High salinity is one of the major problems in agricultural fields and many countries, including India, use an organic sulphur compound thiourea to minimise the negative effect of salt stress. Now, using molecular biology tools, scientists from Bhabha Atomic Research Centre (BARC), Mumbai have reported how this treatment altered the plant RNA and hormones to facilitate this survival in mustard plants grown with high salt stress (125-150 milliMolar NaCl).
Anthropogenic factors, irregular irrigation and proximity to the sea can cause high salinity in the agricultural fields and this induces redox imbalance and damages the plant. Various studies have shown that thiourea is a good redox stabiliser as it scavenges multiple reactive oxygen species including hydrogen peroxide. The researchers carried out studies to understand how this thiourea activates the tolerance mechanisms.
Mustard seedlings, just 20-day-old plants, grown in a liquid nutrient medium, were given saline treatment with and without thiourea, and their growth was studied for seven days. The plants which were supplemented with 75 micromolar of thiourea showed increased survival and better phenotype with larger leaves compared with the group grown in saline medium.
The researchers then studied the microRNA of the plant as it is an important component that regulates plant transcriptomes according to the environmental conditions.
“We found that downregulated microRNAs were enriched in the thiourea group to facilitate transcriptional activation and adaptation under salt stress conditions,” explains Dr. Ashish Kumar Srivastava, at BARC and first author of the paper published in Scientific Reports.
They also studied different genes and plant hormones that are involved in stress management and identified four key genes responsible for the adaptation. Plant hormones such as ABA, Auxins, jasmonates which have been shown to play important roles in salt tolerance were all found to be co-ordinately regulated upon thiourea treatment.
The team also studied the effect on spraying diluted thiourea directly on the shoot of rice plants grown in arsenic contaminated soil and found it effective in reducing arsenic accumulation in rice grains.
Further studies are underway to validate the effects of thiourea in rice and multiple different crops under varied environmental conditions.
“Thiourea based technology can sprovide easy-cum-affordable solution to the farmers for minimizing abiotic stress induced losses in crop plants,” explains Dr. Penna Suprasanna at BARC one of the authors of the paper.