Loading…

Nitrogen and carbon dynamics of a foliar biotrophic fungal parasite in fertilized Douglas-fir

• We investigated the nutritional dynamics of Phaeocryptopus gaeumannii and the impact of nitrogen (N) fertilization of Douglas-fir (Pseudotsuga menziesii) on the production of P. gaeumannii fungal fruiting bodies. Emergence of P. gaeumannii fungal fruiting bodies (pseudothecia) in Douglas-fir stoma...

Full description

Saved in:
Bibliographic Details
Published in:The New phytologist 2004-07, Vol.163 (1), p.139-147
Main Authors: El-Hajj, Z, Kavanagh, K, Rose, C, Kanaan-Atallah, Z
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:• We investigated the nutritional dynamics of Phaeocryptopus gaeumannii and the impact of nitrogen (N) fertilization of Douglas-fir (Pseudotsuga menziesii) on the production of P. gaeumannii fungal fruiting bodies. Emergence of P. gaeumannii fungal fruiting bodies (pseudothecia) in Douglas-fir stomata has been directly linked to premature needle loss, a symptom of Swiss needle cast disease. • Douglas-fir trees (10-yr-old) naturally infected with P. gaeumannii were treated with soil applications of N fertilizer isotopically enriched with 15 N to increase foliar N and track the movement of N from the host to the fungus. Foliar N, free amino acids, percent of stomata occluded by pseudothecia, N isotope and carbon (C) isotope levels were assessed on treated and control trees. • Higher foliar N resulted in increased %N and %C in P. gaeumannii, as well as increased fungal fruiting and thus disease severity. Comparisons of δ 15 N levels between P. gaeumannii pseudothecia and associated needles indicated an increase in δ 15 N of needles and a simultaneous decline in δ 15 N of pseudothecia coupled with increased levels of foliar and fungal percentage N. • These findings confirm that P. gaeumannii responds to host nutrient status and that increased N availability inside Douglas-fir needles is linked to increased severity of Swiss needle cast disease.
ISSN:0028-646X
1469-8137
DOI:10.1111/j.1469-8137.2004.01102.x