BMC Plant Biology最新文献

Background: The hypocotyl length and elongation is an important characteristic that affect the soybean seedling emergence and photosynthesis. However, the basic genetic mechanism of this feature remains incompletely understood.

Results: In this study, the hypocotyl length of four-day germinated soybean seedlings was evaluated before and after 24 h cultivation to assess hypocotyl elongation (HE) in 330 soybean accessions. Five quantitative trait loci (QTLs) that significantly associated with HE trait were detected by genome-wide association study (GWAS) in two models, and they are located on chromosome (Chr.) 2, 3, 11, 15, and 17, respectively. A total of 84 gene models have been found in HE QTLs candidate regions, and with a large proportion enriched in the biological processes of photosynthesis and cell differentiation. A CCCH zinc finger protein gene of GmZFP1 (Glyma.15G262900) was identified as the candidate in the major locus qHE_8 through the analysis of linkage disequilibrium (LD) blocks, gene expression patterns, and natural variation. Three SNPs substantially associated with HE in the GmZFP1 area resulted in 12 haplotypes (Hap 1-12) and four haplotype groups (Hap Ⅰ-Ⅳ). Soybean accessions carrying superior Hap Ⅲ showed significantly higher HE than the soybean lines containing Hap I, and the Hap Ⅲ made up 13.4% of the G. soja subpopulation and 61.98% of the G. max subpopulation, respectively. In genetic diversity and molecular evolution analysis, the GmZFP1 was also located in the genome selective sweep region during soybean domestication.

Conclusions: Five QTLs were mapped by GWAS in both EMMAX and TASSEL models that significantly associated with soybean hypocotyl elongation (HE). The major candidate gene GmZFP1 underlying the qHE_8 locus was identified, and the superior haplotypes and selective sweep signals were also detected in the GmZFP1 region. The QTLs and GmZFP1 discovered in this study provided potential genetic resources for the soybean molecular breeding in the future.

Background: WRKY transcription factors (TFs) represent one of the largest families of transcriptional regulators in plants, playing a crucial role in plant responses to both biotic and abiotic stresses. Studies have shown that WRKY family members modulate the expression of disease resistance genes, hormone synthesis genes and signal transduction genes, thereby mediating plant resistance to diverse pathogens including fungi, bacteria, and viruses. Although reports have indicated the presence of 120 WRKY family proteins in maize (Zea mays L), research on the molecular regulatory mechanism underlying disease resistance mediated by maize WRKY genes remains limited. In this study, we identified the transcription factor gene ZmWRKY36 in maize and investigated its function in maize's response to infection by Bipolaris maydis, the causal agent of southern corn leaf blight. This work aims to provide a theoretical and experimental basis for exploring maize disease resistant genes and enriching functional studies of WRKY TFs in different crops.

Result: We identified ZmWRKY36 as a nuclear-localized transcription factor in maize. To explore its biological function in resistance to B. maydis, we constructed ZmWRKY36-silenced (FoMV:ZmWRKY36-VIGS) and ZmWRKY36-overexpressed (FoMV:ZmWRKY36-VOX) maize plants using virus-induced gene silencing (VIGS) and transient overexpression (VOX) systems, respectively. Disease resistance assays revealed that transiently silenced FoMV:ZmWRKY36-VIGS plants exhibited reduced resistance to B. maydis infection and suppressed chitin-induced reactive oxygen species (ROS) burst, whereas transiently overexpressed FoMV:ZmWRKY36-VOX plants showed the opposite results. Additionally, overexpressed of ZmWRKY36 upregulated the expression of disease-related genes, suggesting that ZmWRKY36 positively regulates maize resistance to B. maydis. Further functional characterization demonstrated that ZmWRKY36 possesses transcriptional activation activity. Transcriptome analysis of ZmWRKY36-silenced and ZmWRKY36-overexpressed plants revealed that the differentially expressed genes (DEGs) were mainly enriched in pathways related to cellular structure composition, metabolic synthesis, and photosynthesis. Promoter analysis of these DEGs identified 105 genes containing W-box elements the core binding motif of WRKY TFs, which suggested that these pathways and target genes are involved in mediating maize resistance to B. maydis.

Conclusions: These results demonstrate that transcription factor ZmWRKY36 positively regulates maize resistance to B. maydis and identify its potential downstream target genes. This study provides insights into the regulatory role of ZmWRKY36 in maize defense responses and lays a foundation for further dissecting WRKY-mediated disease resistance networks in maize.

Background: Ongoing climate change poses major threats to species worldwide, making it essential to understand local adaptations and vulnerabilities to both climatic and anthropogenic pressures when developing conservation strategies. This study integrated transcriptome-guided SNP of 54 individuals with ecological and environmental analyses to investigate the biogeographic patterns, genetic divergence, demographic trajectories, and climate and anthropogenic threats of the endangered orchid Cypripedium palangshanense.

Results: We identified four distinct lineages, three confined to the Min Mountains and one to the Daba Mountains in China. Climatic fluctuations strongly influenced demographic history and genetic structure, with evidence of a severe recent bottleneck that may reduce adaptive potential and compromise long-term viability. Higher ancestral diversity and/or limited gene flow during prolonged divergence prevented sharp increases in genetic differentiation (F_ST) but allowed the accumulation of absolute divergence (D_XY).

Conclusions: Overall, we detected pressures under climate and anthropogenic activity and identified vulnerability hotspots (JZG2, SP1, SP2 and DB) requiring conservation priority. Alternatively, ecological niche modeling combined with RONA analysis suggests that the marginal population (CK and PW) is likely to have the highest risk of maladaptation in the future. Our findings highlight how population genomics, ecological and environmental data can be integrated to inform targeted conservation.

Medicago sativa is a globally cultivated forage crop, and improving its digestibility and stress tolerance remains a central breeding goal. The Cellulose synthase (CESA) superfamily is central to cell wall biosynthesis and influences plant development, stress responses, and forage quality; however, its evolutionary trajectory in Medicago is poorly resolved. Here, we identified 431 CESA superfamily genes from five Medicago species and four outgroup taxa. Phylogenetic analyses classified these genes into eight clades, including CesA and CslA/B/C/D/E/G/M subfamilies. Gene duplication analyses revealed that both tandem duplication and whole genome duplication (WGD) drove superfamily expansion, with a WGD event occurring in the common ancestor of Papilionooideae (PWGD). Tandem duplication plays a more prominent role than the PWGD-derived duplication. Transcriptomic analyses demonstrated that CESA genes in M. sativa subsp. sativa are broadly involved in development and respond strongly to salt and drought stresses. Notably, loss of CesA gene copies and biased retention of duplicated genes were observed in the MsCslB, MsCslA, MsCslE, and MsCslD subfamilies. Among tandem duplicates, MsCslB5.1 and MsCslB10.1 exhibited pronounced stress-responsive expression. These patterns may reflect domestication-related selection for improved forage quality and stress tolerance. Together, our findings establish a comprehensive evolutionary framework for the CESA superfamily and provide candidate genes with potential value for molecular breeding in Medicago forage crops.