Graduated student University of Tsukuba Tsukuba, Ibaraki, Japan
Body of Abstract:
Tetraploid potato is an important crop cultivated worldwide. Potatoes thrive on nutritional reproduction, so once a disease or pest spreads, it tends to cause damage on a large scale. There is also concern that increased disease, pests, and environmental stress due to climate change, such as global warming, could lead to a decline in potato production. To solve these problems, it is necessary to rapidly develop cultivars with traits that are resistant to disease and environmental stress, but many potato cultivars have cytoplasmic male sterility (CMS), which is caused by a CMS associated gene localized on the mitochondrial genome. CMS is a major impediment to crossbreeding.
Potatoes CMS are classified into 3types (α, β, and γ) according to the polymorphism of genes on the mitochondria. α-CMS causes abnormal pollen tube elongation, which is also observed in tomato CMS, for which the orf137 triggers male sterility (Kuwabara et al.2022). Since CMS tomato carries mitochondrial genome derived from the α-type potato, the orf137 is most likely the causal gene of α-CMS. β-CMS was reported to produce less pollen and abnormal anther development. As β-CMS potato had orf137, another gene responsible for pollen reduction and abnormal anther development might be present. We compared the mitochondrial genomes of α-type, β-type and tomato CMS, and obtained the candidate gene named orf320.
We fused the orf320 with a mitochondrial transition signal and introduced it into the nucleus of the tomato using agrobacterium-method, and the resulting transgenic plants showed underdeveloped anthers and not pollen germination, characteristic of β-CMS.