Abstract
Background
Pennisetum glaucum (L.) R. Br. is mainly grown in arid and semi-arid regions. Being naturally tolerant to various adverse condtitions, it is a good biological resource for deciphering the molecular basis of abiotic stresses such as heat stress in plants but limited studies have been carried out till date to this effect. Here, we performed RNA-sequencing from the leaf of two contrasting genotypes of pearl millet (841-B and PPMI-69) subjected to heat stress (42 °C for 6 h).
Results
Over 274 million high quality reads with an average length of 150 nt were generated. Assembly was carried out using trinity, obtaining 47,310 unigenes having an average length of 1254 nucleotides, N50 length of 1853 nucleotides and GC content of 53.11%. Blastx resulted in annotation of 35,628 unigenes and functional classification showed 15,950 unigenes designated to 51 Gene Ontology terms, 13,786 unigenes allocated to 23 Clusters of Orthologous Groups and 4,255 unigenes distributed into 132 functional KEGG pathways. 12,976 simple sequence repeats were identified from 10,294 unigenes for the development of functional markers. A total of 3,05,759 SNPs were observed in the transcriptome data. Out of 2,301 differentially expressed genes, 10 potential candidates genes were selected based on log2 fold change and adjusted p-value parameters for their differential gene expression by qRT-PCR.
Conclusions
The dynamic expression changes in two genotypes of P. glaucum reflect transcriptome regulation of signaling pathways in heat stress response. In order to develop genetic markers, 12,976 simple sequence repeats (SSRs) were identified. The sequencing data generated in this study shall serve as an important resource for further research in the area of crop biotechnology.
Transcriptome analysis of two contrasting genotypes of pearl millet to gain insight into heat stress responses