BackgroundSoybean is one of the most important crops, providing large amounts of dietary proteins and edible oil, and is also an excellent model for studying evolution of duplicated genes. However, relative to the model plants Arabidopsis and rice, the present knowledge about soybean transcriptome is quite limited.ResultsIn this study, we employed RNA-seq to investigate transcriptomes of 11 soybean tissues, for genome-wide discovery of truly expressed genes, and novel and alternative transcripts, as well as analyses of conservation and divergence of duplicated genes and their functional implications. We detected a total of 54,132 high-confidence expressed genes, and identified 6,718 novel transcriptional regions with a mean length of 372 bp. We also provided strong evidence for alternative splicing (AS) events for ~15.9% of the genes with two or more exons. Among them, 1,834 genes exhibited stage-dependent AS, and 202 genes had tissue-biased exon-skipping events. We further defined the conservation and divergence in expression patterns between duplicated gene pairs from recent whole genome duplications (WGDs); differentially expressed genes, tissue preferentially expressed genes, transcription factors and specific gene family members were identified for shoot apical meristem and flower development.ConclusionsOur results significantly improved soybean gene annotation, and also provide valuable resources for functional genomics and studies of the evolution of duplicated genes from WGDs in soybean.

BackgroundMicroRNAs (miRNAs) play important regulatory roles in development and stress response in plants. Wild soybean (Glycine soja) has undergone long-term natural selection and may have evolved special mechanisms to survive stress conditions as a result. However, little information about miRNAs especially miRNAs responsive to aluminum (Al) stress is available in wild soybean.ResultsTwo small RNA libraries and two degradome libraries were constructed from the roots of Al-treated and Al-free G. soja seedlings. For miRNA identification, a total of 7,287,655 and 7,035,914 clean reads in Al-treated and Al-free small RNAs libraries, respectively, were generated, and 97 known miRNAs and 31 novel miRNAs were identified. In addition, 49 p3 or p5 strands of known miRNAs were found. Among all the identified miRNAs, the expressions of 30 miRNAs were responsive to Al stress. Through degradome sequencing, 86 genes were identified as targets of the known miRNAs and five genes were found to be the targets of the novel miRNAs obtained in this study. Gene ontology (GO) annotations of target transcripts indicated that 52 target genes cleaved by conserved miRNA families might play roles in the regulation of transcription. Additionally, some genes, such as those for the auxin response factor (ARF), domain-containing disease resistance protein (NB-ARC), leucine-rich repeat and toll/interleukin-1 receptor-like protein (LRR-TIR) domain protein, cation transporting ATPase, Myb transcription factors, and the no apical meristem (NAM) protein, that are known to be responsive to stress, were found to be cleaved under Al stress conditions.ConclusionsA number of miRNAs and their targets were detected in wild soybean. Some of them that were responsive to biotic and abiotic stresses were regulated by Al stress. These findings provide valuable information to understand the function of miRNAs in Al tolerance.

No abstract

No abstract

No abstract