A time-course transcriptome reveals the response of watermelon to low-temperature stress

Abstract

Watermelon (Citrullus lanatus) is an economically important horticultural crop. However, it is susceptible to low-temperature stress, which significantly challenges its production and supply. Despite the great economic importance of watermelon, little is known about its response to low-temperature stress at the transcriptional level. In this study, we performed a time-course transcriptome analysis to systematically investigate the regulatory network of watermelon under low-temperature stress. Six low-temperature-responsive gene clusters representing six expression patterns were identified, revealing diverse regulation of metabolic pathways in watermelon under low-temperature stress. Analysis of temporally specific differentially expressed genes revealed the time-dependent nature of the watermelon response to low temperature. Moreover, ClMYB14 was found to be a negative regulator of low-temperature tolerance as ClMYB14-OE lines were more susceptible to low-temperature stress. Co-expression network analysis demonstrated that ClMYB14 participates in the low-temperature response by regulating the unsaturated fatty acid pathway and heat shock transcription factor. This study provides substantial information for understanding the regulatory network of watermelon in response to low-temperature stress, and identifies candidate genes for the genetic improvement of watermelon with higher low-temperature tolerance.

Keywords

• watermelon
• time-course transcriptome
• low temperature
• ClMYB14
• co-expression