Present address: KWS Saat AG, Einbeck, Germany.
Maize endosperm secretes a novel antifungal protein into adjacent maternal tissue
Article first published online: 6 APR 2002
The Plant Journal
Volume 25, Issue 6, pages 687–698, March 2001
How to Cite
Serna, A., Maitz, M., O'Connell, T., Santandrea, G., Thevissen, K., Tienens, K., Hueros, G., Faleri, C., Cai, G., Lottspeich, F. and Thompson, R. D. (2001), Maize endosperm secretes a novel antifungal protein into adjacent maternal tissue. The Plant Journal, 25: 687–698. doi: 10.1046/j.1365-313x.2001.01004.x
- Issue published online: 6 APR 2002
- Article first published online: 6 APR 2002
- Received 27 November 2000; revised 22 January 2001; accepted 23 January 2001.
- transfer layer;
A series of endosperm transfer layer-specific transcripts has been identified in maize by differential screening of a cDNA library of transcripts at 10 days after pollination. Sequence comparisons revealed among this class of cDNAs a novel, small gene family of highly diverged sequences encoding basal layer antifungal proteins (BAPs). The bap genes mapped to two loci on chromosomes 4 and 10. So far, bap-homologous sequences have been detected only in maize, teosinte and sorghum, and are not present in grasses outside the Andropogoneae tribe. BAP2 is synthesized as a pre-proprotein, and is processed by successive removal of a signal peptide and a 29-residue prodomain. The proprotein can be detected exclusively in microsomal membrane-containing fractions of kernel extracts. Immunolocalization reveals BAP2 to be predominantly located in the placentochalazal cells of the pedicel, adjacent to the basal endosperm transfer layer (BETL) cells, although the BAP2 transcript is found only in the BETL cells. The biological roles of BAP2 propeptide and mature peptide have been investigated by heterologous expression of the proprotein in Escherichia coli, and by tests of its fungistatic activity and that of the fully processed form in vitro. The mature BAP2 peptide exhibits potent broad-range activity against a range of filamentous fungi, including several plant pathogens.