Transcriptomic profiling identifies candidate genes involved in salt tolerance of the xerophyte Pugionium cornutum
Abstract Background: Pugionium cornutum is a xerophytic plant that primarily adapts to salt stress by accumulating inorganic ions (e.g., Cl-) for osmoregulation, improving its reactive oxygen species (ROS)-scavenging ability and maintaining high photosynthetic carbon assimilation efficiency, but the associated molecular mechanisms still remain unclear. Results: Here, we present an analysis of gene responses to salt stress based on the transcriptome of P. cornutum exposed to 50 mM NaCl treatment. The data revealed that, after NaCl treatment for 6 or 24 h, the transcript levels of multiple genes encoding proteins facilitating Cl- accumulation and NO3- homeostasis such as SLAH1, CLCg, CCC1, and NPF6.4, as well as the transport of other major inorganic osmoticums were significantly upregulated in roots and shoots, which should be favorable to enhancing osmotic adjustment capacity and maintaining the plant uptake and transport of nutrient elements; a large number of genes related to ROS-scavenging pathways were also significantly upregulated, which should be beneficial for mitigating salt-induced oxidative damage to the cell metabolism. Meanwhile, many genes encoding components of the photosynthetic electron transport and carbon fixation enzymes were significantly upregulated in shoots after salt treatment, possibly resulting in a high carbon assimilation efficiency in P. cornutum. Additionally, numerous salt-inducible transcription factor genes probably regulating the abovementioned processes were found. Conclusion: Candidate genes involved in salt tolerance of P. cornutum were identified, which lays a preliminary foundation for clarifying the molecular mechanism of the xerophytes adapting to harsh environments.