Evolutionary history reveals two phylogenetically distinct species within Puccinia graminis

• The cereal pathogen Puccinia graminis is considered to have high genetic diversity within the species. We hereby hypothesize that the different formae speciales of P. graminis have co-evolved with their various grass hosts. Elongation factor 1 alpha (EF-1α) and beta-tubulin (BT) genes, the internal transcribed spacer (ITS) region and mitochondrial cytochrome oxidase subunit I (COI) were sequenced from DNA isolated from Puccinia graminis collected from cereal and wild grasses to infer the phylogeny of the fungus. The related species Puccinia coronata, collected from both oats and wild grasses, were used as a reference throughout the analysis. Coalescence analysis showed that the time to the most recent common ancestor (TMRCA) for P. graminis and P. coronata were in all models further away in time than TMRCA for the two formae speciales. Within the species P. graminis, two main clades were formed; one including samples collected from Avena sativa, Avena fatua, Phleum pratense, and the other including samples collected from Triticum aestivum, Triticum monoccocum, Secale cereal and Hordeum vulgare, suggesting that P. graminis is to be divided into two different taxa. However, samples collected from the weed host Elytrigia repens, did not show any clear pattern, the samples equally grouped with either of the two groups. The phylogeny of P. graminis was thus congruent with its respective grass hosts, which confirm a co-evolution with the host.

Ämnesord

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Jordbruksvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Agricultural Science (hsv//eng)

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