The maize disease resistance gene Htn1 against northern corn leaf blight encodes a wall-associated receptor-like kinase

Abstract

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.wall-associated receptor-like kinase | quantitative disease resistance | pattern recognition receptor | Exserohilum turcicum | maize

The hijacking of a receptor kinase–driven pathway by a wheat fungal pathogen leads to disease

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Genome Analysis Identified Novel Candidate Genes for Ascochyta Blight Resistance in Chickpea Using Whole Genome Re-sequencing Data

“…Two recent studies in maize showed that WAK played an important role in response to head smut soil-borne disease caused by fungus Sporisorium reilianum (Zuo et al, 2015) and northern corn leaf blight caused by fungus Exserohilum turcicum (Hurni et al, 2015). One WAK gene was detected in the AB4.1 region under selection for AB resistance.…”

Genome-Wide Association of Stem Water Soluble Carbohydrates in Bread Wheat

“…In addition, the WAK gene plays critical roles in cell expansion, pathogen resistance, and heavy-metal stress tolerance in Arabidopsis [51]. Hurni et al [52] isolated northern corn leaf blight resistance gene Htn1 that encodes WAK in maize. These candidate genes provide a basis for dissecting the genetic mechanism of WSC and will be useful in further investigations of the various functions of WSC in wheat.…”