Sanetomo Rena, Gebhardt Christiane
Obihiro University of Agriculture and Veterinary Medicine, Potato Germplasm Enhancement Laboratory, West 2-11, Inada, Obihiro, Hokkaido, 080-8555, Japan.
Max-Planck Institute for Plant Breeding Research, Department of Plant Breeding and Genetics, Carl von Linné Weg 10, 50829, Cologne, Germany.
BMC Plant Biol. 2015 Jun 26;15:162. doi: 10.1186/s12870-015-0545-y.
Various wild species germplasm has been used in European potato breeding since the first introduction of potato (Solanum tuberosum L.) to Europe. As the plant cytoplasmic genome including chloroplast and mitochondrial genomes is transmitted only through the maternal parent, cytoplasmic markers are useful tools in breeding programs to determine cytoplasmic genome types and to trace maternal ancestors. The potato cytoplasmic genome can be distinguished into six distinct types (M, P, A, W, T, and D). Male sterility was found in genotypes with S. demissum-derived D-type cytoplasm and S. stoloniferum-derived W/γ-type cytoplasm. These wild species were frequently used to incorporate superior pathogen resistance genes. As a result, the percentage of these two types is increasing unintentionally in the European germplasm pool. Other than cytoplasmic male sterility, little is known about effects of the cytoplasmic genome on complex agronomic traits in potato.
The cytoplasm types of 1,217 European potato cultivars and breeding clones were determined with type specific DNA markers. Most frequent were T- (59.4 %), D- (27.4 %), and W- (12.2 %) type cytoplasm, while A- (0.7 %) and M-type cytoplasm (0.3 %) was rare and P-type cytoplasm was absent. When comparing varieties with breeding clones, the former showed a relatively higher frequency of T-type and lower frequency of D- and W-type cytoplasm. Correlation analysis of cytoplasm types and agronomic data showed that W/γ-type cytoplasm was correlated with increased tuber starch content and later plant maturity. Correlation with quantitative resistance to late blight was observed for D-type and M-type cytoplasm. Both cytoplasm types had a positive effect on resistance.
This study revealed and quantified the cytoplasmic diversity in the European potato germplasm pool. Knowledge of cytoplasm type is important for maintaining genetic diversity and managing the male sterility problem in breeding programs. This is the first comprehensive study to show correlations of distinct cytoplasmic genomes with complex agronomic traits in potato. Correlations particularly with tuber starch content and resistance to late blight provided new knowledge on cytoplasmic effects on these important traits, which can be exploited for genetic improvement of potato.
自马铃薯（Solanum tuberosum L.）首次引入欧洲以来，各种野生种质已被用于欧洲马铃薯育种。由于包括叶绿体和线粒体基因组在内的植物细胞质基因组仅通过母本传递，细胞质标记是育种计划中确定细胞质基因组类型和追溯母本祖先的有用工具。马铃薯细胞质基因组可分为六种不同类型（M、P、A、W、T和D）。在具有源自S. demissum的D型细胞质和源自S. stoloniferum的W/γ型细胞质的基因型中发现了雄性不育。这些野生种经常被用于导入优良的抗病基因。结果，这两种类型在欧洲种质库中的比例无意中正在增加。除了细胞质雄性不育外，关于细胞质基因组对马铃薯复杂农艺性状的影响知之甚少。
利用类型特异性DNA标记确定了1217个欧洲马铃薯品种和育种无性系的细胞质类型。最常见的是T型（59.4%）、D型（27.4%）和W型（12.2%）细胞质，而A 型（0.7%）和M型细胞质（0.3%）很少见，P型细胞质不存在。与育种无性系相比，品种中T型细胞质的频率相对较高，D型和W型细胞质的频率较低。细胞质类型与农艺数据的相关性分析表明，W/γ型细胞质与块茎淀粉含量增加和植株成熟较晚相关。观察到D型和M型细胞质与晚疫病的定量抗性相关。这两种细胞质类型对抗性都有积极影响。
本研究揭示并量化了欧洲马铃薯种质库中的细胞质多样性。细胞质类型的知识对于维持遗传多样性和解决育种计划中的雄性不育问题很重要。这是第一项全面研究，表明不同细胞质基因组与马铃薯复杂农艺性状之间的相关性。特别是与块茎淀粉含量和晚疫病抗性的相关性，为细胞质对这些重要性状的影响提供了新知识，可用于马铃薯的遗传改良。
