01900nas a2200205   4500008004100000245008100041210006900122300001300191490000800204520121900212653002801431653001701459653002301476653002201499653001501521100001701536700001801553700001701571856010601588       2005                        eng d00aCompetition, facilitation, and niche differentiation in two foliar pathogens0 aCompetition facilitation and niche differentiation in two foliar  a449 -4570 v1433 aWe studied competition between the obligate biotroph Puccinia triticina (designated here as Puccinia) and the facultative saprophyte Pyrenophora tritici-repentis (designated here as Pyrenophora) in older and younger leaves in a set of three host genotypes selected to be resistant to Puccinia only, Pyrenophora only, or neither. Age-related resistance is important for both of these pathogens. The facultative saprophyte Pyrenophora was generally a stronger competitor than the biotrophic Puccinia, even experiencing facilitation from the presence of Puccinia when Pyrenophora had the advantage of earlier inoculation. Both pathogen species produced the most spores when they were introduced before the competing species and more spores when introduced simultaneously compared to after the competitor. The pre-interactive niche of Puccinia was larger than the post-interactive niche and sporulation by Puccinia was substantially reduced in environments in which Pyrenophora had high sporulation rates. The pre-interactive niche of Pyrenophora was similar to the post-interactive niche and Pyrenophora had proportionally lower reductions in sporulation due to interspecific competition in the pre-interactive niche.10aFacultative saprophytes10aImpact niche10aObligate parasites10aRequirement niche10aRust fungi1 aAl-Naimi, F.1 aGarrett, K.A.1 aBockus, W.W.  uhttp://129.130.186.12/content/competition-facilitation-and-niche-differentiation-two-foliar-pathogens