Use of Comparative Transcriptomics Combined With Physiological Analyses to Identify Key Factors Underlying Cadmium Accumulation in L.

The contamination of soils with cadmium (Cd) has become a serious environmental issue that needs to be addressed. Elucidating the mechanisms underlying Cd accumulation may facilitate the development of plants that accumulate both high and low amounts of Cd. In this study, a combination of phenotypic, physiological, and comparative transcriptomic analyses was performed to investigate the effects of different Cd concentrations (0, 5, 10, 30, 50 mg/kg) on L. Our results suggest that L. seedlings had a degree of tolerance to the 5 mg/kg Cd treatment, whereas higher Cd stress (10-50 mg/kg) could suppress the growth of L. seedlings. The contents of soluble protein, as well as MDA (malondialdehyde), were increased, but the activities of CAT (catalase) enzymes and the contents of soluble sugar and chlorophyll were decreased, when L. was under 30 and 50 mg/kg Cd treatment. Comparative transcriptomic analysis indicated that , and were down-regulated, but and were up-regulated, which might contribute to cell wall integrity maintenance. Moreover, the down-regulation of and up-regulation of , , and might also play roles in reducing Cd toxicity in roots. Taken together, the results of our study may help to elucidate the mechanisms underlying the response of L. to various concentrations of Cd.