DEVELOPMENTAL CELL DEATH IN WHEAT FLAG LEAF TIPS IN TWO WHEAT CULTIVARS

Wheat stripe rust pandemics have been recorded across all cereal growing regions. Lr34 provides an adult plant resistance and flag leaves of many wheat cultivars containing Lr34 develop a necrotic flag leaf tip. We studied cell death process in progressive necrotic and non-necrotic tissues of flag leaves in wheat cultivars Frontana (resistant to stripe rust) and Fielder (highly susceptible to stripe rust). Cleavage of the poly(ADP-ribose) polymerase (PARP) was detected in necrotic tissues of Frontana flag leaves but not in the non-necrotic tissues or in the corresponding leaf sections in Fielder flag leaves. DNA repairing genes were also studied but their expression was similar in the two different leaf sections for both cultivars. Our work may indicate that protein cleavage is involved in the cell death of flag leaf tips in Frontana.