Senescence is the final stage of leaf development, which is an orderly dismantling of the leaf organ that functions to mobilize nutrients prior to organ death. The aim of this study was to determine whether chloroplast protein degradation, the first step in nitrogen remobilization, occurred via an autophagy-related pathway. Previous studies demonstrated that Rubisco containing bodies (RCBs) form during senescence. autophagy 5 (atg5 ) and autophagy 7 (atg7) mutants were examined to determine whether RCBs could be produced in mutants that cannot form autophagosomes, and whether RCB production affected stromal protein degradation. The results indicated that RCBs were not produced in atg5 and atg7 mutants and that autophagy-dependent processes, likely the production of RCBs, contribute to chloroplast protein degradation during senescence. In addition, the senescence up-regulated gene S33Ab, a protease/lipase, was investigated to determine whether S33Ab functions in thylakoid membrane dismantling during senescence. The results show a delay in thylakoid membrane dismantling during senescence in two alleles, suggesting S33Ab may function in thylakoid dismantling.
|Commitee:||Brusslan, Judith, Eldon, Elizabeth, Malcomber, Simon|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 51/04M(E), Masters Abstracts International|
|Subjects:||Biology, Molecular biology, Biochemistry|
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