Accumulation of defence-related transcripts and cloning of a chitinase mRNA from pea leaves ( Pisum sativum L.) inoculated with Ascochyta pisi Lib

• Published in: Plant science (Limerick) Vol. 92; no. 1; pp. 69 - 79
• Main Authors: Vad, Knud, de Neergaard, Eigil, Madriz-Ordeñana, Kenneth, Mikkelsen, Jørn D., Collinge, David B.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 1993; Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chalcone synthase; Extensin; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Hydrolase (antifungal); Hypersensitive response; Pathogenesis-related protein; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; Polymerase chain reaction; Polymerase chain reaction; Hypersensitive response; Extensin; Hydrolase (antifungal); Pathogenesis-related protein; Chalcone synthase; Chitinase; Plant pathogen; Fungi; Messenger RNA; Dicotyledones; Ascochyta pisi; Angiospermae; Fungi Imperfecti; Aminoacid sequence; Thallophyta; Acyltransferases; Enzyme; Transferases; Hypersensitivity; Host agent relation; Pathogenesis related protein; Resistance; Grain legume; Leguminosae; Naringenin-chalcone synthase; Glycosidases; Pisum sativum; Phenols; Hydrolases; Spermatophyta; Biological accumulation; O-Glycosidases
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/0168-9452(93)90067-A

The race specific resistance of pea to Ascochyta pisi Lib. was shown to be exhibited as a hypersensitive response associated with the production of polyphenolic substances in epidermal and mesophyll cells. The levels of transcripts representing a pathogenesis-related (PR) protein (chitinase) and an enzyme of phytoalexin biosynthesis (chalcone synthase) were shown to accumulate more rapidly during the hypersensitive response than during lesion development in the compatible interaction. A full-length (1143 bp) cDNA sequence of a pea chitinase (EC 3.2.1.14) (coding for an approx. 34 500 Da protein) was deduced by combining the overlapping sequences of three clones obtained following PCR amplification of cDNA prepared from mRNA isolated 24 h after inoculation of pea leaves with Ascochyta pisi. The combined sequences were identified as a class I chitinase corresponding to the basic A1-chitinase enzyme previously isolated from pea leaves (Vad et al., Planta, 184 (1991) 24–29). Like class III and IV chitinases, the pea sequence differs from other class I chitinases in the absence of a hydrophobic C-terminal domain.