Arroyo Analilia, Bossi Flavia, Finkelstein Ruth R, León Patricia
Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001 Chamilpa, Apartado Postal 510-3 Cuernavaca, Morelos 62271, Mexico.
Plant Physiol. 2003 Sep;133(1):231-42. doi: 10.1104/pp.103.021089.
Mutant characterization has demonstrated that ABI4 (Abscisic Acid [ABA] Insensitive 4), ABI5 (ABA Insensitive 5), and CTR1 (Constitutive Triple Response 1) genes play an important role in the sugar signaling response in plants. The present study shows that the transcripts of these three genes are modulated by glucose (Glc) independently of the developmental arrest caused by high Glc concentrations. ABI4 and ABI5 transcripts accumulate in response to sugars, whereas the CTR1 transcript is transiently reduced followed by a rapid recovery. The results of our kinetic studies on gene expression indicate that ABI4, ABI5, and CTR1 are regulated by multiple signals including Glc, osmotic stress, and ABA. However, the differential expression profiles caused by these treatments suggest that distinct signaling pathways are used for each signal. ABI4 and ABI5 response to the Glc analog 2-deoxy-Glc supports this conclusion. Glc regulation of ABI4 and CTR1 transcripts is dependent on the developmental stage. Finally, the Glc-mediated regulation of ABI4 and ABI5 is affected in mutants displaying Glc-insensitive phenotypes such as gins, abas, abi4, abi5, and ctr1 but not in abi1-1, abi2-1, and abi3-1, which do not show a Glc-insensitive phenotype. The capacity of transcription factors, like the ones analyzed in this work, to be regulated by a variety of signals might contribute to the ability of plants to respond in a flexible and integral way to continuous changes in the internal and external environment.
突变体表征表明，ABI4（脱落酸[ABA]不敏感4）、ABI5（ABA不敏感5）和CTR1（组成型三重反应1）基因在植物的糖信号响应中起重要作用。本研究表明，这三个基因的转录本受葡萄糖（Glc）调节，与高浓度Glc引起的发育停滞无关。ABI4和ABI5转录本在糖响应时积累，而CTR1转录本则先短暂减少，随后迅速恢复。我们对基因表达的动力学研究结果表明，ABI4、ABI5和CTR1受包括Glc、渗透胁迫和ABA在内的多种信号调控。然而，这些处理引起的差异表达谱表明，每个信号使用不同的信号通路。ABI4和ABI5对Glc类似物2-脱氧-Glc的反应支持了这一结论。Glc对ABI4和CTR1转录本的调控取决于发育阶段。最后，在显示Glc不敏感表型的突变体如gins、abas、abi4、abi5和ctr1中，Glc介导的ABI4和ABI5调控受到影响，但在不显示Glc不敏感表型的abi1-1、abi2-1和abi3-1中则不受影响。像本研究中分析的转录因子那样受多种信号调控的能力，可能有助于植物以灵活和整体的方式对内部和外部环境的持续变化做出反应。
