Auxins biosynthesis for hormone crosstalk and plant development

Auxins are a class of compounds showing lower molecular weight with growth-promoting properties. Auxin, which is mostly characterized by indole-3-acetic acid (IAA), is a phytohormone that regulates plant development and growth. Despite the fact that IAA was the first plant hormone discovered, the biosynthesis pathway has remained a mystery at the genetic level. Both the tryptophan (Trp)-independent and Trp-dependent routes for IAA production have been postulated. The Trp-dependent IAA production from tryptophan was proposed by four diverse ROUTES such as the indole-3-acetamide route, the indole-3-pyruvic acid route, the tryptamine route, and the indole-3-acetaldoxime route. However, several studies on auxin signal transduction, polar transport, and sensing have been conducted. However, auxin biosynthesis crosstalk has received too little attention. Therefore, this chapter presents a summary of recent developments in auxins biosynthesis for phytohormone crosstalk and plant development.