Induction of pathogen defence genes in parsley (<em>Petroselinum crispim</em> L.) plant by ozone.

Abstract

Parsley (Petroselinum crispum L.) is known to respond to pathogen attack by the synthesis of furanocoumarins and to UV-irradiation by the synthesis of flavone glycosides, whereas ozone treatment results in the induction of both pathways. Ozone treatment (200 nl 1&minus;1, 10 h) of parsley seedlings results in an increased mRNA level of early genes within 3 h [pathogenesis related proteins PR1, PR2 and an elicitor-induced protein with unknown function (Eli 16)], of intermediate induced genes within 6 h [phenylalanine ammonia-lyase (PAL), 4-coumaroyl-CoA ligase (4CL), chalcone synthase (CHS)], and of late genes within 12 h [hydroxyproline-rich glycoprotein (HRGP), peroxidase (POD)]. 2D-PAGE of in vitro translated poly(A)+ RNA isolated from ozone-treated parsley seedlings revealed about 20 induced and 10 repressed translation products. A cDNA library from parsley seedlings was differential screened, yielding several induced cDNA clones. One of the ozone-induced cDNA clones could be identified as coding for PR1-1 by hybrid-selected in vitro translation and by DNA sequence analysis