Chromosomal location of the OsNAC genes

The genes encoding the NAC domain, such as CUC2 and NAP in Arabidopsis and NAM in petunia, play essential roles in plant development, that is, the formation of shoot apical meristem, organ separation, and flower morphogenesis. To elucidate the function in rice as a model plant in monocot, we have cloned and characterized the OsNAC genes, the-genes encoding the NAC domain in rice (Kikuchi et al. 1997). The OsNAC genes constituted a large gene family in the rice genome. The sequence comparison and Southern blot analysis showed the OsNAC genes are divided into several subfamilies. In this article, we report the chromosomal location of the OsNAC genes.

The 71 recombinant inbred lines of rice (Tsunematsu et a!. 1996), which have the chimera chromosomes derived from Asominori (Japonica) and 1R24 (Indica), were used for mapping. The polymorphism in chromosomes from both lines was detected by SSLP (simple sequence length polymorphism) or CAPS (cleaved amplified polymorphic sequence) method. The positions of OsNAC genes on rice chromosome were examined by using 375 RFLP markers and a program, Mapmaker (Lander eta!. 1987).

The chromosomal locations of four OsNAC genes were determined (Fig. 1). The OsNAC genes were distributed on three chromosomes. OsNAC3 and OsNAC5 were located on chromosome 7 and 11, respectively. On the other hand, OsNAC4 and OsNAC6 were located on chromosome 1, but the two genes were separated by about 23 cM.

40. Chromosomal location of the OsNAC genes K. KIKUCHI, K.T. YOSHIDA, Y. NAGATO and H.Y. Hirano Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, 113-8657 Japan The genes encoding the NAC domain, such as CUC2 and NAP in Arabidopsis and NAM in petunia, play essential roles in plant development, that is, the formation of shoot apical meristem, organ separation, and flower morphogenesis. To elucidate the function in rice as a model plant in monocot, we have cloned and characterized the OsNAC genes, the-genes encoding the NAC domain in rice (Kikuchi et al. 1997). The OsNAC genes constituted a large gene family in the rice genome. The sequence comparison and Southern blot analysis showed the OsNAC genes are divided into several subfamilies. In this article, we report the chromosomal location of the OsNAC genes. The 71 recombinant inbred lines of rice (Tsunematsu et a!. 1996), which have the chimera chromosomes derived from Asominori (Japonica) and 1R24 (Indica), were used for mapping. The polymorphism in chromosomes from both lines was detected by SSLP (simple sequence length polymorphism) or CAPS (cleaved amplified polymorphic sequence) method. The positions of OsNAC genes on rice chromosome were examined by using 375 RFLP markers and a program, Mapmaker (Lander eta!. 1987). The chromosomal locations of four OsNAC genes were determined (Fig. 1). The OsNAC genes were distributed on three chromosomes. OsNAC3 and OsNAC5 were located on chromosome 7 and 11, respectively. On the other hand, OsNAC4 and OsNAC6 were located on chromosome 1, but the two genes were separated by about 23 cM. Thus, the four OsNAC genes were not clustered in a specific chromosome such as homeobox genes in animals. These results suggest that many of the OsNAC genes other than the four genes analyzed here are dispersed throughout rice chromosomes. We have detected about 20 genes encoding the NAC domain in rice EST. The analysis of the function of the OsNAC genes and their distribution on chromosomes is underway. References Kikuchi, K., K.T. Yoshida, M. Uekuchi-Tanaka, M. Matsuoka, Y. Nagato and H.Y. Hirano, 1997. Molecular characterization of the OsNAC genes. Rice Genet. Newslett 14: 125-126. Harushima, Y., M. Yano, A. Shomura, M. Sato, T. Shimano, Y. Kuboki, T. Yamamoto, S.Y. Lin, B.A. Antonioa, A. Parco, H. Kajiya, N. Huang, K. Yamamoto, Y. Nagamura, N. Kurata, G.S. Khush and T. Sasaki, 1998. A high-density rice genetic linkage map with 2275 markers using a single F2 population. Genetics 120: 479-494. Lander, E.S., P. Green, J. Abrahamson, A. Barlow, M.J. Daly, S.E. Lincoln and L. Newburg, 1987. MAPMAKER: an interactive computer package for primary linkage maps of experimental and natural populations. Genomics 1: 174-181. Tsunematsu, H., A. Yoshimura, Y. Harushima, Y. Nagamura, N. Kurata, M. Yano, T. Sasaki and N. Iwata, 1996. RFLP framework map using recombinant inbred lines in rice. Breed. Sci. 46: 279-284.

Thus, the four OsNAC genes were not clustered in a specific chromosome such as homeobox genes in animals. These results suggest that many of the OsNAC genes other than the four genes analyzed here are dispersed throughout rice chromosomes. We have detected about 20 genes encoding the NAC domain in rice EST. The analysis of the function of the OsNAC genes and their distribution on chromosomes is underway.

References

Kikuchi, K., K.T. Yoshida, M. Uekuchi-Tanaka, M. Matsuoka, Y. Nagato and H.Y. Hirano, 1997. Molecular characterization of the OsNAC genes. Rice Genet. Newslett 14: 125-126.

Harushima, Y., M. Yano, A. Shomura, M. Sato, T. Shimano, Y. Kuboki, T. Yamamoto, S.Y. Lin, B.A. Antonioa, A.

Parco, H. Kajiya, N. Huang, K. Yamamoto, Y. Nagamura, N. Kurata, G.S. Khush and T. Sasaki, 1998.

A high-density rice genetic linkage map with 2275 markers using a single F2 population. Genetics 120:

479-494.

Lander, E.S., P. Green, J. Abrahamson, A. Barlow, M.J. Daly, S.E. Lincoln and L. Newburg, 1987. MAPMAKER: an interactive computer package for primary linkage maps of experimental and natural populations. Genomics 1: 174-181.

Tsunematsu, H., A. Yoshimura, Y. Harushima, Y. Nagamura, N. Kurata, M. Yano, T. Sasaki and N. Iwata, 1996. RFLP framework map using recombinant inbred lines in rice. Breed. Sci. 46: 279-284.