Cis-regulation of the amino acid transporter genes ZmAAP2 and ZmLHT1 by ZmPHR1 transcription factors in maize ear under phosphate limitation
Cis-regulation of the amino acid transporter genes ZmAAP2 and ZmLHT1 by ZmPHR1 transcription factors in maize ear under phosphate limitation
复制标题
磷酸盐限制下ZmPHR1转录因子对玉米穗氨基酸转运蛋白基因ZmAAP2和ZmLHT1的顺式调控
DOI：
10.1093/jxb/erab103
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发表时间：
2021
影响因子：
6.9
通讯作者：
Li Xuexian
中科院分区：
文献类型：
--
作者：
Wang Ruifeng;Zhong Yanting;Liu Xiaoting;Zhao Cheng;Zhao Jianyu;Li Mengfei;Ul Hassan Mahmood;Yang Bo;Li Dongdong;Liu Renyi;Li Xuexian
磷和氮营养具有深刻而复杂的先天联系;然而，潜在的分子机制大多是难以捉摸的。PHR 1是一个主要的磷酸信号传导组分，它是否直接在磷-氮串扰中起作用仍然是一个特别有趣的问题。在玉米中，氮限制导致顶端籽粒败育和穗缩短。相比之下，适度低磷酸盐在现场减少整个穗粒，保持穗伸长和显着降低浓度的总游离氨基酸和可溶性蛋白质吐丝后2周。转录组分析显示，在低磷下，耳朵中的运输基因的显着富集和整体下调。重要的是，847个差异表达基因中有313个含有PHR 1结合序列（P1 BS），包括控制氨基酸/多胺转运和代谢的序列。ZmAAP 2和ZmLHT 1都是质膜定位的广谱氨基酸转运蛋白，ZmPHR1.1和ZmPHR1.2能够与含有P1 BS的ZmAAP 2和ZmLHT 1结合，下调它们在植物体内的表达。综上所述，结果表明，P1 BS元件的流行使ZmPHR 1 s能够调节大量的低磷酸盐响应基因。此外，与游离氨基酸积累减少一致，ZmPHR 1 s下调ZmAAP 2和ZmLHT 1的表达，作为磷和氮营养的直接联系人，在低磷条件下不依赖于NIGT 1。
Phosphorus and nitrogen nutrition have profound and complicated innate connections; however, underlying molecular mechanisms are mostly elusive. PHR1 is a master phosphate signaling component, and whether it directly functions in phosphorus–nitrogen crosstalk remains a particularly interesting question. In maize, nitrogen limitation caused tip kernel abortion and ear shortening. By contrast, moderately low phosphate in the field reduced kernels across the ear, maintained ear elongation and significantly lowered concentrations of total free amino acids and soluble proteins 2 weeks after silking. Transcriptome profiling revealed significant enrichment and overall down-regulation of transport genes in ears under low phosphate. Importantly, 313 out of 847 differentially expressed genes harbored PHR1 binding sequences (P1BS) including those controlling amino acid/polyamine transport and metabolism. Specifically, both ZmAAP2 and ZmLHT1 are plasma membrane-localized broad-spectrum amino acid transporters, and ZmPHR1.1 and ZmPHR1.2 were able to bind to P1BS-containingZmAAP2andZmLHT1and down-regulate their expressionin planta. Taken together, the results suggest that prevalence of P1BS elements enables ZmPHR1s to regulate a large number of low phosphate responsive genes. Further, consistent with reduced accumulation of free amino acids, ZmPHR1s down-regulateZmAAP2andZmLHT1expression as direct linkers of phosphorus and nitrogen nutrition independent ofNIGT1in maize ear under low phosphate.