摘要
为研究‘砀山酥梨’及其褐皮芽变木葡聚糖转葡糖苷酶基因(PbXET)表达水平差异,该实验利用RACE技术,克隆了梨PbXET基因;采用实时荧光定量PCR技术,分析了梨树叶片、果皮和果肉等不同组织及花后不同时期果皮中PbXET基因表达差异。结果表明:(1)梨PbXET3(KJ690921)和PbXET4(KJ690922)开放阅读框分别为903bp和891bp,分别编码300和296个氨基酸;氨基酸序列聚类分析显示,PbXET3与苹果MdXET-3以及PbXET4与苹果MdXET-5的亲缘关系最近。(2)半定量PCR分析显示,花后150d,PbXET3和PbXET4基因在‘砀山酥梨’和‘锈酥’不同组织中均有表达,且PbXET3在叶片中表达量很低,在果皮、果肉中表达相对较强,其中叶片中PbXET3表达量低于PbXET4,而果肉和果皮中PbXET3的表达均明显高于PbXET4。(3)荧光定量PCR分析发现,在‘砀山酥梨’和‘锈酥’果皮中,PbXET3和PbXET4基因不同时期的表达量变化趋势不同;与‘砀山酥梨’相比,果皮颜色发生变化(花后100d)之后,‘锈酥’果皮中PbXET3表达量骤减;而果皮颜色发生变化(花后100d)之前,PbXET4表达量均显著降低。由此推测,PbXET3和PbXET4基因参与了‘锈酥’果皮褐色形成的调节,其表达水平差异可能是改变‘锈酥’表皮细胞结构的重要原因之一。
To investigate the differences in expression of xyloglucan endotransglycosylase gene（PbXET） in ＇Dangshansuli＇ and its russet mutant ＇Xiusu＇ pear（Pyrus bretschneideri Rehd. ）, we cloned the cDNA fragment of PbXET by rapid amplification of cDNA ends（RACE）. The level of relative expression of PbX- ET in leaf,exocarp and sarcocarp and in the exocarp at different stages（days after full bloom,DAFB） were determined by real time quantitative reverse transcription-PCR（qRT-PCR）. The results showed that：（1） PbXET3, with the accession number of KJ690921 in the National Center for Bioteehnology Information （NCBI） ,and PbXET4,with the accession number of KJ690922 in NCBI had a open read frame（ORF） of 903 bp and 891 bp,respectively,encoding the corresponding polypeptide of 300 amino acids or 296 amino acids. Clustering analysis by sequences of amino acids showed that the structure of PbXET3 and PbXET4 in pear plant had a closer relationship to MdXET-3 and MdXET-5 in apple plant respectively. （2）The resuits of semi-quantitative PCR demonstrated that PbXET3 and PbXET4 had expressed in leaf, exocarp and sarcocarp of ＇ ＂ Dangshansub and its russet mutant ＇Xiusu＇ pear at 150 DAFB,but expression of the two genes were lower in leaves and higher in exocarps and sarcocarps. Compared with PbXET4, the relative levels of PbXET3 expression were lower in leaves,but were higher in exocarps and sarcocarps. （3）The ex- pression of PbXET3 and PbXET4 genes showed different trend lines of the dynamic change in exocarps of ＇Dangshansuli＇ and its russet fruit mutant Xmsu pear. The expression of PbXET3 decreased sharply af- ter the beginning of exocarp turning russet（100 DAFB）,whereas,the expression of PbXET4 decreased be- fore 100 DAFB in exocarps of ＇Xiusu＇ pear in compare with that of ＇Dangshansuli＇ pear. It was postulated that the expression of PbXET3 and PbXET4 may be involved in formation of russet exocarps in pear fruit, and the difference in the expression of the two ge
出处
《西北植物学报》
CAS
CSCD
北大核心
2014年第12期2388-2393,共6页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家现代农业产业技术体系建设专项(CARS-29-14)
国家自然科学基金(31101519)
