Zhang Yu, Wang Jie, Pu Qiuhong, Yang Ying, Lv Yonggang, Zhou Jiawu, Li Jing, Deng Xianneng, Wang Min, Tao Dayun
Yunnan Key Laboratory for Rice Genetic Improvement, Food Crops Research Institute, Yunnan Academy of Agricultural Sciences (YAAS), Kunming, China.
Institute of Plant Resources, Yunnan University, Kunming, China.
Front Plant Sci. 2022 Jun 27;13:908342. doi: 10.3389/fpls.2022.908342. eCollection 2022.
Intraspecific hybrid sterility is a common form of postzygotic reproductive isolation in Asian cultivated rice, which is also the major obstacle to utilize the strong heterosis in the rice breeding program. Here, we review recent progress in classification and hybrid sterility in Asian cultivated rice. A genome-wide analysis of numerous wild relatives of rice and Asian cultivated rice has provided insights into the origin and differentiation of Asian cultivated rice, and divided Asian cultivated rice into five subgroups. More than 40 conserved and specific loci were identified to be responsible for the hybrid sterility between subgroup crosses by genetic mapping, which also contributed to the divergence of Asian cultivated rice. Most of the studies are focused on the sterile barriers between and crosses, ignoring hybrid sterility among other subgroups, leading to neither a systematical understanding of the nature of hybrid sterility and subgroup divergence, nor effectively utilizing strong heterosis between the subgroups in Asian cultivated rice. Future studies will aim at identifying and characterizing genes for hybrid sterility and segregation distortion, comparing and understanding the molecular mechanism of hybrid sterility, and drawing a blueprint for intraspecific hybrid sterility loci derived from cross combinations among the five subgroups. These studies would provide scientific and accurate guidelines to overcome the intraspecific hybrid sterility according to the parent subgroup type identification, allowing the utilization of heterosis among subgroups, also helping us unlock the mysterious relationship between hybrid sterility and Asian cultivated rice divergence.
种内杂交不育是亚洲栽培稻中一种常见的合子后生殖隔离形式，这也是水稻育种计划中利用强大杂种优势的主要障碍。在此，我们综述了亚洲栽培稻在分类和杂交不育方面的最新进展。对众多水稻野生近缘种和亚洲栽培稻进行的全基因组分析，为亚洲栽培稻的起源和分化提供了见解，并将亚洲栽培稻分为五个亚组。通过遗传定位，已鉴定出40多个保守和特异位点与亚组间杂交不育有关，这也促成了亚洲栽培稻的分化。大多数研究集中在特定亚组间的不育障碍，而忽略了其他亚组间的杂交不育，导致既没有系统地理解杂交不育的本质和亚组分化，也没有有效利用亚洲栽培稻亚组间的强大杂种优势。未来的研究将致力于鉴定和表征杂交不育和分离畸变相关基因，比较和理解杂交不育的分子机制，并绘制出源于五个亚组间杂交组合的种内杂交不育位点蓝图。这些研究将根据亲本亚组类型鉴定，为克服种内杂交不育提供科学准确的指导方针，从而实现亚组间杂种优势的利用，也有助于我们解开杂交不育与亚洲栽培稻分化之间的神秘关系。
