Transcriptome changes induced by drought stress in Jerusalem artichoke (Helianthus tuberosus L.) and weighted gene co-expression network analysis (WGCNA)

Abstract

Background: Jerusalem artichoke (Helianthus tuberosus L.) is strongly resistant to stress and an important plant used for ecological management in northern China in recent years. Currently, Jerusalem artichoke has been widely planted in the area around Qinghai Lake in Qinghai Province, China. Jerusalem artichoke can not only prevent land desertification but also has maintain most of its level of production. However, there is little research on the mechanism of drought resistance of Jerusalem artichoke.Results: We conducted transcriptome sequencing under drought stress and normal watering treatment for two varieties, QY1 and QY3, with differing degrees of drought tolerance. In the three stress periods of QY1 and QY3, 5,613, 12,985 and 24,923 differentially expressed genes (DEGs) were identified, respectively. GO analysis showed that there were more DEGs in QY1 than in QY3, but there were more up-regulated genes in QY3 than in QY1. Based on an additional analysis of the metabolic pathways under drought stress using MapMan, the most different types of metabolism included secondary metabolism, light reaction metabolism and cell wall. The up-regulated genes in QY3 were significantly more prevalent than those in QY1 and were primarily concentrated in flavor IDS, phenylpropanoids, and the shikimate and terpenoids pathway. As a whole, QY1 and QY3 both had a large number of up-regulated genes in the flavor pathway. In addition, the gene analysis of the ABA key metabolic pathway showed that QY3 had more genes in NAC and WRKY than QY1. A weighted gene co-expression network was constructed and divided into modules. By specifically analyzing the expressed modules, four modules were found to have the highest correlation with drought. Further research on the genes revealed that all 16 genes related to histone, ABA and protein kinase were the most significant in these pathways.Conclusions: In summary, these findings represent the first RNA-Seq analysis of drought stress in Jerusalem artichoke, which is of substantial significance to explore the function of drought resistance in Jerusalem artichoke and the unearthing of related genes.