红肉桃两类花色素苷积累模式与相关基因表达差异

The Difference of Anthocyanin Accumulation Pattern and Related Gene Expression in Two Kinds of Red Flesh Peach

【目的】分析中国主要红肉桃种质呈色类型及分子机理,为红肉桃种质优异基因发掘和分子标记辅助选择育种奠定理论基础。【方法】选择8份红肉桃种质和1份白肉桃种质为试材,分别在花后一个月开始采集样品,以后每隔10 d左右采集一次,至果实成熟期为止;用2%甲酸甲醇提取不同种质果肉的花色素苷,分别测定其在510 nm和700 nm的吸光值;利用实时荧光定量PCR(q RT-PCR)方法,测定与花色素苷合成相关的13个关键结构基因和调节基因的表达水平。【结果】根据果实发育中后期花色素苷含量的变化趋势可将8份红肉桃种质分为2类,一类种质的花色素苷合成高峰出现在果实成熟期(成熟期积累型),如‘郑引82-9’‘大红袍’‘黑布袋’‘红桃’和‘天津水蜜’;另一类种质的花色素苷合成高峰出现在果实发育中期,在成熟期花色素苷含量有所下降(发育中期积累型),如‘哈露红’‘大果黑桃’和‘乌黑鸡肉桃’。在与花色素苷合成相关的结构基因中,Pp CHS和Pp UFGT的表达量与成熟期积累型种质的花色素苷含量的变化趋势一致;而发育中期积累型种质,果肉中花色素苷的大量积累与所有结构基因的表达趋势一致。在4个调控基因中,只有Pp MYB10.1的表达水平较高,且表达模式同红肉桃种质两类花色素苷积累模式相似。【结论】根据桃果肉着色规律和花色素苷积累模式,8份红肉桃可以分为成熟期积累型和发育中期积累型种质。Pp CHS和Pp UFGT是成熟期积累型种质的关键结构基因,而Pp MYB10.1在供试的所有红肉桃种质花色素苷合成中起关键作用。

【Objective】The objective of this experiment is to investigate the coloring mechanism of Chinese red-flesh peach germplasms and lay a theoretical foundation for excellent gene identifying and molecular marker assisted breeding in blood-flesh peach accessions.【Method】Eight red flesh peaches and one white flesh peach were selected as samples. The samples were collected one month after full bloom, and then collected every 10 days until the mature period. The anthocyanin of pulp of different germplasms was extracted with 2% formic acid methanol, determining the absorbance at 510 nm and 700 nm. The expression of 13 key structural genes and regulatory genes associated with anthocyanin synthesis was determined by real-time quantitative PCR（q RT-PCR）.【Result】According to the accumulation of anthocyanin at middle-late stages of fruit, eight red-flesh peaches could be divided into two categories. The peak of anthocyanin biosynthesis appeared at mature stage, which was referred to as mature period accumulation type, including Zheng Yin 82-9, Da Hong Pao, Hei Bu Dai, Hong Tao and Tianjin Shui Mi; The peak of anthocyanin synthesis occurred at the middle stage of fruit development, and the content of anthocyanin decreased at mature stage, which was referred to as the mid-developmental accumulation type, including Harrow Blood, Da Guo Hei Tao and Wu Hei Ji Rou Tao. In the structural genes associated with anthocyanin, the expression of Pp CHS and Pp UFGT was consistent with the trend of the variation of the anthocyanin content of mature period accumulation type germplasms, which were the key speed-limiting genes of these kinds of germplasms. In the mid-developmental accumulation type, the accumulation of anthocyanin in the mesocarp was consistent with the trend of expression of all structural genes. Among the four regulatory genes, only the expression level of Pp MYB10.1 was high and the expression pattern was similar to the pattern of anthocyanin accumulation in the two types of red flesh germplasms during fruit developmental stages. 【Conclusion】According to the coloring pattern of peach fruit and the pattern of anthocyanin accumulation, eight red-flesh peaches could be divided into two types, namely mature period accumulation type and mid-developmental accumulation type. The Pp CHS and Pp UFGT genes were the key structural genes of mature period accumulation type accessions, while Pp MYB10.1 played a key role in the synthesis of anthocyanin in all red-flesh peach germplasms.