Transcriptome Analysis of Sweet Potato Responses To Potassium Deficiency

Abstract

Abstract Background: Potassium is one of the three essential nutrients and is regarded as a main limited factor for growth and development in plant. Sweet potato (Ipomoea batatas L.) is one of the seven major food crops grown worldwide, and it is both a nutrient-rich food and a bioenergy crop. Sweet potato is a typical “K-favoring” crop, and the level of potassium ion (K+) supplementation directly influences its production. However, little is known about the transcriptional changes in sweet potato genes under low-K+ condition. To uncover the effect of low-K+ stress, we analyzed the transcriptomic profiles of sweet potato roots in response to K+ deficiency.Result: The roots of sweet potato seedlings with or without K+ treatment were harvested and used for transcriptome analyses. The results showed 559 differently expressed genes (DEGs) in low and high K+ groups. Among the DEGs, 336 were upregulated and 223 downregulated. These DEGs were involved in transcriptional regulation, calcium binding, redox-signaling, biosynthesis, transport, and metabolic process. In the result, some new genes were founded that involved in low-K+ stress, which can be further investigated to improve low K+ tolerance in plant. Confirmation of RNA-seq results using qRT-PCR displayed a high level of consistency between the two experiments. Our analysis showed that many auxin-related genes, ethylene-related genes and jasmonic acid-related genes responsed to K+ deficiency, indicated that these hormones may play more important roles in K+ nutrient signaling in sweetpotato. Conclusions: According to the transcriptome data, fewer sweetpotato genes showed transcriptional changes in response to low-K+ stress. However, the expression level of some kinases, transporters, transcription factors, hormone-related genes, and plant defense related genes were markedly changed, suggesting that they play important roles during K+ deficiency. This study identifes potential genes for genetic improvement of low-K+ stress and provides valuable insight into the molecular mechanisms regulating low K+ tolerance in sweet potato. Further research is required to clarify the founction of these significant changed genes under low-K+ stress.