Dichotomy in the NRT Gene Families of Dicots and Grass Species

PLoS One

Trevor Garnett¹  Darren Plett¹  Ute Baumann¹  John Toubia¹  Mark Tester¹  Brent N. Kaiser² 

[1] Australian Centre for Plant Functional Genomics, Waite Research Institute, University of Adelaide, Adelaide, South Australia, Australia;School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, South Australia, Australia

关键词: Arabidopsis thaliana;    Grasses;    Maize;    Plant genomics;    Sorghum;    Poplars;    Rice;    Dicotyledons;   

DOI  :  10.1371/journal.pone.0015289

学科分类：医学（综合）

来源: Public Library of Science

【 摘 要 】

A large proportion of the nitrate (NO3−) acquired by plants from soil is actively transported via members of the NRT families of NO3− transporters. In Arabidopsis, the NRT1 family has eight functionally characterised members and predominantly comprises low-affinity transporters; the NRT2 family contains seven members which appear to be high-affinity transporters; and there are two NRT3 (NAR2) family members which are known to participate in high-affinity transport. A modified reciprocal best hit (RBH) approach was used to identify putative orthologues of the Arabidopsis NRT genes in the four fully sequenced grass genomes (maize, rice, sorghum, Brachypodium). We also included the poplar genome in our analysis to establish whether differences between Arabidopsis and the grasses may be generally applicable to monocots and dicots. Our analysis reveals fundamental differences between Arabidopsis and the grass species in the gene number and family structure of all three families of NRT transporters. All grass species possessed additional NRT1.1 orthologues and appear to lack NRT1.6/NRT1.7 orthologues. There is significant separation in the NRT2 phylogenetic tree between NRT2 genes from dicots and grass species. This indicates that determination of function of NRT2 genes in grass species will not be possible in cereals based simply on sequence homology to functionally characterised Arabidopsis NRT2 genes and that proper functional analysis will be required. Arabidopsis has a unique NRT3.2 gene which may be a fusion of the NRT3.1 and NRT3.2 genes present in all other species examined here. This work provides a framework for future analysis of NO3− transporters and NO3− transport in grass crop species.

【 授权许可】

CC BY