Abstract
Phosphate homeostasis was studied in a monocotyledonous model plant through the characterization of the PHO1 gene family in rice (Oryza sativa). Bioinformatics and phylogenetic analysis showed that the rice genome has three PHO1 homologs, which cluster with the Arabidopsis (Arabidopsis thaliana) AtPHO1 and AtPHO1;H1, the only two genes known to be involved in root-to-shoot transfer of phosphate. In contrast to the Arabidopsis PHO1 gene family, all three rice PHO1 genes have a cis-natural antisense transcript located at the 5 ' end of the genes. Strand-specific quantitative reverse transcription-PCR analyses revealed distinct patterns of expression for sense and antisense transcripts for all three genes, both at the level of tissue expression and in response to nutrient stress. The most abundantly expressed gene was OsPHO1;2 in the roots, for both sense and antisense transcripts. However, while the OsPHO1;2 sense transcript was relatively stable under various nutrient deficiencies, the antisense transcript was highly induced by inorganic phosphate (Pi) deficiency. Characterization of Ospho1;1 and Ospho1;2 insertion mutants revealed that only Ospho1;2 mutants had defects in Pi homeostasis, namely strong reduction in Pi transfer from root to shoot, which was accompanied by low-shoot and high-root Pi. Our data identify OsPHO1;2 as playing a key role in the transfer of Pi from roots to shoots in rice, and indicate that this gene could be regulated by its cis-natural antisense transcripts. Furthermore, phylogenetic analysis of PHO1 homologs in monocotyledons and dicotyledons revealed the emergence of a distinct clade of PHO1 genes in dicotyledons, which include members having roles other than long-distance Pi transport.
Highlights
Phosphate homeostasis was studied in a monocotyledonous model plant through the characterization of the PHO1 gene family in rice (Oryza sativa)
The first genes involved in phosphate transport were characterized in Arabidopsis (Arabidopsis thaliana; Muchhal et al, 1996), the study of Pi transport and homeostasis at the molecular level has been expended to other plants
This is true for genes encoding the high-affinity Pi transporters belonging to the Pht1 family and involved in Pi uptake into cells, as well as some aspect of the Pi-deficiency signaling cascades, which have been studied in barrel medic (Medicago truncatula), potato (Solanum tuberosum), tomato (Solanum lycopersicum), rice (Oryza sativa), barley (Hordeum vulgare), and maize (Zea mays; Leggewie et al, 1997; Liu et al, 1998a, 1998b; Chiou et al, 2001; Paszkowski et al, 2002; Hou et al, 2005; Nagy et al, 2005, 2006; Yi et al, 2005; Tesfaye et al, 2007; Zhou et al, 2008)
Summary
Phosphate homeostasis was studied in a monocotyledonous model plant through the characterization of the PHO1 gene family in rice (Oryza sativa). The first genes involved in phosphate transport were characterized in Arabidopsis (Arabidopsis thaliana; Muchhal et al, 1996), the study of Pi transport and homeostasis at the molecular level has been expended to other plants This is true for genes encoding the high-affinity Pi transporters belonging to the Pht family and involved in Pi uptake into cells, as well as some aspect of the Pi-deficiency signaling cascades, which have been studied in barrel medic (Medicago truncatula), potato (Solanum tuberosum), tomato (Solanum lycopersicum), rice (Oryza sativa), barley (Hordeum vulgare), and maize (Zea mays; Leggewie et al, 1997; Liu et al, 1998a, 1998b; Chiou et al, 2001; Paszkowski et al, 2002; Hou et al, 2005; Nagy et al, 2005, 2006; Yi et al, 2005; Tesfaye et al, 2007; Zhou et al, 2008). To investigate the potential role of the rice PHO1 gene family in Pi homeostasis and their regulation by cis-NATs, we analyzed the expression profiles of the sense and antisense transcripts, in the shoots and in the roots, in response to different nutrient stresses, and in different tissues. Phylogenetic analysis of PHO1 genes in monocotyledons and dicotyledons revealed the evolution of a distinct clade of PHO1 genes only in dicotyledons, which include members having roles other than long-distance Pi transport
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
