<p>Steroidal alkaloids play a crucial role in plant defense and exhibit distinct stereochemistry at C25, forming either the tomato-type (25<i>S</i>) or eggplant-type (25<i>R</i>) isomers. Here, we uncover the molecular mechanisms shaping this stereochemical diversity. Phylogenetic analysis of <i>GLYCOALKALOID METABOLISM 8</i> (<i>GAME8</i>) cytochrome P450 hydroxylases across the Solanaceae family revealed two distinct clades producing either 25<i>S</i> or 25<i>R</i> isomers. Ancestral <i>GAME8</i> likely favored 25<i>R</i>, with gene duplications giving rise to 25<i>S</i>-producing enzymes in more recent <i>Solanum</i> species. In <i>S. nigrum</i> and <i>S. dulcamara</i>, multiple <i>GAME8</i> copies generate mixed isomeric profiles. Notably, in wild <i>S. cheesmaniae</i> from the Galápagos, mutations in <i>GAME8</i> have driven a shift from 25<i>S</i> back to the ancestral 25<i>R</i>, suggesting reverse evolution. Our findings highlight how <i>GAME8</i> evolution has shaped alkaloid diversity in the genus <i>Solanum</i>, demonstrating a complex interplay between enzyme function, genetic variation, and evolutionary adaptation.</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

Enzymatic twists evolved stereo-divergent alkaloids in the Solanaceae family

  • Adam Jozwiak,
  • Michaela Almaria,
  • Jianghua Cai,
  • Sayantan Panda,
  • Hadas Price,
  • Ron Vunsh,
  • Margarita Pliner,
  • Sagit Meir,
  • Ilana Rogachev,
  • Asaph Aharoni

摘要

Steroidal alkaloids play a crucial role in plant defense and exhibit distinct stereochemistry at C25, forming either the tomato-type (25S) or eggplant-type (25R) isomers. Here, we uncover the molecular mechanisms shaping this stereochemical diversity. Phylogenetic analysis of GLYCOALKALOID METABOLISM 8 (GAME8) cytochrome P450 hydroxylases across the Solanaceae family revealed two distinct clades producing either 25S or 25R isomers. Ancestral GAME8 likely favored 25R, with gene duplications giving rise to 25S-producing enzymes in more recent Solanum species. In S. nigrum and S. dulcamara, multiple GAME8 copies generate mixed isomeric profiles. Notably, in wild S. cheesmaniae from the Galápagos, mutations in GAME8 have driven a shift from 25S back to the ancestral 25R, suggesting reverse evolution. Our findings highlight how GAME8 evolution has shaped alkaloid diversity in the genus Solanum, demonstrating a complex interplay between enzyme function, genetic variation, and evolutionary adaptation.