Submitted to: Plant Pathology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 16, 2007
Publication Date: June 1, 2007
Citation: Prom, L.K. 2007. Claviceps africana spore germination as influenced by components of sorghum floral extracts. Asian Journal of Plant Pathology. 1(1):12-17. Interpretive Summary: Sorghum ergot, a fungal disease, was first observed in the United States in 1997. Ergot poses a serious threat to sorghum, especially in hybrid seed production fields. Since the fungus infects the plant through the flower, it is important to determine whether there are chemicals in some of the floral tissues of different sorghum lines that can reduce or stop the fungus from germinating. The fungus was placed on water media containing certain amounts of flower parts. The fungus did not germinate very well when they were placed on water medium containing flower part solution from Novartis KS310 and NC+7W97 sorghum lines. This means there are certain chemical components in the flower of some sorghum lines that will reduce the ability of the ergot to germinate. These chemicals can be identified and then possibly used to control the disease in the field. This in turn could lead to higher sorghum yields and profits for growers in the United States.
Technical Abstract: The effect in vitro of washed and crushed anther/pollen and stigma extracts from six sorghum lines with different levels of ergot susceptibility on ergot conidial germination was determined. Conidia plated on water agar amended with either anther/pollen or stigma extracts generally stimulated higher rates of conidia germination than conidia plated on water agar alone. However, conidia germinations were suppressed on water agar plates amended with washed anther/pollen extracts from Novartis KS310, washed stigma extracts from NC+7W97, and crushed stigma extracts from NC+8R18. Compared to the other plates with stigma extracts, plates containing extracts from male-sterile line ATx623 stimulated up to 227% higher conidia germination over the control plates. Overall, plates amended with anther/pollen extracts had significantly higher rates of germinated conidia than those containing stigma extracts. Anther/pollen and stigma extracts had an overall tendency to stimulate ergot conidia germination. However, components in the anther/pollen or stigma extracts from some of the sorghum lines exhibited the capacity to suppress spore germination. The critical factors from these floral components could be identified and used to minimize the impact of the disease.