Morphological, physiological, biochemical, and transcriptome analysis of Phyllostachys edulis seedlings response to low potassium

Potassium (K+) is an indispensable mineral nutrient for the growth and development of plants. Understanding how plants cope with low-K+ stress exerts a crucial role in enhancing breeding programs aimed at improving tolerance to K+ deficiency. However, the responses of Phyllostachys edulis to K+ deficiency remain poorly understood. In this study, a pot hydroponic experiment was performed to explore the morphological and physiological differences in P. edulis seedlings under low-K+ and normal-K+ conditions. Our findings revealed that K+ deficiency resulted in stunted plant growth, reduced taproot length, fewer lateral roots, diminished photosynthetic pigment content, impaired photosynthetic machinery, and increased accumulation of O2⋅- and H2O2 in leaves. In addition, it affected the uptake and distribution of K, N, and P nutrients. Furthermore, RNA sequencing (RNA-Seq) of roots and leaves from both treatments identified a number of differentially expressed genes (DEGs), many of which were correlated with cell wall biosynthesis. The activation of the auxin signaling pathway under K+ deficiency suggested its pivotal role in this response. Moreover, several genes related to peroxidase, cytochrome P450, glutathione, and H2O2 removal were upregulated under K+ deficiency. Notably, some of these genes were enriched in glutathione metabolism and phenylpropanoid biosynthesis pathways, underscoring the significance of these pathways in eliminating reactive oxygen species (ROS). Moreover, the upregulation of the K+ transporter HAKs and the K+ channel gene SKOR in low-K+-treated roots indicates their crucial role in efficiently absorbing potassium nutrients during potassium deficiency. In conclusion, our study elucidates the responses of P. edulis adapts to potassium deficiency, providing valuable insights for future breeding efforts aimed to enhance K+ tolerance in plants.