selecta Fungorum Carpologica” (1861 –
1865)
Charles Tulasne

18. 1858- J. G. Kuhn (Germany)-
• Published 1st text book in plant
pathology “ The diseases of cultivated
crops, their causes and their control” in
1858
• Considered as ‘Microscopic manager’

19. M. J. Berkeley (England)-
• Coined the term “ Mycology”
• Systematist to mycology with 6000 species
• Published “Introduction to Cryptogamic Botany” in 1857
• “ Outlines of British fungology” in 1860
• Began the publications of “Vegetable Pathology” in 1854
• Given "Oidium tuckerii” to grape powdery mildew

20. Modern era
1831-1888 - Heinrich Anton De Bary (Germany):-
• He was a German surgeon, Botanist, Microbiologist, and Mycologist
• Largely Considered as “ Father of Plant pathology”, “Father of Modern Plant
• Pathology” and “Father and Founder of modern Experimental Plant Pathology”
• He wrote a books are “Comparative Morphology and the Biology of Fungi, Myceteoza
and bacteria” (1866)
“Lectures on bacteria” 1885
“On Mildew and Fermentation” 1872
“Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns
“Morphologie und Physiologie der pilze, Funchten und Mycomycetes” in 1866,
English translation happens in 1887, Authorised translation by Henry E. F.
Garnsey. Revised by Isaac Bayley Balfour

21. • Introduced the terms ”Haustoria / Sinkers”, ”Symbiosis”,
”Teletospores”,“Myceteoza”, “Sex hormone”, (Sirenin,
Antheridiol), Autoecious and Heteroecious rust, and
“Chlamydospores”
• His students are M. S. Woronin (Russia), O. Brefelds
(Germany), A. Millardet (France), H. M. Ward (England),
W. G. Farlow (USA) and Fisher (Switzerland)
• Discoverd the life cycle of Phytophthora infestans (late
blight of potato) that causes Irish famine.
• Demonstrated the heteroecios nature of stem rust of wheat
in 1865.
• 1st physiological plant pathogen work on ‘Botrytis cineria
• Reported the roe of enzymes and toxins in ‘direct
penetration’ by tissue degradation
• Sclerotinia sclerotiorum in 1886.
• Phytophthora means Plant destroyer

22. 1878 – M. S. Woronin (Russia)-
• Discovered and named the Club root of
Cabbage pathogen as Plasmodiophora
brassicae in 1875
• Found out the life cycle of potato wart
(Synchitrium endobioticum) disease in 1878.
• Discovered the Woronin bodies.

23. 1880 H. M. Ward (England) -
• “Father of Tropical Plant Pathology”
• Emphasises the Role of environment on
epidemiology of coffee rust gave the bridging
host theory in 1903
• Recognised necrotic active defence in
Bromus, later known as hypersentive
response

24. 1882-1885 PMA Millardet (France)-
• Discovered “Bordeaux mixture” for the control of
downy mildew of grapes
• This discovery is considered as serendicity
discovery (accidental discovery)
• Bordeaux mixture Composition 1:1:100 (1kg of
copper sulphate, 1kg of hydrated lime, 100lit
water)
• The original formula developed by Millardet
contains 5 lbs of CuSO4 + 5 lbs of lime 50
gallons of water.
• “Bordeaux” (founded in June 7, 1441 ) is the
university name in France.

25. 1894 – Erikson (Sweden) –
described the phenomenon of
physiological specialization of
wheat stem rust fungus (Puccinia
graminis tritici)

26. 1845-1920 – Pier Andrea Saccardo (Italy) –
• Professor at Pauda university (Italy) developed spore
group system for Ascomycetes (Sac fungi) and
Duteromycetes ( Dust bin fungi/ fungi imperfecti ) fungi
and systematically arranged and initiated systemic
grouping of fungi
• His famous book is “ Syllome fungorum ”(1882-
1931,1972) ( 26 volumes )
• Most of the books mentioned 25 volumes, originally its 26
volumes of work]
• Full name is “Syllome fungorum omnium hucusque
cognitorum”
• Saccardo’s other important treatise “ fungi italic “ (1877-
1886) appeared in 38 volumes

27. 1886- 1971- J. F .Dastur –
• First Indian plant pathologist,
internationally known for the
establishment of genus
• Phytophthora and diseases caused by
castor (Phytophthora parasitica) and
potato
• 1st president of the “Indian
Phytopathological Society” (IPS) in
1948.
• Reported the 1st plant viral diseases in
India (Sugarcane mosaic virus)

28. 1874- 1943 – Edwin John Butler
(Ireland)-
• 1st Imperical Mycologist in India
• Considered as ‘ Father of modern plant pathology in
india”, “ Father of Indian mycology”
• First director of the “Imperical bureau of mycology” in
England from 1920-1935
• His book was “ Fungi and Disease in Plants” in 1918
• Monograph on “Pythiaceous and allied fungi”
“The fungi of India” (along with
Guy and Richard Bisby) in 1931
“Plant Pathology (with S.G. Jones)”
• Discovered genus “Allomyces”
• Reported bangle blight of potato (1st record of bacterial
disease in India)
• He was appointed as the first Cryptogamic Botanist to the
Government of India at Calcutta

29. Elvin Charles Stakman (USA) –
• Distinguished biological forms of cereal rust
• Coined the term “hypersensitivity”(Autolysis)
• (hypersensitive reaction - abnormal death of host cells
when attacked by rust) in 1915
• Demonstrated physiological forms of stem rust of
wheat in 1917
• Also studied the air dispersal of rust fungus in 1920s

30. 1927- J. H. Craigie (1887-1989) –
• Discovered the sexual stage of rust fungus as Pycnia or
Spermatia ( “0” stage )
• Discovered heterothallism of Puccinia graminis to
reveal the function of pycnium as sexual organ

31. 1928 – Alexander Fleming (United Kingdom) –
• Isolated Penicillin from Pencillium notatum (now called as Penicilium chrysogenum)
• Shared noble prize in Physiology and medicine along with Ernst B. Chain & Howard
Walter Florey in 1945
• When I woke up just after dawn on September 28, 1928, I certainly didn't plan to
revolutionise all medicine by discovering the world's first antibiotic, or bacteria killer.
But I suppose that was exactly what I did. — Alexander Fleming

32. 1929 – J C Walker –
• Identified Catechol and Protocatechuic acid as a
pre formed disease resistance factors against
onion smudge (Colletotrichum circinans) disease
(red onion bulbs)
• Due to phenolic compounds the onions are
resistant against smudge diseases
• First scientist to demonstrate the “chemical nature
of disease resistance in plants".
• Walker is most known for developing disease-
resistant varieties of onions, cabbages, beans,
peas, beets and cucumbers

33. 1933 – K. C .Mehta –
• Considered as “Father of Indian Rust”
• Discovered the life cycle of stem rust of wheat in India and
reported the barberry (alternate host)
• Published two monographs “ Further studies on cereal rust
in India” Part 1 (1940) and Part 2 ( 1952)
• Established three laboratories for rust research at Agra,
Almora and Shimla.

34. 1940 – K. O. Muller and H. Borger –
• Coined the term “Phytoalexins”( antimicrobial compounds in plants)
• The 1st phytoalexin is “Pisatin ”(produced from Pea plant), The molecular formula is C17H14O6
1940 – Paul Neergaard (Denmark) –
• Considered as “Father of Seed Pathology” along with Mary Noble coined the term in the 1940s
• Authored a book “ Seed Pathology” in 1977 (2 volumes)
• He served as the Chairman of the Plant Disease Committee of the International Seed Testing Association
(ISTA) from 1956 to 1974

35. 1946 - Harold Henry Flor –
• Gave gene for gene hypothesis of plant-pathogen genetic
interaction whilst working on rust (Melampsora lini) of flax
(Linum usitatissimum)
• He proposed the term "Avirulence gene"(Avr)
• Gene for gene hypothesis :- One is a plant gene called the
resistance (R) gene. The other is a parasite gene called the
avirulence (Avr) gene. Plants producing a specific R gene
are resistant towards a pathogen that produces the
corresponding Avr gene product.

36. 1947 – B. B. Mundukur –
• Started Indian Phytopathological Soeiety
(IPS)
• Worked on cotton wilt in Bombay state,
published Ustilaginales in India
• First issue of the journal “ Indian
phytopathology” in 1948
• Published a text book “ Fungi and plant
diseases “ in 1949, which was a second
book of plant pathology after Butller

37. 1952 – G. Pontecorvo and JA Roper -
• Discovered parasexuality in Aspergillus
nidulans
(parasexuality : - plasmogamy, karyogamy and
meiosis not occurs in a regularstage/manner)
• J A Roper reported the hormonal control of
sexuality in fungi

38. 1963 – J. E. Vander Plank –
• Considered as “Father of Epidemiology”
• Gave the concept on horizontal and vertical resistance in plants in
1968
• Coined the term “ Vertiofolia effect ”to describe horizontal
resistance
• (Vertifolia effect – loss of horizontal resistance during breeding for
vertical resistance in the German potato variety ‘Vertifolia’ with late
blight resistance set the scentesnse
Published “Plant Disease Epidemics and Control ” in 1963
“Diseases Resistance in Plants” (1968)
“Principles of Plant Infection” (1975)
“Genetics and Molecular Basis of Plant Pathogen” (1978)
“Host Pathogen Interaction in Plant Disease” (1982)

39. 1964 – Norman E. Borlaug (USA) –
• Developed semi-dwarf, high-yield stem rust resistant wheat
varieties
• He was often called “ The father of the Green Revolution”
• he was awarded the Noble Peace Prize in 1970 in recognition of
his contributions to world peace through increasing food supply
• He worked in the fields of Agronomy, Plant pathology and
Genetics
• ( Ph.D. in plant pathology and genetics)
1964 – M. J. Thirumalachur –
• He was known for the development of antifungal antibiotics such
as Aureofungin, Hamycin, Dermostatin, MYc-4 and tertaenenin.
• Book “ Antibiotics in Plant Disease Control ”
• Conducted extensive studies in rusts and smut
• Wrote monograph on “ Ustilaginales in India, Uredinales of the
world, Cercosporae, Physoderma and Cephalosporium

40. 1976. Jacoov Katan (Israel)-
• “Father of soil solarisation”
• Originally developed solarisation (solar heating of the soil) to control soil borne
pathogens (Ex: Damping off – Pythium apanidermatum)
• Suggested Polythene bag size -100 microns)

41. 1989 – M.B. Dickman and P.E. Kolattakudy –
• Successfully transformed a wound infection fungus with a gene coding for enzymes
cutinase degrading cuticle for penetration
• Demonstrated the function of enzyme cutinase which are responsible for direct
penetration of pathogen
• The cutinase gene from Fusarium solani f.sp. pisi (Nectria hematococa) was cloned and
sequenced.

42. 1990. DF Klessig and I Raskin; JP Metraux and J Ryals
Demonstrated cracking concept that Salicylic acid is associated with Systemic
Acquired Resistance (SAR)
1991. R. Broglie and R. Chen et al -
• The plant transformed with chitinase gene (Genes that codes for chitinase) exhibit
enhanced resistance to disease by fungi that contains chitin in their cell walls.
• Demonstrated increased disease resistance in tobacco plants by transferring gene
• Stilbene synthetase, the enzyme that synthatise phytoalexin and exhibit enhanced
diseases resistance

43. 1991. PJ GM De Wit et al -
• Cloned/ isolated 1st fungal avirulent gene from Cladosporium fulvum (CF 9, avr6)
1992. SP. Briggs, JD Walton et al –
• Cloned the first resistance gene (Hm-1) from corn demonstrated that its protein
product detoxified the host selective toxin of Cochliobolus carborum
2005. RA Dean et al (Centre for Integrated Fungal Research, North Carolina Sate
University, USA)
• The first complete genome sequenced of a plant pathogenic fungus Magnoporthe
grisea

44. bacteriology
Ehrenberg – Coined the term “Bacteria”
1665 – Francesco Redi (Italy) –
• “Founder of Experimental Biology” and “Father of
Modern Parasitology”
• 1st disapproved the Spontaneous generation theory (He
was the first person to challenge the theory
of Spontaneous generation by demonstrating
that maggots come from eggs of flies)
• Experiments on the Generation of Insects, published in
1668.

45. 1675 – Leeuwenhoek –
• Developed 1st microscope, Considered as
‘Father of Bacteriology’
• Developed hundreds of microscopes and obtain
a magnification of 50-300 diameters.
• Also discovered the Spermatozoa and the red
blood cells
• 1st publication in bacteria was in 1683
(Dear god what marvels they are so small a
creature – Leeuwenhoek)

46. 1858 – Louis Pasteur (France) –
• Father of “Modern Bacteriology” and “Founder
of Microbiology”
• Formulated germ theory of diseases and
demolished the spontaneous generation theory
• Developed the principles
of vaccination, microbial
fermentation and pasteurization.
• Created the first vaccines for Rabies and Anthrax
• (Pasteurization: - Heat-treatment process that
destroys pathogenic microorganisms in certain
foods and beverages.
• Fermentation of wine and beer is about 57° C
(134.6° F) for a few minutes. Pasteurization
of milk of about 62.8° C (145.04° F) for 30
minutes or, alternatively, heating to a higher
temperature, 72° C (161.6° F), and holding for 15
seconds,

47. Robert Heinrich Herman Koch 1890-
• Father of Modern Bacteriological techniques and
microbial techniques
• ‘Founder of modern bacteriology’.
• Proposed the Koch’s Postulates and pure culture
technique.
• First bacterium – Bacillus anthracis

48. E.F. Smith 1901-1920
• Final proof that bacteria could cause the disease,
• Worked on bacterial wilt of cucurbits (1896) and crown
gall (1911).
• “Father of Phytobacteriology”
• Book : “Bacteria in Relation to Plant Diseases” in 1905,
1911 and 1914, “ Introduction to Bacterial Diseases of
Plants” in 1920.

49. • 1877 – Nageli – Suggested that pleomorphism in bacteria, which
refers the existence of a single species in several morphological
forms, which is accepted by most bacte
• 1878 – Se’dillot – French retired army surgeon , coined the term
“microbe”riologists in his time

50. T.J. Burrill 1882-
Founder of Phytobacteriology, identified first bacterial disease Erwinia
amylovora in apple and pear.

51. 1884 – Christian Gram-
• Developed bacterial staining technique
• Based on staining bacteria can be
divided into gram positive (+ve) and
gram negative (-ve)

52. • F. W. Twort (1915), F. D’ Herelle (1917) – Discovered Bacteriophage
individually.
• 1923 – “Bergey’s Manual of Determinative Bacteriology” was published
(David H. Bergy)
• 1925 – Johnson and WF Murwin – Demonstrated the role of toxin in
wild fire disease of Tobacco caused by Pseudomonas syringae pv. tabaci
• 1925 – G. H. Koons and J. E. Kotila – Isolated bacteriophages of
Bacillus caratovorus

53. Selman A. Waksman –
• Considered as “Father of soil
microbiology” and “Father of
antibiotics”
• Discovered the antibiotic
‘Streptomycin’ (Streptomyces griseus)
in 1943
• Awarded Noble Prize in Physiology of
Medicine in 1952 (for the discovery of
streptomycin)

54. 1946 – J. Lederberg and Edward Tatum-
• Discovered the bacterial Conjugation in
Escherichia coli.
• Coined the term ‘plasmid’
• Lederberg received Nobel prize (physiology
and medicine) in 1958 for his discoveries
concerning genetic recombination and the
organization of the genetic material of bacteria

55. 1964 – Z. Klemment –
• Recognised the hypersensitivity response (HR) in bacterial pathogens
• (Hypersensitive response:- plant defence response is the induction of
programmed cell death, Autolysis happens to prevent the diseases spread)
1977 - M. D. Chilton et al - Introduced DNA plasmid of Agrobacterium
tumefaciens into Cells of higher plants

56. 1984 – BJ Staskawicz -
• Cloned the first Avirulent gene from Pseudomonas syringae pv. glycinea
DC300
• Provoded the first molecular evidence in support of the “gene-for-gene’
hypothesis for plant pathogenic response
• Done this experiments along with his long-time friend Noel Keen (coined the
term elisitor)

57. virology
1886 – Adolf Mayer (Germany)-
• Coined the term ‘Mosaic’
• He thought that the causal agent was the bacteria.
• First to prove the transmissible plant virus i.e. TMV
• He called sap transmission of tobacco disease is
‘Mosaikkrankheit’
• Later he performed experiments with Chamber land filter
paper, even though the virus retains infectivity.
• He taught that the causal agent was the bacteria.

58. 1892 – D. Ivanovsky (Russia) –
• Proved that the causal agent of tobacco mosaic disease could
pass through bacteria proof filters.
• Concluded that the causal agent of tobacco mosaic (virus) is
smaller than bacteria.
• 1st man who discovered ‘inclusion bodies’
• Described the horizontal transmission of plant viruses

59. 1898 – Beijerinck –
• Dutch microbiologist and botanist.
• Founder and Father of Virology / Father of Environmental
Ecology
• Performed agar diffusion experiments and coined the term
‘Virus’
• He called the liquid material of virus is “Contagium vivum
fluidum” which cause the repeated infection in Tobacco
mosaic virus
• He also worked on nitrogen fixation in which Nitrogen is
converted into Ammonium
• The first known sulfate-reducing bacterium, was isolated
and described by Beijerinck (Spirillum desulfuricans, now
called as Desulfovibrio desulfuricans)
• Clostridium beijerinckii is a gram positive, rod
shaped; motile bacterium was named after Beijerinck.

60. 1915 – Twort, 1917 -F. D. Herelle – Individually
discovered bacteriophages
1929 – Holmes – Developed local lesion assay in
Nicotiana glutinosa
• (Local lesion assay - A tool by which virus could be
measured by showing that the amount of virus
present in the plant sap preparation is proportional to
the number of lesions produced on appropriate host
plant leaves rubbed with the sap)
• Observed that single dominant gene controlling the
hypersensitive reaction (HR) and proposed the “viral
hypersensitivity”. Single dominant gene
subsequently transferred from N. glutinosa to N.
tabacum in which the TMV resistant cultivars are
produced

61. 1929 – Mckinney –
• Developed cross protection/ pre-immunization technique for control of citrus
tristeza virus (CTV)
• Cross protection was 1st used against TMV

62. 1931-1933 - Knoll and Ruska-
• The first prototype of electron microscope was developed by Ernst
Ruska (1931) and Knoll which is capable of 400 magnification power
• Then, Ruska (1933) built the first electron microscope that attains high
resolution with an optical (light) microscope.
• He won the Nobel Prize in Physics in 1986 for his fundamental work
in electron optics, including the design of the first electron microscope.

63. 1935- W. M. Stanley –
• American biochemist, virologist
• Done Purification/ Crystallisation of virus (by using
ammonium sulphate)
(Preparation of enzymes and virus proteins in a pure form)
• He received Nobel Prize in 1946 (for crystallisation of virus)
• He believed that virus was an autocatalytic protein that could
multiply with in the living cell
• Molecular plant pathology work can be initiated with W. M.
Stanley work
• (Note - X-ray diffraction studies by J.D. Bernal and I.
Fankuchen showed that they are true three dimensional
crystals, they were paracrystalline and that the rod like virus
particles.

64. 1936 – F. E. Bawden and N. W. Pirie –
• Demonstrated that virus is a nucleoprotein which
consists both nucleic acid and protein
• They also purified/ crystallised TMV in 1936 (after
W. M. Stanley experiment), further purification of
protein in neutral aqueous solution can be obtained
in liquid crystalline states.
• First suggested that virus replication might be
analogous to the synthesis of cellular components
(1936)
• Detect that phosphate is inherent part in RNA
molecule.
• Their studies reveals that 1-2gm of protein can be
isolated from a litre of sap, it depends based on the
age of the plant and duration of infection

65. 1952- 1953 – Watson and Crick –
• Discovered the double helical structure of DNA, in which their discovery
revolutionized the entire biology.
• They contended that all viruses must be built up symmetrically from identical protein
subunits that surround the nucleic acid in 1956
• General theory of structure of capsid of virus; the coat protein made up of numerous
identical subunits as helicle rods or spherical shell.
• Got noble prize in physiology and medicine in 1962

66. 1956 – Gierrer and Schramm –
• Showed that nucleic acid is the infectious agent
• (Showed that only nucleic acid of TMV is infective and protein coat does not
• have any role in infection, Nucleic acids carry hereditary information and that
• nucleic acid alone is sufficient for viral infectivity)
• Also investigated about double standard RNA viruses (ds RNA)

67. 1975– Kohler and Milstein-
Developed “Hybridoma technology” in
monoclonal antibodies production –
Nobel prize in 1984.
1976 – Voller et al, 1977 – Clark and
Adams – Developed ELISA technique
and used ELISA in Plant virus
detection.
1984- Prusiner-
• Discovered of Prions in animals:
• Received Nobel Prize in 1997 in
physiology of Medicines for the
discovery of ‘Prions’ and biological
principles of infection

68. 1998 - Andrew Fire & Craig Mello –
• First described their work on RNA interference Gene silencing by
dsRNA, in the nematode Caenorhabdatis elegans.
• RNA interference is traditionally/ otherwise called as Post
transcriptional gene silencing (PTGS)
• shared Nobel prize in 2006.

69. The man who studies history can makes history

70. The man who studies
history can makes
history