Peptide signals for plant defense display a more universal role.
Hydroxyproline-rich systemins (HypSys) are small defense signaling glycopeptides found within the Solanaceae family that until recently were thought to only induce defense genes to herbivore attack. The glycopeptides are processed from larger proproteins with up to 3 different glycopeptides being processed out of a single precursor protein. A conserved central hydroxyproline motif within each HypSys is the site of pentose sugar attachment. Recently, it was found that in Petunia hybrida, these defense signaling glycopeptides did not induce protease inhibitor but instead, increased levels of defensin, a gene that is involved in pathogen attack. More recently, a HypSys peptide was isolated from Ipomoea batatas (sweet potato) of the Convolvulaceae family and found to induce sporamin. The proprotein precursor contained six putative peptide signals and had a propeptidase processing region with homology to solanaceous proHypSys. Thus, the HypSys defense peptides are no longer confined to defense against herbivory or exclusivity to the Solanaceae family, redefining both function and dispersion.
Pearce
Gregory
G
Institute of Biological Chemistry; Washington State University; Pullman, Washington USA.
Bhattacharya
Ramcharan
R
Chen
Yu-Chi
YC
J Biol Chem. 2007 Jun 15;282(24):17777-84
17449475
Planta. 2004 Jan;218(3):360-9
14534786
Proc Natl Acad Sci U S A. 2006 Jun 27;103(26):10104-9
16785433
Science. 1991 Aug 23;253(5022):895-7
17751827
Proc Natl Acad Sci U S A. 2006 Jun 27;103(26):10098-103
16785434
Plant Cell. 2002;14 Suppl:S251-64
12045281
Proc Natl Acad Sci U S A. 2005 Sep 6;102(36):12974-7
16126900
Proc Natl Acad Sci U S A. 1996 Oct 29;93(22):12053-8
8901530
J Biol Chem. 2008 Apr 25;283(17):11469-76
18299332
J Plant Growth Regul. 2000 Jun;19(2):195-216
11038228
Science. 1992 Mar 20;255(5051):1570-3
1549783
Nature. 2001 Jun 14;411(6839):817-20
11459063
J Biol Chem. 2003 Aug 8;278(32):30044-50
12748180