Transcriptome analysis of drought-responsive genes regulated by hydrogen sulfide in wheat (Triticum aestivum L.) leaves

Drought is an environmental factor that deeply impacts wheat yield and quality. Hydrogen sulfide (H2S) is a known regulator of drought resistance in plants. To preliminarily elucidate the regulatory mechanisms of H2S on drought tolerance, the effects of H2S on drought-responsive genes were investigated by transcriptome analysis. As a result, a total of 7552 transcripts not only responded to drought stress but also exhibited differential expression relative to the polyethylene glycol (PEG) treatment (P) and the NaHS pretreatment with PEG treatment (SP). GO categories of 'transport' were especially enriched under the SP treatment and ion transport categories (especially 'iron ion transport') were more significantly enriched among up-regulated transcripts in SP versus P treatments (SP.vs.P). Indeed, a higher translocation of iron from root to shoot and iron availability in shoots was detected in SP compared to P. The KEGG pathway of 'ribosome biogenesis in eukaryotes', 'protein processing in endoplasmic reticulum', 'fatty acid degradation', and 'cyanoamino acid metabolism' was induced by H2S under drought stress. Further, H2S was involved in plant hormones signal transduction, and drought-induced transcription factors, protein kinases, and functional genes exhibited higher expression levels under SP relative to P. Additionally, several effectors or master regulatory genes of H2S were identified genome-wide. Summarily, these results showed that H2S alleviated drought damage probably related to transport systems, plant hormones signal transduction, protein processing pathway, fatty acids and amino acids metabolism, which provides a guide for future experimentation to analyze hydrogen sulfide-dependent drought tolerance mechanisms in wheat.