2个淀粉含量差异显著粉葛品种叶片的比较转录组学分析

Analysis on Comparative Transcriptomic for the Leaves of Two Cultivars of Pueraria thomsonii with the Significant Different Starch Content

粉葛是豆科葛属植物,其块根富含淀粉,具有重要的食用和药用价值。不同粉葛品种的淀粉含量存在明显差异。为揭示粉葛淀粉合成调控的相关基因,利用高通量测序技术,对2个淀粉含量存在显著差异的赣葛1号(高淀粉含量,鲜葛根含淀粉20%,干葛根含淀粉35%)和赣葛2号(低淀粉含量,鲜葛根含淀粉14%,干葛根含淀粉25%)的叶片进行转录组学测序和比较分析。结果表明,获得228740426条高质量测序数据,拼接组装成71910条单基因,43978条单基因获得蛋白序列而被注释(占61.12%),在Nr、KEGG、KOG和SwissProt四大数据库中均被注释的单基因有20110条,其中差异表达基因4267个。GO富集分析显示,上调和下调最多的基因富集在生物学过程中的新陈代谢和细胞过程功能中。KEGG代谢通路富集分析发现,通路显著富集在前位的是核糖体、蛋白质在内质网中的加工过程、氧化磷酸化、植物与病原体的相互作用和植物激素信号转导等。差异表达基因中,赣葛1号中的上调(2143个)和下调(2124个)基因相差不大,|log2(FC)|>5.0的表达上调(593个)和下调(402个)的表达基因数差异较大,|log2(FC)|>10.0的表达上调(368个)和下调(146个)的表达基因数差异巨大;未能被归入KEEG A类的差异表达基因数(3512个)是被归入KEEG A类(755个)的4.65倍,占总差异表达基因数的82.31%;未能被功能描述的差异表达基因数(840个)分别占未能被归入KEEG A类的和总差异表达基因数的23.92%和16.69%。在被归入KEEG A类中,差异表达基因数最多的是代谢,其次是遗传信息处理,而环境信息处理、生物系统和细胞过程的较少。上调位列前5位的差异表达基因分别涉及几丁质酶同源物、FERONIA亚型X2类受体激酶、异黄酮-7-O-甲基转移酶9、FERONIA类受体激酶和Kunitz家族胰蛋白酶及蛋白酶抑制剂前体合成,下调位列前5位的差异表达基因分别涉及叶绿体DCL同源蛋白合成、假定蛋白VIGAN_02061800、假定蛋白Lal_00008628、可能的NAD(P)H脱氢酶(醌)FQR1和17.6 kDⅠ类热休克蛋白3。

Pueraria thomsoniibelongs to Pueraria in Leguminosae family,its tuberous roots were rich in starchand had the important edible and medicinal values.There were significant differences in starch content among differentvarieties of Pueraria thomsonii.In order to reveal the involved genes regulating starch synthesis,in this study,high-throughput sequencing technology was used to perform transcriptome sequencing and comparative analysis on the leavesof Gange 1 with high starch content(fresh and dry kudzu roots contain 20%and 35%starch,respectively)and Gange 2with low starch content(fresh and dry kudzu roots contain 14%and 25%starch,respectively).The results showed that228740426 high-quality sequencing data were obtained,and 71910 unigenes were assembled,43978 unigenesobtained protein sequences and were annotated(61.12%),20110 unigenes including 4267 differentially expressedgenes were annotated in Nr,KEGG,KOG and Swiss Prot databases.GO enrichment analysis showed that the most up-regulated and down-regulated genes were enriched in metabolism and cellular process functions in biological processes.KEGG pathway enrichment analysis found that the pathway was significantly enriched in the front of ribosomes,proteinprocessing in the endoplasmic reticulum,oxidative phosphorylation,plant-pathogen interaction and plant hormonesignal transduction.Among the differentially expressed genes(DEGs)of Gange 1,there was no significant differencebetween the up-regulated(2143)and down-regulated(2124)DEGs,the number of up-regulated(593)and down-regulated(402)DEGs with|log2(FC)|>5.0 was quite different,and the number of up-regulated(368)and down-regulated(146)DEGs with|log2(FC)|>0.0 was quite different;the number of DEGs(3512)that failed to be classifiedinto KEEG A was 4.65 times as much as those to be classified into KEEG A(755),accounting for 82.31%of the totalnumber of DEGs;the number of DEGs(840)that failed to be described by function accounted for 23.92%and 16.69%ofthat failed to be classified into KEEG A class and total DEGs,respectively.In the KEEG A group,the most DEGs wererelated to metabolism,followed by genetic information processing,and environmental information processing,biologicalsystems and cellular processes were less.The up-regulated DEGs at the top five positions were related to chitinasehomologue,receptor-like protein kinase FERONIA isoform X2,isoflavone-7-O-methyltransferase 9,FERONIAreceptor-like kinase,kunitz family trypsin and protease inhibitor precursor,respectively.The down-regulated DEGs atthe top five positions were related to chloroplast DCL homolog ousprotein,hypothetical protein VIGAN_02061800,hypothetical protein Lal_00008628,probable NAD(P)H dehydrogenase(quinone)FQR1-like 1 and 17.6 k D class I heatshock protein 3,respectively.