Rust fungi belonging to the order Uredinales have
usually been considered the classical examples of obligate
parasites amongst plant pathogenic fungi.
The development of our knowledge of the metabolism,
nutrition and physiology of the rust fungi has been restricted
because of our inability to grow these fungi in axenic culture.
In the past the physiological and biochemical investigations
on rust fungi perse have been limited to studies of the germination and development of germ tubes.
The cultivation invitro of Puccinia graminis tritici
(Erikss . and .Henri.), Australian race ANZ 126-6,7, by Williams
et al. (1966, 1967), together with the report of Turel (1969)
on the axenic culture of Melampsora lini (Ehrenb) Lev, race 3
promoted research on culturing rust fungi on artificial medium.
An artificial medium containing 3% glucose, Czapek's
Mineral salts, 0.1% Evan's peptone, plus defatted BSA supported
growth and sporulation of Puccinia graminis tritici race
ANZ 126-6,7. Typical pigmented uredospores and teliospores
were formed after 6-3 weeks growth. The uredospores were
capable of infecting the mesophyll of wheat leaves exposed
by stripping back the lower epidermis. Scanning electron
microscopy revealed the presence of a coating of unknown chemical composition around the uredospores developed in vitro and
not observed on uredospores grown on wheat leaves. Two different strains of Melampsoralini (Ehrenb)
Lev were grown on solid media containing 4% sucrose, modified
Knop's tissue culture macro nutrients, Berthelot's micro nutrients, yeast extract and peptone. The mycelium was generally binucleate. Spore-like structures were recorded in the stroma which resembled uredospores and teliospores . Addition of 1%
defatted BSA to the medium described above greatly increased
the frequency of establishment off lax rust colonies. A defined liquid medium, containing Czapek's minerals y Ca++, glucose, as particacid, glutathione and cysteine, and inoculated
with uncontaminated uredospores, supported good vegetative
growth and sporulation of wheat stem rust (Puccini agraminis
f. sp. tritici race ANZ 1 2 6 - 6 , 7). Of six North American races
of wheat stem rust fungus tested, only three grew vegetatively
on artificial medium.
Finally a chemically defined liquid medium containing sucrose , Knop's mineral salts, micro nutrients, aspartic
(or glutamic) acid and cysteine supported the growth of vegetative colonies of Melampsora lini race 3 from uncontaminated
uredospores in a highly reproducible manner. The formation of
uredospores and telio spores of these colonies in the liquid
medium was controlled by the level of Ca++ (as Ca(NO₃)₂) and
the number of colonies per flask. With 60-70 colonies per
flask, uredospore formation occurred on 60 to 70% of the
colonies at a Ca++ level 8. 5 mM. A decrease in the Ca++
level to 4.5 mM or colony frequency to 10 per flask resulted in only in frequent sporulation
vitro infected in tactcotyledons
result with flax rust represents
ability to control the growth of
parasite in axenic culture.
The uredospores produced in a normal manner. This
a substantial advance in our
this important obligate parasite in axenic culture. / Land and Food Systems, Faculty of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41263 |
| Date | January 1973 |
| Creators | Bose, Amitava |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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