Zhang Zuxin, Wei Liya, Zou Xilin, Tao Yongsheng, Liu Zhijie, Zheng Yonglian
College of Agronomy, Hebei Agricultural University, Baoding 071001, China.
Ann Bot. 2008 Oct;102(4):509-19. doi: 10.1093/aob/mcn129. Epub 2008 Jul 31.
Anaerobic or low oxygen conditions occur when maize plants are submerged or subjected to flooding of the soil. Maize survival under low oxygen conditions is largely dependent on metabolic, physiological and morphological adaptation strategies; the regulation mechanisms of which remain unknown. MicroRNAs (miRNAs) play critical roles in the response to adverse biotic or abiotic stresses at the post-transcriptional level. The aim of this study was to understand submergence-responsive miRNAs and their potential roles in submerged maize roots.
A custom muParaflo microfluidic array containing plant miRNA (miRBase: http://microrna.sanger.ac.uk) probes was used to explore differentially expressed miRNAs. Small RNAs from treated roots were hybridized with the microarray. The targets and their cis-acting elements of small RNA were predicted and analysed by RT-PCR.
Microarray data revealed that the expression levels of 39 miRNAs from nine maize and some other plant miRNA families were significantly altered (P < 0.01). Four expression profiles were identified across different submergence time-points. The zma-miRNA166, zma-miRNA167, zma-miRNA171 and osa-miRNA396-like were induced in the early phase, and their target genes were predicted to encode important transcription factors, including; HD-ZIP, auxin response factor, SCL and the WRKY domain protein. zma-miR159, ath-miR395-like, ptc-miR474-like and osa-miR528-like were reduced at the early submergence phase and induced after 24 h of submergence. The predicted targets for these miRNAs were involved in carbohydrate and energy metabolism, including starch synthase, invertase, malic enzyme and ATPase. In addition, many of the predicted targets were involved in the elimination of reactive oxygen species and acetaldehyde. Overall, most of the targets of induced miRNAs contained the cis-acting element, which is essential for the anaerobic response or hormone induction.
Submergence-responsive miRNAs are involved in the regulation of metabolic, physiological and morphological adaptations of maize roots at the post-transcriptional level.
当玉米植株被淹没或土壤遭受水淹时，会出现厌氧或低氧条件。玉米在低氧条件下的存活很大程度上依赖于代谢、生理和形态适应策略；但其调控机制仍不清楚。微小RNA（miRNA）在转录后水平对不利生物或非生物胁迫的响应中起关键作用。本研究的目的是了解淹水响应性miRNA及其在淹水玉米根中的潜在作用。
使用包含植物miRNA（miRBase：http://microrna.sanger.ac.uk）探针的定制muParaflo微流控芯片来探索差异表达的miRNA。将处理过的根中的小RNA与微阵列杂交。通过RT-PCR预测并分析小RNA的靶标及其顺式作用元件。
微阵列数据显示，来自九个玉米和其他一些植物miRNA家族的39个miRNA的表达水平发生了显著变化（P < 0.01）。在不同的淹水时间点鉴定出四种表达模式。zma-miRNA166、zma-miRNA167、zma-miRNA171和osa-miRNA396-like在早期被诱导，其靶基因预计编码重要的转录因子，包括；HD-ZIP、生长素响应因子、SCL和WRKY结构域蛋白。zma-miR159、ath-miR395-like、ptc-miR474-like和osa-miR528-like在淹水早期降低，淹水24小时后诱导。这些miRNA的预测靶标参与碳水化合物和能量代谢，包括淀粉合酶、转化酶、苹果酸酶和ATP酶。此外，许多预测靶标参与活性氧和乙醛的清除。总体而言，诱导miRNA的大多数靶标包含顺式作用元件，这对于厌氧响应或激素诱导至关重要。
淹水响应性miRNA在转录后水平参与调控玉米根的代谢、生理和形态适应。
