中国沙棘HrANR基因及黄酮类累积与抗旱的关系

花青素还原酶(anthocyanidin reductase, ANR)是合成黄酮类物质的关键酶之一,为明确其编码基因结构及干旱胁迫下的表达模式和黄酮类物质含量及二者之间的相关性,该文从中国沙棘转录组数据中筛选获得1个ANR基因,命名为HrANR基因。采用生物信息学软件对基因序列及编码蛋白进行分析,并对不同胁迫下各组织中HrANR基因的表达量和叶中黄酮类化合物含量进行相关性分析。结果表明:(1)中国沙棘HrANR基因ORF为1 017 bp,编码338个氨基酸,为稳定的亲水性蛋白,其ANR同源蛋白具有明显的科属特性。(2)干旱胁迫下HrANR基因在中国沙棘根、茎、叶中均有表达,但表达趋势不同,其中在根中的表达呈先升高后降低再升高的趋势,在茎中呈持续下降的趋势,在叶中呈先升高后持续降低的趋势。(3)通过芦丁标准曲线获得不同胁迫程度下中国沙棘叶内黄酮类的含量,表明黄酮类含量呈先持续上升,随后略有下降,复水后上升至最高点的变化趋势,表明干旱胁迫初期叶黄酮类含量与干旱胁迫呈正相关,在严重胁迫下黄酮类含量与胁迫呈负相关。(4)叶和茎的HrANR基因表达量与黄酮类含量呈负相关(P_叶=-0.751,P_茎=-0.934),根中呈正相关(P_根=0.444)。综上表明,中国沙棘HrANR基因的表达及黄酮类含量变化与其抗旱性密切相关,其结果为中国沙棘抗旱机制的阐明提供了依据。

Correlation of HrANR genes and flavonoid accumulation with drought resistance in sea buckthorn(Hippophae rhamnoides subsp. sinensis)

Anthocyanidin reductase is one of the key enzyme involved in the synthesis of flavonoids. In order to explore the structure of ANR gene, ANR enzyme expression pattern and flavonoid content under drought stress and their correlation, a HrANR gene identified from RNA-seq data of sea buckthorn was screened and analyzed by bioinformatics soft, the expression patterns of HrANR gene in different tissues and of flavonoid contents in leaves were performed. The results were as follows:(1)The ORF of HrANR gene was 1 017 bp, which encoded 338 amino acids. It was a stable hydrophilic protein, and the homologous protein had significant family and genus characteristics.(2)HrANR gene was expressed in roots, stems and leaves of sea buckthorn under drought stress, but the expression trends were different, with an increase followed by a decrease and then an increase in roots, a continuous decrease in stems, and an increase followed by a continuous decrease in leaves.(3)The flavonoid contents in leaves of sea buckthorn under different levels of stress showed a trend that first increased continuously and then decreased slightly, increased to the highest point after rehydration. The above results indicated that the expression of HrANR gene and the changes of flavonoid content were closely related to the drought resistance of sea buckthorn. The flavonoid content in leaves was positively correlated with drought stress at the beginning of drought stress and negatively correlated with drought stress under severe stress.(4)Leaf expression, stem expression and flavonoid content of HrANR gene were negatively correlated(P_leaf= -0.751, P_stem= -0.934)and root expression was positively correlated with flavonoid content(P_root= 0.444). The above results indicate that the expression of HrANR genes and changes of flavonoid content in sea buckthorn are closely related to drought resistance, and it provides a reference for elucidating the drought resistance mechanism of sea buckthorn.