Transcriptome Analysis and Morphological Changes in Response to Waterlogging in Iris pseudacorus

Iris pseudacorus is a widely cultivated and studied ornamental plant with a large biomass,strong adaptability and extensive management.Moreover,it has the ability to decontaminate and enrich heavy metals.However,few studies have been conducted on its submergence tolerance with little known about the molecular response of I.pseudacorus to flooding.Morphologically,I.pseudacorus had strong adaptability to waterlogging,the aerenchyma was gradually enlarged and adventitious roots developed between 0 and 14 d.The transcriptome data showed that the differentially expressed genes counts in plants flooded for 2 h,4 h,12 h and 24 h compared with the unflooded controls were 3555,9439,10734,and 4997,respectively.For GO term entries enriched by different genes,many biological processes,cell components and molecular processes in the I.pseudacorus roots were affected by flooding stress.Pathways enrichment analysis showed DEGs involved in hormone signal transduction pathways,glucose metabolism,glycolysis,and fermentation.The quantitative real-time PCR analysis of DEGs was basically consistent with the trend of transcriptome data,indicating reliability of the transcriptome data.The transcriptome analysis showed that formation of aerenchyma and adventitious roots was mainly induced by IAA(auxin)and accompanied by other hormone signals.Energy production was the primary coping mechanism of I.pseudacorus when aerenchyma was not sufficiently enlarged under water flooding.These results laid a foundation for further study on the mechanism of submerging-tolerance of I.pseudacorus and other aquatic plants.

Physiological and Biochemical Responses of Iris pseudacorus to Lead Stress

[Objectives]This study was conducted to discuss the Pb-enrichment ability of Iris pseudacorus,and reveal the effects of different concentrations of Pb stress on the physiological metabolism of I.pseudacorus.[Methods]I.pseudacorus L.as a test material was cultured by the nutrient solution culture method and analyzed for malondialdehyde(MDA),glutathione(GSH),cysteine(Cys)and proline(Pro)contents of plant leaves as well as catalase(CAT)and superoxide dismutase(SOD)activity under different concentrations of Pb stress(0,200,400,600,800,1000,1200 mg/L).[Results]With the increase of Pb concentration,the Pb content of leaves and roots gradually increased,and the order of increase was root>leaf.Roots and leaves reached maximums at the high concentration of 1200 mg/L Pb,and their contents were 9034.6 and 11.2 mg/kg,respectively.Under Pb stress,the contents of GSH,Cys and Pro,and the activity of CAT and SOD in I.pseudacorus showed a trend of first increasing and then decreasing with the increase of Pb concentration,and each index reached a maximum under the treatment of 400 mg/L.The level of MDA in the leaves of I.pseudacorus rose significantly under Pb stress,indicating that Pb stress caused the cell membrane of I.pseudacorus to be damaged by peroxidation.[Conclusions]This study provides a theoretical basis for further research and use of this plant for metal pollution remediation in the future.