Glycine max Transcriptome or Gene expression
To identify low N-responsive miRNAs at whole genome level, we constructed sixteen libraries from two soybean genotype (“116”, low N-tolerant variety; “84-70”, low N-sensitive variety) shoots and roots exposed to both long-term and short-termlow N-stress. Using the high-throughput sequencing technology (Illumina-Solexa), we identified 362 known miRNAs variants belonging to 158 families and 90 new miRNAs belonging to 55 families, among these known miRNAs variants, almost 50% were not different from annotated miRNA in miRBase. Analyses of their expression patterns showed 184 known miRNAs variants as well as 7 novel miRNAs with differential expressions. These differentially expressed miRNAs between the two soybean genotypes were also compared and classified into three groups type based on their expression patterns. Predicted targets of these miRNAs were involved in various metabolic and regulatory pathways such as protein degradation, carbohydrate metabolism, hormone signaling pathway, and cellular transport. These findings suggest that miRNAs play important roles in soybean response to low N and contribute to the understanding of the genetic basis of adaptive responses difference to N limitation between the two soybean genotypes. Furthermore, this provides basis of expounding the complex gene regulatory network of these miRNAs