Elicitor-induced metabolic changes in cell cultures of chickpea (Cicer arietinumL.) cultivars resistant and susceptible toAscochyta rabiei
✍ Scribed by Susanne Daniel; Karin Tiemann; Uta Wittkampf; Wolfang Bless; Walter Hinderer; Wolfgang Barz
- Book ID
- 104659525
- Publisher
- Springer-Verlag
- Year
- 1990
- Tongue
- English
- Weight
- 900 KB
- Volume
- 182
- Category
- Article
- ISSN
- 0032-0935
No coin nor oath required. For personal study only.
✦ Synopsis
Cell-suspension cultures of Ascochyta rabieiresistant (ILC 3279) and -susceptible (ILC 1929) chickpea (Cicer arietinum L.) cultivars were compared with regard to their elicitor-induced accumulation of pterocarpan phytoalexins and increases in the activities of biosynthetic enzymes. The growth performances and protein patterns of the two cell-culture lines were essentially identical. Treatment of cell cultures with a polysaccharide elicitor from A. rabiei induced fivefold-higher amounts of the phytoalexins medicarpin and maackiain in the cells of the resistant than in the susceptible cultivar. Glucose 6-phosphate dehydrogenase and eight enzymes representing the general phenylpropanoid pathway, the flavonoid-forming steps and the pterocarpanspecific branch of phytoalexin biosynthesis were found to be elicitor-induced. Phenylalanine ammonia-lyase and chalcone synthase reached sharp, transient optima some 8 h after elicitor application in the cells of both cultivars. The activities of isoflavone 2'-and 3'-hydroxylases were only induced in cells of the resistant cultivar with a maximum after 8 h. Cinnamic acid 4-hydroxylase, chalcone isomerase, 2'-hydroxyisoflavone reductase and pterocarpan synthase showed a later or no sharp optimum. The isoflavone-specific 7-O-glucosyltransferase was not induced in either cell-culture line. Cells of the susceptible cultivar failed to induce significant activities of isoflavone 2'-hydroxylase and these cells produced only very low amounts of phytoalexins. Isoflavone 2'-hydroxylase is postulated to be the main limiting enzyme for pterocarpan biosynthesis in cells of the susceptible cultivar.
The pterocarpan biosynthetic pathway in chickpea cells
Abbreviations: C4H=cinnamic acid 4-hydroxylase; CHI=chalcone isomerase; CHS=chalcone synthase; Glc6PDH=glucose 6phosphate dehydrogenase; IFR = NADPH : isoflavone oxidoreductase; IGT = UDP-glucose isoflavone 7-O-glucosyltransferase; 2'-(3')-IDH =isoflavone 2'(3')-hydroxylase; ILC =international legume chickpea; PAL=phenylalanine ammonia-lyase; PTS =pterocarpan synthase represents a suitable model for investigations of differential gene activation in connection with the expression of antimicrobial defence reactions.