Leaf senescence, is characterized by chlorophyll and protein degradation. More than 50% of the cellular protein is found in the chloroplasts, and chloroplast-localized proteases may play an important role in leaf senescence. Bioinformatics analysis identified 18 putative Arabidopsis thaliana chloroplast proteases that were up-regulated during senescence based on prior microarray analyses. Real-time qPCR was used to confirm up-regulation of the putative protease-encoding genes during senescence to determine the expression patterns as the plant matures. Our study included older plants and thus extended gene expression patterns. Relative expression levels for each gene were calculated using the Delta Delta Ct (ΔΔ Ct) method. Four (At2g39710, At5g13800, At5gl0770, and At5g11650) out of 18 genes increased significantly in expression at 7- and 8-weeks of growth compared to 4-weeks of growth, and one (Atlg79720) decreased significantly in expression through older tissues. Two (At5g13800 and At5g10770) of the 4 genes showing and increase were also shown to be targeted to the chloroplast. The genes showing a significant increase in expression are most likely to play a role in senescence, and warrant further study.
|Commitee:||Gharakhanian, Editte, Young, Kelly A.|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 52/01M(E), Masters Abstracts International|
|Subjects:||Plant biology, Genetics|
|Keywords:||Arabidopsis thaliana, Chloroplast, Gene expression, Real-time qPCR|
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