Identification of two loci causing F1 pollen sterility in inter- and intraspecific crosses of rice

Abstract

F 1 sterility, one of the most common post-zygotic reproductive barriers, is frequently observed in both interspecific and intraspecific crosses of rice. Elucidating the genetic and cytological mechanisms of F 1 pollen sterility is important to exploit genetic resources and to understand the evolutionary dynamics of post-zygotic reproductive isolation in rice. Here, we report two F 1 pollen sterility loci, designated S36 and S25, found in an interspecific cross between O. sativa ssp. japonica (Taichung 65) and O. nivara (IRGC105444), and an intraspecific cross between O. sativa ssp. japonica (Asominori) and ssp. indica (IR24). Genetic analyses revealed that both loci are located on distal end of the short arm of chromosome 12 and that allelic interaction at the heterozygous locus caused the sterility of male gametes carrying the japonica alleles in both cases.Comparison of map positions of S36 and S25 suggested that these two loci might be the same locus. Cytological investigation revealed that abnormality of sterile pollen grains caused by S36 occurred mainly at the late bicellular stage after initiation of starch accumulation. This study would provide the better understanding on the genetic nature and the cytological mechanism of F 1 pollen sterility in rice.

Chromosome Segment Substitution Lines: A Powerful Tool for the Introgression of Valuable Genes from Oryza Wild Species into Cultivated Rice (O. sativa)

“…sativa ssp. japonica), largely due to the prevalence of subpopulation incompatibilities (Harushima et al 2002;Oka 1988;Sano 1993;Win et al 2009). The long-term consequence of restricting crossing and population development to within subpopulations is a limited pool of genetic variation available to rice breeders for identifying new and useful combinations of genes.…”

“…2 A backcross scheme for developing chromosome segment substitution lines (CSSL) utilizing molecular markers for selecting the progeny each generation. some researchers have chosen to develop CSSLs to introgress chromosome segments containing genes of interest from either indica or japonica cultivars into the desired genetic background (Harushima et al 2002;Oka 1988;Sano 1993) even though limited success was achieved because of high sterility or hybrid breakdown (Miura et al 2008;Win et al 2009). Reported successful intra-specific CSSLs include 'IR24', an indica donor parent, introgressed into 'Asominori', a japonica recurrent parent, in which alleles for some important quantitative traits were mapped including eating quality , grain dimension and chalkiness (Wan et al 2005;Wang et al 2007), grain length (Wan et al 2006), and the sterility gene, S31 (Zhao et al 2007).…”

Genetic characterization and fine mapping of <i>S25</i>, a hybrid male sterility gene, on rice chromosome 12

“…In our earlier work, the S24 and S35 loci were finely mapped on chromosomes 5 and 1, respectively, and the genetic mechanisms with their interacting partner genes (EFS and INK) were characterized (Kubo et al, 2011(Kubo et al, , 2016b. In contrast, S25, which is located on rice chromosome 12, remains only roughly mapped and mostly uncharacterized (Win et al, 2009). The aim of this study was to characterize more completely the S25 gene toward the goal of elucidating the genetic mechanism of hybrid male sterility caused by S25.…”

Identification of QTLs for hybrid fertility in inter-subspecific crosses of rice (Oryza sativa L.)

“…Some useful agronomic traits were possessed only by indica and by japonica rice and the combination of these traits in breeding programs has been limited mainly due to the known phenomenon of reproductive barriers between subspecies, such as hybrid sterility (Oka, 1953;Wan et al, 1993;Cheng et al, 2003;Liu et al, 2004;Song et al, 2005;Li et al, 2006a;Li et al, 2006b), hybrid breakdown (Li et al, 1997;Jiang et al, 2008), segregation distortion (SD) or transmission ratio distortion (DRT) (Harushima et al, 1996(Harushima et al, , 1998(Harushima et al, , 2001(Harushima et al, , 2002Koide et al, 2008), and suppressed recombination (Ikehashi, 1982;Tanksley and Nelson, 1996). The mechanism of the hybrid sterility (HS) phenomenon has not been clearly understood yet, although various genetic analyses have been conducted to explain this phenomenon, which have identified 36 S loci (Oka, 1974;Ikehashi and Araki, 1986;Sano, 1990;Wan et al, 1993;Kinoshita, 1995;Yanagihara et al, 1995;Williams et al, 1997;Zhang et al, 1997;Zhuang et al, 2002;Song et al, 2005;Li et al, 2006b;Zhao et al, 2006;Jing et al, 2007;Kubo et al, 2008;Qiao et al, 2008;Win et al, 2009) and four gametophytic F1 sterility genes in an early study by Oka (1974). Through the recent advanced tools for QTL analysis on the genomic level and by developing near isogenic lines (NILs), several research groups have reported fine mapped chromosomal segments or candidate genes associated with HS (Causse ...…”