Abstract
It has been generally accepted that the biosynthetic pathway of phytosteroid is only via cycloartenol. However, recently, we identified lanosterol synthase gene (LAS1) from Arabidopsis and discovered that a part of phytosteroid is biosynthesized via lanosterol by the tracer experiment of labeled mevalonate (MVL). Then, why does plant have the biosynthetic pathway of phytosteroid via lanosterol? Since LAS1 expression is induced by methyl jasmonate treatment, the metabolites of lanosterol may be plant defense related compounds. Tomatine, steroidal alkaroid, which seem to be related to defense response, included in Tomato. Although it is thought that tomatine is biosynthesized from phytosterol, the biosynthetic mechanisms are poorly understood. We undertook the present study to identify the genes for tomatine biosynthesis using Micro-Tom, which is a model plant of Tomato. By the tracer experiment of MVL, it was suggested that biosynthetic pathway via lanosterol exists in the plant. Now, we are screening EMS mutation lines for tomatine biosynthesis deficient mutants by TLC analysis. In this symposium, we discuss the possibility of biosynthetic studies using Micro-Tom.
