Transcriptome analysis of sweet potato responses to potassium deficiency
Fang Wang, Wenfang Tan, Wei Song, Songtao Yang, Shuai Qiao
Abstract
Abstract Background As one of three essential nutrients, potassium is regarded as a main limiting factor for growth and development in plant. Sweet potato ( Ipomoea batatas L.) is one of seven major food crops grown worldwide, and is both a nutrient-rich food and a bioenergy crop. It 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 + conditions. Here, we analyzed the transcriptomic profiles of sweet potato roots in response to K + deficiency to determine the effect of low-K + stress on this economically important crop. Results 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 were downregulated. These DEGs were involved in transcriptional regulation, calcium binding, redox-signaling, biosynthesis, transport, and metabolic process. Further analysis revealed previously unknow genes involved in low-K + stress, which could be investigated further to improve low K + tolerance in plants. Confirmation of RNA-sequencing results using qRT-PCR displayed a high level of consistency between the two experiments. Analysis showed that many auxin-, ethylene- and jasmonic acid-related genes respond to K + deficiency, suggesting that these hormones have important roles in K + nutrient signaling in sweet potato. Conclusions According to the transcriptome data of sweet potato, various DEGs showed transcriptional changes in response to low-K + stress. However, the expression level of some kinases, transporters, transcription factors (TFs), hormone-related genes, and plant defense-related genes changed significantly, suggesting that they have important roles during K + deficiency. Thus, this study identifies potential genes for genetic improvement of responses to 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 function of these DEGs under low-K + stress.