Genetic variation of yellow pigment and its components in foxtail millet(Setaria italica(L.) P.Beauv.) from different eco-regions in China

Kernel color is an important trait for assessing the commercial and nutritional quality of foxtail millet. Yellow pigment content （YPC） and carotenoid components （lutein and zeaxanthin） of 270 foxtail millet accessions, including 50 landraces and 220 improved cultivars, from four different eco-regions in China were surveyed using spectrophotometry and high performance liquid chromatography methods. Results indicated that YPC had rich variance, ranging from 1.91 to 28.54 mg kg-1, with an average value of 17.80 mg kg-1. The average YPC of improved cultivars （18.31 mg kg-1） was significantly higher than that of landraces （15.51 mg kg-l）. The YPC in cultivars from the Loess Plateau spring sowing region （LPSSR） was the highest （20.59 mg kg-~）, followed by the North China summer sowing region （NCSSR, 18.25 mg kg-1）, the northeast spring sowing region （NSSR, 17.25 mg kg-1）, and the Inner Mongolia Plateau spring sowing region （IMPSSR, 13.92 mg kg-1）. The variation coefficients of YPC in cultivars from NSSR, LPSSR, and IMPSSR were higher than that from NCSSR. A similar carotenoid profile was also obtained for 270 foxtail millet cultivars. Lutein and zeaxanthin accounted for approximately 55-65% of YPC in accessions. The lutein content was higher than zeaxanthin content in all cultivars. The ratio of lutein to zeaxanthin ranged from 1.51 to 6.06 with an average of 3.34. YPC was positively correlated with lutein （r=0.935, P〈0.01）, zeaxanthin （r=0.808, P〈0.01 ）, and growth duration （t=0.488, P〈0.01 ）, whereas it was negatively correlated with grain protein （t=-0.332, P〈0.01） and 1 000-kernel weight （t=-0.153, P〈0.05）. Our study is useful for screening and selecting cultivars with high levels of yellow pigment and for enhancing phytochemical concentrations in breeding programs.

Accumulation of carotenoids and expression of carotenoid biosynthesis genes in fruit flesh during fruit development in two Cucurbita maxima inbred lines

Mesocarp color is an important agronomic trait of Cucurbita maxima and is determined mainly by the contents and compositions of the carotenoids.The two inbred lines with significant differences in fruit flesh color were used in the study,the orange’312-1’and white’98-2’.Changes in seven carotenoid contents and compositions in the flesh of fruit produced by inbred lines’312-1’and’98-2’were analyzed during fruit development.The expression of eight key carotenoid biosynthesis genes in the fruit flesh were investigated during five fruit development stage in two inbred lines.As the flesh color intensified,the orange flesh color of’312-1’was determined mainly by the increased contents of lutein,β-carotene and zeaxanthin and the lack of carotenoid accumulation led to the formation of white flesh in’98-2’fruit.The expression of the LCY-e and CHYb genes was significantly stronger in’312-1’than in’98-2’,and their expression was strongly correlated with lutein andβ-carotene contents during fruit development.This study provides a deep understanding of the molecular mechanism of carotenoid biosynthesis in fruit flesh and provides a basis for additional studies on the highly refined improvement of squash quality.

Application of Lutein and Zeaxanthin in nonproliferative diabetic retinopathy

AIM: To compare serum Lutein and Zeaxanthin (L/Z) concentrations between patients with nonproliferative diabetic retinopathy (NDR) and normal subjects,and to explore the effect of L/Z supplementation on serum L/Z level and visual function in NDR patients METHODS: Subjects were divided into three groups: 30 NDR patients supplied with Lutein 6mg/d and Zeaxanthin 0.5mg/d for three months (DR Group),30 NDR patients without L/Z supplementation (DR Control Group) and 30 normal subjects (Control Group).Serum L/Z concentrations were measured by liquid high-resolution chromatography (HPLC).Visual acuity was recorded at baseline,1 month,2 months and 3 months post initial supplementation.Serum L/Z concentration were measured at baseline,1 month and 2 months post initial supplementation.Contrast sensitivity (CS) and fovea thickness were recorded at baseline and 3 months post initial supplementation.RESULTS: Mean serum lutein concentrations in DR group were 0.0686±0.0296μg/mL and zeaxanthin concentration was 0.0137±0.0059μg/mL.The L/Z level of DR group was significantly lower compared to the control group( lutein: 0.2302±0.1308μg/mL,zeaxanthin: 0.0456±0.0266μg/m,P = 0.000).The concentration of lutein and zeaxanthin in the DR control group at base line was 0.0714±0.0357μg/mL and 0.0119±0.0072μg/mL,respectively.There was no significant change of L/Z concentration in the DR control group during the study.Serum L/Z concentrations of DR group increased significantly after supplementation(F=109.124,P=0.000;F=219.207,P=0.000).Visual acuity improved significantly after medication.Compared with pre-medication,the average CS values of 1.5cpd,3cpd and 6cpd after three months increased significantly (P =0.030,0.013,0.008) and the foveal thickness decreased.(P =0.05) CONCLUSION: Serum L/Z concentrations in DR patients are significantly lower than those in normal subjects,and L/Z intake can improve the visual acuity,CS and macular edema in DR patients,suggesting that L/Z supplementation might be targeted as potential potential therapeutic agents in treating NDR.

Involvement of serum retinoids and Leiden mutation in patients with esophageal, gastric, liver, pancreatic, and colorectal cancers in Hungary

AIM: To analyze the serum levels of retinoids and Leiden mutation in patients with esophageal, gastric, liver,pancreatic, and colorectal cancers.METHODS: The changes in serum levels of retinoids (vitamin A, α- and β-carotene, α- and β-cryptoxanthin,zeaxanthin, lutein) and Leiden mutation were measured by high liquid performance chromatography (HPLC)and polymerase chain reaction (PCR) in 107 patients (70 males/37 females) with esophageal (0/8), gastric (16/5), liver (8/7), pancreatic (6/4), and colorectal (30/21including 9 patients suffering from in situ colon cancer)cancer. Fifty-seven healthy subjects (in matched groups)for controls of serum retinoids and 600 healthy blood donors for Leiden mutation were used.RESULTS: The serum levels of vitamin A and zeaxanthin were decreased significantly in all groups of patients with gastrointestinal (GI) tumors except for vitamin A in patients with pancreatic cancer. No changes were obtained in the serum levels of α- and β-carotene,α- and β-cryptoxanthin, zeaxanthin, lutein in patients with GI cancer. The prevalence of Leiden mutation significantly increased in all groups of patients with GI cancer.CONCLUSION: Retinoids (as environmental factors)are decreased significantly with increased prevalence of Leiden mutation (as a genetic factor) in patients before the clinical manifestation of histologically different (planocellular and hepatocellular carcinoma, and adenocarcinoma) GI cancer.

Analysis of Major Carotenoid Composition and Its Content of Citrus Fruit

α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein, zeaxanthin and β-cryptoxanthin. β-carotene content was relatively low and extremely low was the amount of α-carotene. Among the 53 cultivars tested, lycopene was detected only in pulp of Cara Cara navel orange. Carotenoid content in both peel and pulp of citrus fruit was the highest in Citrus reticulata Blanco and lowest in Citrus grandis Osbeck. Consequently, as far as the health protection value is considered, fruit of Citrus reticulata Blanco ranks probably higher than other citrus fruits. In fruit of most Citrus reticulata varities, β-cryptoxanthin was the main carotenoid component in pulp and its amount approximated that of lutein in peel. Content of lutein, zeaxanthin and β-cryptoxanthin in peel was about 2.515 times that in pulp on the basis of fresh weight. Thus peel was inferred to be the principal location for the carotenoid stock in citrus fruit.

Effect of zeaxanthin on porcine embryonic development during in vitro maturation

Zeaxanthin is a common carotenoid, which is a powerful antioxidant that protects against damage caused by reactive oxygen species. The aim of the present study was to investigate the effects of zeaxanthin supplementation on in vitro maturation of porcine embryo development. We investigated nuclear maturation, intracellular glutathione （GSH）, and reactive oxygen species （ROS） levels during in vitro maturation, and subsequent embryonic development following parthenogenetic activation and in vitro fertilization OVF）. The oocytes were maturated and used at the metaphase II stage. After 42 hours of in vitro maturation, the zeaxanthin-treated group （0.5 μmol/L） showed significant increases in nuclear maturation （89.6%） than the control group （83.4%） （P 〈 0.05）. The intracellular GSH levels increased significantly （P 〈 0.05） as zeaxanthin concentrations increased; ROS generation levels decreased with increased zeaxanthin concentrations, but there were no significant differences. There were no significant differences in subsequent embryonic development, cleavage rate, blastocyst stage rate, and total blastocyst cell numbers following parthenogenetic activation and IVF when in vitro maturation media was supplemented with zeaxanthin. These results suggest that treatment with zeaxanthin during in vitro maturation improved the nuclear maturation of porcine oocytes by increasing the intracellular GSH level, thereby slightly decreasing the intracellular ROS level.

Haplotype variation and KASP markers for SiPSY1-A key gene controlling yellow kernel pigmentation in foxtail millet

Carotenoid biosynthesis and accumulation are important in determining nutritional and commercial value of crop products.Yellow pigmentation of mature kernels caused by carotenoids is considered a vital quality trait in foxtail millet,an ancient and widely cultivated cereal crop across the world.Genomic regions associated with yellow pigment content(YPC),lutein and zeaxanthin in foxtail millet grains were identified by genome-wide association analysis(GWAS),and SiPSY1(Phytoene synthase 1 which regulates formation of the 40-carbon backbone of carotenoids)was confirmed as the main contributor to all three components by knockout and overexpression analysis.SiPSY1 was expressed in seedlings,leaves,panicles,and mature seeds,and was subcellularly localized to chloroplasts.Transcription of SiPSY1 in 15 DAP immature grains was responsible for YPC in mature seeds.Selection of SiPSY1 combined with increased YPC in mature grains during domestication of foxtail millet was confirmed.Haplotype analysis suggested that expression level of SiPSY1 could be a selection target for future breeding programs,and a KASP marker was developed for selection of favorable SiPSY1 alleles in breeding.The results of this work will benefit nutritional and commercial improvement of foxtail millet varieties,as well as other cereal crops.

The protective effect of zeaxanthin on human limbal and conjunctival epithelial cells against UV-induced cell death and oxidative stress

AIM: To explore the protective effect of zeaxanthin on human limbal and conjunctival epithelial cells against UVradiation and excessive oxidative stress.METHODS: Human limbal and conjunctival epithelial cells were isolated from cadaver and cultured in vitro. They were challenged with UVB radiation and H2 O2 with and without zeaxanthin pretreatment. Cell viability, p38 and c-JUN NH(2)-terminal kinase(JNK) phosphorylation, IL-6, IL-8 and MCP-1 secretion and malondialdehyde(MDA) content were measured.RESULTS: Zeaxanthin had no measurable cytotoxicity on limbal or conjunctival epithelial cells when used at concentrations of 5 μg/mL and below. At 30 mJ/cm2 UVB, the pretreatment of zeaxanthin increased the percentage of live cells from 50% to 69%(P=0.01) and from 66% to 75%(P=0.05) for limbal and conjunctival epithelial cells, respectively. The concentrations of IL-6, IL-8 and MCP-1 in the culture medium reduced to 66%(for IL-6 and MCP-1)and 56%(for IL-8) of the levels without zeaxanthin. This was accompanied by reduced p38 and JNK protein phosphorylation. Pretreatment of zeaxanthin also reduced intracellular MDA content caused by H2 O2 stimulation from 0.86 μmol/L to 0.52 μmol/L(P=0.02) in limbal epithelial cells and from 0.96 μmol/L to 0.56 μmol/L in conjunctival epithelial cells(P=0.03). However, zeaxanthin did nothave significant effect on H2 O2-induced cell death in limbal or conjunctival epithelial cells.CONCLUSION: Zeaxanthin is an effective reagent in reducing the detrimental effect of UV-radiation and oxidative stress on ocular surface epithelial cells.

Disruption of LEAF LESION MIMIC 4 affects ABA synthesis and ROS accumulation in rice

Lesion mimic mutants(LMMs) are advantageous materials for studying programmed cell death(PCD).Although some rice LMM genes have been cloned, the diversity of functions of these genes indicates that the mechanism of cell death regulation in LMMs needs further study. In this study, we identified a rice light-dependent leaf lesion mimic mutant 4(llm4) that showed abnormal chloroplast structure, photoinhibition, reduced photosynthetic protein levels, massive accumulation of reactive oxygen species(ROS), and PCD. Map-based cloning and complementation testing revealed that LLM4 encodes zeaxanthin epoxidase(ZEP), an enzyme involved in the xanthophyll cycle, which functions in plant photoprotection,ROS scavenging, and carotenoid and abscisic acid(ABA) biosynthesis. The ABA content was decreased,and the contents of 24 carotenoids differed between the llm4 mutant and the wild type(WT). The llm4mutant showed reduced dormancy and greater sensitive to ABA than the WT. We concluded that the mutation of LLM4 resulted in the failure of xanthophyll cycle, in turn causing ROS accumulation. The excessive ROS accumulation damaged chloroplast structure and induced PCD, leading eventually to the formation of lesion mimics.

Comparison of vegetable oils on the uptake of lutein and zeaxanthin by ARPE-19 cells

AIM:To compare the effect of vegetable oils on the uptake of lutein and zeaxanthin by adult retinal pigment epithelial(ARPE)-19 cells in vitro.METHODS:ARPE-19 cells were cultured in Dulbecco’s Modified Eagle Medium-F-12 supplemented with 10%foetal bovine serum and 1%penicillin–streptomycin in a humidified 5%CO_(2) incubator maintained at 37℃.Cells were treated with 247μmol/L lutein,49μmol/L zeaxanthin and 1%(v/v)of either coconut oil,corn oil,peanut oil,olive oil,sunflower oil,soybean oil,castor oil,or linseed oil for 48h.Lutein and zeaxanthin concentration in the cells were quantified by high performance liquid chromatography.RESULTS:Among the oils tested,the highest lutein and zeaxanthin uptake was observed with coconut oil while the lowest was observed with linseed oil.CONCLUSION:ARPE-19 uptake of lutein and zeaxanthin are found to be dependent on the type of oils.

Macular pigment and serum zeaxanthin levels with Goji berry supplement in early age-related macular degeneration

AIM： To evaluate the efficacy of Goji berry supplementation on improving macular pigment, serum zeaxanthin levels and visual acuity in patients with early age-related macular degeneration （AMD）. METHODS： A total of 114 patients （aged from 51 to 92y, mean age 69.53±8.41y） with early AMD were enrolled in our prospective, randomized controlled study. The included patients were assigned randomly to the Goji group （n=57） with 25 g of Goji berries supplementation per day for 90d and the control group （n=57） with their normal diet for 90d. Macular pigment optical density （MPOD） was measured using heterochromatic flicker photometry （HFP）. The levels of serum lutein （L）/zeaxanthin （Z） were analyzed using high-performance liquid chromatography （HPLC）. MPOD, serum L/Z levels and best corrected visual acuity （BCVA） were recorded at baseline and 90d. RESULTS： In the Goji group, there were no statistically significant differences in the serum L levels between the baseline （0.199±0.149 μmol/mL） and 90d （0.203±0.181 μmol/mL） （t=-0.186, P=0.850）; however the serum Z levels were increased at 90d （0.101±0.087 μmol/mL） compared with those at the baseline （0.029±0.032 μmol/mL） （t=6.412, P〈0.001）. Patients treated with Goji berry for 90d showed an elevated MPOD （0.877±0.202 DU） from the baseline （0.731±0.205 DU） （t=-4.741, P=0.000）. In contrast to the control group, the serum Z levels and MPOD were higher in the Goji group at 90d （both P〈0.05）. At 90d, patients with Goji berry supplementation had a relative decrease in BCVA （0.21±0.18 logMAR） compared with the baseline （0.27±0.20） （t=2.397, P=0.020）. CONCLUSION： Overall, daily supplementation with Goji berry for 90d improves MPOD by increasing serum Z levels rather than serum L levels in early AMD patients. Goji berry may be an effective therapeutic intervention for preventing the progression of early AMD.

Optimization of Zeaxanthin Production by Immobilized <i>Flavobacterium</i>sp. Cells in Fluidized Bed Bioreactor

From time immemorial, human beings have used pigments made from vegetables, fruits, superior plants, animal tissues and cereals. One of the greatest sources of pigments is the bacterium that, with the use of the modern technology, has increased the production of metabolites of interest. The microbiological production of carotenoids has not been optimized to obtain pigment production quantities of pigments and carotenoids recovery that lower production costs. The aim of this work was to design a Zeaxanthin production process with Flavobacterium sp. immobilized cells in a fluidized bed bioreactor. An optimum culture medium for Zeaxanthin production in stirred flasks (2.46 g·L–1) was obtained. Furthermore, optimum process conditions for a maximum yield of Zeaxanthin production, by fluidized bed bioreactor, were established. A statistical analysis showed that the most significant factors were air flow, pH and NaCl concentration (4.5 g·L–1). In this study a maximum Zeaxanthin production of 3.8 g·L–1 was reached. The highest reported yield to date was 0.329 g·L–1.

Research Progress on Purification Process Optimization and Content Determination of Zeaxanthin

At present,the purification process of zeaxanthin mainly includes organic solvent extraction,ultrasonic-assisted extraction and enzyme extraction,and the content determination technology mainly includes ultraviolet-spectrophotometry and high performance liquid chromatography.In this paper,the purification process and content determination technology of zeaxanthin in recent years are reviewed in order to provide ideas and theoretical basis for further research and application of zeaxanthin.

Impact of Lutein-Based Food Supplement on Macular Pigment, Glare and Contrast Vision

Purpose: To evaluate the impact of a specially formulated food supplement containing 20 mg free lutein and 2.8 mg zeaxanthin on macular pigment volume (MPV) and visual function. Methods: In this prospective non-comparative study healthy subjects were instructed to take one capsule of Eagle Eye Lutein 20 Vision Caps (Innomedis AG) per day with a meal for 6 months. MPV was measured with the MP-Eye system (AzulOptics) after 3 and 6 months of treatment. Mesopic vision (MV), glare sensitivity (GS) and contrast vision threshold (CVT) were measured with the Binoptometer 4P system (OCULUS Optikgeräte). Results: Twenty-three healthy subjects between 19 and 56 years were enrolled. A significant increase was observed in MPV (p Conclusions: The specially formulated food supplement containing lutein and zeaxanthin induced a significant increase in MPV, and consequently an improvement in the visual function after 3 and 6 months in healthy subjects.

Impact of Lutein-Based Food Supplement on Macular Pigment, Glare and Contrast Vision

Purpose: To evaluate the impact of a specially formulated food supplement containing 20 mg free lutein and 2.8 mg zeaxanthin on macular pigment volume (MPV) and visual function. Methods: In this prospective non-comparative study healthy subjects were instructed to take one capsule of Eagle Eye Lutein 20 Vision Caps (Innomedis AG) per day with a meal for 6 months. MPV was measured with the MP-Eye system (AzulOptics) after 3 and 6 months of treatment. Mesopic vision (MV), glare sensitivity (GS) and contrast vision threshold (CVT) were measured with the Binoptometer 4P system (OCULUS Optikgeräte). Results: Twenty-three healthy subjects between 19 and 56 years were enrolled. A significant increase was observed in MPV (p Conclusions: The specially formulated food supplement containing lutein and zeaxanthin induced a significant increase in MPV, and consequently an improvement in the visual function after 3 and 6 months in healthy subjects.

Enhanced Photoprotection by Protein-Bound vs Free Xanthophyll Pools： A Comparative Analysis of Chlorophyll b and Xanthophyll Biosynthesis Mutants

When light absorbed by plants exceeds the capacity of photosynthesis, the xanthophyll violaxanthin is reversibly de-epoxidized to zeaxanthin in the so-called xanthophyll cycle. Zeaxanthin plays a key role in the protection of photosynthetic organisms against excess light, by promoting rapidly reversible （qE） and long-term （ql） quenching of excited chlorophylls, and preventing lipid oxidation. The photoprotective role of zeaxanthin, either free or bound to light-harvesting complexes （Lhcs）, has been investigated by using mutants lacking Chl b （chl） and/or specific xanthophyll species （npq, lut2）. The chl mutation causes （1） the absence of Lhcb proteins; （2） strong reduction of the feedback deexcitation （qE）; and （3） accumulation of xanthophylls as free pigments into thylakoids. Chl mutants showed extreme sensitivity to photo-oxidative stress in high light, due to higher singlet oxygen （102） release. The double mutant chlnpql was more sensitive to photo-oxidation than chl, showing that zeaxanthin does protect lipids even when free in the membrane. Nevertheless, lack of zeaxanthin had a much stronger impact on the level of lipid peroxidation in Lhcs-containing plants （WTvs npql） with respect to Lhc-less plants （chl vs chlnpql）, implying that its protective effect is enhanced by interaction with antenna proteins. It is proposed that the antioxidant capacity of zeaxanthin is empowered in the presence of PSII- LHCs-Zea complexes, while its effect on enhancement of qE only provides a minor contribution. Comparison of the sensitivity of WT vs npql plants to exogenous 102 suggests that besides the scavenging of 102, at least one additional mechanism is involved in chloroplast photoprotection.

Macular carotenoid supplementation improves disability glare performance and dynamics of photostress recovery

Background:The so-called macular carotenoids(MC)lutein(L),zeaxanthin(Z),and meso-zeaxanthin(MZ)comprise the diet-derived macular pigment(MP).The purpose of this study was to determine effects of MC supplementation on the optical density of MP(MPOD),repeated-exposure photostress recovery(PSR),and disability glare(DG)thresholds.Methods:This was a double-blind,placebo-controlled trial.Fifty-nine young(mean age=21.7),healthy volunteers participated in this study.Subjects supplemented their daily diet with either 10 mg L+2 mg total Z(1 mg Z+1 mg MZ;n=24),20 mg L+4 mg total Z(2 mg Z+2 mg MZ;n=25),or placebo(n=10)for 12 months.The primary outcome was a composite measure of visual performance in glare,defined by change in DG and PSR.Secondary outcomes included MPOD and visual fatigue.The primary endpoint for outcomes was 12 months.MPOD was assessed with customized heterochromatic flicker photometry.PSR times for an 8 cycle/degree,15%contrast Gabor patch target were determined after each of five successive exposures to intense LED lights.DG threshold was defined as the intensity of a ring of lights through which subjects were able to maintain visibility of the aforementioned target.Measures of all parameters were conducted at baseline,6 months,and 12 months.Repeated-measures ANOVA,and Pearson product-moment correlations were used to determine statistically significant correlations,and changes within and between groups.Results:MPOD for subjects in both supplementation groups increased significantly versus placebo at both 6-and 12-month visits(p<0.001 for all).Additionally,PSR times and DG thresholds improved significantly from baseline compared to placebo at 6-and 12-month visits(p<0.001 for all).At baseline,MPOD was significantly related to both DG thresholds(r=0.444;p=0.0021)and PSR times(r=-0.56;p<0.001).As a function of MPOD,the repeated-exposure PSR curves became more asymptotic,as opposed to linear.The change in subjects’DG thresholds were significantly related to changes in PSR times across the study period(r=-0.534;p<0.001).Conclusions:Increases in MPOD lead to significant improvements in PSR times and DG thresholds.The asymptotic shape of the repeated-exposure PSR curves suggests that increases in MPOD produce more consistent steady-state visual performance in bright light conditions.The mechanism for this effect may involve both the optical filtering and biochemical(antioxidant)properties of MP.Trial registration:ISRCTN trial registration number:ISRCTN54990825.Data reported in this manuscript represent secondary outcome measures from the registered trial.

Enrichment of health-promoting lutein and zeaxanthin in tomato fruit through metabolic engineering

Carotenoids constitute a large group of natural pigments widely distributed in nature.These compounds not only provide fruits and flowers with distinctive colors,but also have significant health benefits for humans.Lutein and zeaxanthin,both oxygen-containing carotenoids,are considered to play vital roles in promoting ocular development and maintaining eye health.However,humans and mammals cannot synthesize these carotenoid derivatives,which can only be taken from certain fruits or vegetables.Here,by introducing four endogenous synthetic genes,SlLCYE,SlLCYB,SlHYDB,and SlHYDE under fruit-specific promoters,we report the metabolic engineering of lutein/zeaxanthin biosynthesis in tomato fruit.Transgenic lines overexpression of one(SlLCYE),two(SlLCYE and SlLCYB;SlLCYB and SlHYDB),and all these four synthetic genes re-established the lutein/zeaxanthin biosynthetic pathways in the ripe tomato fruit and thus resulted in various types of carotenoid riched lines.Metabolic analyses of these engineered tomato fruits showed the strategy involved expression of SlLCYE tends to produceα-carotene and lutein,as well as a higher content of β-carotene and zeaxanthin was detected in lines overexpressing SlLCYB.In addition,the different combinations of engineered tomatoes with riched carotenoids showed higher antioxidant capacity and were associated with a significantly extended shelf life during postharvest storage.This work provides a successful example of accurate metabolic engineering in tomato fruit,suggesting the potential utility for synthetic biology to improve agronomic traits in crops.These biofortified tomato fruits could be also exploited as new research subjects for studying the health benefits of carotenoid derivatives.

Suppression of ZEAXANTHIN EPOXIDASE 1 restricts stripe rust growth in wheat

Reducing losses caused by pathogens is an effective strategy for stabilizing crop yields.Daunting challenges remain in cloning and characterizing genes that inhibit stripe rust,a devastating disease of wheat(Triticum aestivum)caused by Puccinia striiformis f.sp.tritici(Pst).We found that suppression of wheat zeaxanthin epoxidase 1(ZEP1)increased wheat defense against Pst.We isolated the yellow rust slower 1(yrs1)mutant of tetraploid wheat in which a premature stop mutation in ZEP1-B underpins the phenotype.Genetic analyses revealed increased H_(2)O_(2) accumulation in zep1 mutants and demonstrated a correlation between ZEP1 dysfunction and slower Pst growth in wheat.Moreover,wheat kinase START 1.1(WKS1.1,Yr36)bound,phosphorylated,and suppressed the biochemical activity of ZEP1.A rare natural allele in the hexaploid wheat ZEP1-B promoter reduced its transcription and Pst growth.Our study thus identified a novel suppressor of Pst,characterized its mechanism of action,and revealed beneficial variants for wheat disease control.This work opens the door to stacking wheat ZEP1 variants with other known Pst resistance genes in future breeding programs to enhance wheat tolerance to pathogens.