Institute of Integrative Biology, ETH Zurich & Zurich-Basel Plant Science Center, Universitätstrasse 16, 8092 Zurich, Switzerland.
Department of Plant and Microbial Biology, University of Zurich and Zurich-Basel Plant Science Center, Zollikerstrasse 107, 8008 Zurich, Switzerland.
Curr Opin Plant Biol. 2021 Jun;61:102015. doi: 10.1016/j.pbi.2021.102015. Epub 2021 Feb 24.
Interest in understanding hybrid seed failure (HSF) has mushroomed, both in terms of identifying underlying molecular processes and their evolutionary drivers. We review phenotypic and molecular advances with a focus on the 'effective ploidy' concept, witnessing a recent revival after long obscurity. Endosperm misdevelopment has now been shown to underlie HSF in many inter-specific, homoploid crosses. The consistent asymmetries in seed size and developmental trajectories likely reflect parental divergence in key, dosage-sensitive processes. Transcriptomic and epigenomic studies reveal genome-wide, polarized expression perturbations and shifts in parental expression proportions, consistent with small-RNA imbalances between parental roles. Among-species differences in levels of parental conflict over resource allocation enjoy strong support in explaining why differences in effective ploidy may evolve.
人们对于理解杂种种子败育（HSF）的兴趣大增，不仅是在鉴定潜在的分子过程及其进化驱动力方面。我们综述了表型和分子方面的进展，重点关注“有效倍性”概念，该概念在长期沉寂后最近又重新受到关注。胚乳发育异常现已被证明是许多种间同倍杂交杂种种子败育的原因。种子大小和发育轨迹的一致不对称性可能反映了亲代在关键的、剂量敏感过程中的分歧。转录组和表观基因组研究揭示了全基因组的、极化的表达扰动以及亲本表达比例的变化，这与亲代角色之间的小 RNA 失衡一致。在解释为什么有效倍性的差异可能进化时，物种间在资源分配上的亲代冲突水平差异得到了强有力的支持。
