Zicong Liang

Nitrate transporter 1/peptide transporter family (NPF) proteins play pivotal roles in nitrogen uptake, translocation, and stress adaptation in plants. To comprehensively investigate this gene family in sorghum (Sorghum bicolor), we conducted the genome-wide identification and characterization of SbNPF genes. A total of 88 SbNPF members were identified and classified into eight subfamilies based on phylogenetic analysis, displaying diverse gene structures, conserved motifs, and evolutionary relationships. Gene duplication analysis revealed that tandem duplication was the primary driver of SbNPF family expansion, with most duplicated pairs undergoing purifying selection. Synteny analysis showed extensive collinearity between sorghum and rice, but limited conservation with Arabidopsis, highlighting the evolutionary divergence between monocots and dicots. Cis-regulatory element prediction suggested that SbNPF genes are widely involved in abiotic stress responses, hormone signaling, and light responsiveness. Expression profiling using RNA-seq data revealed distinct tissue-specific expression patterns, indicating functional specialization across roots, stems, leaves, and reproductive tissues. Furthermore, RT-qPCR analysis under low-nitrogen (LN) conditions demonstrated that several SbNPF genes, including SbNPF1.1, SbNPF2.6, SbNPF2.7, and SbNPF4.5, were significantly upregulated in shoots, whereas SbNPF1.2, SbNPF2.7, and SbNPF3.1 were downregulated in roots, suggesting differential regulatory roles in nitrogen acquisition and utilization under nutrient-limiting environments. Collectively, these findings provide novel insights into the evolutionary dynamics and potential functions of the SbNPF gene family and establish a foundation for future functional studies and molecular breeding aimed at improving nitrogen use efficiency in sorghum.

The transcription factor known as TALE (three-amino acid loop extension) is essential for plant growth, cell differentiation and responses to environmental stresses. Although the TALE gene family has been identified in various plants, there has been a lack of comprehensive whole-genome identification and analysis in Gramineae species. In this study, 123 TALE family genes were identified in five Gramineae species, which can be categorized into two main subgroups: KONX and BELL. Most of the TALE genes in the same subgroup displayed analogous gene structures and conserved motifs. Furthermore, whole genome duplication (WGD) significantly contributes to the expansion of the TALE gene family in Gramineae. The promoter region of TALE genes in Gramineae contains a large number of cis-elements associated with abiotic stress and hormone response. Tissue-specific expression analysis indicated that most OsTALE, ZmTALE and AtTALE genes were highly expressed in stems and leaves. Additionally, RNA-seq data revealed that OsTALE, ZmTALE and AtTALE genes were found to respond to abiotic stress treatments. Furthermore, we found that the expression levels of SbTALE11/19 were up-regulated in response to PEG and NaCl treatment, respectively. This study provides a significant reference for further research on the biological function of TALE transcription factors in Gramineae plants.

High-density planting is crucial for maximizing the genetic potential of soybean cultivars to achieve higher yields. However, increasing the planting density can lead to the risk of plant lodging. Therefore, the identification of gene loci associated with lodging resistance is considered critical for the development of high-yielding, lodging-resistant soybean cultivars. In this study, 338 natural soybean accessions from the similar latitude were used to identify candidate genes associated with lodging resistance. Based on 9,400,987 SNPs, the soybean population was classified into three subpopulations. Genome-wide association analysis revealed that under planting densities of 300,000 and 150,000 plants/ha, a total of 20 significant SNPs were repeatedly detected under both planting densities, distributed across 14 chromosomes of soybeans. A hotspot region was identified on chromosome 19, from which seven candidate genes were detected. Based on haplotype and gene expression analyses, Glyma.19g212800 (SUS3) and Glyma.19g212700 (GH9B13) were found to be associated with significant phenotypic variations and were identified as candidate genes. RNA-seq analysis showed that DEGs were primarily enriched in the starch and sucrose metabolism pathways. The differential expression of Glyma.19g212800 among soybean haplotypes was further validated by qRT-PCR. By participating in sucrose decomposition and polysaccharide metabolism processes, it regulated cellulose content, thereby affecting the soybean plant lodging. This study facilitated the dissection of genetic networks underlying lodging traits in soybean, which benefits the genetic improvement of high-yield soybean with dense planting.

Rapid Alkalization Factor (RALF) is a signaling molecule in plants that plays a crucial role in growth and development, reproductive processes, and responses to both biotic and abiotic stresses. Although RALF peptides have been characterized in Arabidopsis and rice, a comprehensive bioinformatics analysis of the ZmRALF gene family in maize is still lacking. In this study, we identified 20 RALF genes in the maize genome. Sequence alignment revealed significant structural variation among the ZmRALF family genes. Phylogenetic analysis indicates that RALF proteins from Arabidopsis, rice, and maize can be classified into four distinct clades. Duplication events suggest that the expansion of the RALF gene family in maize primarily relies on whole-genome duplication. ZmRALF genes are widely expressed across various tissues; ZmRALF1/15/18/19 are highly expressed in roots, while ZmRALF6/11/14/16 are predominantly expressed in anthers. RNA-seq and RT-qPCR demonstrated that the expression levels of ZmRALF7, ZmRALF9, and ZmRALF13 were significantly up-regulated and down-regulated in response to PEG and NaCl stresses, respectively. Overall, our study provides new insights into the role of the RALF gene family in abiotic stress.

The Casparian strip membrane domain proteins (CASPs) are pivotal for the formation of the Casparian strip (CS) in endodermal cells and play a crucial role in a plant’s response to environmental stresses. However, existing research on the CASP gene family in rice and Arabidopsis lacks a comprehensive bioinformatics analysis and necessitates further exploration. In this study, we identified 41 OsCASP and 39 AtCASP genes, which were grouped into six distinct subgroups. Collinearity analysis underscored the pivotal roles of WGD and TD events in driving the evolution of CASPs, with WGDs being the dominant force. On the one hand, the analysis of cis-elements indicated that most OsCASP and AtCASP genes contain MYB binding motifs. On the other hand, RNA-seq revealed that the majority of OsCASP and AtCASP genes are highly expressed in roots, particularly in endodermal cells, where OsCASP_like11/9 and AtCASP_like1/31 demonstrated the most pronounced expression. These results suggest that OsCASP_like11/9 and AtCASP_like1/31 might be candidate genes involved in the formation of the endodermis CS. RT-qPCR results demonstrated that OsCASP_like2/3/13/17/21/30 may be candidate genes for the ion defect process. Collectively, this study offers a theoretical foundation for unraveling the biological functions of CASP genes in rice and Arabidopsis.