AUTHOR=Majka Maciej , Serfling Albrecht , Czembor Paweł , Ślusarkiewicz-Jarzina Aurelia , Kwiatek Michał Tomasz , Ordon Frank , Wiśniewska Halina 

TITLE=Resistance of (Aegilops tauschii × Secale cereale) × Triticosecale Hybrids to Leaf Rust (Puccinia triticina) Determined on the Macroscopic and Microscopic Level

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01418

DOI=10.3389/fpls.2018.01418

ISSN=1664-462X

ABSTRACT=<p>Leaf rust caused by <italic>Puccinia triticina</italic> Eriks belongs to the most important fungal pathogens of wheat (<italic>Triticum aestivum</italic> L.) and triticale (× <italic>Triticosecale</italic>). Effective resistance to leaf rust is both, cost-effective and environmentally safe. Many wild <italic>Aegilops</italic> species carry unknown resistances against fungal diseases and are characterized by a high genetic variability. The main goal of this work was to examine the resistance of (<italic>Aegilops tauschii</italic> × <italic>Secale cereale</italic>) × <italic>Triticosecale</italic> hybrids to leaf rust in inoculation tests with different races of <italic>P</italic>. <italic>triticina</italic>. Hybrid plants were selected for the presence of 2D chromosome/s in the triticale background using fluorescence and genomic <italic>in situ</italic> hybridization. The presence of leaf rust resistance genes was confirmed with closely linked molecular markers, i.e., <italic>Xgdm35</italic> and <italic>Xgwm296</italic>. 14 genotypes of BC<sub>2</sub>F<sub>4</sub> – BC<sub>2</sub>F<sub>6</sub> hybrid plants with the monosomic addition of chromosome 2D (M2DA) were analyzed together with nine control lines. Resistance was determined at the macroscopic and microscopic level at the seedling and adult plant stage (flag leaf). In general, results revealed limited resistance of hybrid plants at the seedling stage, followed by an increase of the resistance level at later stages of plant development. This indicates that respective hybrid plants may exhibit APR resistance conferred by <italic>Lr22a</italic> introgressed from <italic>Ae</italic>. <italic>tauschii</italic>. On the basis of the macroscopic and microscopic analysis, this kind of resistance turned out to be additive and race-specific. We selected four monosomic 2D addition triticale genotypes highly resistant to <italic>P</italic>. <italic>triticina</italic> infection at the two main stages of plant development. From the selected genotypes, we obtained 26 doubled haploid lines among which two lines with doubled additional chromosomes 2D of <italic>Ae</italic>. <italic>tauschii</italic> can be used for further breeding to increase leaf rust resistance of cultivated triticale.</p>