Quanxiang Tian

Rice is a global staple food crop, and its yield is seriously limited by soil salinity. The high-affinity K ⁺ transporter/K ⁺ uptake permease/K ⁺ transporter (HAK/KUP/KT) family of potassium transporters plays a pivotal role in K ⁺ homeostasis and plant salt tolerance. However, their systematic characterization and functional relevance to salt tolerance in rice have not been clarified. Here, we conducted genome-wide identification and structural characterization of the HAK/KUP/KT family, assessed their expression profiles under salt stress, and examined their K ⁺ transport function. In total, 27 OsHAK genes were identified in the rice genome, most of which exhibited salt-responsive expression. Yeast functional complementation assays confirmed that OsHAK11, OsHAK13, OsHAK23, OsHAK24, OsHAK25, and OsHAK26 can mediate K ⁺ absorption. Among them, OsHAK11 and OsHAK25 showed relatively strong K ⁺ uptake ability. Subcellular localization analysis revealed that OsHAK11 and OsHAK25 were located in the plasma membrane. Our research systematically analyzed the sequence characteristics of the rice HAK gene family, examined their transcriptional responses to salt stress, and further evaluated the K ⁺ uptake capacity of HAK proteins. These results provide a foundation for further elucidating the function of OsHAKs in plant salt tolerance.

Cystathionine β-synthase (CBS) plays crucial roles in abiotic stress responses. However, the molecular characteristics of the OsCBS gene family in rice and its transcriptional response to salt stress remain poorly characterized. This study systematically identified 28 OsCBS genes in the rice genome, unevenly distributed on nine chromosomes. Collinearity analysis revealed three segmental duplication pairs ( OsCBS5 - OsCBS24 , OsCBS 6- OsCBS19 , and OsCBS27 - OsCBS28 ), indicating that segmental duplication is a major force driving family expansion. Gene structure and conserved motif analyses showed that the exon numbers varied among family members, but the core conserved motifs were consistently present. Promoter regions contained numerous cis-acting elements associated with hormone and abiotic stress responsiveness, including salt stress. Quantitative real-time PCR (qRT-PCR) demonstrated that salt stress significantly induced OsCBS genes. Notably, OsCBS13 and OsCBS25 were upregulated in roots, OsCBS6 and OsCBS7 in shoots, and OsCBS3 and OsCBS11 in both tissues. Subcellular localization revealed specific tonoplast targeting of OsCBS11 and dual chloroplast–plasma membrane localization of OsCBS13. This systematic characterization of the OsCBS gene family and its expression patterns under salt stress provides a valuable reference for further functional studies of OsCBS in rice salt tolerance.

EXO70 is a key subunit of the exocyst tethering complex involved in vesicle trafficking and plays important roles in plant growth, development, and stress

Shaker potassium channel proteins are a class of voltage-gated ion channels responsible for K⁺ uptake and translocation, playing a crucial role in plant growth and salt tolerance. In this study, bioinformatic analysis was performed to identify the members within the Shaker gene family. Moreover, the expression patterns of rice Shaker(OsShaker) K⁺ channel genes were analyzed in different tissues and salt treatment by RT–qPCR. The results revealed that there were eight OsShaker K⁺ channel genes distributed on chromosomes 1, 2, 5, 6 and 7 in rice, and their promoters contained a variety of cis-regulatory elements, including hormone-responsive, light-responsive, and stress-responsive elements, etc. Most of the OsShaker K⁺ channel genes were expressed in all tissues of rice, but at different levels in different tissues. In addition, the expression of OsShaker K⁺ channel genes differed in the timing, organization and intensity of response to salt and chilling stress. In conclusion, our findings provide a reference for the understanding of OsShaker K⁺ channel genes, as well as their potential functions in response to salt and chilling stress in rice.

Fatty acyl-CoA reductase (FAR) is an important NADPH-dependent enzyme that can produce primary alcohol from fatty acyl-CoA or fatty acyl-carrier proteins as substrates. It plays a pivotal role in plant growth, development, and stress resistance. Herein, we performed genome-wide identification and expression analysis of FAR members in rice using bioinformatics methods. A total of eight OsFAR genes were identified, and the OsFARs were comprehensively analyzed in terms of phylogenetic relationships, duplication events, protein motifs, etc. The cis-elements of the OsFARs were predicted to respond to growth and development, light, hormones, and abiotic stresses. Gene ontology annotation analysis revealed that OsFAR proteins participate in biological processes as fatty acyl-CoA reductase during lipid metabolism. Numerous microRNA target sites were present in OsFARs mRNAs. The expression analysis showed that OsFARs were expressed at different levels during different developmental periods and in various tissues. Furthermore, the expression levels of OsFARs were altered under abiotic stresses, suggesting that FARs may be involved in abiotic stress tolerance in rice. The findings presented here serve as a solid basis for further exploring the functions of OsFARs.

Stearoyl-acyl carrier protein (ACP) Δ9 desaturase (SAD) is a critical fatty acid dehydrogenase in plants, playing a prominent role in regulating the synthesis of unsaturated fatty acids (UFAs) and having a significant impact on plant growth and development. In this study, we conducted a comprehensive genomic analysis of the SAD family in barley (Hordeum vulgare L.), identifying 14 HvSADs with the FA_desaturase_2 domain, which were divided into four subgroups based on sequence composition and phylogenetic analysis, with members of the same subgroup possessing similar genes and motif structures. Gene replication analysis suggested that tandem and segmental duplication may be the major reasons for the expansion of the SAD family in barley. The promoters of HvSADs contained various cis-regulatory elements (CREs) related to light, abscisic acid (ABA), and methyl jasmonate (MeJA). In addition, expression analysis indicated that HvSADs exhibit multiple tissue expression patterns in barley as well as different response characteristics under three abiotic stresses: salt, drought, and cold. Briefly, this evolutionary and expression analysis of HvSADs provides insight into the biological functions of barley, supporting a comprehensive analysis of the regulatory mechanisms of oil biosynthesis and metabolism in plants under abiotic stress.

In plants, the essential roles played by the regulator of chromosome condensation 1 (RCC1) in diverse biological processes, including UV-B (ultraviolet-B radiation) response, hormonal signal transduction, cold tolerance and phenotypic plasticity, have been identified. No comprehensive study on the evolution and function of RCC1 gene family in rice has been carried out. A genome-wide analysis of this gene family is thus required. In this study, a total of 26 OsRCC1s unevenly distributed across 10 chromosomes were identified in rice. Based on their phylogenetic relationship and sequence composition, the OsRCC1 family could be classified into six groups. Members within the same group share a similar gene structure and protein motif/domain composition. Gene duplication analysis revealed that segmental duplication might be the main contributor to the expansion of the RCC1 gene family in rice. Several cis-regulatory elements (CREs) relevant to light, abscisic acid (ABA) and methyl jasmonate (MeJA) are abundant in the promoters of OsRCC1s. A large number of microRNA (miRNA) target sites were present in OsRCC1 mRNAs. Additionally, we used data from gene microarray and qRT-PCR to analyze the expression of OsRCC1 genes during various developmental stages and under abiotic stress conditions. OsRCC1s were found to be highly expressed in panicles and seeds, and most OsRCC1s were differentially expressed under abiotic stresses. Taken together, our study provides a systematic characterization of OsRCC1s and preliminarily explores their diversity as well as their biological functions. Evidence demonstrates that OsRCC1s may play vital roles in both development and abiotic stress response. The results presented here lay a foundation for further investigating the functions of OsRCC1s.

Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a class of plant-specific serine/threonine (Ser/Thr) protein kinase that plays an important role in rice stress tolerance, growth and development. However, systematic bioinformatics and expression pattern analysis have not been reported. In the current study, ten OsSnRK2 genes were identified in the rice genome and located on 7 chromosomes, which can be classified into three subfamilies (I, II, and III). Many cis-regulatory elements were identified in the promoter region of OsSnRK2 genes, including hormone response elements, defense and stress responsive elements, indicating that the OsSnRK2 family may play a crucial role in response to hormonal and abiotic stress. Quantitative tissue analysis showed that OsSnRK2 genes expressed in all tissues of rice, but the expression abundance varied from different tissues and showed varietal variability. In addition, expression pattern of OsSnRK2 were analyzed under abiotic stress (salt, drought, salt and drought) and showed obvious difference in diverse abiotic stress. In general, these results provide useful information for understanding the OsSnRK2 gene family and analyzing its functions in rice in response to ABA, salt and drought stress, especially salt-drought combined stress.

The myeloblastosis (MYB) family comprises a large group of transcription factors (TFs) that has a variety of functions. Among them, the R2R3-MYB type of proteins are the largest group in plants, which are involved in controlling various biological processes such as plant growth and development, physiological metabolism, defense, and responses to abiotic and biotic stresses. In this study, bioinformatics was adopted to conduct genome-wide identification of the R2R3-MYB TFs in rice. We identified 190 MYB TFs (99 R2R3-MYBs), which are unevenly distributed on the 12 chromosomes of rice. Based on the phylogenetic clustering and protein sequence characteristics, OsMYBs were classified into five subgroups, and 59.6% of the Os2R_MYB genes contained two introns. Analysis of cis-acting elements in the 2000 bp upstream region of Os2R_MYB genes showed that all Os2R_MYB genes contained plant hormones-related or stress-responsive elements since 91.9%, 79.8%, 79.8%, and 58.6% of Os2R_MYB genes contain ABRE, TGACG, CGTCA, and MBS motifs, respectively. Protein–protein network analysis showed that the Os2R_MYBs were involved in metabolic process, biosynthetic process, and tissue development. In addition, some genes showed a tissue-specific or developmental-stage-specific expression pattern. Moreover, the transcription levels of 20 Os2R_MYB genes under polyethylene glycol (PEG) and cadmium chloride (CdCl₂) stress inducers were dissected by qRT-PCR. The results indicated genes with an altered expression upon PEG or CdCl₂ stress induction. These results potentially supply a basis for further research on the role that Os2R_MYB genes play in plant development and stress responses.