Saito Hiroki, Yuan Qingbo, Okumoto Yutaka, Doi Kazuyuki, Yoshimura Atsushi, Inoue Hiromo, Teraishi Masayoshi, Tsukiyama Takuji, Tanisaka Takatoshi
Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Theor Appl Genet. 2009 Jul;119(2):315-23. doi: 10.1007/s00122-009-1040-3. Epub 2009 Apr 29.
A recently established rice breeding program in low latitudes aims to develop varieties with extremely long basic vegetative growth (BVG) periods and weak photoperiod sensitivities. The Taiwanese japonica variety Taichung 65 (T65) harbors a recessive allele ef1 at the Ef1 (Early flowering 1) locus, thereby exhibiting an extremely long BVG period. The previous reported functional allele Ehd1 (Early heading date 1), located on chromosome 10, encodes a B-type response regulator, thereby shortening the BVG period, whereas its nonfunctional allele ehd1 greatly prolongs the BVG period. A conventional analysis using F(2) and F(3) populations and a subsequent CAPS analysis based on the amino acid sequences of Ehd1 and ehd1 showed that Ef1 and Ehd1 were at the same locus. The CAPS analysis also indicated that the Taiwanese japonica varieties with extremely long BVG periods all harbor ef1, but that ef1 does not exist among indica and japonica varieties in the low latitudes. Since ef1 has not been found in any japonica varieties outside Taiwan, this allele might have originated in Taiwan. Sequence analysis revealed that the mutant allele ef1-h, which prolongs the BVG period even more than ef1 does, harbors an mPing insertion in exon 2, which causes the complete loss of gene function. Our results indicate that both ef1 or ef1-h alleles can be used as new gene sources in developing rice varieties with extremely long BVG periods for low latitudes.
最近在低纬度地区建立的一个水稻育种项目旨在培育具有极长基本营长期（BVG）和弱光周期敏感性的品种。台湾粳稻品种台中65（T65）在Ef1（早花1）位点携带一个隐性等位基因ef1，因此表现出极长的BVG期。先前报道的位于第10号染色体上的功能等位基因Ehd1（早抽穗期1）编码一种B型响应调节因子，从而缩短BVG期，而其无功能等位基因ehd1则大大延长BVG期。使用F(2)和F(3)群体进行的常规分析以及随后基于Ehd1和ehd1氨基酸序列的CAPS分析表明，Ef1和Ehd1位于同一位点。CAPS分析还表明，具有极长BVG期的台湾粳稻品种都携带ef1，但低纬度地区的籼稻和粳稻品种中不存在ef1。由于在台湾以外的任何粳稻品种中都未发现ef1，这个等位基因可能起源于台湾。序列分析显示，突变等位基因ef1-h比ef1更能延长BVG期，它在外显子2中存在一个mPing插入，导致基因功能完全丧失。我们的结果表明，ef1或ef1-h等位基因都可作为新的基因源，用于培育低纬度地区具有极长BVG期的水稻品种。
