School of Plant Biology, The University of Western Australia, Perth, Western Australia, 6009, Australia; Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan.
Plant Cell Environ. 2014 Apr;37(4):943-60. doi: 10.1111/pce.12210. Epub 2013 Nov 5.
Recent studies have identified genotypic variation in phosphorus (P) efficiency, but rarely have the underlying mechanisms been described at the molecular level. We demonstrate that the highly P-efficient wheat (Triticum aestivum L.) cultivar Chinese 80-55 maintains higher inorganic phosphate (Pi ) concentrations in all organs upon Pi withdrawal in combination with higher Pi acquisition in the presence of Pi when compared with the less-efficient cultivar Machete. These findings correlated with differential organ-specific expression of Pi transporters TaPHT1;2, TaPHT1;5, TaPHT1;8, TaPHT2;1 and H(+) -ATPase TaHa1. Observed transcript level differences between the cultivars suggest that higher de novo phospholipid biosynthetic activities in Pi -limited elongating basal leaf sections are another crucial adaptation in Chinese 80-55 for sustaining growth upon Pi withdrawal. These activities may be supported through enhanced breakdown of starch in Chinese 80-55 stems as suggested by higher TaGPho1 transcript levels. Chinese 80-55 fine roots on the other hand show strong suppression of transcripts involved in glycolysis, transcriptional regulation and ribosomal activities. Our work reveals major differences in the way the two contrasting cultivars allocate Pi and organic P compounds between source and sink tissues and in the acclimation of their metabolism to changes in Pi availability.
最近的研究已经确定了磷（P）效率的基因型变异，但很少有在分子水平上描述其潜在机制的研究。我们证明，与低效品种 Machete 相比，高磷效率的小麦（Triticum aestivum L.）品种 Chinese 80-55 在停止供应 Pi 时，所有器官中的无机磷酸盐（Pi）浓度保持较高，并且在有 Pi 存在时，Pi 的摄取量也较高。这些发现与 Pi 转运蛋白 TaPHT1;2、TaPHT1;5、TaPHT1;8、TaPHT2;1 和 H(+) -ATPase TaHa1 的器官特异性表达差异相关。在品种间观察到的转录本水平差异表明，在 Pi 限制的伸长基叶段中，新的磷脂生物合成活性更高，这是 Chinese 80-55 在停止供应 Pi 时维持生长的另一个重要适应机制。这些活性可能通过增强 Chinese 80-55 茎中的淀粉分解来支持，正如 TaGPho1 转录本水平较高所表明的那样。另一方面，Chinese 80-55 的细根强烈抑制了糖酵解、转录调控和核糖体活性相关的转录本。我们的工作揭示了两个对比品种在源和汇组织之间分配 Pi 和有机 P 化合物的方式以及它们的代谢对 Pi 供应变化的适应方式存在显著差异。
