温度和光周期影响的当归早薹中AsFT的功能解析

Angelica, belongs to Umbelliferae family, Angelica genus, is a perennial species for medicine that grow originally in Min county of Gansu province. The production of angelica in Min county accounts for 95% of the world overall productivity. However, both quality and yield of it were substantially affected due to the premature bolting. Accumulating evidences have showed that the temperature and photoperiod cycles, putatively long day(LD) or short day(SD), are key factors that involve in its premature bolting. FT(Flower Locus T) is one of key regulators for plant reproductive transition which has been a emerging hot spot for flowering research. Here, we firstly will clone Angelica FT(AsFT), and then to further investigate the critical photoperiod on Angelica premature bolting. Then, based on the proleptic results, three distinguisable combined treatments of temperature and photoperiod cycles will be set to determine the influences of these processes on premature bolting of Angelica, as well as their correlations to AsFT expression. The treatments are designated as following: (1) combinations of vernalization/non-vernalization and LD/SD; (2) photothermal interactions created by transplanting at intervals integrated by LD/SD regimes; (3) integrated effect of photothermal differences caused by transplanting places at various altitudes. Subsequently, the qRT-PCR and in situ hybridization will be applied to analysize AsFT spatial and temporal expression patterns during Angelica vegetative growth or/and premature bolting in the above treatments. Together, this study will strivingly elucdiate the roles of AsFT in Angelica premature bolting engendered by the photothermal factors, which will ultimately enhance knowledge of AtFT on plant reproductive control and provide us with a theoretical foundation for breeding and cultivation adaptability to reduce Angelica premature bolting.

当归(Angelica sinensis)是伞形科当归属多年生药用植物，甘肃岷县及其周边为其地道产区，占世界总产量的95%。当归生产中早薹问题突出，严重影响了其质量和产量，温度和光周期是影响当归早薹的重要因素。FT(Flower Locus T)是植物生殖转变的关键调控基因，也是近年植物开花研究的热点。本项目拟在克隆当归FT(AsFT)和明确当归早薹的临界光周期的基础上，设置3种温度-光周期组合处理：(1)春化/未春化-长/短日间的不同组合；(2)分期移栽，结合长、短日处理形成的光温互作；(3)不同海拔地点移栽引起的光温综合作用。观察上述处理对当归早薹的影响，并利用qRT-PCR 和原位杂交技术分析上述处理的当归营养生长或/和早薹过程中AsFT的时空表达模式。结果将阐明AsFT在当归早薹中的功能和作用，初步明确当归早薹的分子调控机理，为降低当归早薹率的育种和适应性栽培提供理论依据。

早薹是当归(Angelica sinensis (Oliv.) Diels)生产的最大问题，温度和光周期是影响当归早薹的重要因素，温度包括影响当归春化的冬储及生长期的环境温度。冬储期对苗分别进行−5、0和5℃的持续及各温度间的定期转换处理，春季栽植大田后观察当归的早薹，以揭示当归的春化特性；对经0℃和−5℃冬储的当归苗，分别进行同期、晚15 d、晚30 d三个时期的分期栽植，以观察早薹及根农艺性状对冬储温度和栽期的反应；探索当归的实验室培养为研究供材的同时，观察了当归的高温反应。对生长期当归分别进行16 h长日-10 h短日及8 h短日和暗期中断处理，以观察早薹的光周期反应。克隆分析当归开花素编码基因AsFT在当归早薹中的功能和作用以揭开当归早薹的分子调控机制。结果表明，当归的−5℃冬储抽薹率最低，0℃冬储抽薹率最高，因此，0℃是当归春化的最优温度，−5℃冻储可抑制当归的春化而减少抽薹。苗根直径0.65 mm以下的当归苗，经0℃和−5℃冬储、分期栽植，同类苗各处理间早薹差异不显著，但其收获根农艺性状存在差异。未抽薹当归通过休眠来逃匿高温逆境，亚高原常温实验室可进行当归的育苗、成药及成籽在内的绝大部分生命过程的培养，满足了当归基因表达调控等研究对实验材料的需要。长日促使0.45 mm以上的当归栽后60 d抽薹，10 h短日将早薹当归的营养生长期延长30 d；8 h短日将早薹当归限于0.65 mm以上，暗中断将其扩展至0.55 mm以上，并提高了早薹率缩短了抽薹日数，因此，长日可扩展当归的早薹苗类，加快抽薹进程。当归存在AsFT及其同源基因AsFTL，二者均可加快植物开花，以高水平表达于早薹当归叶片，表达量与早薹率相关。本研究深入揭示了当归早薹的春化和光周期特性，弄清了当归早薹关键基因AsFT的功能和作用，对当归栽培和育种具有重要意义。