Data from: Identifying differentially expressed genes under heat stress and developing molecular markers in orchardgrass (Dactylis glomerata L.) through transcriptome analysis

Orchardgrass (Dactylis glomerata L.) is a long-lived, cool-season, forage grass that is most commonly used for hay production. Despite its economic importance, the orchardgrass genome remains relatively unexplored. In this study, we used Illumina HiSeq RNA-sequencing in order to identify gene-associated molecular markers, including simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs), as well as heat stress-induced differentially expressed genes (DEGs) in two orchardgrass genotypes, ‘Baoxing’ and ‘01998’. Approximately 163 million high-quality trimmed reads were generated from 207 million raw reads using the Illumina HiSeq 2000 platform. A total of 126,846 unigenes were obtained by assembling raw reads. A total of 40,078 unigenes were identified as coding sequences (CDSs), with 47,455 unigenes predicted as CDSs from ESTScan. Gene Ontology (GO) annotation showed that 33,581 unigenes were assigned with at least one GO term. KEGG pathway analysis showed that 6,858 unigenes were mapped to 255 pathways, while 11,314 unigenes were annotated by KOG analysis. Based on the assembled unigenes, 669,300 high-quality SNPs including 416,099 transitions and 257,736 transversions from 75,875 unigenes were identified. A total of 8,475 microsatellites were detected in 7,764 unigenes. The total number of DEGs in ‘Baoxing’ was higher than in ‘01998’ when the plants were placed under heat stress, indicating that more unigenes may be related to heat resistance in ‘Baoxing’ (3, 527) than in ‘01998’ (2, 649). Our high-throughput transcriptome sequencing of orchardgrass under heat stress provides information for gene identification and for the development of SNPs and SSRs. This comparison of DEGs under different periods of heat stress allowed the identification of a wealth of candidate DEGs that can be further analyzed to determine the genetic basis of heat tolerance in orchardgrass.