L.Q. qu1, T. kumamaru1, H. satoh1 and M. ogawa2
2) Home Economy,Yamaguchi Prefecture University, Sakurahatake. Yamaguchi, 753 Japan
Three a -2 subunit less mutant lines used in this study were characterized as follows: EM 278 combining with increased a -1 subunit (a -1 H/a -2 L), CM 1707 with increased a -1 and a -3 subunits (a -l,3H/a -2 L) and EM 659 with increased a -3 subunit (a -3H/a -2 L) (Fig. 1). Extracted glutelins of mutant lines were electrophoresed using the discontinuous buffer system of Laemmli (1970) on a slab gel containing a linear of 15% to 25% acrylamide/0.05% to 0.67% BIS concentration gradient.
The mutant lines were crossed reciprocally with their original cultivar, Kinmaze. The SDS-PAGE band patterns of glutelin subunits in F1 seeds showed intermediate types between mutants and Kinmaze in all of the cross combinations with slight differences between reciprocal cross combinations, indicating that the genes have dosage effects. The phenotypes of F2 seeds from the crosses were classified into 4 types — normal (P1P1P1), semi-normal (P1P1P2), semi-mutant (P1 P2P2) and mutant (P2P2P2) types. The segregation mode of the F2 seeds of the crosses between Kinmaze and mutants are shown in Table 1. Since the segregation of the four types fitted the expected ratio of 1:1:1:1, the three mutant characters could be considered to be controlled by a single incompletely
Research Notes 79
l:Kinmaze 2: CM 1707 3:EM278 4:EM659
Segregation in F2 | |||||
Cross combination | P1P1P1 | P1P1P2 | P1P2P2 | P2P2P2 | c 2(1:1:1:1) |
Kinmaze X EM278 | 24 | 23 | 28 | 25 | 0.56 |
Kinniaze X CM1707 | 21 | 26 | 26 | 26 | 0.92 |
Kinmaze X EM659 | 24 | 23 | 26 | 27 | 0.40 |
dominant gene respectively.
The mutant lines were crossed with each other. The phenotypes of the F1 seeds in the cross combinations between EM 278 and CM 1707, CM 1707 and EM 659 showed intermediate types and that of F2 seeds could also be classified into 4 types—mutant I(P1P1P1), semi-mutant I (P1P1P2), semi-mutant II (P1P2P2) and mutant II (P2P2P2) types. The segregation mode of F2 seeds among mutant lines are shown in Table 2. The segregation also fitted the 1:1:1:1 ratio. In the cross combination between EM 278 and
80 Rice Genetics Newsletter Vol. 14
Table 2. Segregation of glutelin types in F2 from the crosses between mutants
|
|||||||
Cross combination | P1P1P1 | P1P1P2 | P1P2P2 | P2P2P2 | c 2(1:1:1:1 or 1:2:1) | ||
EM278 x CM1707 | 26 | 23 | 26 | 25 | 0.24 | ||
CM1707 x EM659 | 24 | 25 | 22 | 23 | 0.22 | ||
EM278 x EM659 | 26 | 48 | 26 | 0.16 |
* m: recessive marker genes,
A series of trisomics with extra chromosome from No.4 to No. 12 and marker gene lines concerning of chromosomes 1, 2 and 3 were crossed with EM659 (Glu4-c) to determine the chromosome on which the genes are located. Glu4-c gene was found to be linked with spl6 and eg genes located on chromosome 1 through F2 and F3 analyses. The cross-over values between Glu-4c and both marker genes, spl6 and eg, were estimated to be 17.2% and 24.2%, respectively (Table 3). Since the cross-over value between spl6 and eg genes was 7% (Kinoshita 1995), the order of the genes must be eg—spl6—glu4-c on
Research Notes 81
chromosome 1 (Fig. 2).
Iida et al. (1994) reported a glu3 gene located on chromosome 1. Similarly another Glu1 (t) gene which was found in local rice cultivars was also reported to be located on chromosome 1 (Uemura et al. 1995). Deduced from the chromosomal locations of the two genes and our result, it seems that the three genes e.g. Glul (t), glu3 (t) and Glu4 (t) are either allelic or these genes are closely linked to each other.
Iida, S., M. Kusaba and T. Nishio. 1994. RFLP mapping of mutated genes lacking a glutelin
subunit of rice glutelin. Breed. Sci. 44 (Suppl. 2): 193.
Kinoshita, T., 1995. Report of committee on gene symbolization, nomenclature and linkage
groups III. Current linkage maps. RGN 12: 94-96.
Laemmli, U.K., 1970. Cleavage of structural protein during the assembly of the head of
bacteriophage T4. Nature 227:680-685.
Satoh, H., L.Q. Qu. T. Kumamaru and M. Ogawa. 1997. Glutelin mutants induced by MNU
treatment in rice. RGN 14: 81-84.
Uemeru, Y.J., H. Satoh. M. Ogawa, H. Suehisa.T.I. Katayama and A.Yoshimura, 1995.
172-177.