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Distorted genetic segregation of the transposon mPing at the long arm of chromosome 12 in rice.

Horibata A, Kakikubo Y, Kato T - Breed. Sci. (2015)

Bottom Line: These results, however, could not explain the lower transmission of male gametes with mPing.At least two ORFs, whose functions have not been identified, are located near this mPing.It is plausible that either of these ORFs or both are necessary for the normal functioning of male gametes.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Biology-Oriented Science and Technology, Kinki University , 930 Nishimitani, Kinokawa, Wakayama 649-6493 , Japan.

ABSTRACT
A class II transposable element, mPing exists in the rice genome ubiquitously and can transpose even in ordinary cultivation conditions. A copy of mPing was identified at the long arm of chromosome 12. In reciprocal backcrossed F1s between a heterozygote and a homozygote without mPing, the male gametes with this mPing from heterozygotes were transmitted to the next generation at a lower frequency than those without mPing, resulting in distorted genetic segregation in self-fertilized progenies, as well as in F1s after backcrossing. Pollens with mPing tended to germinate on stigma less than those without mPing. These results, however, could not explain the lower transmission of male gametes with mPing. In addition, no excision of mPing was observed in a homozygote. Thus, it was suggested that male gametes with mPing were eliminated partly from pollination to fertilization by negative competition against male gametes without mPing. Less formation of microspores with mPing in meiosis could also be a cause for the distorted segregation, although this could not be examined. At least two ORFs, whose functions have not been identified, are located near this mPing. It is plausible that either of these ORFs or both are necessary for the normal functioning of male gametes.

No MeSH data available.


Related in: MedlinePlus

Pollen germination on stigma of homozygotes for the non-insertion of mPing at rice chromosome 12, when pollinated with pollens without mPing (A) (by Hom-n) and those with mPing (B) (by Hom-i). A scale bar indicates 100 μm.
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f1-65_340: Pollen germination on stigma of homozygotes for the non-insertion of mPing at rice chromosome 12, when pollinated with pollens without mPing (A) (by Hom-n) and those with mPing (B) (by Hom-i). A scale bar indicates 100 μm.

Mentions: Table 3 shows the differences in the ratios of ordinary pollens, germinated pollens on stigma of Hom-n, fertilized grains, and germinated grains among Hom-i, Het, and Hom-n plants. No significant differences were observed in the ratios of fertilized grains and germinated grains among these three genotypes. This suggests that the insertion of mPing at chromosome 12 should not affect these fertilization and germination processes. On the other hand, Hom-n showed the highest ratio of pollen germination on stigma, followed by Het and Hom-i (Fig. 1). The difference between the latter two genotypes was significant. This apparently demonstrated that the insertion of the mPing at chromosome 12 reduced the pollen germination on stigma, at least of Hom-n. The pollen viability of Het was also significantly lower than the other two genotypes, although the difference was very small.


Distorted genetic segregation of the transposon mPing at the long arm of chromosome 12 in rice.

Horibata A, Kakikubo Y, Kato T - Breed. Sci. (2015)

Pollen germination on stigma of homozygotes for the non-insertion of mPing at rice chromosome 12, when pollinated with pollens without mPing (A) (by Hom-n) and those with mPing (B) (by Hom-i). A scale bar indicates 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542935&req=5

f1-65_340: Pollen germination on stigma of homozygotes for the non-insertion of mPing at rice chromosome 12, when pollinated with pollens without mPing (A) (by Hom-n) and those with mPing (B) (by Hom-i). A scale bar indicates 100 μm.
Mentions: Table 3 shows the differences in the ratios of ordinary pollens, germinated pollens on stigma of Hom-n, fertilized grains, and germinated grains among Hom-i, Het, and Hom-n plants. No significant differences were observed in the ratios of fertilized grains and germinated grains among these three genotypes. This suggests that the insertion of mPing at chromosome 12 should not affect these fertilization and germination processes. On the other hand, Hom-n showed the highest ratio of pollen germination on stigma, followed by Het and Hom-i (Fig. 1). The difference between the latter two genotypes was significant. This apparently demonstrated that the insertion of the mPing at chromosome 12 reduced the pollen germination on stigma, at least of Hom-n. The pollen viability of Het was also significantly lower than the other two genotypes, although the difference was very small.

Bottom Line: These results, however, could not explain the lower transmission of male gametes with mPing.At least two ORFs, whose functions have not been identified, are located near this mPing.It is plausible that either of these ORFs or both are necessary for the normal functioning of male gametes.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Biology-Oriented Science and Technology, Kinki University , 930 Nishimitani, Kinokawa, Wakayama 649-6493 , Japan.

ABSTRACT
A class II transposable element, mPing exists in the rice genome ubiquitously and can transpose even in ordinary cultivation conditions. A copy of mPing was identified at the long arm of chromosome 12. In reciprocal backcrossed F1s between a heterozygote and a homozygote without mPing, the male gametes with this mPing from heterozygotes were transmitted to the next generation at a lower frequency than those without mPing, resulting in distorted genetic segregation in self-fertilized progenies, as well as in F1s after backcrossing. Pollens with mPing tended to germinate on stigma less than those without mPing. These results, however, could not explain the lower transmission of male gametes with mPing. In addition, no excision of mPing was observed in a homozygote. Thus, it was suggested that male gametes with mPing were eliminated partly from pollination to fertilization by negative competition against male gametes without mPing. Less formation of microspores with mPing in meiosis could also be a cause for the distorted segregation, although this could not be examined. At least two ORFs, whose functions have not been identified, are located near this mPing. It is plausible that either of these ORFs or both are necessary for the normal functioning of male gametes.

No MeSH data available.


Related in: MedlinePlus