The ZIP Transporter Family Member OsZIP9 Contributes To Root Zinc Uptake in Rice under Zinc-Limited Conditions

Abstract

Zinc (Zn) is an important essential micronutrient for plants and humans; however, the exact transporter responsible for root zinc uptake from soil has not been identified. Here, we found that OsZIP9, a member of the ZRT-IRT-related protein, is involved in Zn uptake in rice (Oryza sativa) under Zn-limited conditions. OsZIP9 was mainly localized to the plasma membrane and showed transport activity for Zn in yeast (Saccharomyces cerevisiae). Expression pattern analysis showed that OsZIP9 was mainly expressed in the roots throughout all growth stages and its expression was upregulated by Zn-deficiency. Furthermore, OsZIP9 was expressed in the exodermis and endodermis of root mature regions. For plants grown in a hydroponic solution with low Zn concentration, knockout of OsZIP9 significantly reduced plant growth, which was accompanied by decreased Zn concentrations in both the root and shoot. However, plant growth and Zn accumulation did not differ between knockout lines and wild-type rice under Zn-sufficient conditions. When grown in soil, Zn concentrations in the shoots and grains of knockout lines were decreased to half of wild-type rice, whereas the concentrations of other mineral nutrients were not altered. A shortterm kinetic experiment with stable isotope 67 Zn showed that 67 Zn uptake in knockout lines was much lower than that in wildtype rice. Combined, these results indicate that OsZIP9 localized at the root exodermis and endodermis functions as an influx transporter of Zn and contributes to Zn uptake under Zn-limited conditions in rice.

Comparative Transcriptome Analysis of Iron and Zinc Deficiency in Maize (Zea mays L.)

“…The functional classification of DEGs in the current investigation revealed many of the GO terms associated with ion uptake and homeostasis viz ., cation binding, metal ion binding, oxidoreductase activity etc. The deficiency of Fe and Zn alters the expression of genes associated with Fe and Zn homeostasis to regulate the plant physiological and metabolic requirement of Fe and Zn ions [ 2 , 3 , 23 , 26 , 27 ].…”

“…Similarly, the transcripts of ZIP5 ( GRMZM2G064382 ) were enhanced under Zn deficiency in the roots (–Zn, –Fe–Zn), whereas anti-directional regulation was observed in the shoot. Several authors reported a role of ZIP transporters in the homeostasis of divalent ions viz ., Fe, Zn, Mg [ 17 , 25 , 26 , 27 , 95 ]. In maize, Li et al [ 96 ] showed that the overexpression of ZmZIP5 enhances the Zn and Fe accumulation.…”

“…Various transporters and chelation agents viz ., oligopeptide transporters (OPT) and yellow stripe like (YSL) [ 22 , 23 ], ZIP [ 24 , 25 , 26 , 27 ], ferric reductase defective protein (FRD) transporters [ 28 ], DMA [ 29 ], nicotianamine (NA) [ 22 , 30 ], and citrate [ 31 ] have been reported to be involved in the mobilization of Fe and Zn ions. Furthermore, genome-wide transcriptome assays have been employed to understand the expression pattern of genes and pathways associated with Fe and Zn deficiencies in rice [ 32 ], Arabidopsis [ 33 ], maize [ 34 ], and several other crops [ 35 ].…”

Silicon suppresses zinc uptake through down‐regulating zinc transporter gene in rice

“…Effect of Si on the expression of ZIP family genes ZIP family genes have been proposed to be involved in Zn transport in rice (Grotz et al 1998, Guerinot 2000, Huang et al 2020b. To examine whether Si affects the expression of these genes, we compared the expression of 10 ZIP genes in the roots between WT and lsi1 mutant with and without Si treatment.…”

Two metallothionein genes highly expressed in rice nodes are involved in distribution of Zn to the grain

“…For metal‐response analysis of OsMT2b and OsMT2c expression at the vegetative stage, the seedlings (cv Nipponbare) were exposed to a solution without Cu, Fe, Zn, or Mn for 1 wk, or were exposed to a solution containing 40 μM Zn, 2 μM Cu or 5 μM Cd for 6 h. The shoot basal regions (2 cm above the root–shoot junction) were sampled for RNA extraction. The expression of three marker genes ( OsZIP9 , OsIRT1 and OsCOPT5 ) induced by Zn, Fe and Cu deficiency (Ishimaru et al ., 2006; Yuan et al ., 2011; Huang et al ., 2020a), respectively, were also determined by quantitative RT‐PCR using the same samples.…”