南北芍药种质的需冷量差异分析及关键调控基因筛选

“芍药南移”是我国经典的园林植物与观赏园艺学问题，具有重要的理论与实践意义。因江南地区冬季温度较高而冷量积累不足，导致地下芽休眠解除发生障碍，翌年开花不良甚至退化，严重阻碍了芍药的更广泛应用。本项目拟选择我国南北地区的芍药种质，通过比较需冷量差异，筛选需冷量最高和最低的芍药种质，对其地下芽进行转录组测序，构建关键休眠阶段的基因文库。将芽休眠相关基因分为环境响应、生理代谢和细胞生长发育三类基因，分析表达和调控关系，并与形态和生理观测相关联，探讨最高和最低需冷量种质地下芽休眠解除的生理与分子调控途径。以上述研究为基础，将低温响应基因作为重点候选对象，筛选SOC1、AGL、LHY和CCA1等可能调控芍药需冷量特性的关键基因，并进行表达验证和全长克隆。最终通过高需和低需芍药种质关键基因表达和调控的对比研究，探讨造成需冷量差异的深层原因，以期为选育低需冷量的芍药种质奠定基础，促进“芍药南移”的实现。

The Southward Plantation of Herbaceous Peony (Paeonia lactiflora Pall.) is a classic problem of landscape plants and ornamental horticulture with great theoretical importance and practical significance. The lack of chilling requirement (CR) for herb peony because of the warmer winter in south region of the Yangzi River, results in dormancy release obstacle of underground renewal buds, poor flowering performance in the next year, and even degeneration of growth and flowering year by year. The south and north herb peony germplasms will be introduced to compare the difference of their CRs for releasing bud dormancy in this project, and the herb peonies having the highest and lowest CRs will be singled out. By performing the transcriptome sequencing for underground dormant buds of this two specific herb peonies, we will construct the gene libraries regarding four key dormant stages. Thereafter, the differentially expressed genes (DEGs) will be divided into three categories in terms of their possible functions: environmental response, physiological metabolism, and cell growth and development. The expression and regulation patterns of these genes will be analyzed correlatively with the morphological and physiological traits. Accordingly, the difference of physiological and molecular regulatory pathway for bud dormancy release between the highest and lowest CRs will be deduced. Among of which, we will specially focus on the chilling responsive genes including SOC1, AGL, LHY and CCA1, etc., which would possibly regulate the CR trait. The expression of these key genes will be verified, and full length of one or more genes will be cloned. Finally, the detailed causes of CR difference will be clarified according to the comparison of expression and regulation of these key genes. Information obtained from this study will provide the foundation for breeding purpose of low chilling requirement herbaceous peony, and therefore promote the realization of the Southward Plantation of Herbaceous Peony.