Poster: Reproductive Development

Abs # 495: Synthesis and Function of Pollen Coat Proteins in Maize

Presenter:	Suen, Der-Fen , dfen@citrus.ucr.edu
Authors	Suen, Der-Fen  (A)   Huang, Anthony H C  (A)
Affiliations:	(A): Dept. Botany and Plant Sciences, UC, Riverside

The pollen coat is the outermost layer of the pollen grain and makes the initial contact with the stigma surface during sexual reproduction. A major protein in the ether-extracted maize pollen coat is a 35-kD endoxylanase. This 35-kD endoxylanase is synthesized initially as a 60-kD inactive precursor in the tapetum cells enclosing the developing pollen in the anther. The 60-kD pre-endoxylanase is processed and activated by a serine protease with removals of 198 and 48 residues from N- and C-termini, respectively, to become a mature 35-kD endoxylanase. During development, the appearance of endoxylanase enzyme activity in the anthers parallels that of the 35-kD protein. It is likely that the 35-kD endoxylanase plays a physiological role after the pollen has landed on the stigma. We also study the other proteins in the pollen coat, and also proteins that are secreted from the pollen interior. All the results will be reported.