Transcriptomes of Indian barnyard millet and barnyardgrass reveal putative genes involved in drought adaptation and micronutrient accumulation

Abstract

Indian barnyard millet (Echinochloa frumentacea) is a rich source of dietary fiber, minerals and protein. The lack of genetic resources has slowed the discovery of genes involved in its nutrient accumulation and climate resilience. Here, we present the first transcriptomes of E. frumentacea [97,065 transcripts, including 65,276 protein-coding transcripts, over 90% of which have been functionally annotated, and 31,789 long noncoding RNA (lncRNA) transcripts] and its wild relative E. crus-galli (93,725 transcripts, including 68,480 protein-coding transcripts, 89% of which have been annotated). Comparative transcriptome analysis identified 4159 protein-coding and 2258 lncRNA transcripts in Indian barnyard millet that showed either up- or down-regulated expression when compared with E. crus-galli, and 3489 protein-coding transcripts unique to Indian barnyard millet were also detected. Additional analysis revealed that photosynthesis is likely crucial in the drought adaptation of Indian barnyard millet. We then identified possible genes regulation responsible for drought tolerance and Fe and Zn accumulation. Moreover, based on the simple sequence repeat (SSR)-containing sequence, 30 SSR primer pairs were arbitrarily selected, synthesized and used to screen the 30 E. frumentacea accessions. Of these, 10 SSR primers were polymorphic. Collectively, our results enhance the knowledge of micronutrient accumulation and drought tolerance in Indian barnyard millet, as well as of the genetic diversity of Echinochloa species.