Transcriptome profiling of Jerusalem artichoke seedlings (Helianthus tuberosus L.) under polyethylene glycol-simulated drought stress

Drought stress is one of the most important abiotic stresses affecting crop growth and development, which leads to huge production and economics losses. Jerusalem artichoke (Helianthus tuberosus L.) is a perennial crop with high drought tolerance that can be used in ecological management. In this study, Jerusalem artichoke seedlings under polyethylene glycol (PEG) 6000-simulated drought stress were used for analysis of malonaldehyde, proline, and soluble sugar content, then the differentially expressed unigenes were identified by RNA-sequencing. A total number of 172,291 unigenes were generated from the leaves of Jerusalem artichoke and 17,612 unigenes were identified as differentially expressed unigenes. Gene Ontology enrichment showed that differential expression genes were classified in plastoglobules, photosystem II, and photosystem. Kyoto Encyclopedia of Genes and Genomes enrichment showed that differential expression genes were mainly classified in metabolic pathways; biosynthesis of secondary metabolites; photosynthesis - antenna proteins; circadian rhythm-plant; porphyrin and chlorophyll metabolism; phenylpropanoid biosynthesis; ABC transporters; flavonoid biosynthesis; carotenoid biosynthesis; stilbenoid, diarylheptanoid, and gingerol biosynthesis; cutin, suberin, and wax biosynthesis; and isoquinoline alkaloid biosynthesis. A transcription factor analysis showed that NAC, MYB, WRKY, homeobox-leucine zipper (HD-ZIP) and basic leucine-zipper (bZIP) were considered to be closely related to the response to PEG-simulated drought stress. These findings suggest that transcription factors may respond to drought stress by regulating structural genes expression level in metabolic pathways and then regulating the accumulation of related metabolites. Results obtained in this study will be helpful for cloning and analysis of drought-resistant genes of Jerusalem artichoke in the future, and also lay the foundation for the explanation of the drought resistance mechanism of Jerusalem artichoke and are helpful for the identification of drought tolerant Jerusalem artichoke varieties.

Automated summary

This study identified differentially expressed genes in Jerusalem artichoke seedlings under drought stress, analyzed their roles in metabolic pathways, and conducted a transcription factor analysis focusing on NAC, MYB, WRKY, HD-ZIP, and bZIP. The findings suggest that transcription factors may regulate structural genes expression level in metabolic pathways to respond to drought stress and accumulate related metabolites.