The maize disease resistance geneHtn1against northern corn leaf blight encodes a wall-associated receptor-like kinase

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 112; no. 28; pp. 8780 - 8785
• Main Authors: Hurni, Severine, Scheuermann, Daniela, Krattinger, Simon G., Kessel, Bettina, Wicker, Thomas, Herren, Gerhard, Fitze, Mirjam N., Breen, James, Presterl, Thomas, Ouzunova, Milena, Keller, Beat
• Format: Journal Article
• Language: English
• Published: National Academy of Sciences 14-07-2015
• ISSN: 0027-8424; 1091-6490

Northern corn leaf blight (NCLB) caused by the hemibiotrophic fungusExserohilum turcicumis an important foliar disease of maize that is mainly controlled by growing resistant maize cultivars. TheHtn1locus confers quantitative and partial NCLB resistance by delaying the onset of lesion formation.Htn1represents an important source of genetic resistance that was originally introduced from a Mexican landrace into modern maize breeding lines in the 1970s. Using a high-resolution map-based cloning approach, we delimitedHtn1to a 131.7-kb physical interval on chromosome 8 that contained three candidate genes encoding two wall-associated receptor-like kinases (ZmWAK-RLK1andZmWAK-RLK2) and one wall-associated receptor-like protein (ZmWAK-RLP1). TILLING (targeting induced local lesions in genomes) mutants inZmWAK-RLK1were more susceptible to NCLB than wild-type plants, both in greenhouse experiments and in the field.ZmWAK-RLK1contains a nonarginine-aspartate (non-RD) kinase domain, typically found in plant innate immune receptors. Sequence comparison showed that the extracellular domain of ZmWAK-RLK1 is highly diverse between different maize genotypes. Furthermore, an alternative splice variant resulting in a truncated protein was present at higher frequency in the susceptible parents of the mapping populations compared with in the resistant parents. Hence, the quantitativeHtn1disease resistance in maize is encoded by an unusual innate immune receptor with an extracellular wall-associated kinase domain. These results further highlight the importance of this protein family in resistance to adapted pathogens.