As shown in the previous report (Tian et al., 2001), we have identified
seven 57H mutants genes, esp2 and Glup1 to glup6.
However, the detail genetic behavior of Glup5 remained to be described.
In this report, we describe the inheritance mode of Glup5 mutant
character and the genetic relationship between Glup5 gene and other
5 genes involving in 57H mutation.
The three independent Glup5 mutants, EM675, EM 677 and PMT 19,
were so far isolated by the screening of mutant lines derived from the
mutation treatment of fertilized egg cells of a rice cultivar Taichung65
(TC65) with MNU. SDS-PAGE and western blot analyses of seed storage proteins
in three kinds of 57H mutants showed that Glup5 mutations increased
significantly the amount of glutelin precursor protein with M.M 60kD and
decreased the accumulation of both of 40kD acidic and 20kD basic mature
glutelins (Fig. 1). In addition, Glup5 mutations decreased markedly
the accumulation level of 26kD globulin and 13kD prolamin. All of Glup5
mutations exhibited the opaque phenotype in grain in which the central
potion was transparent as same as the normal grain while the outer potion
was translucent and floury. F1 seeds derived from crosses between
the wild type cultivar TC65 as a female parent and a Glup5 mutant
EM675 as a male parent was normal in the SDS-PAGE profile of seed storage
protein as well as in grain appearance. However, F1 seeds from
crosses between Glup5 mutants as a female parent and TC65 as a
male parent showed 57H in the seed storage proteins and opaque in the
grain phenotype. In F2 seeds derived from the self-pollinated
F1 plants, the segregation
modes of normal and 57H phenotyps fitted well to the expected ratio
of co-dominance inheritance, 1:1 (Table 1). In addition, the complete
linkage relationship was observed between 57H character in seed storage
proteins and opaque phenotype in grain, suggesting that Glup5 gene
result in not only the abnormal accumulation of proglutelin but also the
anomalous grain filling.
Recombinants showing the normal phenotype segregated in all of F2s
derived from crosses between Glup5 mutant lines and each of marker
lines for 5 kinds of 57H mutant genes (Table 1), indicating that Glup5
gene is independent from other six 57H mutant genes. F2 seeds
from the cross of Glup5 with esp2 segregated into a ratio
of 3 (Glup5 type): 2 (esp2 type): 3 (normal) without double
mutant type, suggesting that esp2 gene is epistatic to Glup5
gene. Double mutant types having extremely high amount of proglutelin
were detected in F2 seeds derived from crosses between Glup5
and glup4, indicating that they have the additive effect on the
proglutelin accumulation each other. Double mutant types were not observed
in opaque F2
seeds from cross combinations of Glup5 with Glup1, glup2
and glup3 while opaque and normal seeds segregated into the expected
ratio of 1:1, suggesting that Glup5 are epistatic to these three
Preliminary trisomic analysis showed that trisomic segregation for Glup5
was found in F2 derived from a cross combination of EM675 with
Triplo 12 while disomic segregation was observed in F2s of
crosses between EM675 and other eight trisomic lines (Data not shown).
This results suggest that glup5 gene locates on chromosome 12.
The details including F3 analysis and RFLP mapping are under
This work was supported by the Ministry of Education, Science and Culture
of Japan (Grant no. 12138506) and BRAIN.
Tian, H.D., T. Kumamaru, Y. Takemoto, M. Ogawa and H. Satoh, 2001. Gene
analysis of a new 57H mutant gene, glup6, in rice. RGN 18: