Transcriptomic Analysis of Medicago Truncatula under Long Day Conditions

Abstract

To explore the expression characteristics and biological functions of related genes of medicago terrestris under long day conditions, and to lay a foundation for revealing the molecular mechanism of medicago terrestris under long day conditions. The leaves of 'R108' tribulus Medicago sativa at branch stage (A), bud stage (B), initial flowering stage (C) and full flowering stage (D) were sequenced by RNA-Seq technology. The genome of Medicago sativa, a related species of Tribulus tribulus, was used as a reference genome for sequence comparison. The transcriptomes of three adjacent periods (A vs B, B vs C, C vs D) were analyzed for differentially expressed genes and photoperiod related differentially expressed genes were screened. A total of 6875 differentially expressed genes were detected. GO functional analysis showed that differentially expressed genes were mainly involved in biological processes, cell components and molecular functions, among which the most differentially expressed genes were involved in cell components. KEGG enrichment analysis showed that differentially expressed genes were mainly involved in circadian rhythm, photosynthesis - antenna protein, ribosome metabolism and other pathways. The number of single nucleotide variants detected by cSNP analysis was 312875, and the frequency of A/G and C/T were the highest. The function of eggNOG was divided into 23 categories, with a total of 26745 genes having similarities, 9008 genes were classified as function unknown, 2669 genes were classified as signal transduction mechanism, 2194 genes were classified as transcription, etc. In different developmental stages (A vs B, B vs C, C vs D), 3463 up-regulated and 3412 down-regulated differentially expressed genes were found. The difference between up-regulated and down-regulated genes was the most obvious between bud stage and initial flowering stage. In addition, a total of 79 flowering genes were found, of which 51 differential genes were screened out to participate in photoperiodic regulation pathway, 23 differential genes were up-regulated, and 28 differential genes were down-regulated. The ratio of gene-LOC11410562(GI), gene-LOC11435974(CO), gene-LOC11422615(TOC1) and gene-LOC11432385(LHY) was higher than that of gene-LOC25500742(PHYA) and gene-LOC11 431402(ELF3), gene-LOC11434778(Col13), gene-LOC25498015(Col6), and gene-LOC11415514(Col9) were preexpressed. The above differentially expressed genes were significantly expressed in different development stages of Terrestris alfalfa, which laid a foundation for further study of the molecular mechanism of Terrestris alfalfa.