Stage Specific Comparative Transcriptomic Analysis To Reveal Gene Networks Regulating Iron And Zinc Content In Pearl Millet [Pennisetum glaucum (L.) R. Br.]

Abstract Pearl millet is an important staple food crop of poor people which is rich in micronutrients like iron and zinc and amenable for focused breeding for these micronutrients along with high yield. Transcriptome sequencing using ION S5 Next Generation Sequencer generated 43.5 million sequence reads resulting in 83,721 transcripts with N50 of 597 bp and 84.35% of transcripts matched with the pearl millet genome assembly. The genotypes having high Fe and Zn showed differential gene expression during different stages. Of which, 155 were up-regulated and 251were down-regulated while during flowering stage and milking stage 349 and 378 transcripts were differentially expressed, respectively. Gene annotation and GO term showed the presence of transcripts involved in metabolic activities associated with uptake and transport of iron and zinc. In the present study, the 83,721 transcripts were also examined for identification of SSRs. A total of 4,327 SSRs were identified with dominance of tri-nucleotide SSRs in comparison to di-nucleotide SSRs. These EST-SSRs can be used in molecular breeding, genetic diversity analysis and determination of heterozygosity of the allelic loci. Information generated will help in gaining insights into iron and zinc metabolism and develop genotypes with high yield, grain iron and zinc content.