花生Ca2+/CaM调控的多胺合成对盐胁迫下光合机构的保护作用

The self-sufficiency rate of edible plant oil is less than 32% in our country. It is very important to guarantee national edible oil supply security by improving the total yield of peanut which is one of the important oil crops. Saline-alkali soil is an important factor limiting peanut planting and total yield to be improved further. It will be of great significance to expand peanut cultivation in saline-alkali soil and improve its total yield by studying the mechanisms of peant salt resistance. Polyamine biosynthesis pathway and Ca2+ signal tranduction pathway are two important pathways of plants inherent to response to salt stress, however, the interaction mechanisms of this two pathways and the relationships between them and peanut salt resistance are still needed to be studied further. In the present work, peanut seedlings, transgene tobacco and Arabidopsis AtSAMS mutants are used as materials. The following trials will be as key ones to be done: gene functional analysis of AhSAMS and AhSAMDC, effects of Ca2+/CaM (including exogenous Ca2+) on biosynthesis of different components of polyamines, effects of exogenous Spm on CaM expression and its protein content, determination of protection of Ca2+/CaM and polyamines to photosynthetic apparatus. By these, we try to elucidate the regulating relationships between Ca2+/CaM signal transduction pathway and polyamine biosynthesis pathway, and also to elucidate the role of polyamine biosynthesis pathway in protection to photosynthetic apparatus induced by Ca2+/CaM signal transduction pathway.

我国食用植物油自给率不足32%，作为重要的油料作物之一，提高花生总产对于保证我国食用油供给安全具有重要意义。盐碱地是限制花生种植和总产进一步提高的重要环境因素。探索花生抗盐机理对于扩大花生盐碱地种植和提高总产具有重要意义。多胺合成途径和Ca2+信号转导途径是植物所具有的两条重要的盐胁迫响应途径，但二者之间的相互作用机制及与花生抗盐性关系尚不清楚。以花生、转基因烟草和拟南芥AtSAMS突变体为试材，通过花生AhSAMS与AhSAMDC基因功能分析、Ca2+/CaM（包括外源Ca2+）对多胺不同成分合成影响的分析、外源Spm分别对CaM基因表达及CaM蛋白含量影响的分析、Ca2+/CaM及多胺对光合机构的保护作用测定，研究盐胁迫下Ca2+/CaM信号转导途径和多胺合成途径之间的调控关系，明确多胺合成在Ca2+/CaM信号转导途径中对光合机构的保护作用。

我国食用植物油自给率不足32%，作为重要的油料作物之一，提高花生总产对于保证我国食用油供给安全具有重要意义。盐碱地是限制花生种植和总产进一步提高的重要环境因素。探索花生抗盐机理对于扩大花生盐碱地种植和提高总产具有重要意义。以花生、转基因烟草和拟南芥AtSAMS突变体为试材，通过Pull-Down、Bifc及亚细胞定位实验证明了花生钙调素和S-腺苷甲硫氨酸合成酶（SAMS）能够相互作用，从而通过钙信号途径调节下游功能蛋白。通过Southern blot实验发现SAMS基因家族在花生中包括4个成员。SAM是多胺合成前体，通过过量表达该基因以及多胺合成途径中的另一个重要基因SAMDC发现转基因植株中多胺组分含量增加，多胺类化合物能减轻植物在逆境条件下叶绿素的损失，稳定类囊体膜组份，具体作用机理可能由于多胺化合物直接结合在膜上，阻止了膜脂氧化和膜蛋白降解。通过对盐胁迫下的生理指标检测而发现AhSAMS通过调控抗氧化防御系统及抗逆基因的表达进而提高植株的抗盐性。RNA-Seq分析发现，与WT株系相比，AhSAMS转基因株系中与生长素，抗逆相关基因的表达都发生了变化。进一步证实了AhSAMS通过调控物质合成，激素含量，以及抗逆相关基因的表达进而调控植物耐盐性。