Integrated transcriptomic and metabolomic analyses reveals anthocyanin biosynthesis in leaf coloration of quinoa (Chenopodium quinoa Willd.)

BACKGROUND

Quinoa leaves demonstrate a diverse array of colors, offering a potential enhancement to landscape aesthetics and the development of leisure-oriented sightseeing agriculture in semi-arid regions. This study utilized integrated transcriptomic and metabolomic analyses to investigate the mechanisms underlying anthocyanin synthesis in both emerald green and pink quinoa leaves.

RESULTS

Integrated transcriptomic and metabolomic analyses indicated that both flavonoid biosynthesis pathway (ko00941) and anthocyanin biosynthesis pathway (ko00942) were significantly associated with anthocyanin biosynthesis. Differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) were analyzed between the two germplasms during different developmental periods. Ten DEGs were verified using qRT-PCR, and the results were consistent with those of the transcriptomic sequencing. The elevated expression of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), 4-coumarate CoA ligase (4CL) and Hydroxycinnamoyltransferase (HCT), as well as the reduced expression of flavanone 3-hydroxylase (F3H) and Flavonol synthase (FLS), likely cause pink leaf formation. In addition, bHLH14, WRKY46, and TGA indirectly affected the activities of CHS and 4CL, collectively regulating the levels of cyanidin 3-O-(3'', 6''-O-dimalonyl) glucoside and naringenin. The diminished expression of PAL, 4CL, and HCT decreased the formation of cyanidin-3-O-(6"-O-malonyl-2"-O-glucuronyl) glucoside, leading to the emergence of emerald green leaves. Moreover, the lowered expression of TGA and WRKY46 indirectly regulated 4CL activity, serving as another important factor in maintaining the emerald green hue in leaves N1, N2, and N3.

CONCLUSION

These findings establish a foundation for elucidating the molecular regulatory mechanisms governing anthocyanin biosynthesis in quinoa leaves, and also provide some theoretical basis for the development of leisure and sightseeing agriculture.

Transcriptomics-metabolomics joint analysis: New highlight into the triterpenoid saponin biosynthesis in quinoa (Chenopodium quinoa Willd.)

Quinoa (Chenopodium quinoa Willd.) contains various physiologically active substances, including vitamins, polyphenols, flavonoids, phytosterols, and saponins. Research showed that saponins were the protective substances in the outer layer of quinoa seeds to defend against microbes, herbivores, and insects. Because the aglycones of quinoa saponins are triterpenoids, they are called triterpenoid saponins (TSs). In addition, the presence of TS imparted bitterness in quinoa and resulted in anticancer and anti-inflammatory effects. In this study, the seeds of low-saponin quinoa, NT376-2 (N), and high-saponin quinoa, B-12071(B), at 30 and 60 days after flowering (DAF) were used to measure the TS content and evaluated for their transcriptomic and metabolomic profiles. The amounts of TS were found to significantly differ between all possible comparisons: N and B at 30 DAF (N1_vs_B1), N and B at 60 DAF (N2_vs_B2), N at 30 DAF and 60 DAF (N1_vs_N2), and B at 30 DAF and 60 DAF (B1_vs_B2). RNA sequencing (RNA-seq) was used to screen differentially expressed genes (DEGs) and revealed 14,703 upregulated DEGs and 26,267 downregulated DEGs in the four comparison groups. The 311 overlapping DEGs found in the four comparisons were used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to screen for DEGs related to TS biosynthesis in quinoa. Metabolomics analysis identified acetyl-CoA, 1-hydroxy-2-methyl-2-butenyl-4-diphosphate, farnesal, and (S)-2,3-epoxysqualene as the key differentially accumulated metabolites (DAMs). Transcriptomics-metabolomics joint analysis showed that triterpenoid biosynthesis and terpenoid backbone biosynthesis were the enriched pathways of TS biosynthesis; farnesal were the key DAMs shared in the four comparison groups and associated with 10 key candidate DEGs related to TS biosynthesis in quinoa. These results provided important references for in-depth research on the metabolic mechanism of TS in quinoa.

Corrigendum: Multi-Omics and miRNA Interaction Joint Analysis Highlight New Insights Into Anthocyanin Biosynthesis in Peanuts (Arachis hypogaea L.)

[This corrects the article DOI: 10.3389/fpls.2022.818345.].

Multi-Omics and miRNA Interaction Joint Analysis Highlight New Insights Into Anthocyanin Biosynthesis in Peanuts (Arachis hypogaea L.)

Peanut (Arachis hypogaea L.) is one of the most important economic and oil crops in the world. At present, peanut varieties with rich anthocyanin in testa are rare in the market, but the selection and breeding of varieties with the related traits has always attracted the attention of breeders. In this study, two peanut varieties with the pink and purple testa, G110 (G) and Z18-40 (Z) were used to conduct interaction joint analysis of multi-omics and miRNA-target gene. The anthocyanin content of Z18-40 was 7.49-8.62-folds higher than G110 on 30 DAF (days after flowering) and 45 DAF via Ultraviolet-visible Spectrophotometer (UV-5800, Shanghai, China). And then, a total of 14 candidate genes related with the anthocyanin biosynthesis were identified for correlation in different comparison groups (R ² ≥ 0.80), among of a novel gene Ah21440 related with hydroxycinnamoyl transferase (HCT) biosynthesis was identified. In addition, Cyanidin 3-O-glucoside (Kuromanin, pmb0550) was the only common differentially accumulated metabolite (DAM) identified using multi-omics joint analysis in G1_vs_G2, Z1_vs_Z2, G1_vs_Z1, and G2_vs_Z2, respectively. Correlation analysis of miRNA-target genes and DEGs in the transcriptome shows that, AhmiR2950, AhmiR398, AhmiR50, and AhmiR51 regulated to HCT and chalcone biosynthesis related candidate genes (Ah21440, AhCHS, AhCHI). Lastly, all of 14 candidate genes and 4 differentially expressed miRNAs were validated using quantitative real-time PCR (qRT-PCR), which trends were consistent with that of the former transcriptome data. The results provide important reference for in-depth research on the anthocyanin metabolism mechanism in peanut testa.

Transcriptome and Co-expression Network Analyses Reveal Differential Gene Expression and Pathways in Response to Severe Drought Stress in Peanut (Arachis hypogaea L.)

Drought is one of the major abiotic stress factors limiting peanut production. It causes the loss of pod yield during the pod formation stage. Here, one previously identified drought-tolerant cultivar, "L422" of peanut, was stressed by drought (35 ± 5%) at pod formation stage for 5, 7, and 9 days. To analyze the drought effects on peanut, we conducted physiological and transcriptome analysis in leaves under well-watered (CK1, CK2, and CK3) and drought-stress conditions (T1, T2, and T3). By transcriptome analysis, 3,586, 6,730, and 8,054 differentially expressed genes (DEGs) were identified in "L422" at 5 days (CK1 vs T1), 7 days (CK2 vs T2), and 9 days (CK3 vs T3) of drought stress, respectively, and 2,846 genes were common DEGs among the three-time points. Furthermore, the result of weighted gene co-expression network analysis (WGCNA) revealed one significant module that was closely correlated between drought stress and physiological data. A total of 1,313 significantly up-/down-regulated genes, including 61 transcription factors, were identified in the module at three-time points throughout the drought stress stage. Additionally, six vital metabolic pathways, namely, "MAPK signaling pathway-plant," "flavonoid biosynthesis," "starch and sucrose metabolism," "phenylpropanoid biosynthesis," "glutathione metabolism," and "plant hormone signal transduction" were enriched in "L422" under severe drought stress. Nine genes responding to drought tolerance were selected for quantitative real-time PCR (qRT-PCR) verification and the results agreed with transcriptional profile data, which reveals the reliability and accuracy of transcriptome data. Taken together, these findings could lead to a better understanding of drought tolerance and facilitate the breeding of drought-resistant peanut cultivars.

Molecular cloning and expression characterization of flavonol synthase genes in peanut (Arachis hypogaea)

Flavonol is an important functional bioactive substance in peanut seeds, and plays important roles responding to abiotic stress. The flavonol content is closely related to the activity and regulation of gene expression patterns of flavonol synthase (FLS). In this study, eight FLS genes, AhFLSs were cloned and their expression characterization in different peanut organ and seedling under different abiotic stress were conducted. The results showed that the expressions levels of AhFLSs were differed in all assayed peanut organs and seedlings under abiotic stress treatments. Expression levels of AhFLS2, AhFLS3, AhFLS4, and AhFLS6 were higher than those of other AhFLSs. The flavonol contents of peanut organs and seedlings under different abiotic stress were also determined using high performance liquid chromatography (HPLC). Dried mature peanut seeds were the organ tissue with the highest flavonol content, and flavonol content increased with seed development. Under abiotic stress treatments, the types of flavonols induced differed among stress treatments. Correlation analysis results suggested that eight AhFLS genes may have different functions in peanut. Moreover, changes in the expression of the eight genes appear to has substrate preference. These results can lay the foundation for the study of improving nutritional value of peanut seed and resistance of peanut plant.

Identification and expression analysis of WRKY gene family under drought stress in peanut (Arachis hypogaea L.)

WRKY transcription factors play crucial roles in regulation mechanism leading to the adaption of plants to the complex environment. In this study, AhWRKY family was comprehensively analyzed using bioinformatic approaches in combination with transcriptome sequencing data of the drought-tolerant peanut variety ‘L422’. A total of 158 AhWRKY genes were identified and named according to their distribution on the chromosomes. Based on the structural features and phylogenetic analysis of AhWRKY proteins, the AhWRKY family members were classified into three (3) groups, of which group II included five (5) subgroups. Results of structure and conserved motifs analysis for the AhWRKY genes confirmed the accuracy of the clustering analysis. In addition, 12 tandem and 136 segmental duplication genes were identified. The results indicated that segmental duplication events were the main driving force in the evolution of AhWRKY family. Collinearity analysis found that 32 gene pairs existed between Arachis hypogaea and two diploid wild ancestors (Arachis duranensis and Arachis ipaensis), which provided valuable clues for phylogenetic characteristics of AhWRKY family. Furthermore, 19 stress-related cis-acting elements were found in the promoter regions. During the study of gene expression level of AhWRKY family members in response to drought stress, 73 differentially expressed AhWRKY genes were obtained to have been influenced by drought stress. These results provide fundamental insights for further study of WRKY genes in peanut drought resistance.

Pressure effects on iron-based superconductor CaFe0.88Co0.12AsF

Systematic measurements of electrical resistivity and Hall coefficient under high pressure were performed on CaFe_0.88Co_0.12AsF single crystal samples. The superconductivity is suppressed quickly by pressure and can not be detected down to 2 K at above 12.7 GPa, while the magnitude of the Hall coefficient [Formula: see text] shows a very weak pressure and temperature dependence. A comprehensive analysis considering the pressure dependence of [Formula: see text], [Formula: see text], residual resistivity ratio, and the Fermi-liquid term of the resistivity indicates that the electron correlation is an important factor in superconductivity of iron-based superconductors.

Pressure tuning of iron-based superconductor Ca10(Pt3As8) ((Fe0.95Pt0.05)2As2)5

Systematic high pressure transport measurements were performed on underdoped Ca₁₀(Pt₃As₈)((Fe_0.95Pt_0.05)₂As₂)₅ single crystal sample. At ambient pressure, the sample shows a metallic behavior at high temperatures and then increases with further decreasing temperature. The resistivity dip, which is associated with metal to semiconductor transition is monotonically suppressed by increasing pressure. In contrast, the superconducting transition temperature [Formula: see text] first increases with pressure and then decreases with further increasing pressure. Magnetization measurements, which gives the bulk [Formula: see text], show the same trend as the one obtained from resistivity measurements. An upward curvature is observed in the temperature dependence of the upper critical field [Formula: see text], which suggests the multiband nature of the superconductivity. The constructed temperature-pressure (T-P) phase diagram is very similar to the reported temperature-doping (T  -  x) phase diagram, suggesting the similar role played by pressure and chemical doping.

Construction of High-Density Genetic Map and Mapping Quantitative Trait Loci for Growth Habit-Related Traits of Peanut (Arachis hypogaea L.)

Plant growth habit is an important and complex agronomic trait and is associated with yield, disease resistance, and mechanized harvesting in peanuts. There are at least two distinct growth habits (erect and prostrate) and several intermediate forms existing in the peanut germplasm. A recombinant inbred line population containing 188 individuals was developed from a cross of "Jihua 5" and "M130" for genetically dissecting the architecture of the growth habit. A new high-density genetic linkage map was constructed by using specific locus amplified fragment sequencing technology. The map contains 2,808 single-nucleotide polymorphism markers distributed on 20 linkage groups with a total length of 1,308.20 cM and an average inter-marker distance of 0.47 cM. The quantitative trait locus (QTL) analysis of the growth habit-related traits was conducted based on phenotyping data from seven environments. A total of 39 QTLs for growth habit-related traits was detected on 10 chromosomes explaining 4.55-27.74% of the phenotypic variance, in which 6 QTLs were for lateral branch angle, 8 QTLs were for extent radius, 7 QTLs were for the index of plant type, 11 QTLs were for main stem height, and 7 QTLs were for lateral branch length. Among these QTLs, 12 were co-localized on chromosome B05 spanning an approximately 0.17 Mb physical interval in comparison with the allotetraploid reference genome of "Tifrunner." Analysis of the co-localized genome region has shown that the putative genes are involved in light and hormones and will facilitate peanut growth habit molecular breeding and study of peanut domestication.

[Impacts of airborne particulate matter and its components on respiratory system health]

Nowadays, particulate air pollution has been a global environmental problem. Numerous studies has shown that long-term exposure to high level of airborne particulate matter (PM) can damage human health. Respiratory system, as a direct portal to contact with particulate matter, can be more susceptible to airborne particulates. Summarizing latest five-year epidemiological research, the present review is focused on the effects of PM on respiratory system health in different age groups. In detail, we investigated the harmful effect of PM, or its components on three common respiratory diseases, including lung function decline, chronic obstructive pulmonary disease (COPD) and asthma. The result showed that, to a certain degree, PM could induce the decline of lung function, the development and the exacerbation of COPD and asthma by oxidative stress and inflammatory reaction. And it may prompt that exposure to PM can be an improtant risk factor for the respiratory system health.

Superconducting fluctuation effect in CaFe0.88Co0.12AsF

Out-of-plane angular dependent torque measurements were performed on CaFe0.88Co0.12AsF single crystals. Superconducting fluctuations, featured by magnetic field enhanced and exponential temperature dependent diamagnetism, are observed above the superconducting transition temperature T c, which is similar to that of cuprate superconductors, but less pronounced. In addition, the ratio of T c versus superfluid density follows well the Uemura line of high-T c cuprates, which suggests the exotic nature of the superconductivity in CaFe0.88Co0.12AsF.

Angular dependent torque measurements on CaFe0.88Co0.12AsF

Out-of-plane angular dependent torque measurements were performed on CaFe0.88Co0.12AsF (Ca1 1 1 1) single crystals. In the normal state, the torque data shows [Formula: see text] angular dependence and H (2) magnetic field dependence, as a result of paramagnetism. In the mixed state, the torque signal is a combination of the vortex torque and paramagnetic torque, and the former allows the determination of the anisotropy parameter γ. At T   =  11.5 K, γ (11.5 K ≃ 0.5 T c)  =  19.1, which is similar to the result of SmFeAsO0.8F0.2, [Formula: see text] at [Formula: see text]. So the 11 1 1 is more anisotropic compared to 11 and 122 families of iron-based superconductors. This may suggest that the electronic coupling between layers in 1 1 1 1 is less effective than in 11 and 122 families.

Anisotropic structure of the order parameter in FeSe(0.45)Te(0.55) revealed by angle-resolved specific heat

The central issues for understanding iron (Fe)-based superconductors are the symmetry and structure of the superconducting gap. So far the experimental data and theoretical models have been highly controversial. Some experiments favor two or more constant or nearly constant gaps, others indicate strong anisotropy and yet others suggest gap zeros ('nodes'). A unique method for addressing this issue, and one of very few methods that are bulk and angle resolved, is measuring the electronic-specific heat in a rotating magnetic field. In this study, we present the first such measurement for an Fe-based high-T(c) superconductor. We observed a fourfold oscillation of the specific heat as a function of the in-plane magnetic field direction. Our results are consistent with the expectations for an extended s-wave model, with a significant gap anisotropy on the electron pockets and the gap minima along the ΓM (Fe-Fe bond) direction.

Nonlinear imaging of embedded microstructures inside transparent materials with laser-induced ionization microscopy

We present a novel nonlinear imaging method that utilizes femtosecond laser-induced plasma emission to probe microscopic structures embedded inside transparent materials. This nonlinear diagnostic tool can resolve either elemental or structural variations of the sample of interest and provide significant improvements over the ordinary linear microscopes by having much higher contrast ratios for the observed areas of different refractive indices. Examples of using this technique to examine the microstructures fabricated by ultrashort laser pulses inside optical glass are presented.

Detection of human herpesvirus 8 DNA in acute leukemia patients

OBJECTIVE

To determine the prevalence of human herpesvirus 8 (HHV-8) DNA in acute leukemia (AL) patients.

METHODS

The presence of HHV-8 DNA sequences in peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) from 50 AL patients was examined using polymerase chain reaction (PCR). Nine human hematopoietic cell lines and PBMC from 30 normal donors were also included.

RESULTS

HHV-8 DNA sequences were detected in one case of acute myelogenous leukemia (AML). The specimens from the bone marrow aspirate, peripheral blood and serum of this patient were all positive. None of the normal donors and human hematopoietic cell lines showed evidence of HHV-8 DNA.

CONCLUSION

The results suggest that the prevalence of HHV-8 is low in AL in China.

Edge-enhanced correlation with four-wave mixing in bismuth silicon oxide crystal by use of moving gratings

The nonlinearity of phase-conjugate beam reflection with four-wave mixing in bismuth silicon oxide crystal by use of moving gratings at large fringe modulation formed by the incident-beam ratio is investigated. On the basis of this investigation, the edge enhancement of an object and the edge-enhanced optical correlation with improved discrimination capability are achieved by use of moving gratings at an appropriate fringe velocity. Experimental results are presented.

Four-wave mixing and edge-enhanced optical correlation in a Ce:KNSBN crystal

In the case of degenerate four-wave mixing in a cerium-doped potassium sodium strontium barium niobate (Ce:KNSBN) crystal, it is found that the transmission grating is dominant when the incident beams are extraordinarily polarized, the crystal response is more rapid, and the conjugate beam is more intense. Furthermore, the variation of the conjugate beam intensity forms a loop as the fringe modulation of the transmission grating varies. Based on this observation, we have implemented edge enhancement of an image and edge-enhanced optical correlation via four-wave mixing in a Ce:KNSBN crystal without the requirement of reversal of the signal-pump-beam intensity ratio.

Color-coded projection grating method for shape measurement with a single exposure

A fast and efficient technique for profilometric measurement with a color-coded grating is proposed. Eight colors are used to code the grating, and each color represents only one logical state. There are 64 stripes in one period of the color grating, which is large enough for normal measurement. Compared with the previous techniques, it has the advantages of simple hardware without moving mechanical parts, single exposure for obtaining three-dimensional information, little influence from noise and from nonlinearity of the CCD camera on the measurement accuracy, and higher anti-color-blurring capability. The suggested technique is suitable for on-line inspection and dynamic measurement of moving objects.

[Relationship between human herpesvirus 6 infection and idiopathic thrombocytopenic purpura]

OBJECTIVE

To investigate the pathogenic role of human herpesvirus 6 (HHV-6) in idiopathic thrombocytopenic purpura (ITP).

METHODS

HHV-6 DNA was examined by polymerase chain reaction (PCR) in bone marrow mononuclear cells (BMMNC) of 105 ITP patients. Human cytomegalovirus (HCMV) and parvovirus B(19) DNA were also examined in some cases. Platelet-associated antibodies (PAIg) were measured by competitive ELISA in 66 ITP patients. Serum IgG titer to HHV-6 was observed by indirect immunofluorescence assay in 19 ITP patients.

RESULTS

(1) HHV-6 DNA positivity was 41.0% for ITP patients, significantly higher than that for control group (P < 0.05). HHV-6 DNA positivity for adult ITP patients, especially adult chronic cases was significantly higher than that for childhood patients (P < 0.025). Positivities for parvovirus B(19) and HCMV DNA were 24.1% and 9.7%, respectively. (2) HHV-6 DNA positivity for patients with abnormal level of PAIgG was significantly higher than that for patients with normal level of PAIgG (P < 0.05). (3) Patients coinfected with HHV-6 and B(19) or HCMV had more severe symptoms or poorer prognosis.

CONCLUSION

HHV-6 infection might be associated with excessive PAIgG. Coinfection with HHV-6, B(19) or HCMV may cause more severe symptoms in ITP patients.

Color pattern recognition in white-light joint transform correlation

We first discuss the restriction on the incoherent source and the color filters in a joint transform correlation (JTC) system for white-light color pattern recognition and then report on a novel, to our knowledge, solution of channeling in a white-light JTC system, using a tricolor grating to encode the color patterns in real time. The theoretical analyses and the experimental results show not only that the restriction on the experimental condition is relieved but also that parallel channeling of the power spectra of the encoded pattern is easily performed. In addition, the zero-order power spectrum also forms a useful channel for the shape-only correlation.

Design of efficient lens ducts

Lens ducts have the potential to couple the output from a laser diode array efficiently into the gain medium of a solid-state laser in an end-pumped configuration. Using a ray-tracing method we investigate different design approaches of lens ducts and demonstrate the possibility to obtain an output beam with a symmetric profile that is insensitive to the small displacement from the output surface of a lens duct.

Seroprevalence of human herpesvirus-6 in healthy population in two provinces of north China

BACKGROUND

Human herpesvirus-6 (HHV-6) infection is ubiquitous in selected population with seroprevalence of 60-80%. Little is known for that in China, except few sporadic studies. To understand prevalence of HHV-6 antibody in Chinese population, this seroepidemiological study was conducted.

METHODS

Sera were collected from 430 healthy persons and donors living in North China, and tested for HHV-6 antibodies using IFA with HHV-6 GS strain passaged on HSB-2 cells as antigen, and titer equal or higher than 1:10 was regarded as seropositive.

RESULTS

Of the 430 serum samples tested, 297 (69.1%) were positive for HHV-6 IgG. Both seropositive rate and GMT in females were significantly higher than those in males, with X2 = 7.05, P < 0.01 and F = 7.23, P < 0.01, respectively. Statistically significant difference in prevalence of HHV-6 antibody among various age groups was observed in both sexes, with X2 = 20.08 and 20.28, P = 0.04, respectively, and young children had a higher titer than adults. But, no significant difference in prevalence was observed in blood donors between various age groups or both sexes.

CONCLUSIONS

This study suggests that HHV-6 infection with seropositive IgG is ubiquitous in North China, and its importance should be further studied.

Detection of human herpesvirus 6(HHV-6) DNA in salivary glands by the polymerase chain reaction

To assess the presence of HHV-6-Specific DNA in human salivary glands, eighteen specimens of salivary gland tissue were investigated using the polymerase chain reaction. Eight of nine parotid glands, five of seven submandibular glands and one of two sublingual glands were found to have amplification of the HHV-6-specific sequence. The findings suggest that salivary gland tissue is one of the potential sites for HHV-6 persistence following primary infection and that saliva is a vehicle for transmission of the virus.

[Interspecific protoplast fusion between Bacillus thuringensis Bt-3701 and Bacillus megaterium Bm-107]

The results of the interspecific protoplast fusion between B. thuringensis sub. kurstaki Bt-3701 which has pesticide ability, and B. megaterium var. phosphaticum Bm-107 which has decomposing phosphate activity, were reported. High frequency of protoplast formation and regeneration was obtained with 4h activated Bm-107 treated by 100 micrograms/ml lysozyme, and with 2h activated Bt-3701 treated by 3% glycin and mild temperature. Using 40% PEG and 5% nascent Ca2+ to treat the parential protoplast mixture for 3 min at 37 degrees C, 4 stable fusants were obtained. Biological tests show that they have both pesticide ability and decomposing phosphate activity, but which are weaker than that of parential strains.

Coaxial architecture of an optical neural network with a lenslet array

A theoretical limitation on the neuron numbers (N x N) of a spatial interconnection system based on a lenslet array is analyzed. To improve the limitation, we propose a submatrix coaxial interconnection architecture. Off-axial aberration is decreased, and high light efficiency is achieved. A detailed analysis is given.

Complementary-reference joint transform correlator

We present a new input configuration for the joint transform correlator called a complementary-reference joint transform correlator (CRJTC). The difference between the CRJTC and the existingjoint transform correlator is that the CRJTC has an additional complementary reference in the input plane. We use a criterion defined as the ratio of the cross correlation between the target and the reference to the cross correlation between the target and the complementary reference to perform recognition. This ratio can attain its maximum if and only if the reference and the target are matched and if it is stable to the light-source intensity fluctuations; therefore it is unnecessary to normalize the input images. The CRJTC is suitable for the recognition of a binary-amplitude image only. The experimental demonstration of a CRJTC is given.