Illumina Sequencing Revealed Roles of MicroRNAs in Different Aluminum Tolerance of Two Citrus Species

Seedlings of Citrus sinensis and C. grandis were irrigated with nutrient solution with 0 mM AlCl3.6H2O (control, -Al) or 1 mM AlCl3.6H2O (+Al) for 18 weeks. Al treatment significantly decreased the DW of leaf, stem, shoot and the whole plant of C. grandis, increase the ratio of root DW to shoot DW in C. grandis, whereas did not change these parameters of C. sinensis. Al treatment significantly decreased the S content in C. grandis roots and the P content in both C. sinensis and C. grandis roots. More Al was transported to shoots and leaves in C. grandis than in C. sinensis under Al treatment. Al treatment has more adverse effects on C. grandis than on C. sinensis, as revealed by the higher production of H2O2 and TBARS content in C. grandis roots. Via Illumina sequencing tecnique, we successfully identified and quantified 12 and 16 differentially expressed miRNAs responding to Al stress in C. sinensis and C. grandis roots, respectively.