Eliciting secondary metabolism in plant cell cultures

Abstract

Plant cell cultures are potentially rich sources of valuable pharmaceuticals and other biologically active phytochemicals, but relatively few cultures synthesize secondary compounds over extended periods in amounts comparable to those found in the whole plant. Frequently, no secondary metabolites characteristic of the intact plant are produced. So far, the manipulation of culture media, culture conditions and phytohormone levels have, in general, failed to permit commercial production of those phytochemicals useful in medicine and industry. This almost certainly reflects the lack of understanding of basic secondary metabolic regulation in cultured plant cells. Microbial insult can induce antibiotic phytochemical synthesis in cultured plant cells: the microbial molecules which stimulate synthesis have been called ‘elicitors’. Increased synthesis of secondary products in response to elicitation of various types appear to be the general response of cultured cells. This paper illustrates the immense biotechnological potential of plant cell culture—‘elicitor’ (inducer) interactions to the large scale production of secondary metabolites, and suggests several lines of enquiry that remain to be authoritatively treated.