Journal Article

Identification and expression analysis of miRNAs and elucidation of their role in salt tolerance in rice varieties susceptible and tolerant to salinity

Shaw, Birendra Prasad, Behera, Lambodar, Tagirasa, Ravichandra, Dash, Sushant Kumar, Parmar, Shaifaly, Chandra, Tilak, Gharat, Sachin Ashruba

2020

Overview

Soil salinization is a serious problem for cultivation of rice, as among cereals rice is the most salt sensitive crop, and more than 40% of the total agricultural land amounting to approximately 80 million ha the world over is salt affected. Salinity affects a plant in a varieties of ways, including ion toxicity, osmotic stress and oxidative damage. Since miRNAs occupy the top place in biochemical events determining a trait, understanding their role in salt tolerance is highly desirable, which may allow introduction of the trait in the rice cultivars of choice through biotechnological interventions. High throughput sequencing of sRNAs in the root and shoot tissues of the seedlings of the control and NaCl treated Pokkali, a salt-tolerant rice variety, identified 75 conserved miRNAs and mapped 200 sRNAs to the rice genome as novel miRNAs. Expression of nine novel miRNAs and two conserved miRNAs were confirmed by Northern blotting. Several of both conserved and novel miRNAs that expressed differentially in root and/or shoot tissues targeted transcription factors like AP2/EREBP domain protein, ARF, NAC, MYB, NF-YA, HD-Zip III, TCP and SBP reported to be involved in salt tolerance or in abiotic stress tolerance in general. Most of the novel miRNAs expressed in the salt tolerant wild rice Oryza coarctata, suggesting conservation of miRNAs in taxonomically related species. One of the novel miRNAs, osa-miR12477, also targeted L-ascorbate oxidase (LAO), indicating build-up of oxidative stress in the plant upon salt treatment, which was confirmed by DAB staining. Thus, salt tolerance might involve miRNA-mediated regulation of 1) cellular abundance of the hormone signaling components like EREBP and ARF, 2) synthesis of abiotic stress related transcription factors, and 3) antioxidative component like LAO for mitigation of oxidative damage. The study clearly indicated importance of osa-miR12477 regulated expression of LAO in salt tolerance in the plant.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Abiotic stress / Acetylcysteine / Agricultural land / Agricultural production / Analysis / Ascorbate oxidase / Ascorbic acid / Biology and life sciences / Biotechnology / Blotting, Northern - methods / Cereals / Conservation / Cultivars / Cultivation / Damage / DNA binding proteins / Ecology and Environmental Sciences / Farmlands / Gene expression / Gene Expression Regulation, Plant - genetics / Genomes / Genomics / Grain cultivation / High-Throughput Nucleotide Sequencing - methods / L-Ascorbate oxidase / Life sciences / MicroRNA / MicroRNAs / MicroRNAs - genetics / miRNA / Mitigation / Next-generation sequencing / Northern blotting / Oryza - genetics / Oryza coarctata / Osmotic stress / Oxidative stress / Oxidative Stress - genetics / Physical Sciences / Research and Analysis Methods / Rice / RNA polymerase / Salinity / Salinity effects / Salinity tolerance / Salinization / Salt tolerance / Salt Tolerance - genetics / Seedlings / Seedlings - genetics / Sodium chloride / Soil salinity / Soils, Salts in / Stress, Physiological - genetics / Toxicity / Transcription factors / Transcription Factors - genetics / Wildlife conservation