Genome-wide identification and transcriptional analysis of ammonium transporters in Saccharum

Abstract

Ammonium transporters (AMTs) are plasma membrane proteins that exclusively transport ammonium/ammonia. It is essential for the nitrogen demand of plantsby AMT-mediated acquisition of ammonium from soils. The molecular characteristics and evolutionary history of AMTs in Saccharum spp. remain unclear. We comprehensively evaluated the AMT gene family in the latest release of the S. spontaneum genome and identified 6 novel AMT genes. These genes belong to 3 clusters: AMT2 (2 genes), AMT3 (3 genes), and AMT4 (one gene). Evolutionary analyses suggested that the S. spontaneum AMT gene family may have expanded via whole-genome duplication events. All of the 6 AMT genes are located on 5 chromosomes of S. spontaneum. Expression analyses revealed that AMT3;2 was highly expressed in leaves and in the daytime, and AMT2;1/3;2/4 were dynamic expressed in different leaf segments, as well as AMT2;1/3;2 demonstrated a high transcript accumulation level in leaves and roots and were significantly dynamic expressed under low-nitrogen conditions. The results suggest the functional roles of AMT genes on tissue expression and ammonium absorption in Saccharum. This study will provide some reference information for further elucidation of the functional mechanism and regulation of expression of the AMT gene family in Saccharum.