Axenic culture of wheat stem rust fungus

Bose, A. (Amitava)
1970
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. Most of the physiological and biochemical investigations on rust fungi have been limited to studies of the germination and development of germ tubes. It is not known, whether failure of the rusts to grow axenically is associated with a metabolic block in essential biochemical pathways. The uredial stage of an
more » ... stage of an Australian isolate (ANZ 126-6, 7) of wheat stem rust was grown on a relatively simple medium. Successful in vitro growth was obtained on a medium containing Czapek's minerals, glucose and an organic nitrogen source viz. yeast extract, peptone or BSA. Vegetative growth producing a discrete colony appeared to be dependent upon high density seeding, when conventional dry seeding techniques were followed. When a spore suspension in gelatin was used for inoculation consistent, reproducible vegetative growth at low density seeding was obtained. Water spore suspensions failed to support any growth on the same series of media, under identical conditions. Sodium citrate, host extract, and host protein fractions in general inhibited growth whereas pectin increased the lag phase. Spore-like bodies were obtained inside the colony, which were devoid of any pigmentation. It is suggested that the combination of physical and chemical factors surrounding the germinating spore play an important role in the in vitro development of rust fungi.
doi:10.14288/1.0102051 fatcat:qfnhibmv7vfi5cejaai7u2b7re