GhGRF4/GhARF2-GhGASA24 module regulates fiber cell wall thickness by modulating cellulose biosynthesis in upland cotton (Gossypium hirsutum).

Fiber elongation rate is an essential characteristic of cotton fiber in the textile industry, yet it has been largely overlooked in genetic studies. Gibberellins (GAs) and auxin (IAA) are recognized for their role in directing numerous developmental processes in plants by influencing cell differentiation and elongation. However, the degree to which GA-IAA interaction governs cellular elongation in cotton fiber cells remains to be fully understood. In this study, we identified a causal gene, Gibberellic Acid-Stimulated in Arabidopsis 24 (GhGASA24), that appears to be responsible for fiber elongation rate via regulating fiber cell wall thickness. Subsequent experiments revealed that GhGASA24 influences cell wall formation by promoting the expression of GhCesA8 and GhCesA10. Our findings suggest that Auxin Response Factor 2 (GhARF2) regulates fiber elongation rate by directly binding to the AuxRE elements in GhGASA24 promoter. In addition, we identified Growth Regulation Factor 4 (GhGRF4) as a transcription factor that interacts with GhARF2 to form a heterodimer complex, which also transcriptionally activates GhGASA24. Intriguingly, GhGRF4 regulates GhARF2 expression by directly binding to its promoter, thereby acting as a cascade regulator to enhance the transcriptional levels of GhGASA24. We propose that the GhGRF4/GhARF2-GhGASA24-GhCesAs module may contribute to fiber cell wall thickness by modulating cellulose biosynthesis, and provide a theoretical basis for improvement of fiber quality.

Strigolactone-gibberellin crosstalk mediated by a distant silencer fine-tunes plant height in upland cotton.

Optimal plant height is crucial in modern agriculture, influencing lodging resistance and facilitating mechanized crop production. Upland cotton (Gossypium hirsutum) is the most important fiber crop globally; however, the genetic basis underlying plant height remains largely unexplored. In this study, we conducted a genome-wide association study to identify a major locus controlling plant height (PH1) in upland cotton. This locus encodes gibberellin 2-oxidase 1A (GhPH1) and features a 1133-bp structural variation (PAVPH1) located approximately 16 kb upstream. The presence or absence of PAVPH1 influences the expression of GhPH1, thereby affecting plant height. Further analysis revealed that a gibberellin-regulating transcription factor (GhGARF) recognizes and binds to a specific CATTTG motif in both the GhPH1 promoter and PAVPH1. This interaction downregulates GhPH1, indicating that PAVPH1 functions as a distant upstream silencer. Intriguingly, we found that DWARF53 (D53), a key repressor of the strigolactone (SL) signaling pathway, directly interacts with GhGARF to inhibit its binding to targets. Moreover, we identified a previously unrecognized gibberellin-SL crosstalk mechanism mediated by the GhD53-GhGARF-GhPH1/PAVPH1 module, which is crucial for regulating plant height in upland cotton. These findings shed light on the genetic basis and gene interaction network underlying plant height, providing valuable insights for the development of semi-dwarf cotton varieties through precise modulation of GhPH1 expression.

A Compensation Method for Full-Field-of-View Energy Nonuniformity in Dark-and-Weak-Target Simulators.

Dark-and-weak-target simulators are used as ground-based calibration devices to test and calibrate the performance metrics of star sensors. However, these simulators are affected by full-field-of-view energy nonuniformity. This problem impacts the quality of output images and the calibration accuracy of sensors and inhibits further improvements in navigational accuracy. In the study reported in this paper, we sought to analyze the factors which affect full-field-of-view energy uniformity in dark-and-weak-target simulators. These include uneven irradiation in backlight sources, the leakage of light from LCD display panels, and the vignetting of collimating optical systems. We then established an energy transfer model of a dark-and-weak-target simulator based on the propagation of a point light source and proposed a self-adaptive compensation algorithm based on pixel-by-pixel fitting. This algorithm used a sensor to capture the output image of a dark-and-weak-target simulator and iteratively calculated the response error matrix of the simulator. Finally, we validated the feasibility and effectiveness of the compensation algorithm by acquiring images using a self-built test system. The results showed that, after compensating an output image of the dark-and-weak-target simulator, the grayscale standard display function (SDF) of the acquired sensor image was reduced by about 50% overall, so the acquisition image was more accurately compensated, and the desired level of grayscale distribution was obtained. This study provides a reference for improving the quality of output images from dark-and-weak-target simulators, so that the working environments of star sensors may be more realistically simulated, and their detection performance improved.

Research on ultraviolet-visible composite optical target simulation technology.

This study proposes an ultraviolet-visible composite optical target simulation technique based on a liquid crystal display (LCD) spatial light modulation device to solve the problem of not being able to satisfy the demand for optical target simulation for both ultraviolet and visible light operating spectral ranges in a single system when composite simulation of multi-source spatial targets is performed. We establish a composite light source model of an ultraviolet light emitting diode (LED) and a xenon lamp to enhance the energy simulation of the ultraviolet portion, and the light is mixed and homogenized by an integrating sphere. We analyze the light transmission principle of LCD display devices and derive the equation for the relationship between its working band and transmittance. We design a transmission-type projection system with a wide spectral range and simulate the transmittance of the whole system, and demonstrate the optical target simulator can realize the simulation requirements of a wide working spectral range, high interstellar angular distance accuracy, and high magnitude accuracy.

Research on optical simulation of dim target based on passive detection link analysis.

In order to meet the ground calibration requirements of optical detection equipment to identify optical characteristics of dim targets, an optical simulation method of dim targets based on passive detection link analysis and bidirectional scattering distribution function model is proposed. The off-axis collimation system for long focal length, the simulated energy transmission model of dim targets and the simplified model of bidirectional scattering distribution function are established. An internal stray light suppression baffle was designed to effectively suppress secondary scattering, and an optical simulation system for dim targets was built. The experimental results show that the system can simulate +7 Mv∼+20 Mv, and the simulation accuracy is better than 0.07 Mv. At the same time, the detection ability of the camera is tested by using the +15 Mv point simulated by the system. The signal-to-noise of the star point target reaches 6.7, which meets the requirements of detection rate and false alarm rate, and realizes the ground test of the camera's detection ability of the dim target.

Simulation method for multi-source information fusion space target.

Current space target simulation systems suffer from limitations, such as a single simulated spectral band, inability to allocate spectral ratios between bands, and poor imaging quality of multi-spectral simulated images. We propose a multi-source information fusion spatial target simulation method system that features a "series-parallel" hybrid connection. We optimize the design of a multi-spectral common aperture optical system and experimentally verify the proposed method. The experimental results show that the proposed system can simulate a wide range of spectral bands ranging from ultraviolet to long-wave infrared. Furthermore, it achieves precise control over the ratio of simulated radiant energy among spectral bands, with a spectral simulation error of less than 4.8%. Notably, it effectively images stars against the cosmic background and spacecraft across different spectral bands. This system serves as a theoretical cornerstone and provides crucial technological support for performance testing and rapid iterative development of multi-source information fusion space exploration systems.

Design and analysis of unequal aperture off-axis optical integrator for solar simulators.

The unequal aperture off-axis optical integrator design method is proposed to improve the irradiation uniformity of solar simulators and solve the problem of limited uniformity of optical integrator due to aberrations and uneven distribution of incident radiation. Firstly, the unequal aperture off-axis optical integrator structure is designed based on the scalar diffraction theory to analyze the factors affecting the optical homogenization ability of the optical integrator. Then, the relationship between sub-eye lens aperture and arrangement is explored in combination with Lagrange invariance principle and semi-definite programming theory. Finally, the optimum off-axis amount of sub-eye lens with different ring band is determined from the perspective of geometric optics by using the aberration theory and following the principle of edge light, so as to improve the evenness of optical integrator. The design results are verified by the simulation analysis. The simulation results show that: In the picture plane of optical integrator, the irradiation non-uniformity in the ф 26 mm irradiation plane is 14.87%, which is better than 26.02% in the traditional optical integrator. At the same time, at the effective irradiated surface, the irradiation non-uniformity of 0.53% within the ф 300 mm reaches the irradiation standard of the class A + solar simulator, and the irradiance only decreases by 16.5% compared with the traditional optical integrator, which still meets the index requirement of a solar constant. The goal of improving the evenness of optical integrator is realized without greatly affecting irradiance and without introducing aspherical design.

High contrast ratio optimized total internal reflection prism for compact medium-wave IR target simulation system.

The existing infrared target simulation system with a total internal reflection (TIR) prism has the problem of low imaging contrast ratio, which will seriously affect the quality of the simulated image. This study proposes a design method of optimized TIR prism (OTIR) based on Snell's law in medium-wave infrared (MWIR) to solve the problem. The radiation theory is used to construct the constraint model of the OTIR prism in the MWIR target simulation system. Further, this study investigates the influence of different states of the digital micromirror device on the beam direction and derives the design equation of the OTIR prism composed of three prisms based on Snell's law. Finally, the designed OTIR prism is simulated and experimentally verified. The simulated results show that the OTIR prism of the compact MWIR target simulation system can enhance the contrast ratio. The experimental results show that the output contrast ratio of the simulation system at 700 K is about 298:1. In the specified temperature range, the contrast ratio of the infrared target simulation system increases with the increase of the light source temperature. Thus, the OTIR prism has the function of improving the contrast ratio of MWIR target simulation system.

Identification and characterization of candidate genes for primary root length in Asiatic cotton (Gossypium arboreum L.).

KEY MESSAGE: One major gene controlling primary root length (PRL) in Gossypium arboreum is identified and this research provides a theoretical basis for root development for cotton. Primary root elongation is an essential process in plant root system structure. Here, we investigated the primary root length (PRL) of 215 diploid cotton (G. arboreum) accessions at 5, 8, 10, 15 days after sowing. A Genome-wide association study was performed for the PRL, resulting in 49 significant SNPs associated with 32 putative candidate genes. The SNP with the strongest signal (Chr07_8047530) could clearly distinguish the PRLs between accessions with two haplotypes. GamurG is the only gene that showed higher relative expression in the long PRL genotypes than the short PRL genotypes, which indicated it was the most likely candidate gene for regulating PRL. Moreover, the GamurG-silenced cotton seedlings showed a shorter PRL, while the GamurG-overexpressed Arabidopsis exhibited a significantly longer PRL. Our findings provide insight into the regulation mechanism of cotton root growth and will facilitate future breeding programs to optimize the root system structure in cotton.

Genomic loci associated with leaf abscission contribute to machine picking and environmental adaptability in upland cotton (Gossypium hirsutum L.).

INTRODUCTION: Defoliation by applying defoliants before machine picking is an important agricultural practice that enhances harvesting efficiency and leads to increased raw cotton purity. However, the fundamental characteristics of leaf abscission and the underlying genetic basis in cotton are not clearly understood. OBJECTIVES: In this study, we aimed to (1) reveal the phenotypic variations in cotton leaf abscission, (2) discover the whole-genome differentiation sweeps and genetic loci related to defoliation, (3) identify and verify the functions of key candidate genes associated with defoliation, and (4) explore the relationship between haplotype frequency of loci and environmental adaptability. METHODS: Four defoliation-related traits of 383 re-sequenced Gossypium hirsutum accessions were investigated in four environments. The genome-wide association study (GWAS), linkage disequilibrium (LD) interval genotyping and functional identification were conducted. Finally, the haplotype variation related to environmental adaptability and defoliation traits was revealed. RESULTS: Our findings revealed the fundamental phenotypic variations of defoliation traits in cotton. We showed that defoliant significantly increased the defoliation rate without incurring yield and fiber quality penalties. The strong correlations between defoliation traits and growth period traits were observed. A genome-wide association study of defoliation traits identified 174 significant SNPs. Two loci (RDR7 on A02 and RDR13 on A13) that significantly associated with the relative defoliation rate were described, and key candidate genes GhLRR and GhCYCD3;1, encoding a leucine-rich repeat (LRR) family protein and D3-type cell cyclin 1 protein respectively, were functional verified by expression pattern analysis and gene silencing. We found that combining of two favorable haplotypes (HapRDR7 and HapRDR13) improved sensitivity to defoliant. The favorable haplotype frequency generally increased in high latitudes in China, enabling adaptation to the local environment. CONCLUSION: Our findings lay an important foundation for the potentially broad application of leveraging key genetic loci in breeding machine-pickable cotton.

Design of an optical illumination system for a long wave infrared scene projector based on diffraction characteristics.

This study proposes an optical illumination system design based on vector diffraction characteristics and the Scheimpflug principle to determine an optimal relationship between illumination uniformity, energy utilization, and system size in an infrared scene projector. We investigate the influence of digital micromirror device (DMD) diffraction efficiency at different incidence angles on energy utilization rate and establish a two-dimensional diffraction grating model to determine the optimal incidence angle of the DMD beam. We demonstrate that the optical illumination system of a long-wave infrared (LWIR) scene projector based on diffraction characteristics can simulate an infrared scene with a compact structure, high energy efficiency, and high uniformity.

Analysis on the instability of the surface profiles of precision molding chalcogenide glass aspherical lenses in mass production.

Chalcogenide glass lenses have been widely applied in infrared optical systems for their outstanding optical performance. It is a tendency for complex optical glass elements to be mass-produced with precision glass molding (PGM) technology, of course including chalcogenide glass aspheric lenses. But there is a problem that sometimes the surface profiles of the molded lenses are unstable which leads to a low pass-yield. Precision glass molding experiments and finite elements simulations are carried out to study the reasons for the mentioned problem in this paper. The results reveal that the laying error of the ball chalcogenide glass preform does not have a significant effect on the surface profile of the molded lens. However, in mass production the control of the temperature after forming stage in the PGM process is very important for obtaining the molded lenses with very similar surface profiles. The research results could help relevant researchers design the PGM processing parameters to overcome some errors in the mass production and manufacture precision glass molding machines. The increase in the yield of complex optical glass elements fabricated by PGM technology will further promote the application of such elements in various fields.

Integrating Genome-wide association and whole transcriptome analysis to reveal genetic control of leaf traits in Gossypium arboreum L.

Leaves are important organs for crop photosynthesis and transpiration, and their morphological characteristics can directly reflect the growth state of plants. Accurate measurement of leaf traits and mining molecular markers are of great significance to the study of cotton growth. Here, we performed a Genome-wide association study on 7 leaf traits in 213 Asian cotton accessions. 32 significant SNPs and 44 genes were identified. A field experiment showed significant difference in leaf hair and leaf area between DPL971 and its natural mutant DPL972. We also compared the leaf transcriptome difference between DPL971 and DPL972, and found a batch of differentially expressed genes and non-coding RNAs (including lncRNAs, microRNAs, and circRNAs). After integrating the GWAS and transcriptome results, we finally selected two coding genes (Ga03G2383 and Ga05G3412) and two microRNAs (hbr-miR156, unconservative_Chr03_contig343_2364) as the candidate for leaf traits. Those findings will provide important genomic resources for cotton leaf improvement breeding.

Deltapine 15 contributes to the genomic architecture of modern upland cotton cultivars.

Foundation parents play a critical role in the genetic constituents of the derived genotypes. Deltapine-15 (DLP-15), introduced to China in 1950, is one of the most commonly used parents for early breeding programs in China. However, the formation and inheritance patterns of genomic constituents have not been studied. Therefore, this study aimed at understanding and exploring the genomic architecture of 146 DLP-15 derived cultivars with a common foundation parent DLP-15. Population structure based on sequencing data clustered genotypes into two groups (G1 and G2) supported by principal component analysis. Further exploration led to the identification of Chr-A08 with significantly differentiated regions between two groups. Moreover, we identified genome-wide identity by descent (IBD) segments (840 segments) to understand the genomic inheritance pattern in DLP-15 derived cultivars, spanning the 20-95 Mb region on Chr-A08. Interestingly, Chr-A08 depicted a unique inheritance pattern from DLP-15 to its derived cultivars. IBD-segment-based haplotype analysis suggested significant differences among the two groups. Phenotypic trait association with DLP-derived haplotypes concerning Chr-A08 suggested a significant increase in yield and fiber quality. Furthermore, distinguished IBD segments overlapped with previously reported QTLs concerning fiber yield and quality. Our results systematically identified genomic signatures transmitted from the foundation parent DLP-15 to its derived cultivars and provided a basis for further exploiting excellent haplotypes associated with DLP-15.

Mapping of dwarfing QTL of Ari1327, a semi-dwarf mutant of upland cotton.

BACKGROUND: Upland Cotton (Gossypium hirsutum L.) has few cotton varieties suitable for mechanical harvesting. The plant height of the cultivar is one of the key features that need to modify. Hence, this study was planned to locate the QTL for plant height in a 60Co γ treated upland cotton semi-dwarf mutant Ari1327. RESULTS: Interestingly, bulk segregant analysis (BSA) and genotyping by sequencing (GBS) methods exhibited that candidate QTL was co-located in the region of 5.80-9.66 Mb at D01 chromosome in two F2 populations. Using three InDel markers to genotype a population of 1241 individuals confirmed that the offspring's phenotype is consistent with the genotype. Comparative analysis of RNA-seq between the mutant and wild variety exhibited that Gh_D01G0592 was identified as the source of dwarfness from 200 genes. In addition, it was also revealed that the appropriate use of partial separation markers in QTL mapping can escalate linkage information. CONCLUSIONS: Overwhelmingly, the results will provide the basis to reveal the function of candidate genes and the utilization of excellent dwarf genetic resources in the future.

Genome-wide association study for seedling biomass-related traits in Gossypium arboreum L.

BACKGROUND: Seedling stage plant biomass is usually used as an auxiliary trait to study plant growth and development or stress adversities. However, few molecular markers and candidate genes of seedling biomass-related traits were found in cotton. RESULT: Here, we collected 215 Gossypium arboreum accessions, and investigated 11 seedling biomass-related traits including the fresh weight, dry weight, water content, and root shoot ratio. A genome-wide association study (GWAS) utilizing 142,5003 high-quality SNPs identified 83 significant associations and 69 putative candidate genes. Furthermore, the transcriptome profile of the candidate genes emphasized higher expression of Ga03G1298, Ga09G2054, Ga10G1342, Ga11G0096, and Ga11G2490 in four representative cotton accessions. The relative expression levels of those five genes were further verified by qRT-PCR. CONCLUSIONS: The significant SNPs, candidate genes identified in this study are expected to lay a foundation for studying the molecular mechanism for early biomass development and related traits in Asian cotton.

Genetic Factors Underlying Single Fiber Quality in A-Genome Donor Asian Cotton (Gossypium arboreum).

The study of A-genome Asian cotton as a potential fiber donor in Gossypium species may offer an enhanced understanding of complex genetics and novel players related to fiber quality traits. Assessment of individual fibers providing classified fiber quality information to the textile industry is Advanced Fiber Information System (AFIS) in the recent technological era. Keeping the scenario, a diverse collection of 215 Asiatic cotton accessions were evaluated across three agro-ecological zones of China. Genome-Wide Association Studies (GWAS) was performed to detect association signals related to 17 AFIS fiber quality traits grouped into four categories viz: NEPs, fiber length, maturity, and fineness. Significant correlations were found within as well as among different categories of various traits related to fiber quality. Fiber fineness has shown a strong correlation to all other categories, whereas these categories are shown interrelationships via fiber-fineness. A total of 7,429 SNPs were found in association with 17 investigated traits, of which 177 were selected as lead SNPs. In the vicinity of these lead SNPs, 56 differentially expressed genes in various tissues/development stages were identified as candidate genes. This compendium connecting trait-SNP-genes may allow further prioritization of genes in GWAS loci to enable mechanistic studies. These identified quantitative trait nucleotides (QTNs) may prove helpful in fiber quality improvement in Asian cotton through marker-assisted breeding as well as in reviving eroded genetic factors of G. hirsutum via introgression breeding.

Favorable pleiotropic loci for fiber yield and quality in upland cotton (Gossypium hirsutum).

Upland cotton (Gossypium hirsutum L.) is an important economic crop for renewable textile fibers. However, the simultaneous improvement of yield and fiber quality in cotton is difficult as the linkage drag. Compared with breaking the linkage drag, identification of the favorable pleiotropic loci on the genome level by genome-wide association study (GWAS) provides a new way to improve the yield and fiber quality simultaneously. In our study restriction-site-associated DNA sequencing (RAD-seq) was used to genotype 316 cotton accessions. Eight major traits in three categories including yield, fiber quality and maturation were investigated in nine environments (3 sites × 3 years). 231 SNPs associated with these eight traits (- log10(P) > 5.27) were identified, located in 27 genomic regions respectively by linkage disequilibrium analysis. Further analysis showed that four genomic regions (the region 1, 6, 8 and 23) held favorable pleiotropic loci and 6 candidate genes were identified. Through genotyping, 14 elite accessions carrying the favorable loci on four pleiotropic regions were identified. These favorable pleiotropic loci and elite genotypes identified in this study will be utilized to improve the yield and fiber quality simultaneously in future cotton breeding.