摘要
【目的】9-顺式环氧类胡萝卜素双加氧酶(NCED)、醛氧化酶(AAO)和玉米黄质环氧化酶(ZEP)在脱落酸(abscisic acid,ABA)间接途径合成中发挥主要调节作用,它们是ABA合成相关基因。以桑树栽培品种嘉陵40号(Morus atropurpurea Roxb.)果实为材料,测定其发育过程中ABA的含量,分析桑椹成熟过程中ABA合成相关基因的转录表达、ABA及其合成抑制剂对果实发育的影响,为研究ABA在桑椹成熟和衰老过程中的作用机制提供基础数据。【方法】根据从单倍体川桑(Morus notabilis Schneid.)基因组数据库(http://morus.swu.edu.cn/morusdb)下载的ABA合成相关基因序列,对其DNA及推导的氨基酸序列进行分析。使用RNAiso Plus(Ta Ka Ra)提取总RNA。以c DNA为模板,利用real-time PCR方法检测不同时期和不同处理桑椹中ABA合成相关基因的转录表达差异。利用高效液相色谱法,测定桑椹发育过程中的ABA含量。【结果】在川桑基因组数据库筛选鉴定到6个ABA合成相关基因:1个Mn AAO、2个Mn ZEP和3个Mn NCED。Mn NCED1-3氨基酸序列高度保守,聚类分析表明它们与双子叶果树NCEDs序列同源性较高,与单子叶植物同源性较低;转录分析表明它们在叶中转录水平相对高于其他组织,在根中最低。其中Mn NCED2和Mn NCED3在根、皮、冬芽、雄花、叶中的转录水平较高。随着果实的发育,ABA含量在转色期开始逐渐上升。外源ABA处理后,桑椹脱落率升高,而氟啶酮(fluridone)可以抑制桑椹的脱落。Mn NCED1-3在果实发育中后期的转录水平较高,与ABA含量的升高相一致,而Mn AAO和Mn ZEP1-2在中后期下调。离体桑椹经ABA处理后,Mn NCED1、Mn AAO和Mn ZEP1的转录水平直到第4天才出现上调,Mn NCED3在第3天和第4天被上调,Mn ZEP2一直上调;氟啶酮处理后Mn NCED1和Mn ZEP2的转录表达量只在第1天和第3天被下调,Mn AAO和Mn ZEP1只在第4天升高,Mn ZEP1只在处理后第1天被下调,Mn NCED2在ABA和氟啶酮处理�
【 Objective 】 9-cisepoxycarotenoid dioxygenase（NCED）, ABA-aldehyde oxidase（AAO）, Zeaxanthin epoxidase（ZEP） are the key enzymes involved in biosynthesis of abscisic acid（ABA） via indirect pathway. The aim of this study was to analyze the transcriptional expression of ABA biosynthesis related genes and detect the content of ABA during Jialing 40（Morus atropurpurea Roxb.） fruit development. The effects of ABA and its synthesis inhibitors on fruit development were also explored.This work will lay a foundation for further studying the role of ABA on mulberry（Morus alba L.） fruit maturity and senescence.【Method】In this study, the sequences of six putative ABA biosynthesis related genes were obtained from Morus notabilis genome database and its deduced amino acid sequences were analyzed by using bioinformatics tools. Total RNA was extracted from mulberry fruit using RNAiso Plus（Ta Ka Ra） and reverse transcribed to synthesize c DNA. The relative transcriptional expression of ABA biosynthesis related genes in different developmental stages and treated mulberry fruits was investigated by using q RT-PCR. The content of ABA was determined by using HPLC.【Result】Six ABA biosynthesis related genes were isolated from mulberry, including one AAO gene, two ZEP genes and three NCED genes. Multiple-sequence alignment results showed that Mn NCEDs amino acids are relatively conserved in higher plants. Cluster analysis revealed that Mn NCED1-3 are closely related with dicotyledons plants and farther with monocotyledons plants. Transcription analysis indicated that the expression of ABA biosynthesis related genes was higher in leaves and the lowest expression was detected in roots. Particularly, the expression level of Mn NCED2 and Mn NCED3 was higher in different plant tissues compared to other genes. The concentration of ABA was strongly increased after the conversion stage of fruit. Exogenous ABA significantly promoted fruit maturity, whereas fluridone remarkably inhibited fruit ripening compar
出处
《中国农业科学》
CAS
CSCD
北大核心
2015年第5期1011-1022,共12页
Scientia Agricultura Sinica
基金
国家公益性行业(农业)科研专项(201403064)
国家自然科学基金(31360190)
国家现代农业产业技术体系建设专项(CARS-22)
