Natural resistance-associated macrophage proteins (NRAMPs) are involved in cadmium enrichment in peanut (Arachis hypogaea L.) under cadmium stress

Abstract

Cadmium (Cd) is a hazardous heavy metal, and Cd pollution has become a serious problem worldwide. Peanut ( Arachis hypogaea L.) is an important oil crop in the world and has a strong capacity to accumulate Cd in soil. The natural resistant-associated macrophage protein (NRAMP) plays an important part in the absorption and transportation of Cd in plants. To date, the NRAMP family in peanut is ill-informed. In the present study, 29 AhNRAMPs were identified and were classified into three groups and fourteen proteins in group 1 (G1), ten proteins in group 2 (G2) and five proteins in group 3 (G3). There are 71-1347 amino acids in AhNRAMPs. Most of the AhNRAMPs exhibited tissue-specific expression patterns. For instance, AhNRAMP10 and AhNRAMP26 from G1 were highly expressed in roots, G2 genes in shoots and leaves and G3 genes in shoots. The transcriptional levels of AhNRAMPs in roots can be regulated by Cd. Notably, 55% of (16) AhNRAMPs genes were upregulated in peanut roots and positively responded to Cd stress. It’s worth noting that the relative expressions of AhNRAMP2 and AhNRAMP11, which were increased by 6.9-fold and 14.1-fold at 3 h in roots of Cd-enriched variety under Cd stress while decreasing by 44% and 25% at the same time in Cd sensitive variety. In a word, the comprehensive research of the AhNRAMP family provides insights into the capacity of Cd enrichment in peanut.