Transcriptome and ionome analysis of nitrogen, phosphorus and potassium interactions in sorghum seedlings

Abstract

Nitrogen (N), phosphorus (P) and potassium (K) are essential macronutrients for plant growth and development. Although single N, P, or K starvation responses have been well studied individually at the morphological, physiological and transcriptional levels in many plant species, there is little knowledge about their interaction during the combined NPK starvation response. In this study, we compared sorghum seedling growth performance, nutrient concentrations and gene expression profiles between single N, P, and K and triple nutrient deficiencies (–NPK). The results showed that sorghum seedlings have significantly distinct responses to –N, –P and –K. Plants under –NPK conditions showed highly similar performance as –N-treated plants at multiple levels. Most typical –P- and –K-associated responses were modified in –NPK-treated plants. One common cluster was found between plants treated with –N and –P. Two Pi-deficiency tightly linked clusters were also identified using weighted gene coexpression network analysis. Moreover, we identified several ions transport-related genes and possible interactions between nutrients by combined transcriptome and ionome analyses. In this manuscript, we present a comprehensive transcriptome and ionome comparative analysis of sorghum responses to –N, –P and –K and showed –N is apparently prioritized over –P and –K under –NPK conditions. N starvation has a very strong influence on –P and –K responses, and NPK single starvation signaling was integrated into a combined network under multiple nutrient deficient conditions.