THE ORIGIN OF HELIANTHUS MULTIFLORUS

Heiser , CHARLES B., Jr . (Indiana U., Bloomington), and Dale M. Smith . The origin of Helianthus multiflorus. Amer. Jour. Bot. 47(10): 860–865. Illus. 1960.—The cultivated ornamental sunflower, Helianthus multiflorus L., has been known since 1591 when it was described from Europe by Tabernaemontanus. Both Gray and Bailey concluded that it was a variety of H. decapetalus. The plant is invariably sterile and Dod was first to suggest a hybrid origin from H. annuus and H. decapetalus. Helianthus multiflorus has been found to be triploid (2n = 51) and at meiosis generally shows 17 bivalents and 17 univalents. Morphologically, the plant is similar to H. decapetalus (n = 34) but differs from it in the more hispid stem, broader leaves and phyllaries, and other characters, all of which could have been derived from H. annuus (n = 17). The artificial hybrid between H. decapetalus and H. annuus, while not readily obtained, has been secured, and the hybrid is rather similar to H. multiflorus. It is concluded that this taxon most likely originated in Europe from spontaneous hybridization between H. decapetalus and H. annuus, following the introduction of these species from North America.     

Identification of pre-zygotic reproductive and morphological barriers limiting controlled crossed seed production of triploid Acacia mearnsii

A study of the reproductive biology of black wattle (Acacia mearnsii de Wild) was conducted, specifically with regard to the compatibility of the diploid × tetraploid cross to produce a triploid variety, together with identifying ways of increasing triploid seed production. Fluorescent microscopy was used to determine pollination and fertilisation rates and to identify any pre-zygotic barriers at the stigma, style and ovary. Both diploid and tetraploid families were tested as maternal parents to establish if this was imperative to producing a triploid. Morphological measurements were documented in order to determine any incompatibilities in the cross to produce a triploid. The in vivo results showed that successful fertilisation of the ovary was possible whether one used a diploid or tetraploid maternal parent. When the maternal parent was a tetraploid, however, the pollination rate (polyads adhering to the stigma) and ovary fertilisation rates were significantly (p < 0.05) greater. Morphological measurements and observations also revealed that tetraploid floral parts were significantly (p < 0.05) larger than the diploids. The morphological size differences between the diploid and tetraploid polyads and pistils did not appear to influence the fertilisation of the ovaries and thus did not pose any identifiable barrier in the cross to produce a triploid. When considering the results from the cross to produce a triploid (2n × 4n or 4n × 2n), the diploid polyads were significantly (p < 0.05) more vigorous and suitable in fertilising the tetraploid ovaries as opposed to the reverse. Possible pre-zygotic barriers at the stigma, style or ovary were investigated and the only area that could be identified limiting seed production was within the ovary.     

Novel neofusapyrones isolated from Verticillium dahliae as potent antifungal substances

Novel fusapyrone analogs, deoxyneofusapyrone and 7-desmethyldeoxyneofusapyrone were isolated from a pathogenic fungus, Verticillium dahliae, which causes Verticillium wilt disease in Helianthus annuus. Spectral analyses revealed that these are 2-pyrone type analogs of deoxyfusapyrone and its 7-desmethyl derivative, respectively. Biological assay disclosed that 10 μg of deoxyneofusapyrone inhibited the growth of MRSA clinical isolate 87-7927.     

Cytology and embryology of the pompom weed,Campuloclinium macrocephalum (Eupatorieae,Asteraceae)

Campuloclinium macrocephalum (Less.) DC. is a perennial herb widely distributed in the New World, but introduced to South Africa, where it is commonly called “pompom weed”. This species is considered one of the most important weeds from Brazil and it has been included among the plant invaders of South Africa. Results of the meiotic and embryological analyses of six populations of C. macrocephalum are reported in this paper. The microsporogenesis analysis revealed five triploid (2n = 3x = 30) and one diploid (2n = 2x = 20) populations with a basic chromosome number x = 10. The diploid specimens showed regular meiotic behavior, but the triploid plants presented irregular chromosome pairing which result in the formation of univalents, bivalents and trivalents at diakinesis. In consequence, laggard chromosomes, unbalanced nuclei and micronuclei were observed in subsequent phases of meiosis. The embryological analysis showed that the triploid specimens of C. macrocephalum have embryo sac development from a nucellar cell (apospory), which indicates that these specimens are apomictic. Almost all cases of apomixis found in tribe Eupatorieae are diplosporous apomixis. Campuloclinium macrocephalum constitutes the second species of the tribe and the first of the genus with apospory as reproductive system. The aposporous apomixis combined with the presence of xylopodium would be two important factors responsible for the invasiveness of C. macrocephalum.     

Comprehensive genomics and expression analysis of eceriferum (CER) genes in sunflower (Helianthus annuus)

Sunflower occupies the fourth position among oilseed crops the around the world. Eceriferum (CER) is an important gene family that plays critical role in very-long-chain fatty acids elongation and biosynthesis of epicuticular waxes under both biotic and abiotic stress conditions. The aim of present study was to investigate the effect of sunflower CER genes during drought stress condition. Thus, comparative analysis was undertaken for sunflower CER genes with Arabidopsis genome to determine phylogenetic relationship, chromosomal mapping, gene structures, gene ontology and conserved motifs. Furthermore, we subjected the sunflower cultivars under drought stress and used qRT-PCR analysis to explore the expression pattern of CER genes during drought conditions. We identified thirty-seven unevenly distributed CER genes in the sunflower genome. The phylogenetic analysis revealed that CER genes were grouped into seven clades in Arabidopsis, Helianthus annuus, and Gossypium hirsutum. Expression analysis showed that genes CER10 and CER60 were upregulated in sunflower during drought conditions, indicating that these genes are activated during drought stress. The results obtained will serve to characterize the CER gene family in sunflower and exploit the role of these genes in wax biosynthesis under limited water conditions.Key messageCuticular waxes protect the plants from drought stress, so we observed the expression of wax bio synthesis genes in recently sequences genome of Helianthus annuus. We observed that expression of wax biosynthesis genes CER10 and CER60 was upregulated when the plants were subjected to drought stress.     

Chloroplast DNA variation and phylogeographic patterns in the Chinese endemic marsh herb Sagittaria potamogetifolia

We examined chloroplast DNA (cpDNA) atpB–rbcL intergenic spacer sequences variation within Sagittaria potamogetifolia, an endangered and endemic marsh herb in China. Sequence data were obtained from 54 individuals in six extant populations of the species. Sequences appeared to evolve neutral (Tajima's criterion D = −1.59826, 0.1 > P > 0.05 and Fu and Li's tests D* = −1.44484, P > 0.1; F* = −1.83446, P > 0.1). Eleven haplotypes were identified in S. potamogetifolia. A relatively high level of haplotype diversity (h = 0.0.699) and low level of nucleotide diversity (pi = 0.0035 ± 0.0020) were detected in S. potamogetifolia. Pairwise comparisons of F_st and Nm deduced from cpDNA variation suggested no significant genetic differentiation between populations of S. potamogetifolia excepted for the WY-1 population. Low genetic differentiation among populations and also among regions was consistently indicated by both hierarchical analyses of molecular variance (AMOVA) and the structure of a neighbor-joining tree. Lack of population differentiation between populations or between regions in cpDNA sequences may be due to effects of lower substitution rates or lineage sorting. In the minimum spanning network, all tip haplotypes except for the haplotype J were unique to a particular population, while the interior nodes except for the haplotype E were widespread (haplotype A). From nested clade analysis (NCA), the evolutionary events such as restricted gene flow with isolation by distance and allopatric fragmentation were inferred to responsible for the current distribution of S. potamogetifolia populations, as well as their genetic diversity.     

Growth and loss of distal tissue in blades of Lessonia nigrescens and Lessonia trabeculata (Laminariales)

Meristematic growth and loss of distal tissue from blades of two ecologically important species in the south-east Pacific, Lessonia nigrescens and Lessonia trabeculata, was evaluated during 1 year. Comparative growth was determined by a hole-punch method, loss of distal tissue from the blades was determined by subtracting final blade length (with loss) from expected blade lengths (without loss); growth and tissue loss were transformed to fresh biomass units for calculation of inter-algae differences. The results showed that blade elongation rate increased at the beginning of spring, and declined towards the end of summer, with mean values between 0.40 and 0.08 cm day⁻¹ for L. nigrescens, and 0.65–0.17 cm day⁻¹ for L. trabeculata. Loss of distal tissue varied seasonally when examined as length units for both species; with mean values between 0.24 and 0.10 cm day⁻¹ for L. nigrescens, and 0.51–0.25 cm day⁻¹ for L. trabeculata. Variations in fresh biomass units were only observed in Lessonia trabeculata, increasing in spring, with mean values to 0.13 g (fresh weight) day⁻¹. Annual growth and loss of distal tissue were higher in L. trabeculata (0.41 and 0.39 cm day⁻¹, respectively) than in L nigrescens (0.19 and 0.15 cm day⁻¹). When growth and tissue loss were considered as fresh biomass, monthly gains significantly outweighed loss of distal tissue in both species, but parallel results based on length data followed a different trend. L. trabeculata released about 50% of its growth biomass as particulate organic matter, while the comparative value for L. nigrescens was about 20%.     

Expression of allograft inflammatory factor-1 (AIF-1) in response to bacterial challenge and tissue injury in the pearl oyster,Pinctada martensii

Allograft inflammatory factor-1 (AIF-1), an interferon (IFN)-γ-inducible calcium-binding cytokine, is associated with the inflammatory response and defense. We cloned and analyzed the expression pattern of the AIF-1 gene of the pearl oyster Pinctada martensii, hereafter designated PmAIF-1. The full-length PmAIF-1 cDNA is 946 bp in length and consists of a 5′-untranslated region (UTR) of 120 bp, a 3′-UTR of 376 bp, and an open reading frame (ORF) of 450 bp encoding a polypeptide of 149 amino acids with an estimated molecular mass of 17 kDa. Sequence analysis reveals that PmAIF-1 contains two EF hand Ca⁺²-binding motifs like those in previously characterized AIF-1s while alignment with known AIF-1 protein sequences reveals higher similarity to invertebrate orthologs than to those of vertebrates.Quantitative PCR analysis reveals that PmAIF-1 is constitutively expressed, with the highest expression detected in hemocytes, and the expression level of PmAIF-1 mRNA was significantly up-regulated in hemocytes, gill, digestive gland under bacterial challenge and tissue injury. After challenged by gram-negative bacteria Vibrio alginolyticus and Vibrio parahaemolyticus, gram-positive bacteria Bacillus subtilis, the expression level of this gene in hemocytes were all up-regulated and reached the maximum point at 12 h (5.80 folds, P < 0.01), 6 h (5.02 folds, P < 0.01) and 12 h (5.49 folds, P < 0.01), respectively. Under shell damage and mantle injury, PmAIF-1 mRNA increased gradually in the first 3 h and reached a peak of expression at 6 h post-injury. These findings suggest that PmAIF-1 is an acute-response protein involved in the innate immune responses of pearl oysters, and provide general information about the mechanisms of innate immune defense against bacterial infection in pearl oysters.     

Characterization and site-directed mutagenesis of a novel class II 5-enopyruvylshikimate-3-phosphate (EPSP) synthase from the deep-sea bacterium Alcanivorax sp. L27

The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) is a key enzyme in the aromatic amino acid biosynthetic pathway in microorganisms and plants, which catalyzes the formation of 5-enolpyruvylshikimate-3-phosphate (EPSP) from shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP). In this study, a novel AroA-encoding gene was identified from the deep sea bacterium Alcanivorax sp. L27 through screening the genomic library and termed as AroA_A.sp. A phylogenetic analysis revealed that AroA_A.sp (1317 bp and 438 amino acids) is a class II AroA. This enzyme exhibited considerable activity between pH 5.5 and pH 8.0 and notable activity at low temperatures. The K_M for PEP and IC₅₀ [glyphosate] values (the concentration of glyphosate that inhibited enzyme activity by 50%) of AroA_A.sp were 78 μM and 1.5 mM, respectively. Furthermore, site-directed mutagenesis revealed that the G100A mutant had a 30-fold increase in the IC₅₀ [glyphosate] value; while the L105P mutant showed only 20% catalytic activity compared to wild-type AroA_A.sp. The specific activity of the wild-type AroA_A.sp, the G100A mutant and the L105P mutant were 7.78 U/mg, 7.26 U/mg and 1.76 U/mg, respectively. This is the first report showing that the G100A mutant of AroA displays considerably improved glyphosate resistance and demonstrates that Leu105 is essential for the enzyme's activity.     

LaaA,a novel high-active alkalophilic alpha-amylase from deep-sea bacterium Luteimonas abyssi XH031T

Alpha-amylase is a kind of broadly used industrial enzymes, most of which have been exploited from terrestrial organism. Comparatively, alpha-amylase from marine environment was largely undeveloped. In this study, a novel alkalophilic alpha-amylase with high activity, Luteimonas abyssi alpha-amylase (LaaA), was cloned from deep-sea bacterium L. abyssi XH031^T and expressed in Escherichia coli BL21. The gene has a length of 1428 bp and encodes 475 amino acids with a 35-residue signal peptide. The specific activity of LaaA reached 8881 U/mg at the optimum pH 9.0, which is obvious higher than other reported alpha-amylase. This enzyme can remain active at pH levels ranging from 6.0 to 11.0 and temperatures below 45 °C, retaining high activity even at low temperatures (almost 38% residual activity at 10 °C). In addition, 1 mM Na⁺, K⁺, and Mn²⁺ enhanced the activity of LaaA. To investigate the function of potential active sites, R227G, D229K, E256Q/H, H327V and D328V mutants were generated, and the results suggested that Arg227, Asp229, Glu256 and Asp328 were total conserved and essential for the activity of alpha-amylase LaaA. This study shows that the alpha-amylase LaaA is an alkali-tolerant and high-active amylase with strong potential for use in detergent industry.     

Opisthorchis viverrini and Haplorchis taichui: Development of a multiplex PCR assay for their detection and differentiation using specific primers derived from HAT-RAPD

Specific primers for the detection of Opisthorchis viverrini and Haplorchis taichui were investigated by using the HAT-RAPD PCR method. Fourteen arbitrary primers (Operon Technologies) were performed for the generation of polymorphic DNA profiles. The results showed that a 319 bp fragment generated from the OPA-04 primer was expected to be O. viverrini-specific while a 256 bp fragment generated from the OPP-11 primer was considered to be H. taichui-specific. Based on each sequence data, two pairs of specific primers were designed and sequences of each primer were as follows; H. taichui; Hapt_F5′-GGCCAACGCAATCGTCATCC-3′and Hapt_R1 5′-CTCTCGACCTCCTCTAGAAT-3′ which yielded a 170 bp PCR product. For O. viverrini, OpV-1F: 5′-AATCGGGCTGCATATTGACCGAT-3′ and OpV-1R: 5′-CGGTGTTGCTTATTTTGCAGACAA-3′ which generated a 319 bp PCR product. These specific primers were tested for efficacy and specific detection for all parasites DNA samples. The results showed that 170 and 319 bp specific PCR products were generated as equivalent to positive result in H. taichui and O. viverrini, respectively by having no cross-reaction with any parasites tested. PCR conditions are recommended at 68 °C annealing temperature and with 0.5 mM magnesium chloride (Mg Cl₂). Additionally, specific primers developed in this study were effective to determine the presence of both parasites in fish and snail intermediate hosts, which the DNA of O. viverrini was artificially spiked since it is rarely found in northern Thailand.The H. taichui and O. viverrini-specific primers successfully developed in this study can be use for epidemiological monitoring, preventing management and control programs.     

Heifer nutrition during early- and mid-pregnancy alters fetal growth trajectory and birth weight

Maternal nutrient intake during gestation can alter fetal growth. Whilst this has been studied extensively in the sheep, less is known about effects in the bovine. Composite-breed beef heifers were allocated to either a high (H/? = 76 MJ metabolisable energy (ME) and 1.4 kg crude protein (CP)) or low (L/? = 62 MJ ME and 0.4 kg CP daily) nutritional treatment at artificial insemination. Half of each nutritional group changed to an opposite nutritional group at the end of the first trimester (?/H = 82 MJ ME and 1.4 kg CP; ?/L = 62 MJ ME and 0.4 kg CP daily), resulting in 4 treatment groups: HH (n = 16); HL (n = 19); LH (n = 17); LL (n = 19). During the third trimester all heifers were fed the same diets. Fetuses were measured at 4-weekly intervals beginning at day 39 of gestation. Calves were also measured at birth for physical body variables. Low maternal nutrient intake was associated with decreased crown-rump length at day 39 (P < 0.01) and increased thoracic diameter at day 95 (P < 0.01). Umbilical cord diameter was reduced in L/? fetuses in the first trimester (P < 0.05) but was greater in ?/L fetuses in the second trimester compared to their respective H counterparts (P < 0.05). Calf birth weight was decreased in association with ?/L maternal diets (P < 0.05). In conclusion, fetal development of cattle may be affected by maternal nutrition as early as day 39 of gestation. This may be followed by either compensatory fetal growth, or alternatively, preferential fetal tissue growth that is dependant upon maternal nutrition. Clearly, calf birth weight may be altered by maternal nutrition during mid-gestation.     

Galanthamine production by Leucojum aestivum in vitro systems

The callus induction from young fruits of Leucojum aestivum was performed on Murashige–Skoog nutrient medium supplemented with 4 mg/L 2,4 dichlorphenoxyacetic and 2 mg/L 6-benzylamynopurine. Further, by planting the obtained calluses on the same nutrient medium supplemented with 1.15 mg/L α-naphtylacetic acid and 2.0 mg/L 6-benzylamynopurine shoot cultures were established. The growth and galanthamine accumulation of obtained L. aestivum in vitro systems were studied. It was established that the amount of accumulated galanthamine strongly depended on the level of the differentiation. The maximum yield of biomass (17.8 g/L) and the maximum amount of accumulated galanthamine (2.5 mg/L) were achieved after day 35 of submerged cultivation of L. aestivum 80 shoot culture, performed under illumination. Data concerning the time courses of the utilization of the main nutrient components of the medium during cultivation of L. aestivum shoot culture are presented as well.     

Genome size variation and polyploidy in the resurrection plant genus Ramonda: Cytogeography of living fossils

The genus Ramonda includes three preglacial paleoendemic species surviving as the rare resurrection angiosperms of the Northern hemisphere in refugia habitats in the Balkan (Ramonda nathaliae and Ramonda serbica) and Iberian Peninsulas (Ramonda myconi). This study focuses on: assessing genome size and base composition, determining chromosome number and ploidy level in several populations, evaluating inter- and intra-specific variations in DNA content and chromosome number as well as looking for the possible hybridization in the sympatric zones of Balkan species. R. nathaliae and R. myconi are diploid species (2n = 2x = 48) while R. serbica is hexaploid (2n = 6x = 144). The mean 2C DNA values ranged from 2.30 pg for R. nathaliae to 2.59 pg for R. myconi compared to 7.91 pg for R. serbica. The base composition for R. nathaliae was 42.1% GC, for R. myconi 39.9% and for R. serbica 41.2%. In one population of R. serbica the DNA content ranged from 2C = 7.65 to 11.82 pg, revealing different ploidy levels among its individuals. In sympatric populations genome size was intermediary (～5 pg) between the diploid and hexaploid classes which indicates the hybridization ability between R. serbica and R. nathaliae. It appears that polyploidization is the major evolutionary mechanism in the genus Ramonda.     

Optimisation of pollen viability tests for Acacia podalyriifolia and two ploidys of Acacia mearnsii

Acacia mearnsii (black wattle) is a commercially important forestry species in South Africa, grown for its timber as well as its bark. It is, however, also considered to be an alien invader of indigenous vegetation and for this reason the production of a sterile variety would be highly desirable for commercial forestry in South Africa. Previous research on crosses between diploid and tetraploid parent plants to produce triploid progeny has resulted in poor seed set. One possible barrier preventing seed set could be the viability of the pollen used in the cross pollination operations. Thus a study was conducted to test the pollen viability. In vitro agar media germination tests (ACIAR and Brewbaker and Kwack media) were optimised on Acacia podalyriifolia pollen and then used together with vital stain tests (Sigma® DAB peroxidase and p-phenylendiamine) to test pollen germination and viability of A. mearnsii pollen. These were then compared to in vivo pollen germination on the stigma, and were conducted on both diploid and tetraploid pollen mixes. Results showed that the vital stain tests gave significantly (p < 0.05) higher pollen viability than the agar germination tests and were more in agreement with the results from the pollen germination rate on the stigma. For both the diploid and tetraploid pollen mixes tested, there were no significant differences (p > 0.05) between the two agar media germination tests and between the two vital stain tests.     

The site-directed mutation I(L177)H in Rhodobacter sphaeroides reaction center affects coordination of PA and BB bacteriochlorophylls

To explore the influence of the I(L177)H single mutation on the properties of the nearest bacteriochlorophylls (BChls), three reaction centers (RCs) bearing double mutations were constructed in the photosynthetic purple bacterium Rhodobacter sphaeroides, and their properties and pigment content were compared with those of the correspondent single mutant RCs. Each pair of the mutations comprised the amino acid substitution I(L177)H and another mutation altering histidine ligand of BChl P_A or BChl B_B. Contrary to expectations, the double mutation I(L177)H + H(L173)L does not bring about a heterodimer RC but causes a 46 nm blue shift of the long-wavelength P absorbance band. The histidine L177 or a water molecule were suggested as putative ligands for P_A in the RC I(L177)H + H(L173)L although this would imply a reorientation of the His backbone and additional rearrangements in the primary donor environment or even a repositioning of the BChl dimer. The crystal structure of the mutant I(L177)H reaction center determined to a resolution of 2.9 Å shows changes at the interface region between the BChl P_A and the monomeric BChl B_B. Spectral and pigment analysis provided evidence for β-coordination of the BChl B_B in the double mutant RC I(L177)H + H(M182)L and for its hexacoordination in the mutant reaction center I(L177)H. Computer modeling suggests involvement of two water molecules in the β-coordination of the BChl B_B. Possible structural consequences of the L177 mutation affecting the coordination of the two BChls P_A and B_B are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.     

Cloning and characterization of a novel cry8Ab1 gene from Bacillus thuringiensis strain B-JJX with specific toxicity to scarabaeid (Coleoptera: Scarabaeidae) larvae

Isolation of Bacillus thuringiensis (Bt) strain or its cry gene encoding insecticidal crystal protein (ICP) with specific toxicity is of great importance to biological control of insect pests. In this study, by screening 66 strains of Bt isolated from soil samples collected in Shandong Province, China, a new cry8-type gene from Bt strain B-JJX was identified via PCR-RFLP method. This novel gene, cry8Ab1, was cloned from the Bt strain B-JJX and expressed in an acrystalliferous mutant strain HD-73^?. The open reading frame of the cry8Ab1 gene consists of 3543 bp with a G + C content of 37.99% and encodes a protein of 1180 amino acids with a putative MW of 133.3 kDa which was confirmed by SDS-PAGE analysis. The Cry8Ab1 protein was expressed and released as spherical parasporal crystals from Bt acrystalliferous mutant strain HD-73^? along with the presence of spores. In bioassays, this protein was toxic to 3-day-old larvae of the scarabaeid pests, Holotrichia oblita and H. parallela, with an LC₅₀ of 5.72 and 2.00 μg toxin g^?1 soil, respectively. The results are in accordance with the insecticidal activities of the original Bt strain B-JJX, which had an LC₅₀ of 1.72 and 0.96 μg toxin g^?1 soil against H. oblita and H. parallela, respectively.