Rice PCR1 influences grain weight and Zn accumulation in grains

Abstract

Proteins containing a placenta-specific 8 domain (PLAC8) function as major organ size regulators in Solanum lycopersicum and Zea may, and putative metal ion transporters in Arabidopsis thaliana, Oryza sativa and Brassica juncea. However, it is unknown how PLAC8 domain-containing proteins fulfill such diverse roles. Here, we found that plant cadmium resistance 1 (PCR1) influences both zinc (Zn) accumulation and grain weight in rice. OsPCR1 knockout and knockdown lines produced lighter grains than the wild type, while OsPCR1 overexpression lines produced heavier grains. Furthermore, the grains of OsPCR1 knockdown lines exhibited substantially higher Zn and lower cadmium (Cd) concentrations than the control, as did yeast heterologously expressing OsPCR1. Through sequence analysis, we showed that the amino acid sequence of japonica-type PCR1 was distinct from that of indica-type and wild rice accessions. This difference was correlated with distinct Zn-related phenotypes. Japonica-type PCR1 had a shorter N-terminus than did PCR1 in the other rice types, and yeast heterologously expressing japonica-type PCR1 was more sensitive to Zn than was yeast expressing indica-type PCR1. Furthermore, japonica-type grains accumulated less Zn than did indica-type grains. Our study suggests that rice PCR1 maintains metal ion homeostasis and grain weight and might have been selected for during domestication.

Generation of High Yielding and Fragrant Rice (Oryza sativa L.) Lines by CRISPR/Cas9 Targeted Mutagenesis of Three Homoeologs of Cytochrome P450 Gene Family and OsBADH2 and Transcriptome and Proteome Profiling of Revealed Changes Triggered by Mutations

“…OsHAP3H is a HAP3 subunit of the HAP complex and transcription factor containing “CCAAT box-binding protein”, which regulates rice yield [ 67 , 68 , 69 ]. OsPCR1 (protein containing a placenta-specific 8 domain) knockdown lines had lighter grains, shorter grain lengths, and decreased grain weight by 12%, while OsPCR1 overexpressed plants had an 8% increase in grain weights and increased grain lengths [ 70 ]. PGL2 ( POSITIVE REGULATOR OF GRAIN LENGTH 2 ) is an antagonistic pair of basic helix-loop-helix (bHLH) protein gene which regulated grain length by increasing the cell length [ 71 ].…”

Identification of QTLs associated with cadmium concentration in rice grains

“…Moreover, some QTLs detected in our study overlap with cloned Cd-related genes. For example, qCCMR5-1 was mapped to the interval RM1024-RM169, which contains OsMTP1 (Yuan et al 2012), and the mapping interval of qCCBR10 contains OsPCR1 (Song et al 2015). In addition, three pairs of novel and important loci for grain Cd concentration on chromosomes 2, 4, and 9, were detected in multiple trials in our study, qCCBR2-2 and qCCMR2-2, could explain 19.0 and 6.6% of the phenotypic variance, respectively with background from YK17.…”

A novel family of PLAC8 motif-containing/PCR genes mediates Cd tolerance and Cd accumulation in rice

“…And similar results were shown by Song et al about the function of OsPCR genes in rice. Their recent reports suggested that OsPCR (Loc_Os10g02300) could influence Zn accumulation and grain weight in rice, and the OsPCR-knockdown rice seedlings showed lower Cd concentrations than the control rice grain which indicated that OsPCR played an important role in Cd accumulation in rice grain [27]. Recently, Xiong et al [28] reported a FW2.2-like family gene in rice (OsFWL4, Os03g614440) which contained a PLAC8 that could not only regulate grain size and plant height, but also involved in Cd translocation form roots to shoots in rice.…”