The contribution of foliar endophytes to quantitative resistance to Melampsora rust
Article first published online: 10 DEC 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 197, Issue 3, pages 909–918, February 2013
How to Cite
Raghavendra, A. K. H. and Newcombe, G. (2013), The contribution of foliar endophytes to quantitative resistance to Melampsora rust. New Phytologist, 197: 909–918. doi: 10.1111/nph.12066
- Issue published online: 7 JAN 2013
- Article first published online: 10 DEC 2012
- Manuscript Accepted: 26 OCT 2012
- Manuscript Received: 18 SEP 2012
- Boise Cascade Inc
- Greenwood Resources and Boise Cascade Inc
- induced resistance;
- model forest tree;
- plant symbionts;
- quantitative resistance
- Foliar endophytes of Populus do not induce the hypersensitive response associated with major genes for resistance to Melampsora leaf rust. But they could contribute to the quantitative resistance that represents a second line of defense. Quantitative resistance is thought to be determined by suites of minor genes in both host and pathogen that are influenced by the abiotic environment. Here, we determined the relative importance to quantitative resistance of foliar endophytes, one element of the biotic environment.
- Leaves of six host genotypes differing in genetic resistance to Melampsora × columbiana were inoculated first with one of four foliar endophytes (Stachybotrys sp., Trichoderma atroviride, Ulocladium atrum or Truncatella angustata), and then with Melampsora.
- These endophytes greatly reduced rust severity within inoculated leaves (i.e. local effects), but they had no systemic effect on rust of leaves not inoculated with endophytes. Differences among endophytes and their controls explained 54% of the total variation in quantitative resistance (i.e. rust severity); the six host/pathogen genotypes explained just 5%. In terms of magnitude of effect on rust severity, Stachybotrys, Trichoderma, Ulocladium and Truncatella were ranked in this order on all host/pathogen genotypes.
- Endophytes may contribute significantly to quantitative resistance to Melampsora in leaves of Populus.