While there are many theories and a variety of innovative datasets contributing to our understanding of the mechanism generating root pressure in vascular plants, we are still unable to produce a specific cellular mechanism for any species. To discover these mechanisms, we used RNA-Seq to explore differentially expressed genes in three different tissues between individual plants expressing root pressure and those producing none. Working from the perspective that roots cells are utililizing a combination of osmotic exudation and hydraulic pressure mechanisms to generate positively-pressured flow of water into the xylem from the soil, we hypothesized that differential expression analysis would yield candidate genes coding for membrane transporters, ion channels, ATPases, and hormones with clear relevance to root pressure generation. In basal stem and coarse root tissue, we observed these classes of differentially expressed genes and more, including a strong cytoskeletal remodeling response. Fine roots displayed remarkably little differential expression relevant to root pressure, leading us to conclude that they either do not contribute to root pressure generation or are constitutively expressing root pressure mechanisms regardless of soil water content.

中文翻译：

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寻找驱动玉米根部压力的机制——转录组学方法

尽管有许多理论和各种创新数据集有助于我们理解维管植物产生根部压力的机制，但我们仍然无法为任何物种产生特定的细胞机制。为了发现这些机制，我们使用 RNA-Seq 来探索表达根压力的个体植物和不产生根压力的个体植物之间的三种不同组织中的差异表达基因。从根细胞利用渗透渗出和水压机制的组合产生从土壤进入木质部的正压水流的角度来看，我们假设差异表达分析将产生编码膜转运蛋白、离子通道的候选基因、ATP酶和激素与根压的产生有明显的相关性。在基部茎和粗根组织中，我们观察到这些类别的差异表达基因以及更多基因，包括强烈的细胞骨架重塑反应。细根与根压相关的差异表达非常小，这使我们得出结论，它们要么对根压的产生没有贡献，要么构成性地表达根压机制，而与土壤含水量无关。