Abiotic Stress and Agro-Biotechnology Lab, Institute of Life Sciences, Bhubaneswar, Odisha, India.
Crop Improvement Division, ICAR-National Rice Research Institute (Formerly Central Rice Research Institute), Cuttack, Odisha, India.
PLoS One. 2020 Apr 15;15(4):e0230958. doi: 10.1371/journal.pone.0230958. eCollection 2020.
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.
土壤盐渍化是水稻种植的一个严重问题,因为在谷物中,水稻对盐最敏感,全世界有超过 40%的农业用地(约 8000 万公顷)受到盐的影响。盐度通过多种方式影响植物,包括离子毒性、渗透胁迫和氧化损伤。由于 miRNA 在决定性状的生化事件中占据首要地位,因此了解它们在耐盐性中的作用是非常可取的,这可能允许通过生物技术干预将该性状引入所选的水稻品种中。对对照和 NaCl 处理的耐盐水稻品种 Pokkali 幼苗的根和茎组织中的 sRNA 进行高通量测序,鉴定了 75 个保守 miRNA,并将 200 个 sRNA 映射到水稻基因组作为新的 miRNA。通过 Northern 印迹证实了 9 个新 miRNA 和 2 个保守 miRNA 的表达。在根和/或茎组织中表达差异的几种保守和新 miRNA 靶向转录因子,如 AP2/EREBP 结构域蛋白、ARF、NAC、MYB、NF-YA、HD-Zip III、TCP 和 SBP,这些转录因子被报道参与耐盐性或一般的非生物胁迫耐受性。在耐盐野生稻 Oryza coarctata 中表达的大多数新 miRNA 表明 miRNA 在分类上相关的物种中保守。新 miRNA 之一 osa-miR12477 也靶向 L-抗坏血酸氧化酶(LAO),表明植物在盐处理后会产生氧化应激,这一点通过 DAB 染色得到了证实。因此,耐盐性可能涉及 miRNA 介导的对 1)激素信号成分(如 EREBP 和 ARF)的细胞丰度的调节,2)非生物胁迫相关转录因子的合成,和 3)抗氧化成分(如 LAO)的调节,以减轻氧化损伤。该研究清楚地表明,osa-miR12477 调控 LAO 的表达在植物的耐盐性中很重要。