<p>Indole is an important biomolecule in plants, essential for amino acid biosynthesis, defense, pollinator attraction and plant–plant communication. Its biosynthesis is reported to be catalyzed by standalone indole-3-glycerol phosphate lyases, which are, however, absent in core eudicots. Here we show that, in core eudicots, indole production for defense and signaling occurs through an alternative pathway. The tryptophan synthase α subunit (TSA), which is typically complexed with the β subunit (TSB) to synthesize tryptophan through indole as an intermediate, can be hijacked by a noncatalytic paralog of TSB (TSB-like) to produce free indole. TSB-like is a pseudoenzyme that evolved from TSB by mutagenesis of two key essential residues, retaining the ability to allosterically activate TSA to allow formation and release of indole. The widespread occurrence and expression pattern of TSB-like genes in plants suggest that this is a general mechanism for the formation of free indole in plant defense and communication.</p><p></p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

A pseudoenzyme enables indole biosynthesis in eudicot plants

  • Matilde Florean,
  • Hedwig Schultz,
  • Veit Grabe,
  • Katrin Luck,
  • Grit Kunert,
  • Sarah E. O’Connor,
  • Tobias G. Köllner

摘要

Indole is an important biomolecule in plants, essential for amino acid biosynthesis, defense, pollinator attraction and plant–plant communication. Its biosynthesis is reported to be catalyzed by standalone indole-3-glycerol phosphate lyases, which are, however, absent in core eudicots. Here we show that, in core eudicots, indole production for defense and signaling occurs through an alternative pathway. The tryptophan synthase α subunit (TSA), which is typically complexed with the β subunit (TSB) to synthesize tryptophan through indole as an intermediate, can be hijacked by a noncatalytic paralog of TSB (TSB-like) to produce free indole. TSB-like is a pseudoenzyme that evolved from TSB by mutagenesis of two key essential residues, retaining the ability to allosterically activate TSA to allow formation and release of indole. The widespread occurrence and expression pattern of TSB-like genes in plants suggest that this is a general mechanism for the formation of free indole in plant defense and communication.