Phosphate or nitrate imbalance induces stronger molecular responses than combined nutrient deprivation in roots and leaves of chickpea plants.

The negative effects of phosphate (Pi) and/or nitrate (NO ) fertilizers on the environment have raised an urgent need to develop crop varieties with higher Pi and/or nitrogen use efficiencies for cultivation in low-fertility soils. Achieving this goal depends upon research that focuses on the identification of genes involved in plant responses to Pi and/or NO starvation. Although plant responses to individual deficiency in either Pi (-Pi/+NO ) or NO (+Pi/-NO ) have been separately studied, our understanding of plant responses to combined Pi and NO deficiency (-Pi/-NO ) is still very limited. Using RNA-sequencing approach, transcriptome changes in the roots and leaves of chickpea cultivated under -Pi/+NO , +Pi/-NO or -Pi/-NO conditions were investigated in a comparative manner. -Pi/-NO treatment displayed lesser effect on expression changes of genes related to Pi or NO transport, signalling networks, lipid remodelling, nitrogen and Pi scavenging/remobilization/recycling, carbon metabolism and hormone metabolism than -Pi/+NO or +Pi/-NO treatments. Therefore, the plant response to -Pi/-NO is not simply an additive result of plant responses to -Pi/+NO and +Pi/-NO treatments. Our results indicate that nutrient imbalance is a stronger stimulus for molecular reprogramming than an overall deficiency.