乙烯诱导菠萝开花的生理基础与分子途径

Ethylene is the only proven hormone to directly activate the reproduction of pineapple. In practice, ethephon or CaC2 is widely applied to adjust the harvest time of fruits by the induction of pineapple flowering, but the underlying structure and physiological basis and molecular pathways are not illuminated. This project will focus on the physiological and molecular mechanisms of ethylene-induced flowering of pineapple, including (1) Comparative anatomical investigation of florescence process in pineapple, including the morphological characteristics and changes of apical meristem of pineapple during cold-,ethylene- and acetylene-induced flowering; (2) Comparative physiology of florescence process in pineapple, including the changes of GA, IAA, CTK, ABA,polyamine,and other hormones,and soluble sugar and ACC oxidase activity in pineapples during cold-,ethylene- and acetylene-induced flowering, aiming to clarify the physiological bases of natural blossom, cold-,ethylene- and acetylene-induced flowering in pineapple; (3) Expression and regulation of key genes related to pineapple flowering, focusing on the responses of pineapple flowering key genes, such as FLC, SOC1, FT, LFY et al, to low temperature,Ethephon, acetylene and ethylene and aiming to further understand the molecular basis of ethylene-induced flowering in pineapple. According to the advances on flowering-pathways of model plant Arabidopsis thaliana, the underlying molecular pathways will be speculated in the low temperature-, acetylene-, and ethylene- induced flowering in pineapple. All the results will contribute to further understanding the structure base and physiological and molecular mechanisms of ethylene-induced flowering in pineapple, and the theory of flower bud differentiation and flowering in fruit tree.

乙烯是目前发现的惟一被证实能够直接启动菠萝生殖生长的激素,实践中主要通过施用乙烯利或CaC2诱导菠萝成花达到调节菠萝上市时间的目的，但其结构与生理基础、分子途径并不清楚。本项目主要研究内容包括:⑴ 菠萝成花过程比较解剖学研究。对比研究乙烯、冷诱导、乙炔诱导成花过程中,菠萝顶端分生组织形态学变化特征;(2)菠萝成花过程比较生理学研究。对比研究乙烯、冷诱导、乙炔诱导成花过程中，菠萝内源激素、可溶性糖、多胺、ACC氧化酶活性等的变化规律,旨在阐明菠萝自然开花、低温、乙炔、乙烯诱导成花的生理学基础;(3)菠萝成花关键基因的表达调控。借鉴模式植物拟南芥的研究成果,重点研究乙烯、乙炔、低温对菠萝开花关键基因的调控作用,旨在深入了解乙烯诱导菠萝成花的分子生物学基础,推测乙烯、乙炔、低温诱导菠萝成花可能的分子途径。研究结果有助于深入了解乙烯控制菠萝成花的生理和分子机制,对果树花芽分化及成花理论做出贡献。

乙烯是重要的植物激素，在启动菠萝生殖生长和胁迫响应中具有重要的调节功能。本项目系统观察了乙烯、冷诱导、乙炔诱导菠萝成花过程以及菠萝顶端分生组织形态学变化特征；以此为基础，开展了乙烯处理后菠萝顶芽转录组数据分析工作，筛选出一批乙烯诱导菠萝开花早期响应的相关途径及基因；结合基因组数据，发现菠萝至少拥有40个MADS-box基因和104个R2R3-MYB基因，在初筛获得13个FLC-like基因的基础上基本锁定了4个FLC候选基因（控制菠萝开花的关键基因）。完成了多个与开花有关的基因克隆及表达分析，包括10个MADS-box基因等；完成了菠萝乙烯生物合成途径多个关键基因的克隆与分析工作，包括3个AcEIN3基因等。完成了乙烯利、冰块、乙炔灌心处理后台农16号菠萝不同发育阶段内源激素含量、可溶性糖、ACC 氧化酶活性等的测定工作并初步发现了其变化规律。研究结果初步揭示了乙烯诱导菠萝成花过程的形态学和解剖学变化规律、生理变化基础以及部分分子途径，筛选获得多个与乙烯诱导菠萝成花及其相关的基因，为深入开展和进一步阐明菠萝诱导成花的机理奠定了良好的基础。