Novel defensin subfamily from spinach (Spinacia oleracea).
Antimicrobial peptides (So-D1-7) were isolated from a crude cell wall preparation from spinach leaves (Spinacia oleracea cv. Matador) and, judged from their amino acid sequences, six of them (So-D2-7) represented a novel structural subfamily of plant defensins (group IV). Group-IV defensins were also functionally distinct from those of groups I-III. They were active at concentrations < 20 microM against Gram-positive (Clavibacter michiganensis) and Gram-negative (Ralstonia solanacearum) bacterial pathogens, as well as against fungi, such as Fusarium culmorum, F. solani, Bipolaris maydis, and Colletotrichum lagenarium. Fungal inhibition occurred without hyphal branching. Group-IV defensins were preferentially distributed in the epidermal cell layer of leaves and in the subepidermal region of stems.
Departamento de Biotecnología-UPM, ETS Ingenieros Agrónomos, Madrid, Spain.
A
A
Segura
M
M
Moreno
A
A
Molina
F
F
García-Olmedo
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000302:isolation & purification*; D023082:Defensins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification*; D016415:Sequence Alignment; D017421:Sequence Analysis; D018724:Spinacia oleracea / Q000235:genetics / Q000378:metabolism*
D000890:Anti-Infective Agents; D023082:Defensins; D010940:Plant Proteins