46. Relationship between transposon and mutability
caused by hybrid dysgenesis in rice
Y. tsuchimine 1, Y. miyashita1,
R. isikawa1, M. senda2, S. akada2, T.
harada1 and M. niizeki1
1) Faculty of Agriculture. Hirosaki University, Hirosaki,
036 Japan
2) Gene Research Center, Hirosaki University, Hirosaki,
036 Japan
High instability was noted in the progeny of a cross between
Japonica strains and a particular Indica strain (Acc435) which originated
from Sri Lanka. We found maize Mutator-like transposon in rice (Rmu1
IR36). We tried to find a relationship between the hybrid dysgenesis and
the activity of rice RMu family in the hybrid progeny. We used five
reciprocal crosses consisting of ten F2 populations of crosses
between the Indica strain Acc435 and five Japonica strains. We observed
mutation rate at third leaf stage (Table 1). Chlorophyll mutants were easily
detected, which included striata (0.4%), albinos (0.2%) and virescents
(0.04%). In addition, 0.2% plants were aborted and some morphological mutants
were found, for examples, tall, twin shoot, and shootless.
Southern hybridization analysis was carried out using
ten related progenies originating from Acc435. Several kinds of RFLP patterns
were found (Fig. 1). As the Acc435 did not show any RT-PCR product of ORF
in Rmu1 with cDNA templates from mature leaves, this mutability
within the strain may be kept at lower level than usual state. The mutability
would be increased by genomic shock when crossed with Japonica strains
ir which abundant RT-PCR products of ORF in Rmu1 has been known
(Ishikawa, unpublished data).
Several kinds of hybrid dysgenesis have been known in
Drosophila such as P-M hybrid dysgenesis caused by re-activation
of transposable elements. And also in maize, high mutability was gained
when mutable strains carrying active Mutator were crossed
| Table 1. Mutation
rate in reciprocal crosses consisting F2 populations between
Indica Acc435 and five Japonica strains |
| Cross
combination |
Total plants |
No.of
aborted
Plants (~3rd
leaf) (%) |
Total
mutants
(%) |
No.of
mutants concerning to leaf |
| Striata(%) |
Albino(%) |
Virescent(%) |
| Acc435 X L119
L119 X Acc435
|
1061 1127 |
76 ( 7.2)
135 (12.0) |
21 (2.0) 14(1.2) |
6 (0.6)
0 (0.0) |
1 (0.1)
1 (0.1) |
0 (0.0)
0 (0.0) |
| Acc435 X Oou195
Oou195 X Acc435 |
638
664 |
2 ( 0.3)
102 (15.4) |
8 (1.3) 10(1.5) |
2 (0.3)
1 (0.2) |
2 (0.3)
6 (0.9) |
1 (0.2)
0 (0.0)
|
| Acc435 X Acc504
Acc504 X Acc435 |
704
698 |
237 (33.7) 116(16.6) |
26 (3.7) 12(1.7) |
1 (0.1)
2 (0.3) |
2 (0.3)
0 (0.0)
|
0 (0.0)
0 (0.0)
|
| Acc435 X T65(Hg)
T65(Hg) X Acc435 |
961 1055 |
80 ( 8.3)
10 ( 0.9) |
32 (3.3) 25 (2.4) |
7 (0.7)
8 (0.8) |
1 (0.1)
1 (0.1) |
1 (0.1)
1 (0.1)
|
| Acc435 X E18
E18 X Acc435 |
156
141 |
36 (23.1)
115 (81.6) |
2 (1.3)
(2.1) |
0 (0.0)
0 (0.0) |
0 (0.0)
1 (0.7) |
0 (0.0)
0 (0.0) |
130 Rice Genetics Newsletter Vol. 14
Fig. 1. RFLPs detected in self-pollinated progeny of Acc435.
Genomic DNA was digested with Xho I (lanes 1 to 10) and Xmn
I (lanes 11 to 12). Blot was hybridized with TNP domain of Rmu1.
Lanes 1 to 10 and lanes 11 to 20 were corresponding different families
in the progeny of single Acc435 accession.
with stable lines carrying non-autonomous Mutator
members. Thus we suggest that the hybrid dysgenesis phenomenon found in
rice would be caused by Rice Mutator which are activated by crossing
with other strains carrying an active element.