{
  "id": 12526695,
  "title": "A broadly conserved phytoplasma α/β-hydrolase effector, SGP-7, is a catalytically active esterase that hydrolyses strigolactone analogues and alters shoot architecture",
  "url": "https://urgent.news/2026/10/06/a-broadly-conserved-phytoplasma-hydrolase-effector-sgp-7-is-a",
  "topic": "science",
  "section": "Science",
  "published": "2026-10-06T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.10.05.756913v1?rss=1"
  },
  "original_language": "en",
  "account": "Phytoplasmas are bacterial pathogens that infect the phloem of plants, causing developmental changes through the secretion of effectors. Previous studies have identified effectors like SAP11, SAP54/PHYL1, SAP05, and SWP1, which primarily bind and destabilize host transcription factors. However, no phytoplasma effector has been found to directly target plant hormones until now. The rice yellow dwarf phytoplasma RY378 produces SGP-7, an effector that induces excessive tillering and dwarfing in rice, and alters the expression of strigolactone- and auxin-responsive genes. SGP-7 has a typical /beta-hydrolase fold with a catalytic triad (Ser116-Asp229-His261), and its substrate pocket is similar in size to that of the Arabidopsis strigolactone receptor AtD14. Reactions involving SGP-7 show it to be an esterase with a preference for short-chain acyl esters, specifically hydrolyzing Yoshimulactone Green and the strigolactone analogue rac-GR24. These activities are lost when the catalytic serine (SGP-7S116A) is replaced. In Nicotiana benthamiana, SGP-7 expression reduces plant height by 46%, increases axillary bud growth fourfold, and lowers expression of the strigolactone-responsive marker NbBRC1. These findings establish the biochemical role of a conserved phytoplasma effector family and demonstrate that strigolactone-like molecules are direct enzymatic targets of a bacterial plant pathogen.",
  "summary": "Phytoplasmas are obligate, phloem-limited bacterial pathogens that reprogram host development through secreted effector proteins. The effectors characterized to date, including SAP11, SAP54/PHYL1, SAP05 and SWP1, act principally by binding and destabilizing host transcription factors. Although /{beta}-hydrolase-fold phytoplasma proteins with catalytic activity toward lipid substrates have…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}