Molecular analysis of an additional case of hybrid sterility in rice (Oryza sativa L.)

Abstract

Hybrid sterility hinders the exploitation of the heterosis displayed by japonica × indica rice hybrids. The variation in pollen semi-sterility observed among hybrids between the japonica recipient cultivar and each of two sets of chromosome segment substitution lines involving introgression from an indica cultivar was due to a factor on chromosome 5 known to harbor the gene S24. S24 was fine mapped to a 42 kb segment by analyzing a large F(2) population bred from the cross S24-NIL × Asominori, while the semi-sterility shown by the F(1) hybrid was ascribable to mitotic failure at the early bicellular pollen stage. Interestingly, two other pollen sterility genes (f5-Du and Sb) map to the same region (Li et al. in Chin Sci Bull 51:675-680, 2006; Wang et al. in Theor Appl Genet 112:382-387, 2006), allowing a search for candidate genes in the 6.4 kb overlap between the three genes. By sequencing the overlapped fragment in wild rice, indica cultivars and japonica cultivars, a protein ankyrin-3 encoded by the ORF2 was identified as the molecular base for S24. A cultivar Dular was found to have a hybrid-sterility-neutral allele, S24-n, in which an insertion of 30 bp was confirmed. Thus, it was possible to add one more case of molecular bases for the hybrid sterility. No gamete abortion is caused on heterozygous maternal genotype with an impaired sequence from the hybrid-sterility-neutral genotype. This result will be useful in understanding of wide compatibility in rice breeding.

Evidence of Natural Selection Acting on a Polymorphic Hybrid Incompatibility Locus in Mimulus

“…Instead, it has been proposed that rapid divergence at hybrid incompatibility loci might be driven by recurrent bouts of intragenomic conflict involving segregation distorters (Frank 1990;Hurst and Pomiankowski 1991). Consistent with this idea, studies in Drosophila and rice find that hybrid segregation distortion maps to the same genomic locations as hybrid sterility (Tao et al 2001;Long et al 2008;Phadnis and Orr 2009;Zhao et al 2010;Yang et al 2012). Ultimately, an important challenge for speciation geneticists is to determine which evolutionary forces cause the initial spread of incompatibility alleles within species.…”

Hybrid Male Sterility in Rice Is Due to Epistatic Interactions with a Pollen Killer Locus

“…Using different cross combinations of indica and japonica varieties, other researchers have reported on hybrid male sterility genes named f5-Du (Wang et al 2006) and Sb (Li et al 2006), which map to the S24 region on chromosome 5. S24, f5-Du, and Sb occur within a single 90-kb region and are therefore likely to be the same gene (Zhao et al 2010). Zhao et al (2010) used a fine mapping strategy to identify two candidate genes for S24 (f5-Du and Sb), one encoding an Ankyrin domain protein and the other encoding an uncharacterized protein.…”

“…S24, f5-Du, and Sb occur within a single 90-kb region and are therefore likely to be the same gene (Zhao et al 2010). Zhao et al (2010) used a fine mapping strategy to identify two candidate genes for S24 (f5-Du and Sb), one encoding an Ankyrin domain protein and the other encoding an uncharacterized protein. Thus, S24 (f5-Du and Sb) appears to be an important factor controlling hybrid male sterility in the indica/japonica hybrids.…”

Hybrid Sterility in Rice (Oryza sativa L.) Involves the Tetratricopeptide Repeat Domain Containing Protein

“…According to the classical Dobzhansky-Muller model, postzygotic isolation results from a deleterious interaction between functionally diverged genes from the hybridizing species (Dobzhansky 1937;Ting et al 1998;Barbash et al 2003;Presgraves et al 2003;Brideau et al 2006;Bayes and Malik 2009;Ferree and Barbash 2009;Phadnis and Orr 2009;Tang and Presgraves 2009;White et al 2011). Genes for hybrid sterility, a common pattern of postzygotic isolation, have been reported in several organisms, including fungi, animals, and plants (Brideau et al 2006;Lee et al 2008;Bikard et al 2009;De Vienne et al 2009).Major progress has been made in rice and the interspecific and intersubspecific hybrid sterilities are perhaps the best known examples (Chen et al 2008;Long et al 2008 Wan and Ikehashi 1995;Zhu et al 2005;Li et al 2007;Zhao et al 2007;Chen et al 2008Chen et al , 2012Yang et al 2012), pollen sterility Jing et al 2007;Kubo et al 2008Kubo et al , 2011Long et al 2008;Zhang et al 2011;Zhao et al 2011), and both in a few cases (Koide et al 2008(Koide et al , 2012. The S7 locus was first identified causing hybrid sterility between an Aus variety "Ingra" and some javanica varieties by Ikehashi and Araki (1987).…”

“…The Asian cultivated rice consists of two major types or subspecies, indica and japonica, which are also referred to as "hsien" and "keng," respectively, since the Han Dynasty (2000 years ago) in China (Ting 1957). Recently, a large numbers of loci causing interspecific or intersubspecific hybrid sterility have been identified, including embryo sac abortion (Wan et al 1993Wan and Ikehashi 1995;Zhu et al 2005;Li et al 2007;Zhao et al 2007;Chen et al 2008Chen et al , 2012Yang et al 2012), pollen sterility Jing et al 2007;Kubo et al 2008Kubo et al , 2011Long et al 2008;Zhang et al 2011;Zhao et al 2011), and both in a few cases (Koide et al 2008(Koide et al , 2012. The S7 locus was first identified causing hybrid sterility between an Aus variety "Ingra" and some javanica varieties by Ikehashi and Araki (1987).…”