New Sources of Eastern Filbert Blight Resistance and Simple Sequence Repeat Markers on Linkage Group 6 in Hazelnut (Corylus avellana L.)

Abstract

Commercial production of hazelnut (Corylus avellana) in Oregon’s Willamette Valley is threatened by eastern filbert blight (EFB), a serious canker disease caused by the pyrenomycete Anisogramma anomala (Peck) E. Müller. The fungus also prevents the establishment of hazelnut orchards in eastern North America. Genetic resistance is considered the most effective way to control the disease. A high level of EFB resistance was first discovered in ’Gasaway’. This resistance is conferred by a dominant allele at a single locus on linkage group 6 (LG6). Resistance from several additional sources has been assigned to the same chromosomal region. In this study, new simple sequence repeat (SSR) markers were developed for the resistance region on LG6 and new sources of resistance were investigated. Forty-two new SSR markers were developed from four contigs in the genome sequence of ‘Jefferson’ hazelnut, characterized, and nine of them were placed on LG6 of the genetic map. Accessions representing 12 new sources of EFB resistance were crossed with susceptible selections resulting in 18 seedling populations. Segregation ratios in the seedling populations fit the expected 1:1 ratio for 10 sources, while one source showed an excess of resistant seedlings and another showed an excess of susceptible seedlings. Based on correlation of disease response and scores of SSR markers in the ‘Gasaway’ resistance region in the seedlings, eight resistance sources were assigned to LG6. Linkage maps were constructed for each progeny using SSR markers. The LG6 resistance sources include two selections (#23 and #26) from the Russian Research Institute of Forestry and Mechanization near Moscow, four selections from southern Russia, one selection (OSU 1185.126) from Crimea, one selection (OSU 533.129) from Michigan, Corylus heterophylla ‘Ogyoo’ from the South Korea, and the interspecific hybrid ’Estrella #1’. These new LG6 resistance sources and SSR markers should be useful in breeding new cultivars, including the pyramiding of resistance genes. For the other four resistance sources (Moscow #37, hybrid selection OSU 401.014, C. americana ‘Winkler’ and C. americana OSU 366.060), SSR marker scores on linkage groups 6, 7 and 2 were not correlated with disease response and merit further investigation.

A haplotype-resolved chromosome-level assembly and annotation of European hazelnut (C. avellana cv. Jefferson) provides insight into mechanisms of eastern filbert blight resistance

“…Since then, this linkage map has been improved by additional SSRs and data from a bacterial artificial chromosome (BAC) library ( Sathuvalli et al 2017 ; Mehlenbacher and Bhattarai 2018 ). To assign the linkage groups to pseudo-chromosomal scaffolds, 18 RAPD, 874 microsatellite, 4,100 paired BAC-ends with proper insert size, and 15,000 biallelic SNP marker sequence fragments were aligned to both Jefferson haplotypes using minimap2 ( Li 2018 ), and compared to previous linkage mapping designations ( Komaei Koma 2020 ). Both haplotypes were successfully assigned the same linkage group for each corresponding pseudo-chromosomal scaffold and renamed appropriately.…”

“…Fine mapping of the “Gasaway” region using bacterial artificial chromosomes (BACs) identified a span of approximately 135 kb and five candidate EFB resistance genes ( Sathuvalli et al 2017 ). Other sources of EFB resistance have been identified and mapped in over 30 C. avellana cultivars and accessions, and while the majority map to LG6 ( Sathuvalli et al 2012 ; Colburn et al 2015 ; Komaei Koma 2020 ), other sources of qualitative and quantitative resistance have been mapped to LG2 ( Sathuvalli, Mehlenbacher, et al 2011 ; Şekerli et al 2021 ), LG7 ( Sathuvalli et al 2011 ; Bhattarai et al 2017 ; Şekerli et al 2021 ), LG10 and LG11 ( Lombardoni et al 2022 ), and more recently LG4 and LG1 (Mehlenbacher personal communication). A complete summary of resistant cultivars and their related linkage groups can be found in Table 1 of Mehlenbacher et al (2023) .…”

The first two chromosome‐scale genome assemblies of American hazelnut enable comparative genomic analysis of the genus Corylus

“…This gene (CamerWinkler.08G009300) is, therefore, a promising target for future functional characterization. Quantitative genetic analyses have revealed numerous loci in C. americana that are associated with EFB resistance (Komaei Koma et al ., 2021 ; Lombardoni et al ., 2022 ; Revord et al ., 2020 ), and the gene reported here could be productively included in any future studies aimed at using expression analysis or forward genetic approaches to validating their role in plant defence pathways.…”

Yield and nut characteristics of hazelnut genotypes grown in San Joaquin Valley, California

“…The disease was reported several decades ago (Barss, 1930; Cameron, 1976). Intense research delivered resistant cultivars, and the search for resistant genotypes continues (Bhattarai et al., 2017; Capik et al., 2013; Coyne et al, 1998; Komaei Koma et al., 2021; Mehlenbacher et al., 1991; Molnar et al., 2007; Muehlbauer et al., 2014).…”