Transcriptome assembly and annotation of johnsongrass (Sorghum halepense) rhizomes identify candidate rhizome-specific genes

Plant Direct. 2018 Jun 19;2(6):e00065. doi: 10.1002/pld3.65. eCollection 2018 Jun.

Abstract

Rhizomes facilitate the wintering and vegetative propagation of many perennial grasses. Sorghum halepense (johnsongrass) is an aggressive perennial grass that relies on a robust rhizome system to persist through winters and reproduce asexually from its rootstock nodes. This study aimed to sequence and assemble expressed transcripts within the johnsongrass rhizome. A de novo transcriptome assembly was generated from a single johnsongrass rhizome meristem tissue sample. A total of 141,176 probable protein-coding sequences from the assembly were identified and assigned gene ontology terms using Blast2GO. Estimated expression analysis and BLAST results were used to reduce the assembly to 64,447 high-confidence sequences. The johnsongrass assembly was compared to Sorghum bicolor, a related nonrhizomatous species, along with an assembly of similar rhizome tissue from the perennial grain crop Thinopyrum intermedium. The presence/absence analysis yielded a set of 98 expressed johnsongrass contigs that are likely associated with rhizome development.

Keywords: RNA‐Seq; Sorghum halepense; next‐generation sequencing; perennial plants; rhizomes; transcriptomics/transcriptome analysis.