Maize VP1 complements Arabidopsis abi3 and confers a novel ABA/auxin interaction in roots.
Maize VP1 complements Arabidopsis abi3 and confers a novel ABA/auxin interaction in roots.
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DOI：
10.1046/j.1365-313x.2001.01165.x
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发表时间：
2002-01
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影响因子：
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通讯作者：
Masaharu Suzuki;C. Kao;S. M. Cocciolone;D. McCarty
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作者：
Masaharu Suzuki;C. Kao;S. M. Cocciolone;D. McCarty
玉米Vp 1基因和拟南芥abi 3基因在突变表型和氨基酸序列上的相似性被认为是同源基因。在这里，我们表明，由35 S启动子驱动的VP 1的表达可以部分地补充abi 3 -6，abi 3的缺失突变等位基因。由abi 3突变体背景中的VP 1表达产生的种子的可见表型几乎与野生型不可区分。VP 1完全恢复种子萌发过程中abi 3对脱落酸（阿坝）的敏感性，并抑制abi 3的早花表型。C1-β-葡萄糖醛酸酶（GUS）和叶绿素a/B结合蛋白（cab 3）-GUS报告基因在35 S-VP 1株系种子发育过程中的时间调控与野生型相似。另一方面，在35 S-VP 1系和野生型之间观察到两个质的差异。CRC和C1-GUS表达水平在35 S-VP 1系种子中明显低于野生型，表明基因激活功能的不完全互补。类似于ABI 3的异位表达（Parcy等人，1994），VP 1在营养组织中的异位表达增强了ABA对根生长的抑制。此外，35 S-VP 1赋予叶片中通常种子特异性十字花科植物素C（CRC）基因的强阿坝诱导表达。相反，C1-GUS的异位阿坝诱导仅限于根伸长区的局部区域。ABA依赖的C1-GUS基因在外源生长素处理的根组织中的表达范围更广。有趣的是，生长素诱导的侧根形成完全抑制阿坝在35 S-VP 1植物，但不是在野生型。这些结果表明VP 1介导阿坝和生长素信号之间的一种新的相互作用，导致发育停滞和基因表达模式的改变。
The maize Vp1 gene and abi3 gene of Arabidopsis are believed to be orthologs based on similarities of the mutant phenotypes and amino acid sequence conservation. Here we show that expression of VP1 driven by the 35S promoter can partially complement abi3-6, a deletion mutant allele of abi3. The visible phenotype of seed produced from VP1 expression in the abi3 mutant background is nearly indistinguishable from wild type. VP1 fully restores abscisic acid (ABA) sensitivity of abi3 during seed germination and suppresses the early flowering phenotype of abi3. The temporal regulation of C1-beta-glucuronidase (GUS) and chlorophyll a/b binding protein (cab3)-GUS reporter genes in developing seeds of 35S-VP1 lines were similar to wild type. On the other hand, two qualitative differences are observed between the 35S-VP1 line and wild type. The levels of CRC and C1-GUS expression are markedly lower in the seeds of 35S-VP1 lines than in wild type suggesting incomplete complementation of gene activation functions. Similar to ectopic expression of ABI3 (Parcy et al., 1994), ectopic expression of VP1 in vegetative tissue enhances ABA inhibition of root growth. In addition, 35S-VP1 confers strong ABA inducible expression of the normally seed-specific cruciferin C (CRC) gene in leaves. In contrast, ectopic ABA induction of C1-GUS is restricted to a localized region of the root elongation zone. The ABA-dependent C1-GUS expression expanded to a broader area in the root tissues treated with exogenous application of auxin. Interestingly, auxin-induced lateral root formation is completely suppressed by ABA in 35S-VP1 plants but not in wild type. These results indicate VP1 mediates a novel interaction between ABA and auxin signaling that results in developmental arrest and altered patterns of gene expression.