Comparative transcriptome profiling of potassium starvation responsiveness in two contrasting watermelon genotypes

Abstract

Potassium (K) is one of the essential nutrients for crops, and K⁺ deficiency highly restricts crop yield and quality. Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] is an economically important crop that often suffers from K⁺ deficiency. To elucidate the underlying tolerance mechanism of watermelon to K⁺ deficiency and to improve K efficiency of watermelon and other crops in the future, two watermelon genotypes, namely, YS and 8424, that exhibit contrasting K efficiencies were studied to compare their response mechanisms to K⁺ deficiency. YS was more tolerant of K⁺ deficiency and displayed less inhibited root growth than 8424. Roots of YS and 8424 seedlings with or without K⁺ supply were harvested at 6 and 120 h after treatment (HAT), and their transcriptomes were analyzed by Illumina RNA sequencing. Different regulation mechanisms of the root K⁺-uptake genes for short- and long-term stress were observed. Genes involved in jasmonic acid and reactive oxygen species production; Ca²⁺ and receptor-like kinase signaling; lignin biosynthesis; and other stress-related genes were repressed in YS, whereas a large number of such stress-related genes were induced in 8424 at 120 HAT. These results suggested that repressed defense and stress response can save energy for better root growth in YS, which can facilitate K⁺ uptake and increase K efficiency and tolerance to K⁺ deficiency. This study presents the first global root transcriptome in watermelon and provides new insights into the molecular mechanisms underlying tolerance to K⁺ deficiency of K-efficient watermelon genotypes.

Identification of the proteins associated with low potassium tolerance in cultivated and Tibetan wild barley

“…Isobaric mass tagging (e.g., TMT and iTRAQ) is a precise and sensitive multiplexed peptide/protein quantification technique in mass spectrometry [22], which has been intensively used for revealing the proteins being differentially expressed under any given conditions, including biotic and abiotic stresses, such as heat stress [23] and Al stress [24]. Recently, some omics methods have been performed on some plants, for instance, rice [25], soybean [26] and watermelon [27], to investigate the underlying tolerance mechanism of plants to K deficiency, mostly at the transcriptional level. The barley proteomics can be mainly summarized as (a) industry driven biotechnology, including seed germination, beer proteomes, and malting proteomes and (b) biology driven proteomics, including abiotic stress tolerance and nitrogen use efficiency [28].…”

Transcriptome Analysis of Differentially Expressed Genes Induced by Low and High Potassium Levels Provides Insight into Fruit Sugar Metabolism of Pear

“…Many processes and functions are affected by changes in plant K + status, such as metabolic processes (as a long-term consequence of cytoplasmic K + decrease), ROS signaling, and protein phosphorylation/dephosphorylation (by CIPKs and phosphatases, for example) (Ma et al, 2012). The genes related to K + signing transduction, hormone signaling, and ROS signaling have important roles in the regulation of plant defense (Shankar et al, 2013; Fan et al, 2014). However, research related to the molecular mechanisms of K + sensing, uptake, distribution, homeostasis and sugar metabolism in rosaceous fruit trees is still lacking.…”

Transcriptome Profiling of Watermelon Root in Response to Short-Term Osmotic Stress

“…Transcriptome analyses have been performed to examine watermelon root responses to K + deficiency [13], but comparative transcriptome analyses of cultivated watermelon root responses to water deficit have not been reported and little is known about how watermelon roots respond to osmotic stress at the transcriptome level.…”