Mantelin Sophie, Touraine Bruno
Université Montpellier II, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR 113 UM2/IRD/CIRAD/INRA/ENSAM, CC 02, Place E Bataillon, 34095 Montpellier cedex 05, France.
J Exp Bot. 2004 Jan;55(394):27-34. doi: 10.1093/jxb/erh010. Epub 2003 Nov 17.
Plant growth-promoting bacteria (PGPB) and NO-3 availability both affect NO-3 uptake and root architecture. The presence of external NO-3 induces the expression of NO-3 transporter genes and elicits lateral root elongation in the part of the root system exposed to the NO-3 supply. By contrast, an increase in NO-3 supply leads to a higher plant N status (low N demand), which represses both the NO-3 transporters and lateral root development. The effects of PGPB on NO-3 uptake and root development are similar to those of low NO-3 availability (concomitant stimulation of NO-3 uptake rate and lateral root development). The mechanisms responsible for the localized and long-distance regulation of NO-3 uptake and root development by NO-3 availability are beginning to be elucidated. By contrast, the signalling and transduction pathways elicited by the rhizobacteria remain totally unknown. This review will compare the effects of NO-3 availability and PGPB on root morphogenesis and NO-3 uptake, in order to determine whether interactions exist between the NO-3-dependent and the PGPB-dependent regulatory pathways.
促进植物生长的细菌（PGPB）和硝酸盐有效性都会影响硝酸盐吸收和根系结构。外部硝酸盐的存在会诱导硝酸盐转运蛋白基因的表达，并促使暴露于硝酸盐供应的根系部分的侧根伸长。相比之下，硝酸盐供应的增加会导致植物氮素状态升高（低氮需求），从而抑制硝酸盐转运蛋白和侧根发育。PGPB对硝酸盐吸收和根系发育的影响与低硝酸盐有效性的影响相似（同时刺激硝酸盐吸收速率和侧根发育）。硝酸盐有效性对硝酸盐吸收和根系发育进行局部和长距离调节的机制已开始得到阐明。相比之下，根际细菌引发的信号传导和转导途径仍然完全未知。本综述将比较硝酸盐有效性和PGPB对根系形态发生和硝酸盐吸收的影响，以确定硝酸盐依赖性和PGPB依赖性调节途径之间是否存在相互作用。
