Huen A K, Rodriguez-Medina C, Ho A Y Y, Atkins C A, Smith P M C
Plant Molecular Biology Lab, School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, Australia.
The Colombian Agricultural Research Corporation (Corpoica), Palmira, Valle del Cauca, Columbia.
Plant Biol (Stuttg). 2017 Jul;19(4):643-649. doi: 10.1111/plb.12568. Epub 2017 Apr 12.
Plant microRNAs are small RNAs that are important for genetic regulation of processes such as plant development or environmental responses. Specific microRNAs accumulate in the phloem during phosphate starvation, and may act as long-distance signalling molecules. We performed quantitative PCR on Arabidopsis hypocotyl micrograft tissues of wild-type and hen1-6 mutants to assess the mobility of several phosphate starvation-responsive microRNA species. In addition to the previously confirmed mobile species miR399d, the corresponding microRNA* (miR399d*) was identified for the first time as mobile between shoots and roots. Translocation by phosphate-responsive microRNAs miR827 and miR2111a between shoots and roots during phosphate starvation was evident, while their respective microRNAs were not mobile. The results suggest that long-distance mobility of microRNA species is selective and can occur without the corresponding duplex strand. Movement of miR399d and root-localised accumulation of miR2111a* opens the potential for persisting microRNA*s to be mobile and functional in novel pathways during phosphate starvation responses.
植物微小RNA是一类小RNA，对植物发育或环境响应等过程的基因调控很重要。在磷酸盐饥饿期间，特定的微小RNA会在韧皮部积累，并可能作为长距离信号分子发挥作用。我们对野生型和hen1-6突变体的拟南芥下胚轴微嫁接组织进行了定量PCR，以评估几种磷酸盐饥饿响应微小RNA种类的移动性。除了先前已确认具有移动性的miR399d外，相应的微小RNA*（miR399d*）首次被鉴定为在地上部和根部之间具有移动性。在磷酸盐饥饿期间，磷酸盐响应微小RNA miR827和miR2111a在地上部和根部之间的易位很明显，而它们各自的微小RNA则没有移动性。结果表明，微小RNA种类的长距离移动具有选择性，并且可以在没有相应双链体的情况下发生。miR399d的移动以及miR2111a在根部的局部积累，为磷酸盐饥饿响应过程中持久存在的微小RNA在新途径中具有移动性和功能性打开了可能性。
