Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
Centre for Crop Sciences, Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Brisbane, Queensland, 4702, Australia.
Curr Opin Plant Biol. 2021 Feb;59:101984. doi: 10.1016/j.pbi.2020.101984. Epub 2021 Jan 5.
Apomixis, is an asexual mode of seed formation resulting in genetically identical or clonal seed with a maternal genotype. Apomixis has not been reported in seed crops where its flexible application in plant breeding could accelerate delivery of new varieties. By contrast, a sporophytic form of apomixis termed nucellar or adventitious embryony is common in the Rutaceae containing Citrus crop species. Here, multiple embryos develop from the maternal, somatic, nucellar cells of the ovule. They are incorporated into the enlarging embryo sac containing the sexually derived zygotic embryo and endosperm, which are products of double fertilization. Recent research has provided insights to the molecular basis for nucellar embryony. Here, we review the current understanding of the initiation, genetic basis and evolution of nucellar embryony in Citrus, and discuss prospects for future study and breeding applications of Citrus sporophytic apomixis.
无融合生殖是一种无性的种子形成方式，导致具有母体基因型的遗传上相同或克隆的种子。无融合生殖尚未在种子作物中报道，其在植物育种中的灵活应用可以加速新品种的推出。相比之下，称为珠心或不定胚的孢子体形式的无融合生殖在含有柑橘作物物种的芸香科中很常见。在这里，多个胚胎从母体、体细胞、胚珠的珠心细胞发育而来。它们被纳入不断增大的胚囊中，其中包含有性衍生的合子胚和胚乳，它们是双受精的产物。最近的研究为珠心胚的分子基础提供了新的认识。在这里，我们综述了柑橘珠心胚发生的起始、遗传基础和进化的当前理解，并讨论了柑橘孢子体无融合生殖的未来研究和育种应用的前景。
