香芹酮对马铃薯种薯的发芽调控机制研究

China is a big producer of potatoes, and it is also a demanding country for seed potatoes, the demand for seed potatoes is about 1,200 ten thousand tons in recent years. In order to resolve the problems of seed potato storage during early germination, seed quality and field yield decreased, the project team members have carried out study on control technology of carvone on germination of seed potato, but the seed germination of carvone regulation remains unclear. Based on this, this project intends to adopt carvone treatment and does not deal with the “Longshu potato seed series” as the object, at the different period which is from the end of the dormancy to complete germination. The effects of carvone treatment on the endogenous hormone metabolism, active oxygen production and scavenging-related enzyme activities and lipid peroxidation products of tuberogemma parts of seed potato, the differential expression of tuber proteins after treatment with carvone was further analyzed through the biotechnology of isobaric tags for relative, absolute quantification (iTRAQ), quantitative real-time PCR (qPT-PCR), high performance liquid chromatography (HPLC). The differences in the types and activities of related proteins/enzymes that are mainly involved in the regulation of germination are determined, and the regulation mechanism of carvone on germination of seed potatoes will be revealed. All of these will provid a scientific basis for the application of carvone in the storage and preservation of potato seed potatoes.

我国是马铃薯生产大国，同时也是种薯需求大国,近年来对种薯的年需求量约为1200多万吨。针对马铃薯种薯贮藏期间早发芽导致种薯品质和田间产量下降的问题，项目组成员通过研究已经掌握了香芹酮对种薯的发芽调控技术，但是香芹酮对种薯的发芽调控机制还不清楚。基于此，本项目拟采用陇薯系列的马铃薯脱毒种薯为研究对象，在种薯休眠结束至完全发芽的不同阶段，综合生理生化和蛋白组学的方法，采用同位素标记相对和绝对定量（iTRAQ）、实时荧光定量PCR（qPT-PCR）、高效液相色谱（HPLC）等技术手段，通过系统研究香芹酮处理对块茎内源激素代谢、活性氧产生和清除相关酶活性及膜脂过氧化产物的影响，进一步分析香芹酮处理种薯后块茎蛋白的差异表达，明确其主要参与发芽调控作用的相关蛋白质/酶的种类或活性差异，以期揭示香芹酮对种薯发芽的调控机制，从而为香芹酮在马铃薯种薯贮藏保鲜中的应用提供科学依据。

我国既是马铃薯生产大国也是种薯需求大国。马铃薯种薯过早发芽易产生种薯活力下降、贮藏损失大以及田间减产等问题，我们前期研究发现香芹酮处理能够有效调控种薯的发芽时效性，但是对其调控机制还不明确。本项目采用600 ppm香芹酮处理“陇薯14号”种薯块茎，综合生理生化、组织形态学和分子生物学等多学科方法，结合香芹酮在块茎不同部位中残留量的变化，分析评价了香芹酮处理对块茎的发芽调控效果，揭示了香芹酮处理对块茎活性氧（ROS）代谢关键酶和相关产物及內源激素含量的影响规律，并利用蛋白组学和代谢组学分析了香芹酮处理对种薯块茎抑芽和恢复发芽的调控机理。结果表明：1）香芹酮处理能够推迟块茎的发芽时间，显著降低块茎的发芽率和发芽指数；通过观察块茎顶芽组织形态发现，香芹酮处理破坏了块茎顶芽组织结构，芽尖变黑坏死，不能正常生长，但是当香芹酮药效散除后，处理块茎又能够正常发芽；块茎不同部位中香芹酮的残留量由大到小依次为：薯皮＞芽眼＞薯肉，香芹酮主要存在于薯皮中。2）香芹酮处理抑制了块茎芽眼处的NOX、SOD、CAT、POD、APX和GR活性，降低了O2•−、H2O2、GSH和MDA含量，但是当处理块茎发芽后，其含量及酶活性均大于对照。3）香芹酮处理降低了块茎芽眼处的GA3、IAA和ZR的含量，促进了ABA含量的升高。4）蛋白组和代谢组分析发现所筛选的差异表达蛋白和差异代谢物主要富集在蔗糖与淀粉代谢、嘧啶代谢、柠檬酸循环和氨基酸代谢等途径。综上所述，香芹酮处理降低了种薯块茎的ROS 代谢水平，低水平的ROS以信号分子作用，可能通过影响蔗糖与淀粉代谢、嘧啶代谢、柠檬酸循环和氨基酸代谢等途径，调节块茎中相关内源激素的含量，进而调控块茎芽的生长，为香芹酮在马铃薯种薯贮藏保鲜中的应用提供了理论依据。