The OSU1/QUA2/TSD2-encoded putative methyltransferase is a critical modulator of carbon and nitrogen nutrient balance response in Arabidopsis.
The OSU1/QUA2/TSD2-encoded putative methyltransferase is a critical modulator of carbon and nitrogen nutrient balance response in Arabidopsis.
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OSU1/QUA2/TSD2 编码的推定甲基转移酶是拟南芥中碳氮营养平衡反应的关键调节剂。
DOI：
10.1371/journal.pone.0001387
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发表时间：
2008-01-02
期刊：
影响因子：
3.7
通讯作者：
Zheng, Zhi-Liang
中科院分区：
文献类型：
--
作者：
Gao, Peng;Xin, Zeyu;Zheng, Zhi-Liang
碳（C）和氮（N）营养之间的平衡必须紧密协调，以便细胞能够优化其代谢，生长和发育的机会。然而，C和N营养平衡的感知和信号传导机制仍然知之甚少。在这里，我们报告的两个等位基因oversensitive糖1突变体（osu 1 -1，osu 1 -2）在拟南芥的分离和表征。利用子叶花青素积累和根生长抑制试验，我们发现osu 1突变体比野生型更敏感的C/N不平衡条件，高C/低N和低C/高N。然而，在平衡C/N条件下（低C/低N或高C/高N），osu 1突变体具有与野生型相似的花青素水平和根长。一致的是，编码两个MYB转录因子（MYB 75和MYB 90）和Asn合成酶亚型（ASN 1）的基因强烈上调OSU 1突变，分别响应高C/低N和低C/高N。此外，MYB 75的共抑制作用可以抑制OSU 1 -1对高C/低N的敏感性，表明MYB 75在高C/低N失衡反应中起着OSU 1下游的作用。基于图位的克隆显示，OSU 1编码的一个大家庭的推定甲基转移酶的成员，是等位基因最近报道的QUA 2/TSD 2基因座中确定的细胞粘附缺陷突变体的遗传筛选。OSU 1/QUA 2/TSD 2转录物的积累不受C和N平衡的调节，但OSU 1启动子在血管系统中的活性略高。两者合计，我们的研究结果表明，OSU 1/QUA 2/TSD 2编码的推定甲基转移酶是所需的正常的C/N养分平衡反应在植物中。
The balance between carbon (C) and nitrogen (N) nutrients must be tightly coordinated so that cells can optimize their opportunity for metabolism, growth and development. However, the C and N nutrient balance perception and signaling mechanism remains poorly understood. Here, we report the isolation and characterization of two allelic oversensitive to sugar1 mutants (osu1-1, osu1-2) in Arabidopsis thaliana. Using the cotyledon anthocyanin accumulation and root growth inhibition assays, we show that the osu1 mutants are more sensitive than wild-type to both of the imbalanced C/N conditions, high C/low N and low C/high N. However, under the balanced C/N conditions (low C/low N or high C/high N), the osu1 mutants have similar anthocyanin levels and root lengths as wild-type. Consistently, the genes encoding two MYB transcription factors (MYB75 and MYB90) and an Asn synthetase isoform (ASN1) are strongly up-regulated by the OSU1 mutation in response to high C/low N and low C/high N, respectively. Furthermore, the enhanced sensitivity of osu1-1 to high C/low N with respect to anthocyanin accumulation but not root growth inhibition can be suppressed by co-suppression of MYB75, indicating that MYB75 acts downstream of OSU1 in the high C/low N imbalance response. Map-based cloning reveals that OSU1 encodes a member of a large family of putative methyltransferases and is allelic to the recently reported QUA2/TSD2 locus identified in genetic screens for cell-adhesion-defective mutants. Accumulation of OSU1/QUA2/TSD2 transcript was not regulated by C and N balance, but the OSU1 promoter was slightly more active in the vascular system. Taken together, our results show that the OSU1/QUA2/TSD2-encoded putative methyltransferase is required for normal C/N nutrient balance response in plants.
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影响因子：
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