论文部分内容阅读
以商业成熟期的桃(Prunus persica)栽培品种秦王(极耐贮)和沙红(不耐贮)为试材,采用气相色谱测定乙烯释放量;利用实时荧光定量PCR(quantitative Real-time PCR,q RT-PCR)技术分析乙烯合成关键酶和果实软化相关基因在两个品种中的表达差异。研究结果表明,秦王果实在贮藏期间ACC合成酶基因(1-aminocyclopropane-1-carboxylic acid synthase gene,Pp ACS1)相对表达量极低,乙烯释放速率也极低,一直保持较高的硬度;而沙红果实在贮藏过程中Pp ACS1的相对表达量随软化进程迅速增加,释放大量乙烯,果实硬度下降快。秦王果实中ACC氧化酶基因(1-aminocyclopropane-1-carboxylic acid oxidase gene,Pp ACO1)虽有一定的表达量,但没有随贮藏时间而增加;而Pp ACO1在沙红桃中随果实的软化表达量呈显著上升的趋势。秦王果实中细胞壁降解酶果胶甲酯酶基因(pectin methylesterase gene,Pp PME)和多聚半乳糖醛酸酶基因(polygalacturonase gene,Pp PG)的表达量都极低;而在沙红果实中其表达量均呈持续增加趋势。此外,秦王果实中扩张蛋白基因(expansin gene,Pp EXP)的表达量也较低;而在沙红中表达量较高。N-聚糖加工酶α-甘露糖苷酶基因(α-mannosidase gene,Ppα-Man)和β-氨基己糖苷酶基因(β-hexosaminidase gene,Pp Hex1,Pp Hex2)在沙红和秦王贮藏期间均有较高表达量,且秦王中的表达量显著高于沙红(P<0.05)。这表明秦王果实采后不软化是由于Pp ACS1的转录受阻,不能产生乙烯,从而致使细胞壁水解酶Pp PME和Pp PG几乎不表达,果胶代谢受阻,因而果实一直保持较高硬度;而沙红果实在采后贮藏中释放大量乙烯,促进了Pp EXP、Pp PME和Pp PG的表达,引起细胞壁果胶的大量降解,导致果实迅速软化。而Ppα-Man、Pp Hex1和Pp Hex2可能不是秦王软化过程的关键基因。本研究为阐明桃果实成熟软化机理及其高效培育耐贮品种提供基础资料。
The ethylene production of Prunus persica cultivar Qin Wang (extremely resistant to storage) and sand red (intolerant to storage) were tested in commercial maturity stage by gas chromatography. The quantitative real-time PCR (q RT-PCR) was used to analyze the expression difference of key enzymes in ethylene synthesis and fruit softening related genes in two cultivars. The results showed that the relative expression level of ACC-producing gene (1-aminocyclopropane-1-carboxylic acid synthase gene) was very low and the ethylene release rate was very low, The relative expression of Pp ACS1 during storage of red fruits rapidly increased with the softening process, releasing a large amount of ethylene, and the hardness of fruits decreased rapidly. Although there was a certain amount of ACC oxidase gene (P-ACO1) in Qin fruit, it did not increase with storage time. However, Pp ACO1 expressed softening in fruit The amount showed a significant upward trend. The expression levels of pectin methylesterase gene (Pp PME) and polygalacturonase gene (Pp PG) in cell wall degrading enzymes of Qinwang were extremely low. However, The expression levels showed a continuously increasing trend. In addition, the expression of expansin gene (Pp EXP) was also lower in Qin fruit and higher in saffron. The N-glycan processing enzyme α-mannosidase gene (Ppα-Man) and β-hexosaminidase gene (Pp Hex1, Pp Hex2) Higher expression level, and the expression of Qin Wang was significantly higher than that of sand red (P <0.05). This indicates that the postharvest Qin fruit softening is due to the inhibition of Pp ACS1 transcription, can not produce ethylene, resulting in the cell wall enzyme Pp PME and Pp PG almost no expression, pectin metabolism is blocked, so the fruit has always maintained a high hardness; In fact, a large amount of ethylene was released during post-harvest storage, which promoted the expression of Pp EXP, Pp PME and Pp PG, caused a large amount of degradation of cell wall pectin, resulting in rapid softening of the fruit. However, Ppα-Man, Pp Hex1 and Pp Hex2 may not be the key genes of Qin Wang softening process. This study provides the basic information for elucidating the ripening and softening mechanism of peach fruit and its efficient cultivation of storages.