Question

Which is the primary precursor of IAA in plants?

Hint:

IAA biosynthesis occurs primarily in shoot apices and young leaves, with tryptophan sourced from the shikimate pathway.

Answer 1

Indole-3-acetic acid (IAA), the primary auxin, is biosynthesized mainly from the amino acid tryptophan via the indole-3-pyruvic acid pathway in plants. Tryptophan is converted to indole-3-acetaldoxime or directly to indole-3-pyruvate, leading to IAA.