Poster Presentation Science Protecting Plant Health 2017

The effect of temperature, water potential and incubation time on the germination of Sporisorium scitamineum teliospores (#318)

Nurul Hidayah 1 , Shamsul Bhuiyan 1 2 , Karen Aitken 3 , Victor Galea 1
  1. The University of Queensland, Gatton, QLD, Australia
  2. Sugar Research Australia, Woodford, QLD, Australia
  3. Commonwealth Scientific and Industrial Research Organisation , Brisbane, QLD, Australia

Sugarcane smut caused by the fungus Sporisorium scitamineum is an important disease of sugarcane. Environmental factors such as temperature and water availability are essential influencers of the germination of smut teliospores. This study aimed to determine the effect of temperature, water potential and incubation time on the germination of teliospores. Teliospores (200 µl each at 1.5 x 106 teliospores per ml) were cultured on water agar amended with various amount of potassium chloride (KCl) or sucrose to achieve water potentials of 0, -5, -15, -25, -35 and -45 bars in 9 cm Petri dishes. Subsequently the plates were incubated at various temperatures (20, 25, 30, 35 and 40°C) for 0.5, 2, 4, 6 and 8 hours. Each combination consisted of five replicates. This study revealed that teliospore germination decreased with declining water potential levels. The highest germination levels (95.76%) occurred with KCl at 30°C and a water potential of 0 bars. Furthermore, at 30°C and at the lowest water potential used (-45 bars), teliospores germination was 50%. This result suggests that smut fungus can germinate under hot and dry conditions. This experiment also showed that teliospore germination was drastically reduced at 40°C. For both media, maximal teliospore germination was observed at 30°C. This study also revealed on sucrose amended media, that teliospore germination commenced after 2 hours incubation, whereas on KCl amended media, germination commenced after 4 hours. This result suggests that the addition of a low concentration of sucrose would stimulate germination of smut teliospores.