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Quem ... Auctoritate & Consensu Illustris ICtorum Ordinis In ... Salana, Praeside Johanne Andrea Gerhard ... Publicae Eruditorum Censurae exponit Johannes Georgius a Kessel, Eques Silesius. Ad d. M. Augusti Anno M.DC.LXIV. ...Druckvariante mit Widmung auf der Rückseite des Titelbl., nicht identisch mit VD17 14:074793

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

Northern corn leaf blight (NCLB) caused by the hemibiotrophic fungus Exserohilum turcicum is an important foliar disease of maize that is mainly controlled by growing resistant maize cultivars. The Htn1 locus confers quantitative and partial NCLB resistance by delaying the onset of lesion formation. Htn1 represents 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 delimited Htn1 to a 131.7-kb physical interval on chromosome 8 that contained three candidate genes encoding two wall-associated receptor-like kinases (ZmWAK-RLK1 and ZmWAK-RLK2) and one wall-associated receptor-like protein (ZmWAK-RLP1). TILLING (targeting induced local lesions in genomes) mutants in ZmWAK-RLK1 were more susceptible to NCLB than wild-type plants, both in greenhouse experiments and in the field. ZmWAK-RLK1 contains 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 quantitative Htn1 disease 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

Alleles of a wall‐associated kinase gene account for three of the major northern corn leaf blight resistance loci in maize

Northern corn leaf blight, caused by the fungal pathogen Setosphaeria turcica (anamorph Exserohilum turcicum), is one of the most devastating foliar diseases of maize (Zea mays). Four genes Ht1, Ht2, Ht3 and Htn1 represent the major sources of genetic resistance against the hemibiotrophic fungus S. turcica. Differential maize lines containing these genes also form the basis to classify S. turcica races. Here, we show that Ht2 and Ht3 are identical and allelic to the previously cloned Htn1 gene. Using a map-based cloning approach and Targeting Induced Local Lesions in Genomes (TILLING), we demonstrate that Ht2/Ht3 is an allele of the wall-associated receptor-like kinase gene ZmWAK-RLK1. The ZmWAK-RLK1 variants encoded by Htn1 and Ht2/Ht3 differ by multiple amino acid polymorphisms that particularly affect the putative extracellular domain. A diversity analysis in maize revealed the presence of dozens of ZmWAK-RLK1 alleles. Ht2, Ht3 and Htn1 have been described over decades as independent resistance loci with different race spectra and resistance responses. Our work demonstrates that these three genes are allelic, which has major implications for northern corn leaf blight resistance breeding and nomenclature of S. turcica pathotypes. We hypothesize that genetic background effects have confounded the classical description of these disease resistance genes in the past