Abstract:

A full-length cDNA (LlpCel1) encoding an endo-1,4-β-glucanase (EGase) was isolated from pollen tubes of Lilium longiflorum Thunb. by RT-PCR and RACE. The deduced protein, which is predicted to be a compact globular protein, is of 490 amino acids, including a putative 21 amino acid-signal peptide. LlpCel1 shares high level of homology (about 50%) with plant secreted EGases, which bear apparently neither trans-membrane domain, nor cellulose-binding domain (CBD). LlpCel1 belongs to glycosyl hydrolase family 9. LlpCel1 transcripts were detected in pollen grains, germinating pollen and elongating pollen tubes with a similar level, whereas LlpCel1 transcripts were not detectable in all other lily tissues examined. The specific expression pattern suggests that LlpCel1 is confined to lily pollen germination and pollen tube elongation.

Key words: endo-1,4-β-glucanase (EGase, cellulase), Lilium longiflorum, pollen germination, pollen tube growth