百香果低温胁迫转录组及茉莉酸代谢基因分析

Transcriptome and Jasmin Metabolism Gene Analysis of Passiflora edulia Sims Under Low Temperature Stress

为研究百香果低温胁迫响应机制,以紫果百香果(Passiflora edulia Sims)为试验材料在0℃下低温胁迫处理,以常温处理为对照组(CK),采用Illumina HiSeq测序平台进行转录组测序,并对茉莉酸代谢相关基因进行挖掘。结果显示,共获得百香果转录组数据45.30 Gb,组装得到39 521条Unigene和5 311个差异基因;GO分类显示注释的Unigene分为细胞组件、分子功能及生物过程三大类,其中差异基因数量最多为生物过程大类的代谢过程,包括甾醇生物合成、类黄酮糖脂化、酪氨酸代谢、L-苯丙氨酸生物合成、软木脂生物合成、芥子油苷代谢及长链脂肪-酰基辅酶A代谢等。KEGG途径富集分析结果显示,核糖体途径、淀粉与蔗糖代谢途径、植物激素信号转导途径及植物与病原体互作途径为百香果响应低温胁迫的重要代谢途径。实时定量PCR(qRT-PCR)分析表明,百香果低温胁迫后其茉莉酸代谢途径相关基因AOC、AOS、JAR1、MYC2、PYL和JAZ均上调表达,该结果与测序获得FPKM值变化趋势较为相似,说明测序结果较为准确。但低温胁迫后,COI1的表达水平呈下调趋势。研究发现,在百香果中茉莉酸对低温胁迫的响应机制大体上与模式植物一致,关于COI1和MYC2等基因的调控方式还有待进一步功能验证。本研究结果为进一步明确百香果抗寒机制提供了科学参考。

To study the response mechanism of Passiflora edulia Sims(P. edulia) to low temperature stress, P. edulia plants treated under 0℃ and 25℃ were used as materials for transcriptome sequencing and digging out genes related jasmonic acid(JA) metabolism on Illumina HiSeq sequencing platform. A total of 45.30 Gb clean data were obtained, and 39 521 unigenes and 5 311 different expression genes(DEGs) were assembled. According to GO classification, these DEGs were classed into cell component, molecular function and biological process. Among them, metabolic pathways in biological process contained most DEGs, including sterol biosynthesis, flavonoid lipidization, tyrosine metabolism, L-phenylalanine biosynthesis, cork-fat biosynthesis, glucosinolide metabolism and long-chain aliphatic acyl coenzyme A metabolism. KEGG pathway enrichment analysis showed that ribosome pathway, starch and sucrose metabolism pathway, plant hormone signal transduction pathway, plant and pathogen interaction pathway were important metabolic pathways of P. edulia in response to low temperature stress. Based on qRT-PCR, AOC, AOS, JAR1, MYC2, PYL and JAZ, the key genes of JA metabolism pathway in P. edulia were all up-regulated under low temperature stress while COI1 was down-regulated. The validation results were similar to the trends of FPKM values obtained by sequencing, indicating that the sequencing results were relatively accurate. Our research indicated that the response mechanism of JA to low temperature stress in P. edulia was basically consistent with that in model plants, but the regulation of genes such as COI1 and MYC2 needed further functional verification. These results would provide scientific references for further research on cold resistant mechanism of P. edulia.