Main content area

Developmental and stress regulation of gene expression for plastid and cytosolic isoprenoid pathways in pepper fruits

Hugueney, P., Bouvier, F., Badillo, A., Quennemet, J., d'Halingue, A., Camara, B.
Plant physiology 1996 v.111 no.2 pp. 619-626
Capsicum annuum, genes, complementary DNA, gene expression, plant development, genetic code, plastids, cytosol, isoprenoids, biosynthesis, biochemical pathways, enzymes, enzyme activity, phosphates, ripening, developmental stages, phytoene synthase, stress response
Plant cells synthesize a myriad of isoprenoid compounds in different subcellular compartments, which include the plastid, the mitochondria, and the endoplasmic reticulum cytosol. To start the study of the regulation of these parallel pathways, we used pepper (Capsicum annuum) fruit as a model. Using different isoprenoid biosynthetic gene probes from cloned cDNAs, we showed that only genes encoding the plastid enzymes (geranylgeranyl pyrophosphate synthase, phytoene synthase, phytoene desaturase, and capasanthin-capsorubin synthase) are specifically triggered during the normal period of development, at the ripening stage. This pattern of expression can be mimicked and precociously induced by a simple wounding stress. Concerning the cytosol-located enzymes, we observed that the expression of the gene encoding farnesyl pyrophosphate synthase is constitutive, whereas that of farnesyl pyrophosphate cyclase (5-epi-aristolochene synthase) is undetectable during the normal development of the fruit. The expression of these later genes are,however, only selectively triggered after elicitor treatment. The results provide evidence for developmental control of isoprenoid biosynthesis occurring in plastics and that cytoplasmic isoprenoid biosynthesis is regulated, in part, by environmental signals.