【摘要】：竹筍即竹子膨大的芽和幼嫩的莖,具有高纖低脂,營養(yǎng)齊全的特點(diǎn),備受消費(fèi)者青睞。但竹筍采收后很快出現(xiàn)木質(zhì)化,喪失鮮嫩可口的食用品質(zhì),成為竹筍產(chǎn)業(yè)發(fā)展的重要限制因素。因此,探究竹筍木質(zhì)化的發(fā)生及其分子機(jī)理為進(jìn)一步研究延長竹筍貯運(yùn)期、降低采后損耗的新技術(shù)提供了理論支撐。本論文以毛竹筍上、中、下3個(gè)部位為試驗(yàn)材料,研究了毛竹筍不同部位細(xì)胞壁的成分變化以及與木質(zhì)化有關(guān)的轉(zhuǎn)錄組差異基因的表達(dá)情況,并初步分析了半纖維素木聚糖合成的關(guān)鍵基因PeIRX10在竹筍組織次生細(xì)胞壁形成中的功能。得到如下結(jié)論:(1)毛竹筍不同部位因木質(zhì)化程度不同,細(xì)胞壁中各組分的含量不同。沿著竹筍的生長方向,木質(zhì)素和纖維素含量由上部到下部逐漸增加,而果膠和半纖維素的含量逐漸降低,同時(shí)木質(zhì)素合成相關(guān)酶PAL、CAD和C4H的活性也由上部到下部逐漸增加,說明毛竹筍在下部的木質(zhì)化程度高于上部和中部。(2)對毛竹筍的上、中、下三個(gè)部分分別進(jìn)行RNA-seq分析,共獲得了大約133.9百萬條reads,總堿基數(shù)為18.13Gbp。在上vs中、上vs下和中vs下的兩兩比對中,發(fā)現(xiàn)的DEG數(shù)目分別為3840、3518和3925,并對其進(jìn)行功能注釋。然后篩選并分析了木質(zhì)化過程中與細(xì)胞壁代謝相關(guān)的差異基因,得到了編碼纖維素、半纖維素和木質(zhì)素合成途徑中相關(guān)酶基因的表達(dá)特點(diǎn),并對其進(jìn)行qRT-PCR驗(yàn)證,qRT-PCR結(jié)果與RPKM值一致。與纖維素和木質(zhì)素合成相關(guān)的基因在下部和中部的表達(dá)量高于上部,這些基因在中下部表達(dá)量的上調(diào)與其較高的木質(zhì)化程度有關(guān)。(3)構(gòu)建了木聚糖合成關(guān)鍵基因PeIRX10過量表達(dá)載體并轉(zhuǎn)化模式植物擬南芥,發(fā)現(xiàn)PeIRX10基因的過量表達(dá)在擬南芥irx1(-/-)irx10(-/-)雙突植株中可以使其表型恢復(fù)正常、細(xì)胞壁不正常的木質(zhì)部消失,且細(xì)胞壁中木聚糖含量恢復(fù)到正常水平。表明毛竹的PeIRX10基因很可能與擬南芥AtIRX10基因具有相同的生物學(xué)功能,通過參與木聚糖的生物合成而導(dǎo)致竹筍組織次生細(xì)胞壁的形成。
[Abstract]:Bamboo shoots are bamboo shoots and young stems with high fiber and low fat and complete nutrition, which are favored by consumers. However, the lignification of bamboo shoots soon after harvest, the loss of fresh and delicious edible quality, has become an important limiting factor for the development of bamboo shoot industry. Therefore, the study of the lignification of bamboo shoots and its molecular mechanism provide theoretical support for further study on the new technology of prolonging the storage and transportation period of bamboo shoots and reducing post-harvest loss. In this paper, the composition changes of cell wall and the expression of transcriptional differentially expressed genes in different parts of bamboo shoot were studied. The function of PeIRX10, the key gene of hemicellulose xylan synthesis, in the formation of secondary cell wall of bamboo shoot was analyzed. The conclusions are as follows: (1) the content of components in the cell wall of bamboo shoots is different because of the different degree of lignification. Along the growth direction of bamboo shoots, the content of lignin and cellulose increased gradually from the top to the bottom, while the contents of pectin and hemicellulose decreased gradually, and the activities of lignin synthase PAL,CAD and C4H increased gradually from the upper to the lower. The results showed that the lignification degree of bamboo shoots in the lower part was higher than that in the upper part and the middle part. (2) the total base number of 133.9 million reads, was obtained by RNA-seq analysis of the upper, middle and lower parts of the bamboo shoot. In the pairwise comparison of the upper vs, the upper vs and the middle vs, the number of DEG found is 3840m3518 and 3925, respectively, and its function is annotated. Then the differentially expressed genes related to cell wall metabolism during lignification were screened and analyzed. The expression characteristics of enzyme genes related to cellulosic hemicellulose and lignin biosynthesis were obtained and verified by qRT-PCR. QRT-PCR results are consistent with RPKM values. The genes related to cellulose and lignin synthesis expressed more in the lower and middle parts than in the upper ones. The upregulation of these genes in the middle and lower part is related to the higher lignification degree. (3) the overexpression vector of PeIRX10, the key gene of xylan synthesis, was constructed and transformed into Arabidopsis thaliana. It was found that overexpression of PeIRX10 gene in Arabidopsis thaliana irx1 (- / -) irx10 (- / -) could make the phenotype return to normal, the abnormal xylem disappeared, and the xylan content in the cell wall returned to normal level. It was suggested that the PeIRX10 gene of Phyllostachys pubescens had the same biological function as the AtIRX10 gene of Arabidopsis thaliana, which resulted in the formation of secondary cell wall of bamboo shoot tissue by taking part in the biosynthesis of xylan.
【學(xué)位授予單位】：南京農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：Q943.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 陳如壽;鄭旭煦;殷鐘意;蔡函江;;竹筍甾醇和膳食纖維的制取方法研究進(jìn)展[J];竹子研究匯刊;2011年03期

2 ;Insights into the Bamboo Genome:Syntenic Relationships to Rice and Sorghum[J];Journal of Integrative Plant Biology;2010年11期

3 Gea Guerriero;Johanna Fugelstad;Vincent Bulone;;What Do We Really Know about Cellulose Biosynthesis in Higher Plants?[J];Journal of Integrative Plant Biology;2010年02期

4 王雪霞;薛永常;趙文超;;木質(zhì)素生物合成中C3H/HCT的研究進(jìn)展[J];生命的化學(xué);2008年05期

5 羅曉莉;曾凱芳;;竹筍的采后生理及貯藏保鮮技術(shù)研究進(jìn)展[J];食品科技;2006年11期

6 江澤慧;于文吉;余養(yǎng)倫;;竹材化學(xué)成分分析和表面性能表征[J];東北林業(yè)大學(xué)學(xué)報(bào);2006年04期

7 羅自生;;采后竹筍木質(zhì)化與內(nèi)源激素的關(guān)系[J];中國農(nóng)業(yè)科學(xué);2006年04期

8 李琴,汪奎宏,張都海;中國竹筍加工與貿(mào)易現(xiàn)狀[J];浙江林業(yè)科技;2001年02期

9 華錫奇,翁甫金,李琴,何奇江;竹筍調(diào)味筍配方和加工工藝的研究[J];浙江林業(yè)科技;2000年06期

10 胡春水,余紅英,佘祥威,駱琴婭,熊芳芳;毛竹筍氨基酸含量的比較[J];竹子研究匯刊;2000年02期

相關(guān)博士學(xué)位論文 前2條

1 金順玉;毛竹四個(gè)木質(zhì)素合成相關(guān)酶基因的克隆及組織特異性表達(dá)分析[D];中國林業(yè)科學(xué)研究院;2009年

2 楊學(xué)文;毛竹木質(zhì)素單體生物合成相關(guān)基因的分離、表達(dá)與功能初步鑒定[D];中國林業(yè)科學(xué)研究院;2009年

，

本文編號：2364071