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Thiourea priming enhances salt tolerance through co-ordinated regulation of microRNAs and hormones in Brassica juncea

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ABSTRACT

Activation of stress tolerance mechanisms demands transcriptional reprogramming. Salt stress, a major threat to plant growth, enhances ROS production and affects transcription through modulation of miRNAs and hormones. The present study delineates salt stress ameliorating action of thiourea (TU, a ROS scavenger) in Brassica juncea and provides mechanistic link between redox, microRNA and hormones. The ameliorative potential of TU towards NaCl stress was related with its ability to decrease ROS accumulation in roots and increase Na+ accumulation in shoots. Small RNA sequencing revealed enrichment of down-regulated miRNAs in NaCl + TU treated roots, indicating transcriptional activation. Ranking analysis identified three key genes including BRX4, CBL10 and PHO1, showing inverse relationship with corresponding miRNA expression, which were responsible for TU mediated stress mitigation. Additionally, ABA level was consistently higher till 24 h in NaCl, while NaCl + TU treated roots showed only transient increase at 4 h suggesting an effective stress management. Jasmonate and auxin levels were also increased, which prioritized defence and facilitated root growth, respectively. Thus, the study highlights redox as one of the “core” components regulating miRNA and hormone levels, and also strengthens the use of TU as a redox priming agent for imparting crop resilience to salt stress.

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Differential phenotype of B. juncea seedlings with/without thiourea (TU) treatment.The seedlings were grown hydroponically under control condition for 10 d and then subjected to different treatments such as control (1/2 MS), NaCl (150 mM), NaCl (150 mM) + TU (75 μM) and TU (75 μM). For NaCl + TU and TU alone treatments, 24 h pre-treatment with same concentration of TU was also given. At 7 d after treatment, differential phenotype was recorded qualitatively (A) and quantified in terms of survival efficiency (B). In order to obtain leaf phenotype, NaCl concentration was reduced to 125 mM and phenotype was recorded at 10 d after treatment both qualitatively (C) and quantitatively in terms of fresh weight per seedling (D) and leaf area (E). The data represents the mean ± SE of three biological replicates. Different letters on bar graph have been put on the basis of LSD value derived from SPSS software (DMRT, P < 0.05).
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f1: Differential phenotype of B. juncea seedlings with/without thiourea (TU) treatment.The seedlings were grown hydroponically under control condition for 10 d and then subjected to different treatments such as control (1/2 MS), NaCl (150 mM), NaCl (150 mM) + TU (75 μM) and TU (75 μM). For NaCl + TU and TU alone treatments, 24 h pre-treatment with same concentration of TU was also given. At 7 d after treatment, differential phenotype was recorded qualitatively (A) and quantified in terms of survival efficiency (B). In order to obtain leaf phenotype, NaCl concentration was reduced to 125 mM and phenotype was recorded at 10 d after treatment both qualitatively (C) and quantitatively in terms of fresh weight per seedling (D) and leaf area (E). The data represents the mean ± SE of three biological replicates. Different letters on bar graph have been put on the basis of LSD value derived from SPSS software (DMRT, P < 0.05).

Mentions: To assess the phenotypic differences, in terms of survival and growth, post-germination phenotyping was performed on hydroponically grown seedlings under NaCl with/without TU treatment. We observed significant increase in survival efficiency in NaCl + TU (69%) as compared with NaCl (24%) treatment at 150 mM NaCl concentration (Fig. 1A,B). The growth phenotype was evaluated at 125 mM NaCl concentration. A greater decrease in biomass accumulation was observed in NaCl (60%) than NaCl + TU (39%) treatment, as compared with that of control (Fig. 1D). This was simultaneous with significant increase in average leaf area by 42% in NaCl + TU as compared with NaCl treatment (Fig. 1C and E). Thus, the observed phenotype clearly demonstrates the ameliorative potential of TU against NaCl stress induced toxicity.


Thiourea priming enhances salt tolerance through co-ordinated regulation of microRNAs and hormones in Brassica juncea
Differential phenotype of B. juncea seedlings with/without thiourea (TU) treatment.The seedlings were grown hydroponically under control condition for 10 d and then subjected to different treatments such as control (1/2 MS), NaCl (150 mM), NaCl (150 mM) + TU (75 μM) and TU (75 μM). For NaCl + TU and TU alone treatments, 24 h pre-treatment with same concentration of TU was also given. At 7 d after treatment, differential phenotype was recorded qualitatively (A) and quantified in terms of survival efficiency (B). In order to obtain leaf phenotype, NaCl concentration was reduced to 125 mM and phenotype was recorded at 10 d after treatment both qualitatively (C) and quantitatively in terms of fresh weight per seedling (D) and leaf area (E). The data represents the mean ± SE of three biological replicates. Different letters on bar graph have been put on the basis of LSD value derived from SPSS software (DMRT, P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382540&req=5

f1: Differential phenotype of B. juncea seedlings with/without thiourea (TU) treatment.The seedlings were grown hydroponically under control condition for 10 d and then subjected to different treatments such as control (1/2 MS), NaCl (150 mM), NaCl (150 mM) + TU (75 μM) and TU (75 μM). For NaCl + TU and TU alone treatments, 24 h pre-treatment with same concentration of TU was also given. At 7 d after treatment, differential phenotype was recorded qualitatively (A) and quantified in terms of survival efficiency (B). In order to obtain leaf phenotype, NaCl concentration was reduced to 125 mM and phenotype was recorded at 10 d after treatment both qualitatively (C) and quantitatively in terms of fresh weight per seedling (D) and leaf area (E). The data represents the mean ± SE of three biological replicates. Different letters on bar graph have been put on the basis of LSD value derived from SPSS software (DMRT, P < 0.05).
Mentions: To assess the phenotypic differences, in terms of survival and growth, post-germination phenotyping was performed on hydroponically grown seedlings under NaCl with/without TU treatment. We observed significant increase in survival efficiency in NaCl + TU (69%) as compared with NaCl (24%) treatment at 150 mM NaCl concentration (Fig. 1A,B). The growth phenotype was evaluated at 125 mM NaCl concentration. A greater decrease in biomass accumulation was observed in NaCl (60%) than NaCl + TU (39%) treatment, as compared with that of control (Fig. 1D). This was simultaneous with significant increase in average leaf area by 42% in NaCl + TU as compared with NaCl treatment (Fig. 1C and E). Thus, the observed phenotype clearly demonstrates the ameliorative potential of TU against NaCl stress induced toxicity.

View Article: PubMed Central - PubMed

ABSTRACT

Activation of stress tolerance mechanisms demands transcriptional reprogramming. Salt stress, a major threat to plant growth, enhances ROS production and affects transcription through modulation of miRNAs and hormones. The present study delineates salt stress ameliorating action of thiourea (TU, a ROS scavenger) in Brassica juncea and provides mechanistic link between redox, microRNA and hormones. The ameliorative potential of TU towards NaCl stress was related with its ability to decrease ROS accumulation in roots and increase Na+ accumulation in shoots. Small RNA sequencing revealed enrichment of down-regulated miRNAs in NaCl&thinsp;+&thinsp;TU treated roots, indicating transcriptional activation. Ranking analysis identified three key genes including BRX4, CBL10 and PHO1, showing inverse relationship with corresponding miRNA expression, which were responsible for TU mediated stress mitigation. Additionally, ABA level was consistently higher till 24&thinsp;h in NaCl, while NaCl&thinsp;+&thinsp;TU treated roots showed only transient increase at 4&thinsp;h suggesting an effective stress management. Jasmonate and auxin levels were also increased, which prioritized defence and facilitated root growth, respectively. Thus, the study highlights redox as one of the &ldquo;core&rdquo; components regulating miRNA and hormone levels, and also strengthens the use of TU as a redox priming agent for imparting crop resilience to salt stress.

No MeSH data available.


Related in: MedlinePlus