Data_Sheet_1_Mapping a Novel Black Spot Resistance Locus in the Climbing Rose Brite Eyes™ (‘RADbrite’).pdf

Rose black spot, caused by Diplocarpon rosae, is one of the most devastating foliar diseases of cultivated roses (Rosa spp.). The globally distributed pathogen has the potential to cause large economic losses in the outdoor cultivation of roses. Fungicides are the primary method to manage the disease, but are often viewed unfavorably by home gardeners due to potential environmental and health impacts. As such, rose cultivars with genetic resistance to black spot are highly desired. The tetraploid climbing rose Brite EyesTM (‘RADbrite’) is known for its resistance to black spot. To better characterize the resistance present in Brite EyesTM, phenotyping was conducted on a 94 individual F1 population developed by crossing Brite EyesTM to the susceptible tetraploid rose ‘Morden Blush’. Brite EyesTM was resistant to all D. rosae races evaluated except for race 12. The progeny were either resistant or susceptible to all races (2, 3, 8, 9, 10, 11, and 13) evaluated. The segregation ratio was 1:1 (χ2 = 0.3830, P = 0.5360) suggesting resistance is conferred by a single locus. The roses were genotyped with the WagRhSNP 68K Axiom array and the ‘polymapR’ package was used to construct a map. A single resistance locus (Rdr4) was identified on the long arm of chromosome 5 homoeolog 4. Three resistance loci have been previously identified (Rdr1, Rdr2, and Rdr3). Both Rdr1 and Rdr2 are located on a chromosome 1 homoeolog. The chromosomal location of Rdr3 is unknown, however, races 3 and 9 are virulent on Rdr3. Rdr4 is either a novel gene or an allele of Rdr3 as it provides resistance to races 3 and 9. Due to its broad resistance, Rdr4 is an excellent gene to introgress into new rose cultivars.

由蔷薇双壳菌（Diplocarpon rosae）引起的月季黑斑病（Rose black spot），是栽培月季（蔷薇属Rosa spp.）最具破坏性的叶部病害之一。该病原菌在全球范围内广泛分布，可在月季露地栽培中造成巨额经济损失。杀菌剂是防治该病害的主要手段，但由于潜在的环境与健康风险，常不被家庭园艺爱好者青睐，因此培育对黑斑病具有遗传抗性的月季品种需求迫切。四倍体藤本月季Brite Eyes™（‘RADbrite’）以其对黑斑病的优异抗性而闻名。为更好地表征Brite Eyes™的抗性特性，研究人员针对将Brite Eyes™与感病四倍体月季‘摩登腮红’（‘Morden Blush’）杂交获得的94株F1群体进行了表型鉴定。Brite Eyes™对除12号生理小种外的所有供试蔷薇双壳菌生理小种均表现出抗性；供试后代对所有评估的生理小种（2、3、8、9、10、11和13号）要么表现为抗性，要么表现为感病，其分离比为1:1（χ²=0.3830，P=0.5360），表明该抗性由单个基因座控制。研究人员使用WagRhSNP 68K Axiom基因芯片（WagRhSNP 68K Axiom array）对该月季群体进行了基因分型，并借助‘polymapR’软件包构建了遗传连锁图谱，最终在5号染色体部分同源组4的长臂上鉴定到一个抗性基因座Rdr4。此前已有3个抗性基因座被报道：Rdr1、Rdr2和Rdr3，其中Rdr1与Rdr2均位于1号染色体同源组上。Rdr3的染色体定位尚不明确，但已知3号和9号生理小种可克服Rdr3的抗性。Rdr4要么是一个全新的抗病基因，要么是Rdr3的等位基因（allele），因其可对3号和9号生理小种产生抗性。鉴于其广谱的抗病性，Rdr4是一个极为优异的可用于导入新型月季品种的抗病基因。