Dirigent gene editing of gossypol enantiomers for toxicity-depleted cotton seeds.

Axial chirality of biaryls can generate varied bioactivities. Gossypol is a binaphthyl compound made by cotton plants. Of its two axially chiral isomers, (-)-gossypol is the bioactive form in mammals and has antispermatogenic activity, and its accumulation in cotton seeds poses health concerns. Here we identified two extracellular dirigent proteins (DIRs) from Gossypium hirsutum, GhDIR5 and GhDIR6, which impart the hemigossypol oxidative coupling into (-)- and (+)-gossypol, respectively. To reduce cotton seed toxicity, we disrupted GhDIR5 by genome editing, which eliminated (-)-gossypol but had no effects on other phytoalexins, including (+)-gossypol, that provide pest resistance. Reciprocal mutagenesis identified three residues responsible for enantioselectivity. The (-)-gossypol-forming DIRs emerged later than their enantiocomplementary counterparts, from tandem gene duplications that occurred shortly after the cotton genus diverged. Our study offers insight into how plants control enantiomeric ratios and how to selectively modify the chemical spectra of cotton plants and thereby improve crop quality.

Gossypol and related compounds are produced and accumulate in the aboveground parts of the cotton plant, independent of roots as the source.

MAIN CONCLUSION: Use of Ultra-low gossypol cottonseed event as a scion in a graft combination confirmed that roots are not a source of terpenoids in the aboveground parts of a cotton plant. Gossypol and related terpenoids, derived from the same basic biosynthetic pathway, are present in the numerous lysigenous glands in the aboveground parts of a cotton plant. Roots, with sparse presence of such glands, do produce significant amount of gossypol and a different set of terpenoids. These compounds serve a defensive function against various pests and pathogens. This investigation was undertaken to examine whether gossypol produced in the roots can replenish the gossypol content of the cottonseed-glands that are largely devoid of this terpenoid in a genetically engineered event. Graft unions between a scion derived from the RNAi-based, Ultra-low gossypol cottonseed (ULGCS) event, TAM66274, and a rootstock derived from wild-type parental genotype, Coker 312 (Coker), were compared with various other grafts that served as controls. The results showed that the seeds developing within the scion of test grafts (ULGCS/Coker) continued to maintain the ultra-low gossypol levels found in the TAM66274 seeds. Molecular analyses confirmed that while the key gene involved in gland development showed normal activity in the developing embryos in the scion, two genes encoding the enzymes involved in gossypol biosynthesis were suppressed. Thus, the gene expression data confirmed the results obtained from biochemical measurements and collectively demonstrated that roots are not a source of gossypol for the aboveground parts of the cotton plant. These findings, combined with the results from previous investigations, support the assertion that gossypol and related terpenoids are produced in a highly localized manner in various organs of the cotton plant and are retained therein.

Identification of Bcl2 as a Stably Expressed qPCR Reference Gene for Human Colon Cancer Cells Treated with Cottonseed-Derived Gossypol and Bioactive Extracts and Bacteria-Derived Lipopolysaccharides.

Cottonseed contains many bioactive molecules including plant polyphenols. Cottonseed value might be increased by providing high-value bioactive polyphenols for improving nutrition and health. However, there was a lack of molecular evidence for cottonseed bioactivity in mammalian cells. One widely used method for evaluating the bioactivity of natural products is quantitative real-time-PCR (qPCR). The selection of stably expressed internal reference genes is a crucial task of qPCR assay for data analysis. The rationale for reference gene selection is that a lower standard deviation of the cycle of threshold (Cq) among the treatments indicates a more stable expression of the gene. The objective of this study was to select reference genes in human colon cancer cells (COLO 205) treated with cottonseed-derived gossypol and bioactive extracts along with bacterial endotoxin lipopolysaccharides (LPS). SYBR Green qPCR was used to analyze the mRNA levels of a wide range of biomarkers involved in glucose transport, lipid biosynthesis, inflammatory response, and cancer development. qPCR data (10,560 Cq values) were generated from 55 genes analyzed from 64 treatments with triplicate per treatment for each gene. The data showed that B-cell lymphoma 2 (Bcl2) mRNA was the most stable among the 55 mRNAs analyzed in the human colon cancer cells. Glyceraldehyde 3 phosphate dehydrogenase (Gapdh) and ribosome protein L32 (Rpl32) mRNAs were not good qPCR references for the colon cancer cells. These observations were consistent regardless of the treatment comparison between gossypol and LPS, glanded and glandless seed extracts, seed coat and kernel extracts, or treatment for 8 and 24 h. These results suggest that Bcl2 is a preferable reference gene for qPCR assays in human colon cancer cells treated with cottonseed-derived gossypol and bioactive extracts as well as LPS. The extensive qPCR results firmly support the conclusion that the Bcl2 gene is stably expressed at the mRNA level in the human colon cancer cells regardless of the treatment, suggesting that Bcl2 gene expression is not regulated at the mRNA level but at the post-transcriptional level. These results should facilitate studies designated to evaluate bioactivity on gene expression regulation by cottonseed molecules and other natural and synthetic molecules for nutrition and health uses.

Effects of cottonseed meal on growth performance, liver redox status, and serum biochemical parameters in goslings at 1 to 28 days of age.

BACKGROUND: Cottonseed meal (CSM), a relatively rich source of protein and amino acids, is used as an inexpensive alternative to soybean meal (SBM) in poultry diets. However, the toxicity of free gossypol in CSM has been a primary concern. The present study was conducted to investigate the effects of CSM on growth performance, serum biochemical parameters, and liver redox status in goslings at 1 to 28 days of age. Three hundred 1-day-old male goslings were randomly divided into 5 groups (10 goslings/pen, 6 replicate pens/group) and subjected to a 28-day experiment. Five isonitrogenous and isoenergetic diets were formulated such that 0% (control), 25% (CSM25), 50% (CSM50), 75% (CSM75), and 100% (CSM100) of protein from SBM was replaced by protein from CSM. The free gossypol contents in the five diets were 0, 56, 109, 166, and 222 mg/kg, respectively. RESULTS: The results showed that dietary CSM was associated with linear decreases in body weight, average daily feed intake and average daily gain and linear increases in the feed-to-gain ratio from 1 to 28 days of age (P < 0.001). As the dietary CSM concentration increased, a numerical increase was found in the mortality of goslings. According to a single-slope broken-line model, the breakpoints for the average daily gain of dietary free gossypol concentration on days 1 to 14, 15 to 28, and 1 to 28 occurred at 23.63, 14.78, and 18.53 mg/kg, respectively. As the dietary CSM concentration increased, serum albumin (P < 0.001) concentrations decreased linearly and serum uric acid (P = 0.011) increased linearly. The hydroxyl radical scavenging ability (P = 0.002) and catalase (P < 0.001) and glutathione peroxidase (P = 0.001) activities of the liver decreased linearly with increasing dietary CSM. However, dietary CSM did not affect the concentrations of reactive oxygen metabolites, malondialdehyde, or protein carbonyl in the liver. CONCLUSIONS: The increasing dietary CSM increased the concentration of free gossypol and altered the composition of some amino acids in the diet. A high concentration of CSM reduced the growth performance of goslings aged 1 to 28 days by decreasing feed intake, liver metabolism, and antioxidant capacity. From the primary concern of free gossypol in CSM, the tolerance of goslings to free gossypol from CSM is low, and the toxicity of free gossypol has a cumulative effect over time.

NMR-based metabolomics reveals tissue metabolic responses to tetramethoxy gossypol in cottonseed oil.

BACKGROUND: Cottonseed oil is one of the most widely consumed cooking oils because of its high nutritional benefits and relatively low price. The present study evaluated the effects of tetramethoxy gossypol (TMG), a rarely reported degradation product of free gossypol produced in crudely extracted cottonseed oil, on the metabolic responses of liver, heart, spleen, kidney and lung tissues in rats using proton nuclear magnetic resonance (1 H NMR) spectroscopy combined with chemometric and bioinformatics techniques. RESULTS: Endogenous low-molecular-weight metabolites in rat liver, heart, spleen, kidney and lung tissues were profiled by 1 H NMR spectroscopy. The unsupervised principal components analysis and the supervised orthogonal partial least squares discriminant analysis revealed that the metabolic profiles in liver samples were greatly changed after TMG administration. Twenty significantly changed liver metabolites were screened out and further evaluated by receiver operating characteristic curve analysis, which were closely related to amino acid, glutathione, energy and lipid metabolism. CONCLUSION: Concerning the potential chronic exposure to TMG in cottonseed oil and other cottonseed products, the cumulative effects of dietary TMG on tissues, especially the liver, should be noted when improving the quality control standard of cottonseed oil. © 2022 Society of Chemical Industry.

Differential expression profiling of Oxycarenus laetus Kirby (Hemiptera: Lygaeidae) upon exposure to gossypol.

BACKGROUND: Gossypium hirsutum seeds are rich in gossypol. In addition to its diverse beneficial properties, it is a known anti-fertility inducing agent in humans. Oxycarenus laetus feeds on the cottonseeds and yet its courtship, mating and reproduction is unaffected. METHODS AND RESULTS: In this study, we performed a transcriptome profiling of O. laetus fed on Abutilon indicum (AB-no gossypol), G. hirsutum (GH-natural gossypol) and 1400 ppm commercial gossypol-soaked GH seeds (GHGO). Illumina NextSeq-500 paired-end 75 bp reads were generated and de novo assembled (48,214 genes) to identify the differentially expressed transcripts (DET) between the samples. Gene enrichment, KEGG pathway and cluster profiling of the DETs resulted in the identification of vital genes involved in the detoxification, pheromone biosynthesis, cuticle protein in the GHGO sample. Cyp4C1, Cyp6a13, Cyp6a14, Cyp4g15, Cyp4em8, Cyp303a1 were the detoxification related genes identified. Similarly, SDR dehydrogenase family 11 and fatty acid synthase in pheromone biosynthesis and cuticle proteins (RR1 and RR2) coding transcripts were found to be differentially expressed. CONCLUSION: This is the first study to report the expression of genes induced by gossypol in O. laetus. Based on the findings from the DET analysis, we conclude that the detoxification related genes of gossypol treated samples were affected.

Chemical Composition and Thermogravimetric Behaviors of Glanded and Glandless Cottonseed Kernels.

Common "glanded" (Gd) cottonseeds contain the toxic compound gossypol that restricts human consumption of the derived products. The "glandless" (Gl) cottonseeds of a new cotton variety, in contrast, show a trace gossypol content, indicating the great potential of cottonseed for agro-food applications. This work comparatively evaluated the chemical composition and thermogravimetric behaviors of the two types of cottonseed kernels. In contrast to the high gossypol content (3.75 g kg-1) observed in Gd kernels, the gossypol level detected in Gl kernels was only 0.06 g kg-1, meeting the FDA's criteria as human food. While the gossypol gland dots in Gd kernels were visually observed, scanning electron microcopy was not able to distinguish the microstructural difference between ground Gd and Gl samples. Chemical analysis and Fourier transform infrared (FTIR) spectroscopy showed that Gl kernels and Gd kernels had similar chemical components and mineral contents, but the former was slightly higher in protein, starch, and phosphorus contents. Thermogravimetric (TG) processes of both kernels and their residues after hexane and ethanol extraction were based on three stages of drying, de-volatilization, and char formation. TG-FTIR analysis revealed apparent spectral differences between Gd and Gl samples, as well as between raw and extracted cottonseed kernel samples, indicating that some components in Gd kernels were more susceptible to thermal decomposition than Gl kernels. The TG and TG-FTIR observations suggested that the Gl kernels could be heat treated (e.g., frying and roasting) at an optimal temperature of 140-150 °C for food applications. On the other hand, optimal pyrolysis temperatures would be much higher (350-500 °C) for Gd cottonseed and its defatted residues for non-food bio-oil and biochar production. The findings from this research enhance the potential utilization of Gd and Gl cottonseed kernels for food applications.

Evaluation of ozone technology as an alternative for degradation of free gossypol in cottonseed meal: a prospective study.

Free gossypol is a toxic compound which naturally occurs in cottonseed and its derivates, affecting animal and possibly human health. Consequently, alternatives for gossypol destruction must be evaluated. This work evaluated the emerging technology of ozone processing for free gossypol destruction in cottonseed meal. Ozonation was carried out in the actual cottonseed meal and also a model system, designed to describe the involved mode of action. The model system consisted of glass pearls beads covered with free gossypol. Ozonation was performed in two ways: as a static process, i.e., without homogenising the sample after placing them in the reactor, and also homogenising it. Ozone degraded free gossypol in all the systems, but reaching different levels. Free gossypol reduction was higher in the model system than the cottonseed meal, and higher in the homogenised processing than the static one: cottonseed meal in homogenised (56%) and static (25%); model system homogenised (98%) and static (80%). The obtained differences suggest a problem of gas penetration in the solid particles, the effect of unexposed surfaces due to contact areas, and the reaction with other organic molecules further than the target. Ozonation is a promising technique for gossypol degradation in cottonseed meal, but additional strategies are needed to optimise the ozonation process and evaluate toxicological aspects.

Molecular cloning and characterization of GhERF105, a gene contributing to the regulation of gland formation in upland cotton (Gossypium hirsutum L.).

BACKGROUND: Gossypium hirsutum L. (cotton) is one of the most economically important crops in the world due to its significant source of fiber, feed, foodstuff, oil and biofuel products. However, the utilization of cottonseed was limited due to the presence of small and darkly pigmented glands that contain large amounts of gossypol, which is toxic to human beings and non-ruminant animals. To date, some progress has been made in the pigment gland formation, but the underlying molecular mechanism of its formation was still unclear. RESULTS: In this study, we identified an AP2/ERF transcription factor named GhERF105 (GH_A12G2166), which was involved in the regulation of gland pigmentation by the comparative transcriptome analysis of the leaf of glanded and glandless plants. It encoded an ERF protein containing a converved AP2 domain which was localized in the nucleus with transcriptional activity, and showed the high expression in glanded cotton accessions that contained much gossypol. Virus-induced gene silencing (VIGS) against GhERF105 caused the dramatic reduction in the number of glands and significantly lowered levels of gossypol in cotton leaves. GhERF105 showed the patterns of spatiotemporal and inducible expression in the glanded plants. CONCLUSIONS: These results suggest that GhERF105 contributes to the pigment gland formation and gossypol biosynthesis in partial organs of glanded plant. It also provides a potential molecular basis to generate 'glandless-seed' and 'glanded-plant' cotton cultivar.

Comparative Proteomic Analysis of Molecular Differences between Leaves of Wild-Type Upland Cotton and Its Fuzzless-Lintless Mutant.

Fuzzless-lintless mutant (fl) ovules of upland cotton have been used to investigate cotton fiber development for decades. However, the molecular differences of green tissues between fl and wild-type (WT) cotton were barely reported. Here, we found that gossypol content, the most important secondary metabolite of cotton leaves, was higher in Gossypium hirsutum L. cv Xuzhou-142 (Xu142) WT than in fl. Then, we performed comparative proteomic analysis of the leaves from Xu142 WT and its fl. A total of 4506 proteins were identified, of which 103 and 164 appeared to be WT- and fl-specific, respectively. In the 4239 common-expressed proteins, 80 and 74 were preferentially accumulated in WT and fl, respectively. Pathway enrichment analysis and protein-protein interaction network analysis of both variety-specific and differential abundant proteins showed that secondary metabolism and chloroplast-related pathways were significantly enriched. Quantitative real-time PCR confirmed that the expression levels of 12 out of 16 selected genes from representative pathways were consistent with their protein accumulation patterns. Further analyses showed that the content of chlorophyll a in WT, but not chlorophyll b, was significantly increased compared to fl. This work provides the leaf proteome profiles of Xu142 and its fl mutant, indicating the necessity of further investigation of molecular differences between WT and fl leaves.

Constitutive and induced insect resistance in RNAi-mediated ultra-low gossypol cottonseed cotton.

BACKGROUND: Besides fibers, cotton plants also produce a large amount of seeds with a high oil and protein content. The use of these seeds is restricted by their high contents of the terpenoid gossypol, which is harmful to humans and livestock. Using a genetic engineering approach, "Ultra-low gossypol cottonseed" (ULGCS) plants were produced by knocking down an enzyme that catalyzes the formation of a precursor of gossypol. This was accomplished via RNAi-mediated silencing of the target gene using a seed-specific α-globulin promotor. Since gossypol is also a crucial defense mechanism against leaf-feeding herbivores, ULGCS plants might possess lower herbivore resistance than non-engineered plants. Therefore, we tested the constitutive and inducible direct insect resistance of two ULGCS cotton lines against the African cotton leafworm, Spodoptera littoralis. RESULT: The herbivore was equally affected by both ULGCS lines and the control (Coker 312) line when feeding on fully expanded true leaves from undamaged plants and plants induced by jasmonic acid. When plants were induced by caterpillar-damage, however, S. littoralis larvae performed better on the ULGCS plants. Terpenoid analyses revealed that the ULGCS lines were equally inducible as the control plants. Levels of terpenoids were always lower in one of the two lines. In the case of cotyledons, caterpillars performed better on ULGCS cotton than on conventional cotton. This was likely caused by reduced levels of gossypol in ULGCS cotyledons. CONCLUSION: Despite those effects, the insect resistance of ULGSC cotton can be considered as largely intact and the plants may, therefore, be an interesting alternative to conventional cotton varieties.

Effects of dietary cottonseed oil and cottonseed meal supplementation on the structure, nutritional composition of egg yolk and gossypol residue in eggs.

The aim of this study was to evaluate the effects of dietary non-gossypol cottonseed oil (CSO) or cottonseed meal (CSM) and their interactions on the texture properties, structure, nutritional composition, and edible safety of egg yolk. A total of 162 24-wk-old Hy-line Brown laying hens were randomly allocated into 9 diet treatments with 6 replicates of 3 hens per cage. A 3 × 3 factorial design using corn soybean meal-based diets supplemented with 0, 6, or 12% CSM and 0, 2, or 4% CSO in place of soybean meal and soybean oil, respectively, was utilized. The experiment lasted for 8 wk. Eggs obtained from the CSO groups had an egg yolk gel structure, and the hardness of egg yolk increased significantly (P < 0.001) after 4°C storaged for 2 wk; the texture properties of eggs storage at 25°C had opposite trend. There were no differences in texture properties of fresh egg yolk among the different groups (P > 0.05). The saturated fatty acid (SFA) content of egg yolk increased in a CSO dose-dependent manner, whereas opposite effects (P < 0.001) were found in the monounsaturated fatty acids (MUFA) and the omega-3/omega-6 fatty acid ratio. CSO-containing diets significantly reduced the cholesterol content (P < 0.05). No significant difference was observed among the different groups on the contents of moisture, crude protein, crude fat, phospholipid, potassium, or iron (P > 0.05) in the egg yolk. Total gossypol residues were increased with the increased amount of CSM (P < 0.05), and these changes were independent of time (P > 0.05). The total gossypol concentration in the yolk was 2.01 to 5.16 mg/kg. These results suggest that CSO has a key influence on egg yolk quality, reducing both its taste and nutritional value. Egg yolk gelation was significantly associated with the change of fatty acid composition caused by CSO and storage conditions. Free gossypol will remain in the egg yolk. Although the residue is low, the edible safety risk of eggs maybe exists.

Differences in Active Defense Responses of Two Gossypium barbadense L. Cultivars Resistant to Fusarium oxysporum f. sp. vasinfectum Race 4.

A highly virulent race 4 genotype of Fusarium oxysporum f. sp. vasinfectum (Fov) was identified for the first time in the western hemisphere in 2002 in cotton fields in the San Joaquin Valley of California. The Gossypium barbadense L. cotton cultivars 'Seabrook Sea Island 12B2' ('SBSI') and 'Pima S-6' are resistant to Fov race 4. Active defense responses were quantitated by monitoring the accumulation of antimicrobial terpenoids (i.e., phytoalexins) in inoculated stem stele tissue in these cultivars. The increase in the concentration of the most toxic phytoalexins was statistically faster after 24 h in 'SBSI' compared to 'Pima S-6'. The sesquiterpenoid hemigossylic acid lactone, which was observed for the first time in nature, also accumulated in diseased plants. Neither hemigossylic acid lactone nor the disesquiterpenoids gossypol, gossypol-6-methyl ether, and gossypol-6,6'-dimethyl ether showed toxicity to Fov. Segregation of F2 progeny from 'SBSI' × 'Pima S-6' crosses gave a few highly susceptible plants and a few highly resistant plants, indicating separate genes for resistance in the two cultivars.

Isolation of Cottonseed Extracts That Affect Human Cancer Cell Growth.

Cottonseeds are classified as glanded or glandless seeds depending on the presence or absence of gossypol glands. Glanded cottonseed has anticancer property and glandless cottonseed was reported to cause cancer in one animal study. It is important to investigate the effect of bioactive components from cottonseeds. Our objectives were to isolate ethanol extracts from cottonseeds and investigate their effects on human cancer cells. A protocol was developed for isolating bioactive extracts from seed coat and kernel of glanded and glandless cottonseeds. HPLC-MS analyzed the four ethanol extracts but only quercetin was identified in the glandless seed coat extract. Residual gossypol was detected in the glanded and glandless seed kernel extracts and but only in the glanded seed coat extract. Ethanol extracts were used to treat human cancer cells derived from breast and pancreas followed by MTT assay for cell viability. Ethanol extracts from glanded and glandless cottonseed kernels and gossypol significantly decreased breast cancer cell mitochondrial activity. Ethanol extract from glanded cottonseed kernel and gossypol also significantly decreased pancreas cancer cell mitochondrial activity. These results suggest that ethanol extracts from cottonseeds, like gossypol, contain anticancer activities.

Development of an RP-UHPLC-PDA method for quantification of free gossypol in cottonseed cake and fungal-treated cottonseed cake.

Cottonseed cake biomass, which is a residue of oil extraction, is potentially appropriate for use as animal feed, given the high mineral, fibre and protein content. The presence of free gossypol, however, a toxic pigment in the glands of the cotton plant, limits use of this biomass for monogastric livestock. A promising method to detoxify cottonseed cake relies on fermentation by fungi, which can eliminate up to 100% of gossypol. In order to quantify trace levels of free gossypol in different cotton materials, including cottonseed cake treated with macrofungi, a simple and rapid chromatographic detection method was developed and validated. Under optimized conditions, extraction was performed using 70% acetone. The extract was then analysed by Ultra High-Performance Liquid Chromatography (UHPLC), with gradient elution on a C18 reverse phase column KINETEX® (100 x 2.10 mm, 2.6 µm). Methanol-0.1% TFA aqueous solution was employed as mobile phase and PDA detection conducted at 254 nm. The optimized method was validated by analysis of specificity, linearity and range, limit of detection, limit of quantification, precision and accuracy. Detection and quantification limits were observed at 0.2 and 0.5 µg/mL, respectively. With good reproducibility, with precision (RSD)<10% and recovery greater than 94%, the developed assay was appropriate for quantification of low quantities of free gossypol. The validated method was successfully applied to determine trace levels of free gossypol cottonseed treated with a macrofungus.

Highly Sensitive and Selective Fluorescent Detection of Gossypol Based on BSA-Stabilized Copper Nanoclusters.

In this paper, fluorescent copper nanoclusters (NCs) are used as a novel probe for the sensitive detection of gossypol for the first time. Based on a fluorescence quenching mechanism induced by interactions between bovine serum albumin (BSA) and gossypol, fluorescent BSA-Cu NCs were seen to exhibit a high sensitivity to gossypol in the range of 0.1⁻100 µM. The detection limit for gossypol is 25 nM at a signal-to-noise ratio of three, which is approximately 35 times lower than the acceptable limit (0.9 µM) defined by the US Food and Drug Administration for cottonseed products. Moreover, the proposed method for gossypol displays excellent selectivity over many common interfering species. We also demonstrate the application of the present method to the measurement of several real samples with satisfactory recoveries, and the results agree well with those obtained using the high-performance liquid chromatography (HPLC) method. The method based on Cu NCs offers the followings advantages: simplicity of design, facile preparation of nanomaterials, and low experimental cost.

Effect of radiation on chemical composition and protein quality of cottonseed meal.

This study was conducted to compare the effects of electron beam (EB) and gamma ray (GR) irradiation treatments at doses of 10, 20 and 30 kGy on chemical composition, protein quality and protein digestibility of cottonseed meal (CSM). GR irradiation in all doses significantly decreased the crude fiber of samples compared to raw CSM. Free and total gossypol content of CSM was decreased significantly by utilizing both types of irradiation in a dose-dependent manner. Also, EB irradiation caused decrease in free and total gossypol content more than that of GR irradiation. GR irradiation at doses of 20 and 30 kGy, and EB irradiation at doses of 10, 20 and 30 kGy can significantly decrease protein solubility of CSM compared to that of a raw sample. GR irradiation at a dose of 30 kGy significantly increased apparent digestibility of protein compared to raw and EB irradiation of CSM at a dose of 10 kGy in Leghorn cockerels. Maximum increase in protein digestibility of CSM was observed in GR irradiation at a dose of 30 kGy. In conclusion, the present study showed that EB and GR irradiation reduced gossypol and crude fiber and increased protein digestibility of CSM but had no effect on protein quality of CSM.

Determination of gossypol content in cottonseeds by near infrared spectroscopy based on Monte Carlo uninformative variable elimination and nonlinear calibration methods.

Near infrared (NIR) spectroscopy combined with Monte Carlo uninformative variable elimination (MC-UVE) and nonlinear calibration methods employed to determine gossypol content in cottonseeds were investigated. The reference method was performed by high performance liquid chromatography coupled to an ultraviolet detector (HPLC-UV). MC-UVE was employed to extract the effective information from the full NIR spectra. Nonlinear calibration methods were applied to establish the models compared with the linear method. The optimal model for gossypol content was obtained by MC-UVE-WLS-SVM, with root mean squares error of prediction (RMSEP) of 0.0422, coefficient of determination (R2) of 0.9331, and residual predictive deviation (RPD) of 3.8374, respectively, which was accurate and robust enough to substitute for traditional gossypol measurements. The nonlinear methods performed more reliable than linear method during the development of calibration models. Furthermore, MC-UVE could provide better and simpler calibration models than full spectra.

Breeding Potential of Introgression Lines Developed from Interspecific Crossing between Upland Cotton (Gossypium hirsutum) and Gossypium barbadense: Heterosis, Combining Ability and Genetic Effects.

Upland cotton (Gossypium hirstum L.), which produces more than 95% of the world natural cotton fibers, has a narrow genetic base which hinders progress in cotton breeding. Introducing germplasm from exotic sources especially from another cultivated tetraploid G. barbadense L. can broaden the genetic base of Upland cotton. However, the breeding potential of introgression lines (ILs) in Upland cotton with G. barbadense germplasm integration has not been well addressed. This study involved six ILs developed from an interspecific crossing and backcrossing between Upland cotton and G. barbadense and represented one of the first studies to investigate breeding potentials of a set of ILs using a full diallel analysis. High mid-parent heterosis was detected in several hybrids between ILs and a commercial cultivar, which also out-yielded the high-yielding cultivar parent in F1, F2 and F3 generations. A further analysis indicated that general ability (GCA) variance was predominant for all the traits, while specific combining ability (SCA) variance was either non-existent or much lower than GCA. The estimated GCA effects and predicted additive effects for parents in each trait were positively correlated (at P<0.01). Furthermore, GCA and additive effects for each trait were also positively correlated among generations (at P<0.05), suggesting that F2 and F3 generations can be used as a proxy to F1 in analyzing combining abilities and estimating genetic parameters. In addition, differences between reciprocal crosses in F1 and F2 were not significant for yield, yield components and fiber quality traits. But maternal effects appeared to be present for seed oil and protein contents in F3. This study identified introgression lines as good general combiners for yield and fiber quality improvement and hybrids with high heterotic vigor in yield, and therefore provided useful information for further utilization of introgression lines in cotton breeding.

Chemical Composition of Defatted Cottonseed and Soy Meal Products.

Chemical composition is critical information for product quality and exploration of new use. Hence defatted cottonseed meals from both glanded (with gossypol) and glandless (without gossypol) cotton seeds were separated into water soluble and insoluble fractions, or water soluble, alkali soluble as well as total protein isolates. The contents of gossypol, total protein and amino acids, fiber and carbohydrates, and selected macro and trace elements in these products were determined and compared with each other and with those of soy meal products. Data reported in this work improved our understanding on the chemical composition of different cottonseed meal products that is helpful for more economical utilization of these products. These data would also provide a basic reference for product standards and quality control when the production of the cottonseed meal products comes to pilot and industrial scales.