Antifungal activity of rice Pex5p, a receptor for peroxisomal matrix proteins.
We have purified a novel antifungal protein from blast fungus (Magnaporthe grisea)-treated rice leaves using consecutive chromatographies on CM-Sepharose ion-change, Affi-gel blue, and HPLC gel filtration columns. We determined the N-terminal peptide sequence of the purified protein and subjected it to the NCBI/BLAST database and found the protein to be a partial fragment of the peroxisomal receptor protein in rice (OsPex5p). After cloning two cDNAs encoding OsPEX5L and OsPEX5S genes that are splice variants of OsPEX5 from a rice leaf cDNA library, we investigated their antifungal properties. The recombinant proteins were expressed in Escherichia coli and found to significantly inhibit cell growth of various pathogenic fungal strains. mRNA expression of the OsPEX5L gene was induced by diverse external stresses such as rice blast fungus, fungal elicitor, and other signaling molecules including H(2)O(2), abscisic acid, jasmonic acid, and salicylic acid. These results suggest that the peroxisomal receptor protein, OsPex5p, plays a critical role in the rice defense system against diverse external stresses including fungal pathogenic attack.
Lee
Jung Ro
JR
Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea.
Park
Seong-Cheol
SC
Kim
Mi-Hyun
MH
Jung
Ji Hyun
JH
Shin
Mi Rim
MR
Lee
Deok Ho
DH
Cheon
Min Gyeong
MG
Park
Yoonkyung
Y
Hahm
Kyung-Soo
KS
Lee
Sang Yeol
SY
D000935:Antifungal Agents / Q000008:administration & dosage*; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D020082:Magnaporthe / Q000187:drug effects* / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000008:administration & dosage* / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism* / Q000382:microbiology*; D000074435:Peroxisome-Targeting Signal 1 Receptor; D029701:Saccharomyces cerevisiae Proteins / Q000008:administration & dosage / Q000378:metabolism
D000935:Antifungal Agents; D026901:Membrane Transport Proteins; C499509:PEX5 protein, S cerevisiae; D000074435:Peroxisome-Targeting Signal 1 Receptor; D029701:Saccharomyces cerevisiae Proteins