Carbohydrate Accumulation and Utilisation Within and Between Rust Pustules in Leaves of Barley Infected with Puccinia hordei

Abstract

Carbon fluxes between and within rust pustules were studied in a barley infected with brown rust Puccinia hordei..  Analysis of the fluxes in whole infected leaves show that sucrose, fructose and glucose were reduced by 30%, 75% and 60% respectively in a typical diurnal cycle.  Soluble sugars and starch accumulated rapidly during a photoperiod and were depleted during the following dark period, similar to the pattern and amount found in healthy leaves.  Localised studies to within and between rust pustules revealed enhanced retension and accumulation of carbohydrates within the rust pustules.  These carbohydrates (sucrose, starch and fructa) showed duirnal fluctuations both within and between pustules.  A 3-fold increase in fructan in infected leaves was another striking observation following leaf infection.  The paper discusses the source-sink relationship between the barley and rust biotrophic system