State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Key Laboratory of Biology of Ornamental Plants in East China, College of Horticulture, National Forestry and Grassland Administration, Nanjing Agricultural University, Weigang No.1, Nanjing, Jiangsu Province, 210095, P.R. China.
Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing, 210014, China.
BMC Plant Biol. 2024 Apr 10;24(1):259. doi: 10.1186/s12870-024-04954-4.
Heterosis breeding is one of the most important breeding methods for chrysanthemum. To date, the genetic mechanisms of heterosis for waterlogging tolerance in chrysanthemum are still unclear. This study aims to analyze the expression profiles and potential heterosis-related genes of two hybrid lines and their parents with extreme differences in waterlogging tolerance under control and waterlogging stress conditions by RNA-seq.
A population of 140 F progeny derived from Chrysanthemum indicum (Nanchang) (waterlogging-tolerant) and Chrysanthemum indicum (Nanjing) (waterlogging-sensitive) was used to characterize the extent of genetic variation in terms of seven waterlogging tolerance-related traits across two years. Lines 98 and 95, respectively displaying positive and negative overdominance heterosis for the waterlogging tolerance traits together with their parents under control and waterlogging stress conditions, were used for RNA-seq. In consequence, the maximal number of differentially expressed genes (DEGs) occurred in line 98. Gene ontology (GO) enrichment analysis revealed multiple stress-related biological processes for the common up-regulated genes. Line 98 had a significant increase in non-additive genes under waterlogging stress, with transgressive up-regulation and paternal-expression dominant patterns being the major gene expression profiles. Further, GO analysis identified 55 and 95 transgressive up-regulation genes that overlapped with the up-regulated genes shared by two parents in terms of responses to stress and stimulus, respectively. 6,640 genes in total displaying maternal-expression dominance patterns were observed in line 95. In addition, 16 key candidate genes, including SAP12, DOX1, and ERF017 which might be of significant importance for the formation of waterlogging tolerance heterosis in line 98, were highlighted.
The current study provides a comprehensive overview of the root transcriptomes among F hybrids and their parents under waterlogging stress. These findings lay the foundation for further studies on molecular mechanisms underlying chrysanthemum heterosis on waterlogging tolerance.
杂种优势育种是菊花最重要的育种方法之一。迄今为止，菊花耐涝性杂种优势的遗传机制仍不清楚。本研究旨在通过 RNA-seq 分析在对照和淹水胁迫条件下，两个耐涝性和耐涝性差异较大的杂交组合及其亲本的表达谱和潜在的杂种优势相关基因。
利用来自南昌菊花（耐涝）和南京菊花（耐涝）的 140 个 F 后代群体，在两年内对 7 个耐涝相关性状的遗传变异程度进行了描述。在对照和淹水胁迫条件下，株系 98 和 95 分别对耐涝性状表现出正向和负向超亲杂种优势，用于 RNA-seq。结果，株系 98 中差异表达基因（DEGs）的数量最多。基因本体（GO）富集分析揭示了多个与共同上调基因相关的生物过程。株系 98 在水淹胁迫下非加性基因显著增加，表现为超亲上调和父本表达优势的基因表达模式。此外，GO 分析鉴定了 55 个和 95 个与两个亲本在应激和刺激反应方面共享的超亲上调基因重叠，共发现 6640 个表现出母本表达优势的基因。此外，在株系 95 中观察到 16 个关键候选基因，包括 SAP12、DOX1 和 ERF017，它们可能对株系 98 耐涝杂种优势的形成具有重要意义。
本研究提供了在淹水胁迫下 F 杂种及其亲本根系转录组的综合概述。这些发现为进一步研究菊花耐涝杂种优势的分子机制奠定了基础。
