TY - JOUR
T1 - A novel epistatic interaction at two loci causing hybrid male sterility in an inter-subspecific cross of rice (Oryza sativa L.)
AU - Kubo, Takahiko
AU - Yamagata, Yoshiyuki
AU - Eguchi, Maki
AU - Yoshimura, Atsushi
PY - 2008
Y1 - 2008
N2 - Postzygotic reproductive isolation (RI) often arises in inter-subspecific crosses as well as inter-specific crosses of rice {Oryza sativa L.). To further understand the genetic architecture of the postzygotic RI, we analyzed genes causing hybrid ste- rility and hybrid breakdown in a rice inter-subspecific cross. Here we report hybrid male sterility caused by epistatic interaction between two novel genes, S24 and S35, which were identified on rice chromosomes 5 and 1, respectively. Genetic analysis using near-isogenic lines (NILs) carrying IR24 (ssp. indica) seg- ments with Asominori (ssp. japonica) genetic background revealed a complicated aspect of the epistasis. Allelic interaction at the S24 locus in the heterozygous plants caused abortion of male gametes carrying the Asominori allele (S24-as) independent of the S35 genotype. On the other hand, male gametes carrying the Asominori allele at the S35 locus (S35-as) showed abortion only when the IR24 allele at the S24 locus (S24-ir) was concurrently introgressed into the S35 het- erozygous plants, indicating that the sterility phenotype due to S35 was depen- dent on the S24 genotype through negative epistasis between S24-ir and S35-as alleles. Due to the interaction between S24 and S35, self-pollination of the double heterozygous plants produced pollen-sterile progeny carrying the S24-irl S24-ir S35-as/S35-ir genotype in addition to the S24 heterozygous plants. This result suggests that the S35 gene might function as a modifier of S24. This study presents strong evidence for the importance of epistatic interaction as a part of the genetic architecture of hybrid sterility in rice. In addition, it suggests that diverse systems have been developed as postzygotic RI mechanisms within the rice.
AB - Postzygotic reproductive isolation (RI) often arises in inter-subspecific crosses as well as inter-specific crosses of rice {Oryza sativa L.). To further understand the genetic architecture of the postzygotic RI, we analyzed genes causing hybrid ste- rility and hybrid breakdown in a rice inter-subspecific cross. Here we report hybrid male sterility caused by epistatic interaction between two novel genes, S24 and S35, which were identified on rice chromosomes 5 and 1, respectively. Genetic analysis using near-isogenic lines (NILs) carrying IR24 (ssp. indica) seg- ments with Asominori (ssp. japonica) genetic background revealed a complicated aspect of the epistasis. Allelic interaction at the S24 locus in the heterozygous plants caused abortion of male gametes carrying the Asominori allele (S24-as) independent of the S35 genotype. On the other hand, male gametes carrying the Asominori allele at the S35 locus (S35-as) showed abortion only when the IR24 allele at the S24 locus (S24-ir) was concurrently introgressed into the S35 het- erozygous plants, indicating that the sterility phenotype due to S35 was depen- dent on the S24 genotype through negative epistasis between S24-ir and S35-as alleles. Due to the interaction between S24 and S35, self-pollination of the double heterozygous plants produced pollen-sterile progeny carrying the S24-irl S24-ir S35-as/S35-ir genotype in addition to the S24 heterozygous plants. This result suggests that the S35 gene might function as a modifier of S24. This study presents strong evidence for the importance of epistatic interaction as a part of the genetic architecture of hybrid sterility in rice. In addition, it suggests that diverse systems have been developed as postzygotic RI mechanisms within the rice.
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U2 - 10.1266/ggs.83.443
DO - 10.1266/ggs.83.443
M3 - Article
C2 - 19282622
AN - SCOPUS:63849292298
VL - 83
SP - 443
EP - 453
JO - Genes and Genetic Systems
JF - Genes and Genetic Systems
SN - 1341-7568
IS - 6
ER -