The ferroxidase LPR5 functions in the maintenance of phosphate homeostasis and is required for normal growth and development of rice

Abstract

<jats:title>Abstract</jats:title> <jats:p>Members of the Low Phosphate Root (LPR) family have been identified in rice (Oryza sativa) and expression analyses have been conducted. Here, we investigated the functions of one of the five members in rice, LPR5. qRT-PCR and promoter–GUS reporter analyses indicated that under Pi-sufficient conditions OsLPR5 was highly expressed in the roots, and specific expression occurred in the leaf collars and nodes, and its expression was increased under Pi-deficient conditions. In vitro analysis of the purified OsLPR5 protein showed that it exhibited ferroxidase activity. Overexpression of OsLPR5 triggered higher ferroxidase activity, and elevated concentrations of Fe(III) in the xylem sap and of total Fe in the roots and shoots. Transient expression of OsLPR5 in Nicotiana benthamiana provided evidence of its subcellular localization to the cell wall and endoplasmic reticulum. Knockout mutation in OsLPR5 by means of CRISPR-Cas9 resulted in adverse effects on Pi translocation, on the relative expression of Cis-NATOsPHO1;2, and on several morphological traits, including root development and yield potential. Our results indicate that ferroxidase-dependent OsLPR5 has both a broad-spectrum influence on growth and development in rice as well as affecting a subset of physiological and molecular traits that govern Pi homeostasis.</jats:p>

Bacterial-type ferroxidase tunes iron-dependent phosphate sensing during Arabidopsis root development

“… 64 Phylogenomics indicates the common ancestor of Zygnematophyceae and embryophytes acquired a LPR1-type MCO from soil bacteria during the first episode, corroborating previous notions that overcoming the challenges of plant terrestrialization profoundly benefited from HGT events. 52 , 55 Although a function of LPR1 in root Pi sensing has been established in Arabidopsis , 15 , 16 , 18 , 20 , 21 , 31 which is likely conserved in the tracheophyte lineage (vascular plants) as recently reported for rice, 46 , 47 the biological role of LPR1-like ferroxidases for Pi nutrition in the bryophyte lineage (nonvascular plants) and in extant Zygnematophyceae algae remains an open question. Elucidation of LPR1 -like gene function across the land plants will require reverse genetics in a bryophyte system, 85 and genetically tractable model systems are beginning to emerge in the Zygnematophyceae.…”

“…Group II comprises bacterial, fungal, and mammalian MCOs of unknown specificities or presumed functions in N assimilation (nitrite reductases), Fe export (ceruloplasmin-related ferroxidases), and hemostasis (blood coagulation factors). CotA and LPR1-like MCOs of Arabidopsis and rice 46 , 47 occupy a monophyletic clade within the bacterial paraphyletic segment. Comparison of the primary and tertiary structures rationalizes the strikingly different substrate specificities of LPR1 and CotA, which oxidizes bulky molecules such as ABTS or bilirubin.…”

Research and Progress on the Mechanism of Iron Transfer and Accumulation in Rice Grains

“…In rice, although root growth is either enhanced or unaffected by low Pi, at least one component of the signaling pathway controlling local Pi-deficiency responses (LPR ferroxidase) has been shown to affect Fe accumulation and Pi translocation. Additionally, the potential involvement of PHR1 in the Pi-Fe signaling crosstalk has been proposed [80]. A recent new study shows that the notable Hemerythrin motif-containing Interesting New Gene-and Zinc-finger proteins (HRZs) and PHRs, forming a mutually repressive module that could coordinate the Pi and Fe signaling and homeostasis [81].…”

Bacterial-type plant ferroxidases tune local phosphate sensing in root development

“…Paraphyletic MCO group II includes bacterial, fungal, and mammalian MCO proteins of unknown specificities, or of presumed functions in N assimilation (Cu-dependent nitrite reductases), Fe export (ferroxidases), and hemostasis (blood coagulation factors). CotA and LPR1-like MCOs of Arabidopsis and rice (Ai et al, 2020) form a monophyletic clade within the bacterial paraphyletic segment of group II (Fig. 7).…”