Diversification of the plant-specific hybrid glycine-rich protein (HyGRP) genes in cereals

Abstract

Plant-specific hybrid proline- or glycine-rich proteins (HyP/GRPs) are involved in diverse gene functions including plant development and responses to biotic and abiotic stresses. The quantitative trait locus, qLTG3-1, enhances seed germination in rice under low-temperature conditions and encodes a member with a glycine-rich motif of the HyP/GRP family. The function of this gene may be related to the weakening of tissue covering the embryo during seed germination. In the present study, the diversification of the HyP/GRP gene family was elucidated in rice based on phylogenetic relationships and gene expression levels. At least 21 members of the HyP/GRP family have been identified in the rice genome and clustered in five regions on four chromosomes by tandem and chromosomal duplications. Of these, OsHyPRP05 (qLTG3-1) and its paralogous gene, OsHyPRP21, had a glycine-rich motif. Furthermore, orthologous genes with a glycine-rich motif and the HyP/GRP gene family were detected in four genome-sequenced monocots: 12 in barley, 10 in Brachypodium, 20 in maize, and 28 in sorghum, using a BLAST search of qLTG3-1 as the query. All members of the HyP/GRP family in these five species were classified into seven main groups, which were clustered together in these species. These results suggested that the HyP/GRP gene family was formed in the ancestral genome before the divergence of these species. The collinearity of chromosomal regions around qLTG3-1 and its orthologous genes were conserved among rice, Brachypodium, sorghum, and maize, indicating that qLTG3-1 and orthologous genes conserve gene function during seed germination.

The bZIP73 transcription factor controls rice cold tolerance at the reproductive stage

“…The qLTG3‐1 protein has two conserved domains, a glycine‐rich protein (GRP) motif and a lipid transfer protein (LTP) motif (Fujino et al ., ). qLTG3‐1 and its orthologs are conserved among rice, Brachypodium , sorghum, maize, and dicots such as Arabidopsis, and orthologous genes have a conserved function during seed germination (Fujino et al ., ; Xu et al ., ). GRP domains are functionally conserved in plants, and many genes coding for those domains are involved in cold signaling.…”

iTRAQ-Based Analysis of Proteins Co-Regulated by Brassinosteroids and Gibberellins in Rice Embryos during Seed Germination

“…Further diversification analysis of the HyGRP gene family in five monocots, namely rice, barley, brachypodium, maize and sorghum, indicated that the HyGRP gene family was formed in the ancestral genome before the divergence of these species. The conserved collinearity of chromosomal regions around qLTG3-1 and its orthologs implies that their functions in seed germination are conserved [ 45 ]. In addition, studies indicated that mutation of PME48 , a member of the pectin esterase family, would cause a significant delay in imbibition and germination of pollen grains in Arabidopsis [ 46 ].…”

OsHyPRP06/R3L1 regulates root system development and salt tolerance via apoplastic ROS homeostasis in rice (Oryza sativa L.)

“…The protein properties and domain analyses were carried out using SMART database (http://smart.embl-heidelberg.de/). The rice genes that homologous to OsR3L1 referenced to the previous study (Fujino et al, 2014) and corresponding amino acid (aa) sequences were downloaded from RAP-DB database (https://rapdb.dna.affrc.go.jp/). The multiple sequence alignments of the 20 rice HyPRPs aa sequences were performed by jalview software, followed by phylogenetic tree generation using MEGA-X software.…”

“…The rice genome‐wide expression profiles of the OsHyP/GRP family have been investigated (Fujino, Obara, & Sato, 2014); however, the functions of most family members remain unknown. OsHyPRP06 , referred to as RCc3‐like1 ( R3L1 ) in our study, was discovered when roots were treated with gibberellin (GA 3 ) and indole acetic acid (IAA) exhibited marked changes in expression (this preliminary experiment was not published).…”