Formation and Comparative Analysis of Full-Length Transcriptome Sequencing and Next Generation Sequencing In Medicago Sativa L. Roots Under Abiotic Stress

Abstract

\n Background: Medicago sativa L. (M. sativa L.) is a legume with high salt tolerance and a major forage crop with high biomass production. However, the large-scale full-length cDNA sequences of M. sativa L. in response to abiotic stress remain unclear. Results: We provided the complete transcriptome for M. sativa L. roots under different abiotic stressors using a combination of single-molecule real-time sequencing and next generation sequencing. Our results indicated that there were 21.53 Gb clean reads, which consisted of 566,076 insert reads and 409,291 full-length non-chimeric reads. We obtained 194,286 consistent transcripts based on a cluster analysis of full-length reads, and 41,248 high quality transcript sequences based on non-full-length reads. After correction using second-generation data for third-generation low-quality data, we obtained 81,017 transcript sequences according to a cogent analysis. The sequence structural analysis acquired 33,058 simple sequence repeats and 42,725 complete coding sequence regions. In addition, 77,221 transcripts were annotated by eight functional databases; 3,043 lncRNAs were predicted and 4,971 alternative splicings were acquired. Moreover, we confirmed the levels of highly differentially expressed transcripts (ADH1, PEPC, MJG19.6, PCKA and GAPC1) in M. sativa L. roots under NaCl and polyethylene glycol stress. Conclusions: Therefore, we fully and massively exposed the full-length transcripts related to abiotic stress in M. sativa L., which will lay the foundation for understanding gene regulation in M. sativa L. under abiotic stress.