Expression of a Solanum tuberosum cyclophilin gene is regulated by fungal infection and abiotic stress conditions

Cyclophilins (CyPs) are ubiquitous proteins with an intrinsic enzymatic act ivity of peptidyl-prolyl cis-trans isomerase that catalyzes the rotation of X-Pro peptide bonds. These enzymes are believed to play a role in the fold ing of certain proteins, In addition, CyPs might be important in signal tra nsduction processes. A cDNA library was prepared from potato (Solamum tuber osusm) tubers infected with the fungus solani f. sp eumartii. Using a PCR-a mplified subtracted cDNA probe, a clone encoding a cytosolic form of CyP, c alled StCyP (Solanum tuberosum CyP), was isolated. Except in tubers, StCyP is expressed at high levels in tissues of healthy potato plants. Northern b lot analyses revealed that both wounding and fungal infection increased the level of StCyP mRNA in tubers. However, whereas wounding causes a transien t accumulation of StCyP mRNA, fungal infection results in a maintained accu mulation of this transcript. StCyP mRNA accumulation is also stimulated by the application of absicic acid (ABA) and methyl jasmonate (MeJA) in tubers . Treatment with fungal elicitor or salicilic acid (SA) has no effect on th e level of StCyP mRNA accumulation. Together these results indicate that th e observed accumulation of StCyP mRNAs in fungal-infected potato tubers mig ht be a response to the wound produced by the penetration and colonization of the tissue by the pathogen. Furthermore, accumulation of StCyP transcrip ts was also detected when the potato tubers were exposed to heat-shock trea tment. These findings support a role for cyclophilins in the plant response to environmental stresses, (C) 2000 Elsevier Science Ireland Ltd. All righ ts reserved.