Transcriptome assembly and annotation of johnsongrass ( <i>Sorghum halepense</i> ) rhizomes identify candidate rhizome‐specific genes

Abstract

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 Blast2 GO . 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.