Poster: Lipids & Related Molecules

Abs # 870: Proteomics study of the Arabidopsis tapetum tapetosomes and elaioplasts

Presenter:	Hsieh, Kai , kaih@citrus.ucr.edu
Authors	Hsieh, Kai  (A)   Huang, Anthony H.C.  (A)
Affiliations:	(A): Dept. Botany and Plant Sciences, UC Riverside

In flowers, the tapetum cells lining the anther locule provide nutrients to the maturing pollen and eventually lyze to deposit special and abundant chemicals onto the mature pollen, forming the pollen coat. In Braassicacea, these special chemicals include steryl esters, oleosins, and others. In the tapetum cells, they are initially accumulated in two abundant organelles, the tapetosomes and the elaioplasts, which are rich in neutral lipids. The tapetosomes contain triacylglycerols and oleosins, whereas the elaioplasts possess steryl esters and PAP (plastid-associated proteins). We have isolated these two organelles from Arabidopsis thaliana and applied proteomics to study their protein constituents. The initial results on the abundant proteins are positive, revealing the presence of oleosins in the tapetosomes and Rubisco subunits and PAP in the elaioplasts. We are studying the less-abundant proteins, which may include the enzymes for the synthesis of triacylglycerols, long-chain alkanes, and steryl esters. Our latest results will be reported.