Transcriptional profiling reveals mechanisms of sexually dimorphic responses of Populus cathayana to potassium deficiency.

Potassium (K) deficiency causes a series of physiological and metabolic disorders in plants, and dioecious species exhibit different responses based on sex. Our previous morphological and physiological observations indicated that Populus cathayana males were more tolerant to K+ deficiency than females. To continue this work, comparative transcriptome analyses were carried out to investigate sexually differentially expressed genes (DEGs) in this study. The results indicate that 10 weeks of K+ deficiency result in 111 and 181 DEGs in males and females, respectively. These DEGs are mainly involved in photosynthesis, cell wall biosynthesis, secondary metabolism, transport, stress responses, gene expression regulation and protein synthesis and degradation. Comparing between sexes, P. cathayana females showed more changes in response to K+ deficiency than males with regard to photosynthesis, gene expression regulation and posttranslational modification but fewer changes in secondary metabolism, stress responses and redox homeostasis. These results provide evidence that P. cathayana females are more susceptible to K+ deficiency than males. Therefore, there are sex-related molecular strategies in response to K+ deficiency between sexes.