Oral Technical Session: Mechanism of Host and Non-Host Resistance

101-O

Arabidopsis nonhost resistance genes to defeat Asian soybean rust.
C. LANGENBACH (1), R. Campe (1), N. Tresch (2), H. Schultheiss (2), U. Conrath (1), K. Goellner (1)
(1) RWTH Aachen University, Aachen, Germany; (2) BASF Plant Science Company GmbH, Limburgerhof, Germany

Soybean is highly susceptible to Phakopsora pachyrhizi, the causal agent of Asian soybean rust (SBR) disease. Since traditional breeding by now has not provided soybean varieties with stable resistance to all Phakopsora isolates, alternative strategies are urgently needed. Nonhost resistance (NHR) is the most durable form of plant disease resistance and is, therefore, ideally suited for the identification of effective resistance traits to SBR. In the present study we used the Arabidopsis-P. pachyrhizi nonhost interaction to identify novel Arabidopsis NHR genes via global transcriptome analysis. By doing so, we found several genes that are essential for Arabidopsis’ postinvasion NHR to SBR. One of these genes encodes UDP-glycosyltransferase UGT84A2/BRT1 in the phenylpropanoid metabolism. We also provide evidence that cross species transfer of identified Arabidopsis NHR genes quantitatively enhanced soybean resistance to P. pachyrhizi in greenhouse experiments. Stable overexpression of Arabidopsis NHR genes in the susceptible soybean cultivar Williams 82 significantly repressed fungal proliferation as well as symptom development when compared to non-transgenic controls. Future studies will confirm the transgenic lines’ potential for application in the field. Currently, we are investigating the candidate genes’ mode of action in plant defense.