Rootstocks resistant to Armillaria root rot

The fact that Armillaria root rot (ARR) is so hard to control with conventional methods makes the development of a resistant rootstock very enticing. There are efforts underway to create resistant rootstocks for peach using traditional breeding and transgenics.

Traditional breeding

Dr. Tom Beckman is running a breeding program at the USDA Station in Byron, GA with the goal to produce ARR resistant rootstocks. He has already developed lines that look promising:

Transgenic rootstocks

The recent discovery of a monocot mannose-binding lectin (gastrodia-anitfungal protein ;GAFP) could impart increased disease resistance against fungi in transgenic rootstocks. The lectin was purified from Gastrodia elata, a Chinese orchid that parasitizes Armillaria mellea. Our lab has shown that GAFP confers resistance to Phytophthora species and root knot nematode in transgenic tobacco (pdf) and transgenic plum (pdf). Current projects include:

  • GAFP localization and mode of action in oomycetes
  • movement of GAFP through graft unions
  • increasing GAFP production in roots
  • field resistance of promising lines to ARR