PRD, an Arabidopsis AINTEGUMENTA-like gene, is involved in root architectural changes in response to phosphate starvation
PRD, an Arabidopsis AINTEGUMENTA-like gene, is involved in root architectural changes in response to phosphate starvation
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DOI：
10.1007/s00425-008-0754-9
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发表时间：
2008-08-01
期刊：
影响因子：
4.3
通讯作者：
Doumas, Patrick
中科院分区：
文献类型：
--
作者：
Jose Camacho-Cristobal, Juan;Rexach, Jesus;Doumas, Patrick
改变根构型是植物用来补偿土壤中局部磷(PI)缺乏的适应性策略之一。在拟南芥中，磷的可获得性所触发的根构型变量已经得到了很好的证明，但这些适应性反应背后的分子机制仍有待阐明。通过转录和定量RT-PCR分析，我们观察到一个类似AINTEGUMENTA的基因，命名为PRD，在低等电点条件下，在根中迅速受到抑制。通过缺失等位基因突变体PRD分析了PrD基因的生理功能，该突变体在PI饥饿条件下表现出比野生型植株更少的主根和侧根的发育。PRD突变体与野生型基因的互补导致了与野生型植物相似的对PI饥饿的反应，表明突变表型完全拯救。这些结果表明，PrD基因通过控制初生根和侧生根的伸长，参与调控根系构型对PI饥饿的反应。这个模型与PRD基因表达的组织特异性模式一致，该模式被观察到在初生根和侧根的顶端都有特异的表达。然而，在野生型和PRD植物中，受PI饥饿诱导的高亲和力PI转运蛋白(PHT1；1和PHT1；4)和酸性磷酸酶(AtACP5)等基因的PI内流、阴离子分布和根表达在响应PI饥饿时是相似的。这些结果支持这样的假设，即PrD基因不是PI饥饿反应的检查点，而是PI饥饿反应的根构型反应的特异性调节因子。
Changes in root architecture are one of the adaptive strategies used by plants to compensate for local phosphate (Pi) deficiency in soils. Root architecture variables triggered by Pi availability are well documented in Arabidopsis (Arabidopsis thaliana), but the molecular mechanisms behind these adaptive responses remain to be elucidated. By the use of transcriptomic and quantitative RT-PCR analysis, we observed that an AINTEGUMENTA-like gene, named PRD for Phosphate Root Development, was rapidly repressed in roots under low Pi conditions. The physiological function of the PRD gene was analyzed through the null allele mutant prd, which displayed less development of primary and lateral roots under Pi-starvation conditions than wild-type plants. Complementation of the prd mutant with the wild-type gene led to a similar response to Pi starvation as wild-type plants, indicating the complete rescue of the mutant phenotype. These results suggest that PRD gene is involved in the regulation of root architectural responses to Pi starvation by controlling primary and lateral root elongation. This model is in agreement with the tissue-specific pattern of PRD gene expression, which was observed to occur specifically in the apex in both the primary and lateral roots. However, Pi influx, anionic profiles and root expression of genes typically induced by Pi starvation, such as high affinity Pi transporters (PHT1;1 and PHT1;4) and an acid phosphatase (AtACP5), were similar in wild type and prd plants in response to Pi starvation. These results support the hypothesis that the PRD gene is not a checkpoint for Pi-starvation responses, but acts specifically as a regulator of root architectural responses to Pi starvation.