Comparative transcriptome profiling of potassium starvation responsiveness in two contrasting watermelon genotypes
The wild watermelon genotype YS (C. lanatus subsp. lanatus) was cultivated hydroponically in a chamber with a controlled environment. Seeds were germinated in a sponge at 30 *C. After seven days, uniform seedlings were cultivated hydroponically with ample K  supply (CK, 3 mM). After five days, half of the numbers of seedlings were transferred to a nutrient solution without K  (lacking KCl) for the K -starvation treatment (LK), whereas the other half were transferred to the CK nutrient solution as control. The roots were harvested after 6 and 120 h for further assays. This library was constructed by mixing equal quantities of RNA from three biological replicates of seedlings with 3 mM K  supply at 120 h after treatment.