Cadmium (Cd) is a widespread environmental pollutant that poses significant health risks through food chain accumulation, highlighting the urgent need for remediation. Phytoremediation, a sustainable and cost-effective approach, has gained increasing attention as a solution. Researchers from Chinese Academy of Sciences, China National Botanical Garden and University of Chinese Academy of Sciences explored the role of long non-coding RNAs (lncRNAs) in cadmium (Cd) stress responses in sweet sorghum, focusing on two genotypes with contrasting Cd tolerance (‘H18’ and ‘L69’). Differential expression analysis identified 1988 lncRNAs in root tissues, with 81 responsive to Cd treatment. Interestingly, the number of lncRNAs in roots was consistently lower than in other plant organs, suggesting a conserved phenomenon across species, though its biological significance remains unclear. LncRNA 15962 was identified as a potential target mimic for miR5565e, influencing cell wall metabolism through the regulation of pectin methylesterase inhibitor and peroxidase genes. These findings highlight the importance of cell wall-related pathways in mediating Cd accumulation in sorghum roots. The study also optimized a protoplast isolation and transformation system, enabling functional validation of lncRNA-mediated gene regulation, a crucial step in understanding lncRNA roles in Cd stress.
Further investigation revealed that lncRNA 11558 positively regulated the expression of the Cd chelate transporter gene SbYS1 in response to Cd stress. This lncRNA was highly expressed in the tolerant genotype ‘H18’, correlating with increased SbYS1 expression. Functional assays demonstrated that overexpression of lncRNA 11558 enhanced SbYS1 expression, while its silencing reduced SbYS1 levels. Notably, the transcription factor SbWRKY72, previously shown to repress SbYS1, may also regulate lncRNA 11558 by binding to W-box motifs in its promoter region. These findings provide novel insights into the regulatory network of lncRNAs in Cd tolerance and accumulation, paving the way for developing sweet sorghum with improved Cd stress resilience and amassment.
SorghumBase examples:
Figures: The authors found in the paper lncRNA 11558 positively regulates SbYS1 (Sobic.004G299500,SORBI_3004G299500), a Cd chelate transporter that enhances Cd uptake and movement within the plant. Silencing lncRNA 11558 using exogenous miRNAs reduced SbYS1 expression, confirming its regulatory role. Searching for SORBI_3004G299500 in SorghumBase, we observe that it is highly expressed in roots (blue squares) from three studies curated in collaboration with the EBI Expression Atlas Figure A.This gene is also annotated in SorghumBase as being involved in auxin influx transport at the plasma membrane, linking it to polar auxin transport Figure B. Since auxin influx transporters regulate auxin distribution in root cells, SbYS1 may influence both Cd uptake and root architecture in response to Cd stress.[/caption]
Reference:
Lin K, Yi Z, Lv S, Zhang B, Guo Z, Li Y. Uncovering the key lncRNAs in regulating cadmium accumulation and translocation in sweet sorghum. Planta. 2024 Dec 11;261(1):12. doi: 10.1007/s00425-024-04589-7. PMID: 39661199. Read more