J. Geike, H. Kaufmann, F. Schürmann, T. Debener
Powdery mildew caused by Podosphaera pannosa is one of the most severe diseases of roses. Especially for greenhouse production of cut roses it depicts a significant problem. Biology and race structure of P. pannosa limit the effectiveness of race-specific, monogenic resistances making the application of fungicides indispensable. However, this application is not very desirable because of high costs, increasing legal restrictions and public concerns. An alternative to overcome this problem can be the mildew resistance locus o (mlo)-mediated resistance. The mlo-based resistance has been characterized in barley, A. thaliana, tomato and pea where the loss-of-function of specific members of the MLO gene-family leads to a recessive and durable broad-spectrum resistance. In rose four MLO homologs (RhMLO1, RhMLO2, RhMLO3 and RhMLO4) closely related to the functional ones in A. thaliana, pea and tomato have been sequenced and mapped. The aim of this work is a reverse genetics approach to verify the functionality of the four mentioned rose MLOs regarding the mediation of susceptibility towards P. pannosa. Therefore, stable transgenics of the tetraploid Rosa hybrid cultivar ‘Pariser Charme’ expressing an RNAi construct for all four genes are produced. Several shoots could be regenerated and transferred to soil and first analyses to determine the transgenic character of the plants have been performed.
Geike, J., Kaufmann, H., Schürmann, F. and Debener, T. (2015). TARGETED MUTAGENESIS OF MLO-HOMOLOGOUS GENES IN THE ROSE GENOME. Acta Hortic. 1087, 507-513
DOI: 10.17660/ActaHortic.2015.1087.68
RNAi, Rosa hybrida, mildew resistance locus o

Acta Horticulturae