Conuping BSA-Seq and RNA-Seq Reveal the Molecular Pathway and Genes Associated with the Plant Height of Foxtail Millet (Setaria italica)

Genomics and transcriptomics identify quantitative trait loci affecting growth-related traits in silver pomfret (Pampus argenteus)

Pampus argenteus, a species distributed throughout the Indo-West Pacific, plays a significant role in the yield of aquaculture species. However, cultured P. argenteus has always been characterised by unbalanced growth synchronisation among individuals, slow growth rate, and lack of excellent germplasm resources. Therefore, we conducted mass selection for fast-growing strain P. argenteus for several consecutive years. Various genetic improvement programs have modified its genome sequence through selective pressure, leaving nucleotide signals that can be detected at the genomic level. In the present study, we combined bulked segregant analysis and transcriptome sequencing to identify candidate single nucleotide polymorphisms (SNPs) and key genes for growth-related traits in P. argenteus. A total of 7,280,936 SNPs and 2,212,379 insertions/deletions were identified in the extreme phenotypes of the fast-growing and slow-growing groups. Based on the examination of SNP frequency differences and sliding-window analysis, 42 SNPs were identified as candidate markers. Moreover, 14 of the 42 SNPs linked to growth-related traits were confirmed to be credible SNPs, and eight growth-related genes were screened, namely myb-binding protein 1 A, insulin A/B chains, α-1B adrenoceptor, engulfment and cell motility protein 3, myosin light chain kinase family member 4, insulin receptor located, unconventional myosin-9b, and matrilin-1. An optimal three-factor model (SNP4&SNP12&SNP14) was constructed using the generalized multifactor dimensionality reduction method, and its accuracy was verified as 67.72 %. These results may benefit genetic studies and accelerate genetic improvement of fast-growing strains of P. argenteus.

Dynamic QTL mapping reveals the genetic architecture of stem diameter across developmental stages in foxtail millet

MAIN CONCLUSION

Dynamic QTL analysis identified the key QTL qSD-9-1 and candidate genes SiGPI8, SiCesA5 and SiNPC1 associated with the developmental stages of foxtail millet stem diameter. Abstact. Stem diameter (SD) is a critical agronomic trait influencing lodging and yield in foxtail millet, yet its potential in selective breeding remains under-explored. Additionally, limited research has examined the dynamics of SD across various developmental stages. To address this gap, this study utilized two RIL populations (F8), RYRIL and JYRIL, comprising 215 and 224 lines, respectively. Dynamic QTL analysis of SD traits was conducted in two distinct environments, encompassing five developmental stages, to comprehensively investigate the genetic architecture of SD. Results revealed that the hB2 values for SD ranged from 60.19% to 82.51%, peaking during the maturity stage in both populations. A total of 26 unconditional and 16 conditional QTLs were identified, explaining 1.09-17.99% and 3.10-16.55% of the phenotypic variations, respectively. Notably, qSD-9-1 was consistently detected in both unconditional and conditional QTL mappings across the two populations, accounting for 1.66-17.99% of phenotypic variation. Phenotype-genotype association analysis within the bin marker interval of qSD-9-1 revealed significant differences in SD among RIL lines carrying parental genotypes. Furthermore, by predicting candidate genes within the physical interval of qSD-9-1 and integrating phenotype-haplotype association analysis, SiGPI8, SiCesA5 and SiNPC1 were identified as key candidate genes potentially regulating SD. This study advances our understanding of the genetic basis of SD in foxtail millet and provides a theoretical foundation for marker-assisted selection (MAS) in breeding lodging-resistant varieties.

Identification of core candidate genes responding to Verticillium wilt (Verticillium dahliae) in cotton via integrated methods

Cotton is a vital natural fiber and oil crop, yet it is severely affected by verticillium wilt (VW), known as the 'cancer' of cotton, hindering the industry's sustainable development. Upland cotton, which is widely cultivated, lacks effective resistance to VW, while most sea island cotton shows strong resistance. In this study, an F2:3 population was constructed by hybridizing the verticillium wilt-resistant island cotton variety 'Hai7124' with the susceptible variety 'Xinhai14'. Using Bulked Segregant Analysis (BSA-seq), we identified 10 genetic intervals significantly associated with resistance. Additionally, two pathogenic strains of Verticillium dahliae, Vd592 (a strong pathogenic type) and VdKT (a weak pathogenic type), were used to infect the 'Hai7124' and 'Xinhai14' for RNA-seq analysis, focusing on differentially expressed genes and signaling pathways in samples treated with different resistant and susceptible materials and infected with different pathogens. By integrating BSA-seq and RNA-seq association analyses, the candidate gene range was further refined. Five genes (GBMYB102, GBWRKY65, GBRDA2, GBSOT16, and GBCWINV1) were validated through virus-induced gene silencing (VIGS). The results revealed that reduced expression of these genes significantly decreases plant disease resistance and leads to a reduction in the activity of defense-related enzymes (such as SOD, CAT or PAL) and secondary metabolites (including lignin or flavonoids). Based on the preliminary functional analysis of these candidate genes, we speculate that redox metabolism and secondary metabolites play crucial roles in the resistance of island cotton to Verticillium wilt, and that the resistance of island cotton to verticillium wilt is the result of multiple genes working together.

Construction of a genetic linkage map and QTL mapping of the agronomic traits in Foxtail millet (Setaria italica)

Foxtail millet (Setaria italica) is one of the most ancient cultivated cereal crops and is ideal for the functional genomics of the Panicoideae crops. In the present study, we generated an F2 population consisting of 300 individuals by crossing an elite foxtail millet variety Jingu28 with a backbone line Ai88, and constructed a genetic linkage map with 213 published SSR markers and two InDel markers. Quantitative trait locus (QTL) mapping identified 46 QTL for 12 agronomic traits, including 13 major effect QTL. Meanwhile, 40 QTL controlling different traits formed 13 co-located QTL clusters. Moreover, one putative candidate gene Seita.9G020100 for qHD9-1 with conserved CCT motif and a gibberellin biosynthesis related GA20 oxidase gene Seita.5G404900 for qPH5-1 were identified based on homologous gene comparison. The 277 bp insertion/deletion on the promoter of Seita.9G020100 and the one-base (G) insertion/deletion in the third exon of Seita.5G404900 might be candidate functional sites. Furthermore, two markers (Ghd7InDel and GA20oxSTARP-1) were developed based on these two variation sites, respectively. These results will help to elucidate the genetic basis of important agronomic traits in foxtail millet and be useful for marker-assisted selection of varieties with ideal plant architecture and high yield potential.

Genome-wide association study and transcriptome analysis reveal the genetic basis underlying the environmental adaptation of plant height in a woody plant

Studies on plant height have been conducted in several crops. However, the underlying genetic mechanisms in woody plants remain unclear. To improve the genetic understanding of plant height, the genome-wide association study (GWAS) was conducted on the 298 individuals of paper mulberry (Broussonetia papyrifera), and the individuals with the highest and lowest plant heights were selected for comparative transcriptome analysis. The analysis of phenotypic data showed that plant height decreased from low latitude (N: 24°30') to high latitude (N: 41°00'), ranging from 372 to 150 cm. Furthermore, the plant height of paper mulberry was significantly correlated with environmental factors, such as latitude, frost-free period, hours of sunshine and so on, indicating adaptive phenotypic divergence across environmental gradients. A total of 228 candidate genes were identified through the GWAS, including three genes (Bp10g0547, Bp10g0551 and Bp10g0817) that contained nonsynonymous SNP variations significantly affecting plant height. A total of 2554 differentially expressed genes (DEGs) were identified through RNA sequencing (RNA-seq) analysis, including 28, 5, 3, 20 and 138 DEGs involved in auxin, gibberellin, cytokinin, ubiquitylation and transcription factors, respectively. Besides, there were 13 common genes identified by integrating GWAS and RNA-seq analysis, including Bp10g0817, which encodes COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC 1) and belongs to the RING type E3 ubiquitin ligase gene family. Collectively, this study provides valuable insights into the genetic mechanisms underlying plant height and adaptation of woody plants to diverse environments.

Assessment of Breeding Potential of Foxtail Millet Varieties Using a TOPSIS Model Constructed Based on Distinctness, Uniformity, and Stability Test Characteristics

Foxtail millet (Setaria italica) is an important cereal crop with rich nutritional value. Distinctness, Uniformity, and Stability (DUS) are the prerequisites for the application of new variety rights for foxtail millet. In this study, we investigated 32 DUS test characteristics of 183 foxtail millet resources, studied their artificial selection trends, and identified the varieties that conform to breeding trends. The results indicated significant differences in terms of the means, ranges, and coefficients of variation for each characteristic. A correlation analysis was performed to determine the correlations between various DUS characteristics. A principal component analysis was conducted on 31 test characteristics to determine their primary characteristics. By plotting PC1 and PC2, all the germplasm resources could be clearly distinguished. The trends in foxtail millet breeding were identified through a differential analysis of the DUS test characteristics between the landrace and cultivated varieties. Based on these breeding trends, the optimal solution types for multiple evaluation indicators were determined; the weight allocation was calculated; and a specific TOPSIS algorithm was designed to establish a comprehensive multi-criteria decision-making model. Using this model, the breeding potential of foxtail millet germplasm resources were ranked. These findings provided important reference for foxtail millet breeding in the future.

Rapidly mining candidate cotton drought resistance genes based on key indicators of drought resistance

BACKGROUND

Focusing on key indicators of drought resistance is highly important for quickly mining candidate genes related to drought resistance in cotton.

RESULTS

In the present study, drought resistance was identified in drought resistance-related RIL populations during the flowering and boll stages, and multiple traits were evaluated; these traits included three key indicators: plant height (PH), single boll weight (SBW) and transpiration rate (Tr). Based on these three key indicators, three groups of extreme mixing pools were constructed for BSA-seq. Based on the mapping interval of each trait, a total of 6.27 Mb QTL intervals were selected on chromosomes A13 (3.2 Mb), A10 (2.45 Mb) and A07 (0.62 Mb) as the focus of this study. Based on the annotation information and qRT‒PCR analysis, three key genes that may be involved in the drought stress response of cotton were screened: GhF6'H1, Gh3AT1 and GhPER55. qRT‒PCR analysis of parental and extreme germplasm materials revealed that the expression of these genes changed significantly under drought stress. Cotton VIGS experiments verified the important impact of key genes on cotton drought resistance.

CONCLUSIONS

This study focused on the key indicators of drought resistance, laying the foundation for the rapid mining of drought-resistant candidate genes in cotton and providing genetic resources for directed molecular breeding of drought resistance in cotton.

Transcriptome and Gene Co-Expression Network Analysis Identifying Differentially Expressed Genes and Signal Pathways Involved in the Height Development of Banana (Musa spp.)

Plant height is an important and valuable agronomic trait associated with yield and resistance to abiotic and biotic stresses. Dwarfism has positive effects on plant development and field management, especially for tall monocotyledon banana (Musa spp.). However, several key genes and their regulation mechanism of controlling plant height during banana development are unclear. In the present study, the popular cultivar 'Brazilian banana' ('BX') and its dwarf mutant ('RK') were selected to identify plant height-related genes by comparing the phenotypic and transcriptomic data. Banana seedlings with 3-4 leaves were planted in the greenhouse and field. We found that the third and fourth weeks are the key period of plant height development of the selected cultivars. A total of 4563 and 10507 differentially expressed genes (DEGs) were identified in the third and fourth weeks, respectively. Twenty modules were produced by the weighted gene co-expression network analysis (WGCNA). Eight modules were positively correlated with the plant height, and twelve other modules were negatively correlated. Combining with the analysis of DEGs and WGCNA, 13 genes in the signaling pathway of gibberellic acid (GA) and 7 genes in the signaling pathway of indole acetic acid (IAA) were identified. Hub genes related to plant height development were obtained in light of the significantly different expression levels (|log2FC| ≥ 1) at the critical stages. Moreover, GA3 treatment significantly induced the transcription expressions of the selected candidate genes, suggesting that GA signaling could play a key role in plant height development of banana. It provides an important gene resource for the regulation mechanism of banana plant development and assisted breeding of ideal plant architecture.