Gossypol Glands Research Articles

Friend or Foe?: A Plant’s Induced Response to an Omnivore

Omnivorous natural enemies of herbivores consume plant-based resources and may elicit induced resistance in their host plant. A greater induction threshold for damage produced by omnivorous predators than for strict herbivores might be expected if omnivore performance is enhanced on noninduced plants, allowing them to reduce future levels of herbivory. Currently, it is not known if a plant responds to feeding by omnivorous predators and by herbivores similarly. To examine this question, we chose herbivore and omnivore species that produce the same kind of quantifiable damage to cotton leaves, enabling us to control statistically for the intensity of plant damage, and ask whether plant responses differed depending on the identity of the damaging species. We first compared changes in plant peroxidase activity, gossypol gland number and density, and leaf area in response to feeding by the spider mite Tetranychus turkestani (Ugarov and Nikolski) (an herbivore) and by one of the mite's principal natural enemies, the western flower thrips Frankliniella occidentalis (Pergande) (an omnivore). Both species increased the activity of peroxidase, but when we controlled for the amount of damage, the peroxidase activity of mite-damaged plants was higher than that of thrips-damaged plants. We also found that thrips, but not spider mites, increased the density of gossypol glands in the second true leaf. In a second experiment we included an additional herbivore, the bean thrips Caliothrips fasciatus (Pergande), to see if the different responses of cotton to thrips and mite herbivory we first observed were attributable to differences in trophic function (herbivore versus omnivore) or to other differences in feeding generated by thrips versus mites. Cotton plants exhibited the same pattern of induced responses (elevated peroxidase, increased number of glands, reduced leaf area) to herbivory generated by the bean thrips (an herbivore) and western flower thrips (an omnivore), suggesting that trophic function was not a key determinant of plant response. Thrips-damaged plants again showed a significantly higher density of gossypol glands than did mite-damaged plants. Overall, our results suggest that (1) an omnivorous predator systemically induces resistance traits in cotton and (2) whereas there is evidence of taxonomic specificity (thrips versus mites), there is little support for trophic specificity (herbivorous thrips versus omnivorous thrips) in the elicitation of induced responses.

Adult attractiveness and oviposition preference of Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae) B-biotype in cotton genotypes

The silverleaf whitefly Bemisia tabaci B-biotype is an important pest of cotton; it affects plant vigour, transmits geminivirus and reduces lint quality. In order to evaluate the resistance of cotton genotypes, Gossypium hirsutum (L.), to the whitefly Bemisia tabaci B-biotype, both free-choice and no-choice attractiveness and non-preference for oviposition tests were carried out in a shade house, at room temperature. Low attractiveness to adults of this whitefly was observed for plants of genotypes Fabrika, CNPA Ita 90, Makina, Coodetec 407, and IAC 01-639 CPA 02-24, which may represent a resistance component of these genetic materials to the insect. Genotypes BRS Aroeira, Coodetec 406, Fabrika, and Coodetec 401 presented the non-preference-for-oviposition type of resistance in the free-choice and no-choice tests. The numbers of trichomes and gossypol glands per cm² were not suitable to evaluate non-preference for oviposition of whitefly adults on cotton genotypes.

Development of a Visual Method to Quantify the Gossypol Content in Cotton Seeds

ABSTRACTTwelve Gossypium genotypes (species, fertile interspecific allotetraploid and allohexaploid hybrids, backcross progeny of interspecific hybrids) characterized by drastic differences in their seed gossypol content were used to design a visual quantification method of the gossypol concentration in cotton seeds. After developing an high performance liquid chromatography (HPLC) method that allowed measurement of gossypol content in single seed samples, the results of 123 HPLC analyses carried out seed‐by‐seed were compared with different parameters characterizing the level of gossypol glands in the seed. A significant correlation was found between the gossypol content %G determined on single seeds by HPLC and the number N of gossypol glands per seed section area (S, expressed in mm2), leading to the establishment of the following model: %G = bi (N/S), where the regression coefficient bi depends on the cotton genotype considered. The estimation of %G directly from N/S is a rapid and accurate method which can be used in breeding programs to screen the progeny of cotton genotypes showing a high segregation for their seed gossypol content.

Spatial and temporal regulation of a soybean (Glycine max) lectin promoter in transgenic cotton (Gossypium hirsutum).

The activity of a soybean (Glycine max L. Merrill) lectin gene promoter was investigated in transgenic cotton plants (Gossypium hirsutum L.) with the view to using this promoter for the seed-specific alteration of gossypol, a secondary metabolite in cotton that has adverse effects on the nutritional value of cottonseed products like oil and protein-rich meal. Agrobacterium-mediated transformation generated stable transformants containing a construct with the lectin promoter fused to the β-glucuronidase reporter gene (pLeGUS). Fluorometric GUS assays and northern hybridization detected strong promoter activity during embryo development. GUS activity in developing embryos was detected as early as 10 d post-anthesis (dpa), peaking late in embryo maturation. Enzyme activity persisted in imbibed mature seed, and negligible activity remained detectable in the roots and cotyledons of 7-d-old seedlings. No GUS activity was detected in leaves and squares of mature plants. GUS transcripts increased during embryo development to peak about 35 dpa, declining to a low level in imbibed mature seed. No transcripts were detected in roots, cotyledons, leaves or squares. Histochemical GUS activity staining indicated promoter activity in all cells of the cotyledons, including the flattened cells of the gossypol glands, the presumed site of synthesis of gossypol. This study concluded that the soybean lectin gene promoter is a useful tool for the seed-specific expression of transgenes in cotton.

Relation of gossypol gland density with bollworm (Helicoverpa armigera incidence in parents and hybirds of American cotton (Gossypium hirsutum L.)

An experiment was conducted to study the effect of gossypol gland density in different plant parts in relation to bollworm incidence (Helicoverpa armigera) and seed cotton yield in 10 bollworm donor lines and their 45 F1's obtained in 10 x 10 diallel fashion (without reciprocals). A wide range of variability was observed for gossypol gland number, size and volume per unit arca on leaf, bract and calyx surfaces both in parents and hybrids. The present study revealed that both in parents and hybrids, the nature of relationship between gland density in different plant parts and bollworm incidence in reproductive parts did not follow similar trend. The study also revealed the scope for utilisation of high gossypol gland density on leaf, bract and calyx in future breeding programmes for development of high yielding cotton cultivars with inbuilt mechanism for bollworm tolerance especially for H. armigera.

Statistical studies on anatomical modifications in the radicle and hypocotyl of cotton induced by NaCl

Salinity affects extensive arid and semiarid areas all over the world, producing diminished yields of many crops. Even though there is a variety of research and reviews related to physiological and anatomical modifications produced in salinity-tolerant species, today there are different points of view in relation to this topic, and especially due to technical limitations, there are few articles in which anatomical modifications have been quantified. The aim of this research is to quantitatively and statistically evaluate the modifications that are produced in radicles and hypocotyles of cotton seedlings growing in NaCl concentrations that affect the early ontogenetic stages of this crop. Germination of two varieties of cotton at increasing concentrations (0 to 450 meq/l) of NaCl was studied as well as the growth of seedlings after their germination in water. Anatomical modifications induced in radicles and hypocotyles were analyzed quantitatively with an image analyzer. There were no differences among varieties. While the percentage of germination decreased at the 252 meq/l NaCl level, the velocity of the process and seedling growth was inhibited at lower concentrations. With increased salinity, the cortex and pith of radicle increased in width, while the xylem decreased. In the hypocotyl, the width of cortex increased, as did the number and diameter of gossypol glands. This change deserves further studies in relation to the participation of these glands in the capacity of the seedlings to tolerate salinity

Inheritance of High Glanding, an Insect Resistance Trait in Cotton

The high glanding (HG) trait [i.e., presence of gossypol glands the upper edge of the sepals of the upland cotton (Gossypium hirsutum L.) flower bud] confers a significant level of resistance to bollworm [Helicoverpa zea (Boddie)] and tobacco budworm [Heliothis virescens (F.)], but the inheritance of this trait is not well understood. The objective of this study was to determine the inheritance of the HG trait to aid breeders in developing improved HG cultivars. Crosses were made among HG, normal glanding (NG), and glandless genotypes, and with isolines of the HG breeding line, XG‐15, which had genotypes 2(Gl2 gl3) and 2(gl2 Gl3). The isoline, XG‐15 gl2Gl3, expressed the HG phenotype, leading to the hypothesis that HG is conferred by a special Gl3 allele derived from XG‐15. Crosses of HG × NG parents resulted in HG F1, 3 HG/1 NG ratios in the F2, and ratios of 1 HG/2 segregating/1 NG among F2:3 progeny. Crosses of XG‐15 gl2Gl3 × NG produced similar results. The cross, XG‐15 gl2Gl3 × HG, did not segregate for calyx margin glanding type. The cross, XG‐15 gl2Gl3 × glandless, resulted in glandless flower buds in the F1 and a ratio of 3 glandless (flower buds)/1 HGin the F2. The F1 HG × glandless had small sparse glands on the base of the sepals. Phenotypes of individual F2 plants did not appear to fit common segregation ratios, but data from F2:3 families supported the hypothesis that a special Gl3 allele confers the HG phenotype. This allele, derived originally from Socorro Island cotton, is tentatively designated GlS3.

Relationships of Glands, Cotton Square Terpenoid Aldehydes, and Other Allelochemicals to Larval Growth of Heliothis virescens (Lepidoptera: Noctuidae)

Female moths of the tobacco budworm, Heliothis virescens (F.), oviposit in terminals of the cotton plant, Gossypium hirsutum (L.). The hatched larvae feed in the terminal area, then migrate to small squares (buds) where they feed and finally burrow into and feed on the anthers, where they grow rapidly. They attempt to avoid feeding on gossypol glands during the first 48 h after hatching. When tobacco bud worm neonate larvae were fed squares of highly glanded lines, growth was decreased by 25–75%. The number of glands in calyx and bract tissues of squares of resistant lines was significantly higher than in susceptible lines. The difference was greatest in the calyx crown where the ratio in resistant to susceptible lines was 10–20 fold. The calyx crown of highly glanded resistant lines also was high in terpenoid aldehydes. High pressure liquid chromatography data showed that the gossypol content of susceptible and resistant glanded lines is equal, whereas three other terpenoid aldehydes, hemigossypolone and heliocides H1 and H2, are greatly increased in resistant lines, and they are presumably more closely associated with resistance.

Representations on pre-columbian spindle whorls of the floral and fruit structure of economic plants

A few of the numerous small clay discs from Pre-Columbian Mesoamerica and South America contain accurate illustrations of the reproductive structures of important economic plants. The arrangement of seeds in fruit sections, axial or parietal, is shown for the Solanaceae (tomato, pepper) and the Cucurbitaceae (squash). The number of locules in Gossypium (cotton) bolls and the external appearance of the boll including the precise arrangement of the gossypol glands are illustrated. What are probably floral diagrams of these plant families are represented. The bell-shaped spindle whorls from the Quimbaya culture of Colombia have varied designs that resemble the campanulate flowers o/Brugmansia (Datura, Solanaceae), which is known for its contorted flowers, and hallucinogenic effects. The native mythology and language, recorded in Mexico at the time of the conquest, indicates a pervasive interest in fruit and flower structure, which is reflected in the designs on the spindle whorls. These functional artifacts provide evidence of the accurate plant observation in the less well known cultures of Colombia and Ecuador.

Effects of cotton plant allelochemicals and nutrients on behavior and development of tobacco budworm

Female moths of the tobacco budworm,Heliothis virescens (F.), oviposit in the terminals of the cotton plant,Gossypium hirsutum (L.). The hatched larvae migrate to the terminal area and then to small squares (buds), on which they feed, finally burrowing into the anthers where they grow and develop. They attempt to avoid gossypol glands as they feed. Chemically related evidence explains, in part, these observations. The calyx crown of resistant lines (which is avoided) is high in the terpenoid aldehydes (TAs) including gossypol. HPLC data showed that the gossypol content of both susceptible and resistant glanded lines is equal, while the hemigossypolone and heliocides H1 and H2 are greatly increased in resistant lines and presumably are more closely associated with resistance. Analysis for total amino acids in cotton square tissues showed that there was a gradation from the calyx and calyx crown, which were lowest, to the anthers, the site of final insect development, which were highest. Synthetic diets mimicking amino acid distribution in anthers were found to be successful for larval growth and development.

Plant Resistance to Insects in Cotton

Entomologists and plant breeders have noted that glandless lines of cotton generally are susceptible to phytophagous insects. Gossypol, the yellow pigment present in the glands, has been shown to be the most important allelochemical that provides resistance. In field tests, high gossypol lines have repeatedly been correlated with lessened insect damage, probably due to toxicity of gossypol to Heliothis sp. and other cotton insects. Recent behavioral-histochemical studies of newly hatched larvae of tobacco budworm, Heliothis virescens (F), feeding on cotton showed that first-stage larvae avoided consuming the glands. However, when these molt between 48 and 72 h of age, they nonselectively consume the glands, suggesting a metabolic adaptation. Young tobacco budworm larvae prefer to feed along the margin area of the calyx crown of the square, an area devoid of gossypol glands. On resistant lines having glands in the calyx crown, the larvae feed sporadically on the tissue thus avoiding the glands. The numbers of gossypol glands on bracts of small squares, calyx crown, bract mid-rib, and the entire calyx differed significantly between the susceptible and resistant lines. First instar larvae placed on squares of cotton genotypes with high gland density in the small square bract and in the calyx crown, were significantly smaller than larvae placed on line with fewer glands. These and related studies suggest that breeding strategies should concentrate on placing gossypol glands in the calyx crown, the primary site of insect attack.

Morphological Basis of Resistance in Cotton to the WhiteflyBemisia Tabaci

The morphological basis of resistance to the whiteflyBemisia tabaci Genn. (Aleyrodidae: Hemiptera) was studied. The plant characters examined were leaf area, thickness of leaf lamina, hair density, hair length, angle of insertion of leaf hair, and density of gossypol glands. Hair density and leaf thickness were positively correlated with the population ofB. tabaci, and a positive correlation was obtained between the adult whitefly population and gossypol glands on stem internodes. Cotton genotype USA-22 (sparsely hairy) was found to be more tolerant toB. tabaci than was genotype USA-13 (velvety hairy). The use of thinner and glabrous leaved cotton varieties is suggested to minimize the whitefly menace in cotton.

Relationship Between Gossypol Gland Density on Cotton Squares and Resistance to Tobacco Budworm (Lepidoptera: Noctuidae) Larvae

Young tobacco budworm, Heliothis virescens (F.), larvae prefer to feed along the margin area of the calyx crown of cotton ( Gossypium hirsute L.) squares. This area is devoid of gossypol glands. On resistant cotton lines, which contain glands in the calyx crown, the larvae feed sporadically on the tissue and avoid the gossypol glands. The numbers of gossypol glands on bracts of small squares, calyx crown, bract mid-rib, and the entire calyx differed significantly between a susceptible and three resistant cotton lines. When young larvae were placed on squares for 12 d, the lines with >80 glands per small square bract or 30 glands per calyx crown produced larvae significantly smaller than did lines with fewer glands.

Nutritional Indices of Second-instar Tobacco Budworm Larvae (Lepidoptera: Noctuidae) Fed Different Cotton Strains

In 1982, second-instar tobacco budworm larvae, Heliothis virescens (F.), were fed leaves, bracts, and squares without bracts (buds) of each of four strains of cotton (‘ST213’, ‘DH121’, ‘RED’, and ‘DH66’) and bud parts (anthers, calyces, and petals) of ‘ST213’. Nutritional indices were measured. Relative growth rates (RGR) of larvae fed on buds of ‘DH121’ were reduced below those of larvae fed buds of the other strains, while RGR’s on leaves and bracts of the glanded strains (‘ST213’, ‘DH121’, and ‘RED’) were no different. Strains high in number of gossypol glands or cyanidin-3-β-glucoside level proved to be effective inhibitors of larval growth, while one high in tannin did not. Relative consumption rates and relative growth rates were highest on buds. Petals and calyces were nutritionally inferior to anthers.

Feeding Behavior of First-Stage Tobacco Budworm (Lepidoptera: Noctuidae) on Three Cotton Cultivars

Feeding behavior and histological-histochemical studies of newly hatched tobacco budworm, Heliothis virescens (F.), larvae feeding on cotton Gossypium hirsutum L. revealed that first-stage larvae avoided consuming glands which contains gossypol, a dimeric sesquiterpenoid aldehyde. Between 48 and 72 h of age, larvae molt and then nonselectively consume the glands. Histological studies show that gossypol glands are surrounded by an envelope; histochemical procedures indicate that the envelope contains anthocyanins which differ from gossypol. We suggest that the allelochemics present in these glands act as feeding deterrents or as antifeedant compounds to first-stage larvae.

Gossypol in cottonseed products: toxicology and inactivation.

The little attention given to the potential of cottonseeds as food for monogastric animals and man is due to the presence of toxic principles in them, especially gossypol. The injury to livestock associated with ingestion of cottonseeds results from the unfavorable physiological effect of gossypol per se, as well as from its adverse effects on the protein nutritive value of the food (mainly by rendering lysine metabolically unavailable). Various approaches have been employed to overcome these problems, by removing the gossypol glands, growing glandless varieties, extraction of gossypol with solvents, or through inactivation by heat processing, reacting with cations or with certain organic compounds. In this study the phospholipid fraction (gums) derived from soybeans, which is relatively rich in phospholipids containing a free amino group, was used with a view to lowering the tendency of gossypol to bind with lysine, and at the same time to inactivate the gossypol by converting it into a bound form. Dehulled and flaked cottonseeds were mixed with 5% soybean gums and 0.5% NaOH, in a laboratory cooker resembling the apparatus used in the cottonseed processing industry. The meat was cooked for different periods and at several temperatures. Later the oil was extracted with hexane and the meal was tested for free gossypol, "available lysine" and protein nutritive value, in comparison with a control batch treated similarly but without gums. The results proved the superiority of the meal treated with gums, as evidenced by all the above parameters.

Methylene Chloride Extraction of Gossypol from Cottonseed Products

ABSTRACTMethylene chloride was used to reduce the amount of free and total (free plus bound) gossypol in hexane‐defatted meal and the liquidcyclone‐processed (LCP) underflow fraction of glanded cottonseeds from 2.6% and 3.4% to 0.013% and 0.15%, respectively (the accepted level of free gossypol in cottonseed products for food is 0.045%). The cottonseed meals were pretreated one of three ways to rupture the gossypol glands: (a) equilibrated with additional water; (b) suspended in various water‐propylene glycol mixtures; or (c) mixed with an acetic acid‐water‐propylene glycol solution. The gossypol was then readily extracted from the meals with methylene chloride. Low levels of water and acetic acid in propylene glycol aided methylene chloride in the removal of free and total gossypol and did not greatly alter the proximate composition, solubility, and gel electrophoretic properties of proteins; amino acid content; and chemical scores of the treated meals. Success with this process should improve the potential of LCP‐cottonseed by‐product (underflow) as feed or food.

Interspecific hybridization in Gossypium L. II. Cytomorphological studies in hybrid G. hirsutum haploid (2n=2x=26,AhDh) * G. thurberi (2n=2x=26,D1D1).

A new interspecific hybrid (2n=26) AhDhD1/2 has been obtained by crossing G. hirsutum L. haploid (2n=2x=26, AhDh) with G. thurberi Tod. (2n=2x=26, D1D1). Observations on its morphological characters and cytology have been recorded. The hybrid was found to be highly vigorous and fairly fertile. The characters in F1 like leaf shape, gossypol glands boll bearing and shape, rind thickness and earliness of G. thurberi which are associated with bollworm tolerance and other economic characters like plant habit, bract shape, flower colour and shape, anther arrangement, seed fuzz and presence of lint of G. hirsutum were found to be dominant. The F1 being fairly fertile it is likely to get segregants with different character combinations both on glanded and glandless background. The possibility of incorporating insect resistance in glandless lines has been indicated.From the chromosome analysis in this plant it was observed that D1 chromosomes of G. thurberi show greater homology with AhDhchromosomes resulting in formation of on an average 8.8 bivalents per cell and thus high degree of fertility.

A New Species of Hampea (Malvaceae) From El Salvador

Hampea reynae is described from the rain forest of Montecristo National Park in northern El Salvador. Discovery of this species has implications for infrageneric subdivision of Hampea. Hampea reynae Fryxell, sp. nov. Arbor ad 8 m alta, caulibus dense atque minute brunneo-puberulis; laminis foliorum vulgo 3-lobulatis, circa quam latioribus quam longiori- bus, plerumque 3 nectariis foliorum prope basim laminae; pedicellis 2-3 in fasciculis axillaribus; nectariis involucellorum carentibus; bracteis in- volucellorum 3, filiformibus, 5-9 mm longis; floribus perfectis; calycibus obscure 5-dentatis; petalis flavidis, 1.5-2 cm longis, manifeste punctatis, glandulis nigris; androeceo conferto; stylis androecia excedentibus, lobis stigmaticis decurrentibus; capsulis 3-locularibus, subglobosis, 2-2.5 cm diametro, extra puberulentibus, intra albo-pubescentibus secus suturas, cetera glabris; seminibus arillatis, 2 in quoque loculo. Tree ca. 8 m tall. Stems densely and minutely brown-puberulent. Leaf blades sometimes simple, more commonly 3-lobulate (the lobes ascend- ing, acuminate), up to 23 cm long, about as broad (or narrower if un- lobed), stellate-pubescent beneath (densely so on nerves), sparsely pu- bescent to glabrate above except densely pubescent on principal nerves, palmately 7-9-nerved, the ultimate venation reticulate, in mature leaf each areola usually with 1(-2) black gossypol glands. Foliar nectaries usually 3, on principal nerves beneath within 1 cm of base of blade. Petioles 1/2-2/3 the length of blade, with pubescence like that of stem except hairs sometimes worn away on lower side revealing surface. Stipules filiform, brown-puberulent, 5-6 mm long, caducous. Pedicels in the axils of the leaves, 0.5-1.5 cm long, in fascicles of 2-3, with pubes- cence like that of stem. Involucellar nectaries lacking. Involucellar bracts 3, brown-puberulent, filiform, (3-)5-9 mm long. Flowers perfect. Calyx 7-10 mm long, brown-puberulent, subtruncate but with 5 obscure teeth discernible, becoming torn in flower and fruit to pseudo-lobate condi- tion, reflexed in fruit. Petals 1.5-2 cm long, pale yellow, prominently dotted with black glands, densely stellate-puberulent externally where exposed in bud, ciliate on claw, otherwise glabrous. Androecium com- pact, ca. half length of petals; anthers and pollen yellow-orange. Style exceeding androecium, pallid, with decurrent stigmatic lobes. Capsules 3-locular, subglobose, 2-2.5 cm long, dark green (but brown when dry), whitish-pubescent along suture margin but otherwise glabrous in- 442

Cytomorphological studies in an intergeneric hybrid between Gossypium hirsutum L. (2n=52) and Hibiscus panduraeformis Burm.

An intergeneric hybrid (2n=38) between Gossypium hirsutum L. (2n=52) × Hibiscus panduraeformisBurm. (2n=24) was obtained by pollinating about 2000 flower buds of G. hirsutum var. Gregg Male Sterile with pollen from H. panduraeformis. The F1 hybrid was intermediate in plant habit, but possessed gossypol glands and nectaries on the leaves, bolls containing seeds with fuzz and lint as dominant characters of G. hirsutum. Flowers with yellow corolla and anthers; purple petal spot, profuse growth of epidermal hairs on all plant parts including the boll sutures, and jassid tolerance were dominant characters of H. panduraeformis. The partial fertility of the F1 indicated the possibilities of combining jassid and drought tolerance of H. panduraeformis with the desired economic characters of G. hirsutum for rainfed cultivation.