Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway.
Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany.
J Exp Bot. 2018 Jun 27;69(15):3759-3771. doi: 10.1093/jxb/ery176.
Roots and root-released organic anions play important roles in uptake of phosphorus (P), an essential macronutrient for food production. Oat, ranking sixth in the world's cereal production, contains valuable nutritional compounds and can withstand poor soil conditions. Our aim was to investigate root transcriptional and metabolic responses of oat grown under P-deficient and P-sufficient conditions. We conducted a hydroponic experiment and measured root morphology and organic anion exudation, and analysed changes in the transcriptome and metabolome. Oat roots showed enhanced citrate and malate exudation after 4 weeks of P deficiency. After 10 d of P deficiency, we identified 9371 differentially expressed transcripts with a 2-fold or greater change (P<0.05): 48 sequences predicted to be involved in organic anion biosynthesis and efflux were consistently up-regulated; 24 up-regulated transcripts in oat were also found to be up-regulated upon P starvation in rice and wheat under similar conditions. Phosphorylated metabolites (i.e. glucose-6-phosphate, myo-inositol phosphate) were reduced dramatically, while citrate and malate, some sugars and amino acids increased slightly in P-deficient oat roots. Our data are consistent with a strategy of increased organic anion efflux and a shift in primary metabolism in response to P deficiency in oat.
根和根释放的有机阴离子在吸收磷（P）方面发挥着重要作用，磷是粮食生产的必需大量营养素。燕麦在世界谷物产量中排名第六，含有有价值的营养化合物，并且能够耐受贫瘠的土壤条件。我们的目的是研究在缺磷和磷充足条件下生长的燕麦根的转录和代谢反应。我们进行了水培实验，测量了根形态和有机阴离子分泌，并分析了转录组和代谢组的变化。燕麦根在缺磷 4 周后表现出柠檬酸和苹果酸分泌增加。在缺磷 10 天后，我们鉴定出了 9371 个差异表达的转录本，其变化倍数为 2 倍或更大（P<0.05）：48 个预测参与有机阴离子生物合成和外排的序列被一致上调；在类似条件下，在缺磷的水稻和小麦中也发现了 24 个上调的燕麦转录本上调。磷酸化代谢物（即葡萄糖-6-磷酸、肌醇磷酸）显著减少，而柠檬酸和苹果酸、一些糖和氨基酸在缺磷的燕麦根中略有增加。我们的数据与燕麦对缺磷的反应中增加有机阴离子外排和初级代谢物转移的策略一致。
