Purification of an isoform of patatin with antimicrobial activity against Phytophthora infestans.
Phytophthora infestans (Mont.) de Bary is infamous as the causal agent of the late blight epidemic contributing to the Irish potato famine of the mid 19th century and remains agriculture's most destructive disease as new mutations and migrations confound control measures. In efforts to develop resistant varieties, a somatic hybrid (the Wisconsin J series) between potato (Solanum tuberosum) and a wild relative (Solanum bulbocastanum) has been found to convey durable resistance against the pathogen. We screened the total protein (100 microg ml(-1)) of somatic hybrid varieties J138, J138A12, J101K12, J103K12, and J101K9 for in vitro spore germination inhibition of P. infestans. Since J138 exhibited maximum inhibition at 150 microg ml(-1) in comparison to other varieties, we purified a 40 kD protein from J138 tubers by assaying its ability to inhibit spore germination in P. infestans spores. The highly purified protein was able to inhibit P. infestans spore germination by 70% at the 2.5 microg ml(-1) concentration. The N-terminal sequence of this protein was found to have exact amino acid homology to patatin, the major storage protein of potato tubers. The inhibitory protein has the same molecular weight as patatin and cross-reacts with patatin antibodies. The infection of J138 plants with spores of P. infestans under greenhouse conditions showed that patatin is expressed in stem tissue 72 h after the plant is inoculated with field isolates of P. infestans (US8). In this communication, we report the purification, characterization and antifungal activity against spores of P. infestans of patatin-J from potato tubers.
Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO 80523-1173, USA.
Neelam
N
Sharma
Hope A
HA
Gruszewski
Sang-Wook
SW
Park
David G
DG
Holm
Jorge M
JM
Vivanco
D000890:Anti-Infective Agents / Q000302:isolation & purification* / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010838:Phytophthora / Q000187:drug effects*; D010935:Plant Diseases; D010940:Plant Proteins / Q000302:isolation & purification* / Q000494:pharmacology
D000890:Anti-Infective Agents; D010940:Plant Proteins; C043222:patatin protein, Solanum tuberosum; D002265:Carboxylic Ester Hydrolases