Characterizing the expression of genes involved in iron transport inPakistani peanut varieties under iron deficiency stress

Authors: SHAMIM AKHTAR, YUSUKE KAKEI, KHURRUM BASHIR, ARMGHAN SHAHZAD, TAKASHI YAMAKAWA, MUHAMMAD ARSHAD, FAYYAZ- UL-HASSAN, HIROMI NAKANISHI, NAOKO K. NISHIZAWA

Abstract: Iron (Fe) deficiency is one of the major yield-limiting factors in peanut (Arachis hypogaea L.), especially when grown in calcareous soils. The soils of the Pothwar region in Pakistan are calcareous in nature, exposing peanut to Fe deficiency. The molecular mechanisms governing Fe deficiency response in peanut have not been fully revealed. We compared 4 locally important varieties of peanut to evaluate Fe deficiency responses at the molecular level. The expression profiles of 7 important genes including AhIRT1, AhFRO1, AhNRAMP1, AhYSL1, AhYSL3.1, AhYSL4, and AhYSL6 in roots and young and old leaves of local peanut varieties were investigated 19 days after Fe deficiency treatment. Significant differences were observed for gene expression patterns among these varieties. The expression of AhIRT1 was upregulated only in Banki and BARD-699. However, some of the genes, like AhFRO1, AhNRAMP1, and other genes of the YSL family, were upregulated in BARI 2000 roots and young and old leaves, which has been reported for uptake and transport of Fe. BARI 2000 and Chakori had more accumulation of Fe in young leaves and roots in Fe deficiency conditions as compared to other varieties. This suggests that other mechanisms of Fe uptake and transport may be more important than AhIRT1 to mitigate Fe deficiency in BARI 2000 and Chakori.

Keywords: Arachis hypogaea, iron, iron deficiency, iron uptake gene

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