Starch accumulation in sugarcane in response to stress

Abstract

Yellow Canopy Syndrome (YCS) is a new problem affecting the Australian sugar industry. It was first reported in 2012 and has increased in occurrence and spread from the initial reports in North Queensland to further south in Mackay last year. While the causal agent is still unknown, several physiological studies have been performed. This paper examines the accumulation of starch in sugarcane leaves. This was an initial observation in YCS affected leaf sections of tillers of KQ228A. Subsequently, a method for routine high throughput qualitative analysis of starch has been developed, enabling rapid assessment of this response. Follow up work has compared this phenomenon in affected stalks, both between leaves of different ages within a stalk, as well as within regions of the same leaf. The accumulation of starch in sugarcane plants in response to biotic stress and in naturally senescing leaves has been undertaken to understand this phenomenon better and will be described in this paper. Our results showed that unlike YCS affected leaves, starch did not accumulate in the leaves of diseased plants nor in senescing leaves collected from the field.