Identification and comparative analysis of aluminum-induced microRNAs conferring plant tolerance to aluminum stress in soybean

Abstract

Aluminum (Al) toxicity in acidic soils is a major factor restricting crop production. Although the molecular mechanisms of Al responses have been extensively investigated, microRNA (miRNA) mediated differential Al tolerance in different soybean genotypes remains largely unknown. In this study, two soybean [Glycine max (L.) Merr.] genotypes, Al-tolerant BX10 and Al-sensitive BD2, were treated with 0 and 50 μM AlCl3 and then used to construct the miRNA libraries for deep sequencing. Results revealed 453 miRNAs, whose expression patterns were affected by Al stress. We also identified 32 differentially expressed miRNAs: 19 in BX10, 7 in BD2, and 6 in both genotypes. The gene ontology analysis of their putative target genes indicated that stress-responsive genes and amino-acid-metabolism-related processes preferentially existed in BX10. Comprehensive analysis demonstrated that conserved miRNAs, such as gma-miR166k/o, gma-miR390g, and gma-miR396c/k, mediated root elongation in BX10, whereas gma-miR169r triggered oxidative stress in BD2. These processes could be regarded as important mechanisms conferring differential Al tolerance in BX10 and BD2. This study provided new insights into different Al response mechanisms in various soybean genotypes.

Keywords

• abiotic stress
• acidic soil
• gene sequencing
• glycine max
• target genes