Tomita Ken-Ichi, Fujita Ryohei
Hokkaido Research Organization Kitami Agricultural Experiment Station, Yayoi 52, Kunneppu, Tokoro-gun, Hokkaido 099-1496, Japan.
Breed Sci. 2018 Dec;68(5):629-638. doi: 10.1270/jsbbs.18031. Epub 2018 Dec 6.
To induce potato variants with enhanced resistance to common scab disease that retain the desirable agronomic traits of the original cultivars, we used a cell culture technique that employs thaxtomin A, the primary phytotoxin that induces scab symptoms. We induced 24 variants from the potato cultivar 'Saya-akane', developed in Japan, and selected two with enhanced resistance to the disease by growing them in planters with bacteriainoculated soil and in a field infested with the disease. We also examined toxin tolerance in micro-tubers of variants that showed a lower degree or percentage of infection in the glasshouse screening, and found no significant difference relative to the original cultivar. To clarify the effect of using thaxtomin A, we examined the efficiency of induction of the potential enhanced resistance by comparing the degree of infection among variants grown in planters with inoculated soil. We observed no significant difference between variants induced on culture medium with and without the toxin. These results suggest that the effect of using the toxin as a positive selection agent is restrictive and that most resistance-enhancing mutations are induced by the cell culture procedure itself.
为诱导出对疮痂病具有增强抗性且保留原始品种优良农艺性状的马铃薯变异体，我们采用了一种细胞培养技术，该技术使用了诱导疮痂症状的主要植物毒素——thaxtomin A。我们从日本培育的马铃薯品种“Saya-akane”中诱导出24个变异体，并通过在接种细菌的土壤种植钵中种植以及在病害侵染的田间种植，筛选出两个对该病具有增强抗性的变异体。我们还检测了在温室筛选中感染程度较低或感染率较低的变异体微型薯块的毒素耐受性，发现与原始品种相比没有显著差异。为阐明使用thaxtomin A的效果，我们通过比较在接种土壤的种植钵中生长的变异体之间的感染程度，检测了潜在增强抗性的诱导效率。我们观察到在添加毒素和不添加毒素的培养基上诱导出的变异体之间没有显著差异。这些结果表明，将毒素用作正向选择剂的效果有限，且大多数抗性增强突变是由细胞培养过程本身诱导产生的。
