LaAP2L转录因子在落叶松超亲速生杂种优势性状形成中的功能及调控机制研究

The heterosis phenomena in Larix is very prevalent, and has played important roles in Larix breeding.However, compared with our knowledge of heterosis in crops,the nature basis of heterosis in Larix is still largely unknown. In our previous study, a transcription factor closely associated with the formation of fast-growing heterotic trait, named as LaAP2L, was obtained in Larix. Sequence analysis indicated that this transcription factor was first found in Larix, and the gene functional analysis in Arabidopsis indicated that overexpression LaAP2L can make the transgenic lines show fast-growing and improved biomass,which are very similar to the fast-growing heterotic trait showed by the hybrid Larix, which implied that LaAP2L may play important roles in the formation of fast-growing heterotic traits in Larix. However, the function and regulation of LaAP2L in Larix is unknown. Consequently,in the present study, different methods such as genetic transformation, Chromatin Immunoprecipitation (ChIP), Co-Immunoprecipitation (Co-IP), Mass spectrometer, Protoplast transformation, Yeast two hybrid were used to further identify the targeted genes regulated by LaAP2L, and the key factors interacted with LaAP2L. Following that the function of the genes and factors should be elucidated, and the final subject of the study is to elucidate the roles of LaAP2L in the formation of Larix fast-growing heterotic trait from the molecular level. The findings should give new insights into the nature basis of heterosis in woody plants, and play important roles in cross beeding of Larix.

落叶松中杂种优势现象十分明显，并在落叶松育种中发挥了重要作用。但相比对农作物杂种优势的认识，对落叶松杂种优势机制的认识十分有限。项目前期获得一个与落叶松超亲速生杂种优势性状形成密切相关的转录因子 LaAP2L，该转录因子为首次报道。基因功能初步分析显示，过表达LaAP2L可使转基因拟南芥在生长速度、生物量方面表现出明显类于速生、高产杂种优势性状的特征。但该转录因子在落叶松超亲速生性状形成中的功能及作用机制仍有待阐释。为此，项目拟通过遗传转化、染色体免疫共沉淀、免疫共沉淀结合质谱分析、原生质体基因表达分析、酵母双杂交分析等手段进一步分离、鉴定参与LaAP2L调控路径的关键因子及LaAP2L调控的靶基因，进而揭示他们的功能，最终阐释LaAP2L调控落叶松超亲速生杂种优势性状形成的分子机制。研究对丰富木本植物杂种优势形成机制的认识具有重要意义，同时将为落叶松杂交育种提供重要理论指导。

落叶松中杂种优势现象十分明显，并在落叶松育种中发挥了重要作用。但相比对农作物杂种优势的认识，对落叶松杂种优势机制的认识十分有限。项目前期获得一个与落叶松超亲速生杂种优势性状形成密切相关的转录因子 LaAP2L，该转录因子为首次报道，其功能及调控机制未知。本项目通过染色体免疫共沉淀、比较转录组学、酵母双杂交分析等手段克隆、鉴定了一系列与LaAP2L发生互作及受其调控的关键基因，证实相应基因主要涉及光合作用及核糖体功能，暗示LaAP2L主要通过对植物光合作用或核糖体功能相关基因的调控而在其生长发育过程中发挥重要作用。此外，研究证实与LaAP2L同属于落叶松AP2/ERF家族的另外两个成员LaERF和LaRAP2在植物高温耐受方面发挥重要作用，其过表达可显著提高转化株对高温的耐受，且LaERF过表达还可以提高转化株的生物量。相关研究成果对于揭示落叶松laAP2L介导的基因调控网络具有重要科学价值。同时对于开展高产、高抗逆落叶松分子育种，培育高产、优质作物及其他经济植物基因工程育种具有巨大应用潜力。