GSE127467
Early responses of Brassica oleracea roots to zinc supply under sufficient and sub-optimal phosphorus supply
Shoot zinc (Zn) in Brassica oleracea is affected by soil Zn and phosphorus (P) concentrations. Most problematic is the negative impact of P fertilizers on Zn concentrations in crops, which makes balancing yield and mineral quality challenging. To evaluate molecular mechanisms involved in the accumulation of large shoot Zn concentrations regardless of the P supply, two B. oleracea accessions were grown hydroponically for two weeks with different combination of P and Zn supply. Ionome profiling and deep RNA sequencing of roots revealed interactions of P and Zn in planta, without apparent phenotypic effects. In addition, increasing P supply did not reduce tissue Zn concentration. Substantial changes in gene expression in roots of both accessions ensured nutritionally sufficient P and Zn uptake. Numerous genes were differentially expressed after changing Zn or P supply and most of them were unique to only one accession, highlighting different strategies in achieving nutrient sufficiency. Thus, different gene networks responded to the changing P and Zn supply in the two accessions. Additionally, enrichment analysis of gene ontology classes revealed that genes involved in lipid metabolism, response to starvation, and anion transport mechanisms were most responsive to the contrasting P and Zn supply in both accessions. The results agreed with previously studies demonstrating alterations in P transport and phospholipid metabolism in response to reduced P supply. Knowledge of genes responsive to P or Zn supply will help illuminate the interactions between these elements in their uptake and accumulation by plants and might highlight candidate genes for breeding high-yield-high-Zn crops. Overall design: Analysis of root material of two different Brassica oleracea accessions grown hydroponically with four different combinations of phosphorus and zinc supply.