本文選題：桃果實 + 冷害　； 參考：《上海海洋大學(xué)》2017年碩士論文

【摘要】：桃果實因其濃郁的香味、柔軟多汁的口感,以及豐富的營養(yǎng)深受消費者的喜愛。桃果實為典型的呼吸躍變型果實,采后在常溫下迅速進入呼吸和乙烯高峰,從而加速衰老和軟化,極易受到機械損傷和病原微生物侵染而導(dǎo)致大量腐爛。低溫冷藏是抑制桃果實采后呼吸代謝進、延長貨架期的有效手段。然而,桃果實又屬于冷敏性果實,低溫貯藏環(huán)境會導(dǎo)致果實冷害的發(fā)生,主要表現(xiàn)為出汁率下降、果肉絮敗、果心褐變等不良性狀。成束狀阿拉伯半乳糖蛋白(FLA)作為一類與細胞壁結(jié)構(gòu)相關(guān)的糖蛋白,與果實軟化之間的聯(lián)系及其作用還不清楚。為此,本研究以“湖景蜜露”桃果實為試材,鑒定了12個假定的FLA家族成員,并對它們進行了生物信息學(xué)分析,測定了這些成員在桃生長發(fā)育組織中的表達;分析了褪黑素處理后的桃果實細胞壁果膠中性糖的組成變化,從細胞壁代謝的層面揭示了褪黑素緩解冷害的機理;研究了外源乙烯和ABA處理對FLA成員在桃果實成熟期間的表達影響,以期為闡明果實軟化的分子調(diào)控機制提供新的視角。研究結(jié)果如下:(1)成束狀阿拉伯半乳糖蛋白(FLA)是阿拉伯半乳糖蛋白(AGP)大家族中的亞族,含有阿拉伯半乳糖糖基化區(qū)域和假定的成束域(FAS)。從桃基因組數(shù)據(jù)庫篩選出了12個假定的FLA序列,對這12個FLA的蛋白結(jié)構(gòu)進行分析,結(jié)果顯示PpFLA7不具有特定的阿拉伯糖或半乳糖糖基化位點,不屬于典型的FLA家族。PpFLA6的氨基酸組成和保守域的分布與其它成員相比差別較大。聚類分析結(jié)果表明PpFLAs家族可以分為CladeⅠ,CladeⅡ,CladeⅢ三類。利用熒光定量PCR(qPCR)對不同組織和成熟階段桃果實進行表達分析,發(fā)現(xiàn)各個成員在不同時期的桃組織中差異化表達。其中,PpFLA4在桃果實成熟階段顯著上調(diào)表達,暗示了它可能在桃果實的成熟階段扮演重要角色。(2)低溫貯藏下的桃果實在經(jīng)過褪黑素處理后質(zhì)地特性發(fā)生了改變,其中包括果實硬度、內(nèi)聚力和粘附力,出汁率得到了明顯提升。中性糖(阿拉伯糖和半乳糖)的流失現(xiàn)象出現(xiàn)在貯藏第7天桃果實CDTA溶性和Na2CO3溶性的果膠組分中,分支程度明顯下降,但在貯藏第21天這一現(xiàn)象得到了改善。原子力顯微鏡結(jié)果顯示處理組桃果實果膠多糖的鏈寬集中在較小的區(qū)間,表明處理組中果膠的降解更為嚴重。FLA家族成員在褪黑素處理的桃果實貯藏后期呈現(xiàn)一致的上調(diào)表達,暗示它們響應(yīng)了褪黑素誘導(dǎo)下的果實軟化,可能起到保護細胞壁結(jié)構(gòu)不被過快分解的作用。(3)外源乙烯和ABA處理上調(diào)了常溫貯藏桃果實中PpFLA2、PpFLA4、PpFLA5、PpFLA6、PpFLA8的表達水平,表明FLA部分成員參與成熟階段乙烯或ABA信號途徑的調(diào)控網(wǎng)絡(luò),與果實的軟化相關(guān)。其中,Pp FLA4和PpFLA6在外源乙烯和ABA處理下上調(diào)表達極為明顯。結(jié)果表明,外源乙烯和ABA影響時會提升FLA家族成員的表達,調(diào)控細胞壁多糖網(wǎng)絡(luò)的代謝,防止果實細胞在其他胞壁相關(guān)的水解酶作用下過快地潰散解體。
[Abstract]:Peach fruit is very popular because of its rich flavour, soft and juicy taste and rich nutrition. Peach fruit is a typical respiratory climacteric fruit. After harvest, it quickly enters the respiration and ethylene peak at the normal temperature, thus accelerating aging and softening. It is extremely vulnerable to mechanical damage and pathogenic microorganism infection, resulting in a large amount of decay. Cold storage is an effective means to inhibit respiration and prolong shelf life after peach fruit. However, peach fruit belongs to cold sensitive fruit, and cold storage environment will lead to the occurrence of cold damage. The main performance is the decline in juice rate, Pulp Flocculation, and browning of fruit. The bundle shaped Arabia semi lactose protein (FLA) is a kind of cells as a kind of cell. The relationship between wall structure related glycoproteins and fruit softening is not clear. In this study, 12 FLA family members were identified and bioinformatics were used to determine the expression of these members in the Peach Growth and development tissues. The changes in the composition of the neutral sugar of pectin in the peach fruit wall were revealed. The mechanism of melatonin to alleviate the cold injury was revealed from the cell wall metabolism. The effects of exogenous ethylene and ABA treatment on the expression of FLA members during peach fruit ripening were studied in order to provide a new perspective for elucidating the molecular regulation mechanism of fruit softening. The results are as follows: (1) the fascicular Arabia galactose protein (FLA) is a subfamily in the large family of Arabia's galactose protein (AGP), containing the Arabia galactoglycosylation region and the presumed bundle domain (FAS). 12 assumed FLA sequences are screened from the peach genome database, and the protein structure of the 12 FLA is analyzed. The results show that PpFLA7 is not specific. The distribution of carbohydrate or galactoglycosylation sites in Arabia, which does not belong to the typical FLA family.PpFLA6, is different from those of other members. The cluster analysis results show that the PpFLAs family can be classified into Clade I, Clade II, Clade III three. Using fluorescent quantitative PCR (qPCR) to make the peach fruit in different tissues and mature stages The expression analysis showed that each member was differential expression in peach tissues at different stages. Among them, PpFLA4 was significantly up-regulated in the ripening stage of peach fruit, suggesting that it may play an important role in the maturity stage of peach fruit. (2) the texture characteristics of peach fruit under melatonin treatment under low temperature storage were changed, including the changes in the properties of melatonin. The fruit firmness, cohesion and adhesion of fruit increased significantly. The loss of neutral sugar (Arabia sugar and galactose) appeared in the CDTA solubility and Na2CO3 soluble pectin components of peach fruit for seventh days, and the branch degree decreased obviously, but the phenomenon was improved at twenty-first days in storage. The chain width of pectin polysaccharides in the peach fruit was concentrated in the smaller interval, indicating that the degradation of pectin in the treatment group was more serious in the late storage of melatonin treated peach fruit, suggesting that they responded to melatonin induced fruit softening, which may protect the cell wall structure from excessive decomposition of the wall structure of the melatonin. (3) exogenous ethylene and ABA treatment up regulate the expression level of PpFLA2, PpFLA4, PpFLA5, PpFLA6, PpFLA8 in peach fruit at normal temperature, indicating that part of FLA members participate in the regulation network of ethylene or ABA signaling pathway in the mature stage, which is related to the softening of fruit. Among them, Pp FLA4 and PpFLA6 are highly expressed under exogenous ethylene and ABA treatment. The results show that exogenous ethylene and ABA affect the expression of FLA family members, regulate the metabolism of cell wall polysaccharide network, and prevent the fruit cells from collapsing and disintegrating over the other cell wall related hydrolases.
【學(xué)位授予單位】：上海海洋大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TS255.1

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本文編號：2049986