Journal of Plant Research

, Volume 122, Issue 2, pp 215–222 | Cite as

Identification of r mutations conferring white flowers in the Japanese morning glory (Ipomoea nil)

  • Atsushi Hoshino
  • Kyeung-Il Park
  • Shigeru Iida
Regular Paper


The wild-type Japanese morning glory [Ipomoea nil (L.) Roth.] exhibits blue flowers with red stems, and spontaneous r mutants display white flowers with green stems. We have identified two r mutations, r1-1 and r1-2, that are caused by insertions of Tpn1-related DNA transposable elements, Tpn3 (5.6 kb) and Tpn6 (4.7 kb), respectively, into a unique intron of the CHS-D gene, which is responsible for flower and stem pigmentation. Both Tpn3 and Tpn6, which belong to the En/Spm or CACTA superfamily, are nonautonomous elements lacking transposase genes but containing unrelated cellular DNA segments including exons and introns. Interestingly, r1-2 contains an additional 4-bp insertion at the Tpn3 integration site in r1-1, presumably a footprint caused by the excision of Tpn3. The results strengthen the previous notion that Tpn1 and its relatives are major spontaneous mutagens for generating various floriculturally important traits in I. nil. Since I. nil has an extensive history of genetic studies, molecular identification of classical spontaneous mutations would also facilitate reinterpretation of the abundant classical genetic data available.


Anthocyanin biosynthesis Chalcone synthase gene Flower pigmentation Ipomoea nil Spontaneous mutants 



We thank Miwako Matsumoto and Kyoko Ikegaya for technical assistance, Yoshiki Habu, Yasuyo Johzuka-Hisatomi and Yasumasa Morita for valuable discussion, and Norio Saito and Eiji Nitasaka for providing r1 mutants and discussion. This work was supported by grants from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.


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Copyright information

© The Botanical Society of Japan and Springer 2008

Authors and Affiliations

  1. 1.National Institute for Basic BiologyOkazakiJapan

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