南湖新闻网讯（通讯员 陈俊霖）近日，我校油菜团队在国际学术期刊New Phytologist发表了题为“Hybrid epigenome unveils parental genetic divergence shaping salt-tolerant heterosis in Brassica napus”的研究论文。该研究以傅廷栋院士选育、农业农村部主导品种“华油杂62”为研究对象，系统解析了该杂交种及其亲本在盐胁迫下染色质可及性重塑与基因转录的动态调控规律，发现耐盐杂种优势主要来自双亲基因组与表观基因组的互补整合，从而揭示了杂交油菜耐盐碱形成机制。

研究发现，杂种不仅继承了双亲的遗传和表观遗传特征，获得了更丰富的基因资源和更多的染色质可及性区域，还能利用优势等位基因应对盐胁迫。这表明，表观遗传通过调控基因表达增强了杂种基因组的可塑性，赋予其更强的环境适应性。同时，研究从耐盐性状层面支持了杂种优势的经典假说：在油菜杂交种“华油杂62”中，遗传效应以不完全显性和加性效应为主，而显性和超显性效应相对较少，说明杂种在单个基因位点上的表现通常高于低值亲本，但未超过高值亲本。然而，不同亲本的优势等位基因通过互补和累积，使总体作用超过了加性效应，从而赋予了杂种在盐胁迫下的优势。上述研究表明，育种者可通过筛选优良耐盐亲本、优化双亲杂交组合，聚合功能位点、实现优势互补，从而培育出强耐盐碱油菜新品种，为耐盐碱油菜育种提供理论指导。

油菜杂交种“华油杂62”聚合双亲耐盐位点产生耐盐杂种优势

据悉，团队专注耐盐碱油菜研究20年，育成“华油杂62”、“饲油2号”、“华油杂158”、“金油杂9号”等一系列代表性耐盐碱杂交品种。该研究回答了“杂交油菜为何更耐盐碱”的基本科学问题，为未来耐盐碱油菜遗传育种提供了重要参考。

华中农业大学博士研究生陈俊霖和张敏燕为该论文的共同第一作者，沈金雄教授和赵伦教授为共同通讯作者。华中农业大学赵虎研究员、江汉大学万何平博士等给予了重要指导。该研究得到了国家自然科学基金、国家重点研发计划等项目资助。

审核人：赵伦 沈金雄

论文链接： http://doi.org/10.1111/nph.70532

英文摘要：

Heterosis holds great potential for improving yield, quality, and environmental adaptability in crop breeding, which suggests that hybrids can exhibit better performance in adapting to extreme environments. However, the epigenetic mechanisms of salt-tolerant heterosis in allopolyploid crop Brassica napus (AACC, 2n = 38), particularly chromatin accessibility, remain largely unexplored.

We investigated the dynamics of chromatin accessibility and transcriptional reprogramming during a time course of salt exposure in Brassica napus hybridization. We observed the importance of epigenetic and transcriptional regulation in plant resilience. The chromatin accessibility and transcriptome rapidly changed within a short time frame of salt exposure.

Hybrid possessed more accessible chromatin and more active transcriptome than that of parents driven by epigenetic aggregation and genetic complementation. Broader and more flexible genomic resources enabled hybrid preferentially unitized advantageous alleles for salt stress adaptation. Meanwhile, these salt stress-responsive genes in hybrid exerted various heterotic effects, with non-additive genetic effects, including full-dominance, partial-dominance, and overdominance effects, playing a crucial role in salt stress adaptation.

Our results expanded the heterosis hypothesis from an epigenetic perspective and emphasized how the combined effects of genetic and epigenetic factors enable hybrid to better withstand salt stress.