Insight of Transcriptional Regulators reveals the Tolerance Mechanism of Carpet-grass (Axonopus compressus) Against Drought

Abstract

Background: Carpet grass [Axonopus compressus (L.)] is an important warm-season perennial grass around the world and is known for its adaptability to varied environmental conditions. However, Carpet grass lacks enough data in public data banks, which confined our comprehension on the mechanisms of environmental adaptations, gene discovery and development of molecular markers. In current study, the DEGs (differentially expressed genes) in Axonopus compressus under drought stress (DS) were identified and compared with CK (control) by RNA-Seq. Results: A total of 263,835 unigenes were identified in Axonopus compressus, and 201,303 (also added to the numbers of the remaining 2 data bases) a sequence of unigenes significantly matched in at least one of the seven databases. A total of 153697 (58.25%) unigenes classified to 144 KEGG pathways, and 7,444 unigenes were expressed differentially between DS and CK, of which 4,249 were up-regulated and 3,195 were down-regulated unigenes. Of the 50 significantly enriched GO terms, 18, 6 and 14 items were related to BP, CC and MF respectively. Analysis of KEGG enrichment revealed 2569 DEGs involved in 143 different pathways, under drought stress. 2,747 DEGs were up-regulated and 2,502 DEGs were down-regulated. Moreover, we identified 352 transcription factors (TFs) in Axonopus compressus, of which 270 were differentially expressed between CK and DS. The qRT-PCR validation experiment also support the transcriptional response of Axonopus compressus against drought. Accuracy of transcriptome unigenes of Axonopus compressus was assessed with BLAST, which showed 3,300 sequences of Axonopus compressus in the NCBI.Conclusion: The 7,444 unigenes were found to be between DS and CK treatments which indicate that there is a strong mechanism of drought tolerance in Axonopus compressus. The current findings provide the first framework for further investigations for the particular roles of these unigenes in Axonopus compressus in response to drought.