采后常温贮藏下菠萝罹病果实转录组测序分析

Transcriptome Sequencing Analysis of Diseased Pineapple Fruits Stored at Room Temperature after Harvest

菠萝在常温贮藏过程中易发生黑心病,为了探索黑心病的发生机制,选取菠萝黑心病初期果实的发病部位和健康部位,每个部位选取3个样本分别进行测转录组RNA-Seq分析,对差异基因进行GO、KEGG、各代谢通路基因表达聚类分析和RT-qPCR验证,对比病部(IB)和健部(WT)的差异基因表达量。通过分析发现,IB vs WT共有1037个差异基因,其中上调886个,下调130个。GO和KEGG分析发现氨基酸生物合成差异基因最显著,而且差异基因数量占比大;通过聚类分析和RT-qPCR验证,糖代谢路径发现果实发病后糖酵解、三羧酸循环(TCA)和氧化磷酸化过程中相关酶基因表达量显著上调;植物应对外界环境信号通路发现抗性酶基因表达量显著下调,致病蛋白基因表达量显著上调,抗病蛋白基因表达量显著下调;抗氧化物质通路发现谷胱甘肽合成基因表达量显著下调,类黄酮生物合成相关基因表达量显著上调,L-抗坏血酸过氧化物酶(APX)基因表达量显著下调,而L-抗坏血酸氧化酶(AOX)同系物基因表达量显著上调。RNA-Seq和RT-qPCR分析结果表明,菠萝组织通过显著上调糖代谢关键基因加速果实病部糖代谢、显著上调表达信号传导关键通路MAPK途径中的关键基因以及显著下调抗氧化物质等代谢通路变化而导致黑心病的发生。通过这些结果可以丰富菠萝黑心病发生的基因网络,为后续菠萝黑心病相关基因筛选提供信息参考。

Pineapple is prone to intern browning during storage at room temperature.Diseased and healthy parts of pineapple at early stage of intern browning were used to explore the mechanism of the disease.Three samples from each part were used for transcriptome RNA-Seq analysis.GO,KEGG,cluster analysis of gene expression in various meta-bolic pathways,and RT-qPCR validation on differential genes were performed and the differential gene expression lev-els between the diseased(IB)and healthy(WT)parts were compared.IB vs WT had 1037 differentially expressed genes,of which 886 were up-regulated and 130 were down-regulated.GO and KEGG analysis found that the differentially expressed genes in amino acid biosynthesis were the most significant,and the proportion of differentially expressed genes was large.Cluster analysis and RT-qPCR validation found that the sugar metabolism pathway significantly up-regulated the expression levels of related enzyme genes in glycolysis,tricarboxylic acid cycle(TCA),and oxidative phosphorylation processes after fruit disease onset.The response of plants to external environmental signaling pathways revealed a significant down-regulation of resistance enzyme gene expression,a significant up-regulation of pathogenic protein gene expression,and a significant down-regulation of resistance protein gene expression.The antioxidant path-way revealed significant down-regulation of glutathione synthesis gene expression,significant up-regulation of flavon-oid biosynthesis related gene expression,significant down-regulation of L-ascorbate peroxidase(APX)gene expression,and significant up-regulation of L-ascorbate oxidase(AOX)homologous gene expression.RNA-Seq and RT-qPCR analysis indicated that pineapple tissue significantly up-regulated key genes in sugar metabolism to accelerate sugar metabolism in fruit disease part,significantly up-regulated key genes in the MAPK signaling pathway,and significantly down-regulated metabolic pathway changes such as antioxidant substances,leading to pineapple intern browning.The results could enrich the gene network of pineapple intern browning and provide a valuable reference for the subsequent gene screening of pineapple intern browning.