Table_1_Implementation of Epigenetic Variation in Sorghum Selection and Implications for Crop Resilience Breeding.XLSX

Crop resilience and yield stability are complex traits essential for food security. Sorghum bicolor is an important grain crop that shows promise for its natural resilience to drought and potential for marginal land production. We have developed sorghum lines in the Tx430 genetic background suppressed for MSH1 expression as a means of inducing de novo epigenetic variation, and have used these materials to evaluate changes in plant growth vigor. Plant crossing and selection in two distinct environments revealed features of phenotypic plasticity derived from MSH1 manipulation. Introduction of an epigenetic variation to an isogenic sorghum population, in the absence of selection, resulted in 10% yield increase under ideal field conditions and 20% increase under extreme low nitrogen conditions. However, incorporation of early-stage selection amplified these outcomes to 36% yield increase under ideal conditions and 64% increase under marginal field conditions. Interestingly, the best outcomes were derived by selecting mid-range performance early-generation lines rather than highest performing. Data also suggested that phenotypic plasticity derived from the epigenetic variation was non-uniform in its response to environmental variability but served to reduce genotype × environment interaction. The MSH1-derived growth vigor appeared to be associated with enhanced seedling root growth and altered expression of auxin response pathways, and plants showed evidence of cold tolerance, features consistent with observations made previously in Arabidopsis. These data imply that the MSH1 system is conserved across plant species, pointing to the value of parallel model plant studies to help devise effective plant selection strategies for epigenetic breeding in multiple crops.

作物抗逆性与产量稳定性是关乎粮食安全的复杂性状。双色高粱（Sorghum bicolor）作为一类重要的粮用作物，其天然耐旱特性突出，且具备在边际土地开展种植的应用潜力。本研究以Tx430遗传背景为基础，培育了MSH1表达受抑制的高粱品系，以此诱导全新表观遗传变异，并利用这些材料评估植株生长活力的变化。在两种不同环境下开展的杂交与筛选实验，揭示了由MSH1调控所产生的表型可塑性特征。在未施加选择压力的前提下，向同基因高粱群体引入表观遗传变异后，在理想田间条件下可实现10%的产量提升，在极端低氮条件下则可获得20%的产量增幅。但若结合早期筛选环节，这一效果得到显著增强：理想条件下产量提升可达36%，边际土地种植条件下增幅可达64%。值得注意的是，最优增产效果并非源自筛选最高产的品系，而是选自中期表现稳定的早期世代品系。实验数据同时表明，由表观遗传变异产生的表型可塑性对环境变化的响应并不均一，但其核心作用是降低基因型×环境互作效应。MSH1调控产生的生长活力提升，似乎与幼苗根系生长增强、生长素响应通路的表达模式改变密切相关，同时该类植株还表现出耐寒性特征，这与此前在拟南芥（Arabidopsis）中观测到的结果一致。上述数据表明，MSH1调控系统在植物物种间具有保守性，这也凸显了开展平行模式植物研究的重要价值，可为多作物表观遗传育种设计高效的植株筛选策略提供理论指导。