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为了揭示西瓜二倍体及三倍体在低温胁迫下的耐冷性分子机制,以西瓜二倍体自交系‘83166’(‘京欣1号’品种的母本)及其同源三倍体为材料,利用MSAP及c DNA-AFLP技术研究低温处理前后基因表达的差异,并对差异带进行克隆、测序和比对。28对MSAP引物扩增得到2 356个位点,其中二倍体经低温处理后总甲基化率下降8.5%,三倍体下降10.4%。将13条差异带与西瓜基因组数据库比对,有7条带确定是西瓜基因组序列。26对c DNA-AFLP引物组合扩增出1 267条带,其中二倍体上调表达占48.2%,下调表达占51.8%;三倍体上调表达占51.3%,下调表达占48.7%。21条差异带在NCBI中找到了同源序列基因,包括假定蛋白(38.1%)、能量与代谢(38.1%)、信号转导(9.5%)、物质运输(9.5%)以及DNA修饰(4.8%),另有9条无同源序列。低温胁迫后,三倍体去甲基化率与上调表达量均大于二倍体,而且三倍体诱导出更多的差异基因参与了能量代谢调控、信号转导、物质运输等过程,说明在抵御低温胁迫中三倍体比二倍体有更强的耐冷性。
In order to reveal the molecular mechanism of cold tolerance in diploid and triploid plants of watermelon under cold stress, the inbred lines ’83166’ (the female parent of ’Jingxin 1’) and its autotetraploid As the material, using MSAP and c DNA-AFLP technology to study differences in gene expression before and after low temperature treatment, and cloning, sequencing and aligning the difference bands. A total of 2856 pairs of MSAP primers amplified 2 356 loci, of which the total methylation rate of diploid decreased 8.5% after cryopreservation, triploid decreased 10.4%. The 13 bands were compared with the watermelon genome database, and 7 bands were identified as the watermelon genomic sequence. A total of 1 267 bands were amplified from 26 DNA-AFLP primer combinations, of which diploid up-regulated 48.2%, down-regulated 51.8%, triploid up-regulated 51.3% and down-regulated 48.7%. 21 differential bands found homologous sequence genes in NCBI including hypothetical protein (38.1%), energy and metabolism (38.1%), signal transduction (9.5%), material transport (9.5%) and DNA modification ), And another 9 non-homologous sequences. After cold stress, the triploid demethylation rate and up-regulated expression were greater than diploid, and triploid to induce more genes involved in differential regulation of energy metabolism, signal transduction, material transport process, indicating that in the Triploid against cold stress is more cold than diploid.