Comparative Transcriptome and MicroRNAs Analyses Between Low- and High-Cd Accumulating Cultivars of Water Spinach

Abstract

AbstractIn this chapter, the transcriptome and microRNAs analyses between low Cd cultivar (QLQ) and the high Cd cultivar (T308) of .water spinach were focused under 5 mg/L Cd treatment. Higher levels of cell wall biosynthesis genes, such as GAUT and laccase, and three Cd efflux genes (Nramp5, MATE9, and YSL7) were observed in QLQ, which was in line with the higher Cd subcellular distribution in cell wall of Chapter 6. Meanwhile the genes involved in sulfur and glutathione metabolism pathway, e.g., sulfate transporter and cysteine synthase, were highly expressed in T308, agreeding with the higher NaCl-extracted Cd in Chapter 6. Only 5 miRNAs were exclusively regulated in QLQ, among which, up-regulation of miRNA395 was supposed to enhance the Cd retention and detoxification in root. A Different strategies were developed between QLQ and T308 in response to Cd stress with higher cell wall Cd block in QLQ and higher Cd efflux in T308. In addition, transcriptomic mechanisms of other crops under Cd exposure were discussed as comparisons. It has been expected that the mechanisms of the cultivar- dependent Cd accumulation would be useful for further understanding of the mechanisms related to cultivar-dependent Cd accumulation and developing the molecular- assisted screening and breeding of low Cd accumulation cultivars for water spinach.