Combining single-molecule sequencing and next-generation sequencing to provide insight into the complex response of Iris halophila Pall. to Pb exposure

Iris halophila Pall., a Pb accumulator with high ecological and industrial values, has enormous application potential for the phytoremediation of Pb-contaminated soil. However, the lack of full-length transcriptome information obstructs understanding of the molecular regulatory network of I. halophila response to Pb. To construct the full-length transcript database and identify the molecular mechanisms underlying I. halophila response to Pb, the shoots, roots, flowers, and Pb-treated seedlings of I. halophila were subjected to single-molecular real-time sequencing and next-generation sequencing. A total of 40,034 complete coding sequences, 2028 alternative splices, 4649 long non-coding RNAs (lncRNAs) were predicted. Among them, 2614 annotated differentially expressed genes (DEGs) and 19 differentially expressed lncRNAs (DELs) were identified in Pb-treated I. halophila shoot, while 7242 annotated DEGs and 57 DELs were identified in root under Pb conditions. Biological function enrichment analysis of DEGs revealed the key roles of hormone signaling transduction, GSH metabolism, metal ion transporters in I. halophila response to Pb. LncRNA play crucial roles in I. halophila resistance to Pb by regulating the key downstream metabolic pathways. These results not only enrich the genetic information of Iris. L plants, but also enhance the understanding of molecular responses to Pb in I. halophila, and will lay an important foundation for future research on Pb phytoremediation or low-Pb food crop and development of I. halophila for industrial uses.