The interplay between P uptake pathways in mycorrhizal peas: a combined physiological and gene-silencing approach
The interplay between P uptake pathways in mycorrhizal peas: a combined physiological and gene-silencing approach
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DOI：
10.1111/ppl.12030
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发表时间：
2013-10-01
影响因子：
6.4
通讯作者：
Jakobsen, Iver
中科院分区：
文献类型：
--
作者：
Gronlund, Mette;Albrechtsen, Merete;Jakobsen, Iver
丛枝菌根真菌（AMF）通过根皮层细胞中的磷转运蛋白有效地捕获土壤中的磷，从而在植物磷吸收中发挥关键作用。这种菌根磷吸收途径的活性通常与直接磷吸收途径中磷转运蛋白基因的下调有关。由于植物吸收的总磷是由菌根和直接途径的联合活性决定的，因此了解这些途径之间的相互作用，特别是途径的实际活性是很重要的。为了研究这种相互作用，我们通过两种方式调节豌豆中通过菌根途径的Pi递送：（1）通过病毒诱导的PsPT 4基因沉默部分下调，PsPT 4是菌根途径中假定的Pi转运基因。这导致根系和土壤中真菌发育减少，并导致植物磷吸收减少。(2)通过使用无、半菌根或全菌根分根系统来改变AMF定殖根长度的百分比。分裂根的组合，使用P-32和P-33同位素和PsPT 4的部分沉默，使我们能够表明，PsPT 1，一个假定的Pi转运基因的直接途径的表达，是负相关的增加菌根吸收能力的植物，局部和系统。然而，PsPT 1的转录变化并没有转化为相应的，系统的变化，在实际的直接磷摄取。我们的研究结果表明，AMF有一个有限的长距离影响的直接途径。
Arbuscular mycorrhizal fungi (AMF) have a key role in plant phosphate (Pi) uptake by their efficient capture of soil phosphorus (P) that is transferred to the plant via Pi transporters in the root cortical cells. The activity of this mycorrhizal Pi uptake pathway is often associated with downregulation of Pi transporter genes in the direct Pi uptake pathway. As the total Pi taken up by the plant is determined by the combined activity of mycorrhizal and direct pathways, it is important to understand the interplay between these, in particular the actual activity of the pathways. To study this interplay we modulated the delivery of Pi via the mycorrhizal pathway in Pisum sativum by two means: (1) Partial downregulation by virus-induced gene silencing of PsPT4, a putative Pi transporter gene in the mycorrhizal pathway. This resulted in decreased fungal development in roots and soil and led to reduced plant Pi uptake. (2) Changing the percentage of AMF-colonized root length by using non-, half-mycorrhizal or full-mycorrhizal split-root systems. The combination of split roots, use of P-32 and P-33 isotopes and partial silencing of PsPT4 enabled us to show that the expression of PsPT1, a putative Pi transporter gene in the direct pathway, was negatively correlated with increasing mycorrhizal uptake capacity of the plant, both locally and systemically. However, transcript changes in PsPT1 were not translated into corresponding, systemic changes in actual direct Pi uptake. Our results suggest that AMF have a limited long-distance impact on the direct pathway.