AUTHOR=Zin Mar Myint  , Koide Yohei 

TITLE=Influence of Gender Bias on Distribution of Hybrid Sterility in Rice

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.898206

DOI=10.3389/fpls.2022.898206

ISSN=1664-462X

ABSTRACT=<p>Hybrid sterility genes define species identities, setting reproductive barriers between distantly related <italic>Oryza</italic> relatives. They induce allelic-specific selective gametic abnormalities by killing pollens, embryo sacs, or both, and thus resulting in the male specific transmission ratio distortion (<italic>m</italic>TRD), female specific transmission ratio distortion (<italic>f</italic> TRD), and/or sex-independent transmission ratio distortion (<italic>si</italic>TRD) in hybrids. Although more than 50 hybrid sterility genes have been reported, comprehensive analysis on the distributional pattern of TRD systems in <italic>Oryza</italic> species is limited. In this review, we surveyed the TRD systems and the underlying possible mechanisms in these species. In rice, pollen killers which cause <italic>m</italic>TRD are often observed in higher frequency than egg killers and gamete eliminators, which are factors affecting <italic>f</italic> TRD and <italic>si</italic>TRD, respectively. Due to the rather massive population of pollen grains, their reduction in the number caused by hybrid sterility possesses a smaller selective disadvantage to the hybrid individuals, in contrast to female gamete abortion. The pattern of TRD distribution displays less abundancy in <italic>si</italic>TRD. It suggests that fixation of <italic>si</italic>TRD might require a certain time rather than single sex-specific factors. The presence of linked sterility factors worked for <italic>m</italic>TRD and <italic>f</italic> TRD, and strength of their linkage in chromosomal regions might determine the type of sterility and TRD. The study of TRD systems has a potential to reveal the relationships between selfish genes and their functions for reproductive isolation.</p>