Department of Biotechnology and Life Science, University of Insubria, Via Dunant, 3, 21100, Varese, VA, Italy.
Department of Chemistry and Biology 'A. Zambelli', University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, SA, Italy.
Sci Rep. 2020 Nov 3;10(1):18890. doi: 10.1038/s41598-020-75150-1.
Despite the large amounts of data available on lateral root formation, little is known about their initiation from secondary structures. In the present work, we applied a bending treatment to Populus nigra (L.) woody taproots to induce the formation of new lateral roots. The development of lateral roots was monitored by stereomicroscopic examination of cross-sections. Tissues were sampled from the bending zone in the proximity of the vascular cambium before (time 0) and after the application of bending at three different time points (24, 48, and 72 h) and analyzed for the expression of P. nigra WOX homologs. The initiation of new lateral roots was observed to originate from the vascular cambium zone and was followed by primordium formation and root emergence. PnWOX4a, PnWOX4b, PnWOX5a, PnWOX5b, PnWOX11/12a, and PnWOX11/12b were shown to be expressed during the formation of new lateral roots at different developmental stages. The mechanical stress simulated by bending treatment was shown to activate the molecular mechanism leading to the expression of WOX genes, which are hypothesized to control SLR formation in the cambium zone of poplar taproot.
尽管已经有大量关于侧根形成的数据，但对于它们从次生结构中起始的过程仍知之甚少。在本研究中，我们对欧洲黑杨木质主根进行了弯曲处理，以诱导新侧根的形成。通过对横切面上的立体显微镜检查，对侧根的发育进行了监测。在弯曲处理前（时间 0）和弯曲处理后 3 个不同时间点（24、48 和 72 h），从靠近维管束形成层的弯曲区域取样，并分析 P. nigra WOX 同源物的表达。观察到新侧根的起始起源于维管束形成层区域，随后是原基形成和根的出现。在新侧根形成的不同发育阶段，PnWOX4a、PnWOX4b、PnWOX5a、PnWOX5b、PnWOX11/12a 和 PnWOX11/12b 被证明表达。弯曲处理模拟的机械应力激活了导致 WOX 基因表达的分子机制，这些基因被假设控制杨树主根维管束形成层中的 SLR 形成。
