Characterization of markers to determine the extent and variability of leaf senescence in Arabidopsis. A metabolic profiling approach

Comparison of the extent of leaf senescence depending on the genetic background of different recombinant inbred lines ( RILs) of Arabidopsis ( Arabidopsis thaliana) is described. Five RILs of the Bay- 0 3 Shahdara population showing differential leaf senescence phenotypes ( from early senescing to late senescing) were selected to determine metabolic markers to discriminate Arabidopsis lines on the basis of senescence- dependent changes in metabolism. The proportion of gamma- aminobutyric acid, leucine, isoleucine, aspartate, and glutamate correlated with ( 1) the age and ( 2) the senescence phenotype of the RILs. Differences were observed in the glycine/ serine ratio even before any senescence symptoms could be detected in the rosettes. This could be used as predictive indicator for plant senescence behavior. Surprisingly, late- senescing lines appeared to mobilize glutamine, asparagine, and sulfate more efficiently than early- senescing lines. The physiological basis of the relationship between leaf senescence and flowering time was analyzed.