Comparative transcriptomic and metabolite profiling reveals genotype-specific responses to Fe starvation in chickpea

Iron deficiency is a major nutritional stress that severely impacts crop productivity worldwide. However, molecular intricacies and subsequent physiological and metabolic changes in response to Fe starvation, especially in leguminous crops like chickpea, remain elusive. In the present study, we investigated physiological, transcriptional, and metabolic reprogramming in two chickpea genotypes (H6013 and L4958) with contrasting seed iron concentrations upon Fe deficiency. Our findings revealed that iron starvation affected growth and physiological parameters of both chickpea genotypes. Comparative transcriptome analysis led to the identification of differentially expressed genes between the genotypes related to strategy I uptake, metal ions transporters, reactive oxygen species-associated genes, transcription factors, and protein kinases that could mitigate Fe deficiency. Our gene correlation network discovered several putative candidate genes like CIPK25, CKX3, WRKY50, NAC29, MYB4, and PAP18, which could facilitate the investigation of the molecular rationale underlying Fe tolerance in chickpea. Furthermore, the metabolite analysis also illustrated the differential accumulation of organic acids, amino acids and other metabolites associated with Fe mobilization in chickpea genotypes. Overall, our study demonstrated the comparative transcriptional dynamics upon Fe starvation. The outcomes of the current endeavor will enable the development of Fe deficiency tolerant chickpea cultivars.