Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India.
Department of Plants, Soils, and Climate, College of Agriculture and Applied Sciences, Utah State University, Logan, UT 84322, USA.
Genes (Basel). 2023 Jul 1;14(7):1390. doi: 10.3390/genes14071390.
Recurrent occurrence of drought stress in varying intensity has become a common phenomenon in the present era of global climate change, which not only causes severe yield losses but also challenges the cultivation of rice. This raises serious concerns for sustainable food production and global food security. The root of a plant is primarily responsible to perceive drought stress and acquire sufficient water for the survival/optimal growth of the plant under extreme climatic conditions. Earlier studies reported the involvement/important roles of microRNAs (miRNAs) in plants' responses to environmental/abiotic stresses. A number (738) of miRNAs is known to be expressed in different tissues under varying environmental conditions in rice, but our understanding of the role, mode of action, and target genes of the miRNAs are still elusive. Using contrasting rice [IR-64 (reproductive-stage drought sensitive) and N-22 (drought-tolerant)] cultivars, imposed with terminal (reproductive-stage) drought stress, we demonstrate differential expression of 270 known and 91 novel miRNAs in roots of the contrasting rice cultivars in response to the stress. Among the known miRNAs, osamiR812, osamiR166, osamiR156, osamiR167, and osamiR396 were the most differentially expressed miRNAs between the rice cultivars. In the root of N-22, 18 known and 12 novel miRNAs were observed to be exclusively expressed, while only two known (zero novels) miRNAs were exclusively expressed in the roots of IR-64. The majority of the target gene(s) of the miRNAs were drought-responsive transcription factors playing important roles in flower, grain development, auxin signaling, root development, and phytohormone-crosstalk. The novel miRNAs identified in this study may serve as good candidates for the genetic improvement of rice for terminal drought stress towards developing climate-smart rice for sustainable food production.
在当前全球气候变化的时代，不同强度的干旱事件反复发生已成为一种常见现象，不仅导致严重的产量损失，还对水稻种植构成挑战。这对可持续粮食生产和全球粮食安全构成了严重威胁。植物的根主要负责感知干旱胁迫，并在极端气候条件下为植物的生存/最佳生长获取足够的水分。早期研究报告称，microRNAs（miRNAs）参与了植物对环境/非生物胁迫的反应。已知有许多（738 个）miRNAs 在不同的组织中表达，并且在不同的环境条件下表达，但我们对 miRNA 的作用、作用模式和靶基因仍知之甚少。本研究使用具有生殖期干旱敏感特性的水稻品种 IR-64 和具有耐旱特性的水稻品种 N-22，施加生殖期干旱胁迫，证明了在逆境下，两种不同水稻品种的根系中 270 个已知和 91 个新的 miRNA 表现出差异表达。在已知的 miRNA 中，osamiR812、osamiR166、osamiR156、osamiR167 和 osamiR396 是两种水稻品种之间差异表达最多的 miRNA。在 N-22 的根中，观察到 18 个已知和 12 个新的 miRNA 特异性表达，而在 IR-64 的根中，只有两个已知（零个新的）miRNA 特异性表达。大多数 miRNA 的靶基因是干旱响应转录因子，在花、籽粒发育、生长素信号转导、根系发育和植物激素互作中发挥重要作用。本研究中鉴定的新 miRNA 可能成为遗传改良水稻对生殖期干旱胁迫的候选基因，以培育适应气候变化的水稻，实现可持续粮食生产。
