A brief note on the study of yieldin,a wall-bound protein that regulates the yield threshold of the cell wall

Yielding of plant-cell walls is defined by the mechanical properties of walls such as their extensibility (Φ for in vivo, φ for in vitro cell wall) and yield threshold (Y for in vivo, y for in vitro cell wall). A protein named yieldin, isolated from the cell wall of growing hypocotyls of Vigna unguiculata L. (cowpea), has been demonstrated to regulate the pH dependency of y in the cell wall of the glycerinated hollow cylinder of the cowpea hypocotyl. This mini-review outlines the process of the discovery of yieldin, and also refers to the progress of studies on yieldin: the molecular cloning of yieldin and its immunolocalization in the etiolated cowpea hypocotyl. Electronic Publication     

Thidiazuron promotes in vitro regeneration of wheat and barley

Summary Thidiazuron (TDZ) is a substituted phenylurea which has been shown to be an efficacious regulator of in vitro morphogenesis of many dicot plant species. However, information regarding the effect of TDZ on in vitro regeneration of monocot species is limited. We investigated the effects of TDZ on in vitro regeneration of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) and found that it promoted shoot regeneration from callus in these two important cereal species. Plant regeneration from calluses derived from immature embryo culture of barley and wheat was observed in regeneration media with a wide range of TDZ concentrations (0.045–45 μM). Shoot regeneration from barley calluses was the highest (38.3% for cv. Golden Promise) at 4.5 μM (1 mg l⁻¹) TDZ, while the optimal TDZ level for wheat regeneration seemed to be 0.9 μM (0.2 mg l⁻¹) (87% for cv. Bob White and 49.4% for cv. Hi Line). Roots developed normally when the regenerated wheat and barley shoots from TDZ-containing media were transferred to the rooting medium. Comparison with other plant growth regulators commonly used in wheat and barley regeneration media suggested that TDZ was among the best for in vitro regeneration of wheat and barley. Both authors contributed equally     

Regeneration in subalpine coniferous forests

The regeneration process of a subalpine coniferous forest, a mixed forest ofTsuga diversifolia (dominant species),Abies veitchii, Abies mariessi, andPicea jezoensis var.hondoensis, was studied on the basis of annual ring data. The age class distribution was discontinuous and four age groups occurred in the study plot (30m×30m). The canopy layer was a mosaic of patches (83.8–133.7 m² patch area), which had different mean ages. The recruitment of canopy trees was carried out only by advance regeneration in the plot. The diameter growth ofAbies andPicea exceeded diameter growth ofTsuga in the gap.Abies lived for 200–300 years and their trunks were susceptible to heart rot.Picea lived for 300–400 years andTsuga for more than 400 years. The regeneration process derived from the analysis of the plot consisted of three phases leading to the development of a even-aged patch; (1) the establishment of saplings before a gap opening, (2) the opening of a gap in the canopy and repair of the canopy by advance regenerated saplings dominated by rapid growth species,Abies andPicea, and (3) the dying off of canopy trees as each species reached the end of its life-span, resulting in pure patches of long-livedTsuga.     

Biological and chemical properties of Zingiber zerumbet Smith: a review

Numerous researches have been carried out in Zingiber zerumbet Smith. Since 1944 till date. Z. zerumbet is a monocotyledonous perennial medicinal plant belonging to Zingiberaceae family. It is commonly known as shampoo ginger. It has many different local names depending on their area of collection and vegetation. It is called as ‘Singkha’ in Manipuri. Various compounds have been reported to be isolated from Z. zerumbet and they serve a very potent and reliable drug candidate for the various diseases. They have been investigated for its prospects of effectiveness against number of activities in in vitro as well as in vivo and mechanisms that may be involved in chemo preventive measures and various pharmaceutical studies.     

Regeneration of plantlets fromEnteromorpha (Ulvales,Chlorophyta) protoplasts in axenic culture

High yields of protoplasts have been obtained from vegetative thalli of three species ofEnteromorpha by enzymatic degradation of the cell wall. Several commercial and crude enzymes prepared from the digestive system and hepatopancrease of abalone and top-shell were tested at different concentrations and combinations to evaluate the yield. Commercial enzymes in combination with either abalone or top-shell crude enzymes, consistently produced a high yield of protoplasts from all three species. High regeneration rate (85–95%) occurred in the protoplasts cultured at a density greater than 1.72 × 10³ cells cm⁻² at 20 and 25°C. Light intensities tested in the present study did not affect protoplast wall formation and regeneration. Protoplasts, after regenerating the cell wall, followed different types of developmental patterns under identical culture conditions. In one type some cells underwent repeated cell divisions and formed a round and oval shaped hollow thallus with a single layer of cells. In the second type many cells underwent one or two cell divisions (occasionally no division) and soon matured and discharged many motile spores, which on germination grew into normal plantlets. In the third type some cells divided irregularly to form a mass of callus-like cells (exceptE. prolifera). Culture medium supplemented with either mannitol, sorbitol, dextrose, saccharose or NaCl at higher concentrations (> 0.4 M) inhibited cell division and further differentiation in all species. author for correspondence     

Embryogenic callus induction and plant regeneration media for bentgrasses and annual bluegrass

Summary Embryogenic callus induction and plant regeneration systems have long been established for creeping bentgrass (Agrostis palustris Huds.), but little research has been reported on optimal medium for embryogenic callus induction and plant regeneration in velvet bentgrass (Agrostis canina L.), colonial bentgrass (Agrostis capillaries L.), and annual bluegrass (Poa annua L.). The present study compared 14 callus induction media and eight regeneration media for their efficacies on embryogenic callus induction and plant regeneration in these four species. The embryogenic callus initiation media contained the Murashige and Skoog inorganic salts and vitamins supplemented with 2,4-dichlorophenoxyacetic acid or 3,6-dichloro-anisic acid and 6-benzyladenine. l-Proline or casein hydrolyzate was included in some media to stimulate embryogenic callus formation and plant regeneration. The frequencies of embryogenic callus formation ranged from 0% to 38% and exhibited medium differences within each of the four species. Callus induction media, plant regeneration media, and genotypes affected plant regeneration rates, which varied between 0% and 100%. The embryogenic callus induced on Murashige and Skoog medium supplemented with 500 mgl⁻¹ casein hydrolyzate, 6.63 mg l⁻¹ (30 μM) 3,6-dichloro-anisic acid and 0.5–2.0 mg l⁻¹ (2–9 μM) 6-benzyladenine had much higher regeneration rates than those formed on other callus induction media. Embryogenic callus of annual bluegrass had higher regeneration rates than those of bentgrass species. MSA2D, a media containing 2 mgl⁻¹ (8 μM) 2,4-dichlorophenoxyacetic acid, 100 mgl⁻¹ myo-inositol, and 150 mgl⁻¹ asparagine, was effective in promoting embryogenic callus formation in creeping bentgrass but not in colonial and velvet bentgrasses and annual bluegrass.     

Efficient in vitro regeneration systems for Vaccinium species

Efficient protocols for shoot regeneration from leaf explants suitable for micropropagation as well as for the development of transgenic plants were developed for blueberry (Vaccinium corymbosum) and lingonberry (Vaccinium vitis-idaea) cultivars. Nodal segments were used to initiate in vitro shoot cultures of lingonberry cultivar ‘Red Pearl’ and southern highbush blueberry cultivar ‘Ozarkblue’. In order to develop an optimized regeneration procedure, different types and concentrations of plant growth regulators were tested to induce adventitious shoot regeneration on excised leaves from micropropagated shoots of both cultivars. The effect on percentage regeneration and number of shoots per explant was investigated. Results indicated that zeatin was superior to TDZ and meta-topolin in promoting adventitious shoot formation. A concentration of 20 μM zeatin was most effective in promoting shoot regeneration in both cultivars, in case of ‘Red Pearl’ along with 1 μM NAA. Shoots were either allowed to root in vitro on medium containing IBA or NAA or ex vitro in a fog tunnel. IBA was superior to NAA for induction of root development in vitro in both Vaccinium cultivars. Ex vitro rooting under high humidity was tested with cuttings from mature field-grown plants, from acclimatized tissue culture derived plants and with unrooted in vitro proliferated shoots planted directly. It was found that in vitro shoots rooted better under fog than cuttings from the other plant sources and rooting was equivalent to that achieved in vitro.     

Bruchid pest management in pulses: past practices,present status and use of modern breeding tools for development of resistant varieties

Bruchids (Callosobruchus spp.) are recognised as the most detrimental storage pest of pulses, especially in the tropics and subtropics. They invade matured pods as well as seeds during storage and, to some extent, farming fields, in turn reducing the net yield of the crops. Several approaches including cultural, biological, physical and chemical control measures have been implemented with the aim of managing these pests, but none of these have been successful across time and space. Recently, transgenic‐ and marker‐assisted breeding approaches have appeared as promising tools for the successful management of these pests. Although some efforts have been made on the development of bruchid‐resistant transgenic crops, the cultivars developed are yet to be commercialised worldwide because of various limitations. In contrast, marker‐assisted breeding involving the identification of DNA‐based markers linked to host resistance against bruchids, have shown some success in the quest for the development of bruchid‐resistant cultivar(s). DNA markers linked to bruchid resistance have been identified in various grain legumes, particularly in the genus Vigna, and include mung bean (Vigna radiata), azuki bean (Vigna angularis), rice bean (Vigna umbellata), cowpea (Vigna unguiculata) and black gram (Vigna mungo). After their validation in different genetic backgrounds, these markers could be utilised for marker‐assisted selection and breeding ventures to protect pulse crops. The present study discusses the pros and cons of different approaches for the successful management of the bruchid pests in pulses. The review also highlights about the integrative approach aided with molecular interventions to improve productivity by avoiding losses incurred due to bruchids, and to attain sustainable yields for major pulse crops.     

Effect of radiation on regeneration of Chinese narcissus and analysis of genetic variation with AFLP and RAPD markers

The aim of our study was to establish an efficient in vitro propagation protocol for Chinese narcissus (Narcissus tazetta var. chinensis) to obtain variants of this species using γ-radiation treatment and evaluate the effectiveness of this system for variant induction using amplification fragment length polymorphism (AFLP) and randomly amplified polymorphic DNA (RAPD) analysis. Various doses (5–100 Gy) of gamma rays were applied to investigate the effect of radiation on adventitious bud formation from bulb-scales and the survival rate of plantlets. It was demonstrated that the regeneration of Chinese narcissus was very sensitive to gamma radiation even at low doses. The survival and multiplication rate significantly decreased with an increase of radiation dose. The optimal irradiation dose for survival and mutation induction was approximately 10 Gy. The genetic variations among the regenerants derived from irradiated explants were evaluated by DNA fingerprinting using RAPD and AFLP markers which detected a variation frequency of 8.33% and 15.48% respectively. The high frequency of mutants detected by molecular markers indicated that treatment of in vitro cultures with γ-rays may be an effective way to improve narcissus cultivars.     

Hypericum sp.: essential oil composition and biological activities

Phytochemical composition of Hypericum genus has been investigated for many years. In the recent past, studies on the essential oils (EO) of this genus have been progressing and many of them have reported interesting biological activities. Variations in the EO composition of Hypericum species influenced by seasonal variation, geographic distribution, phenological cycle and type of the organ in which EO are produced and/or accumulated have also been reported. Although many reviews attributed to the characterization as well as biological activities of H. perforatum crude extracts have been published, no review has been published on the EO composition and biological activities of Hypericum species until recently (Crockett in Nat Prod Commun 5(9):1493–1506, 2010; Bertoli et al. in Global Sci Books 5:29–47, 2011). In this article, we summarize and update information regarding the composition and biological activities of Hypericum species EO. Based on experimental work carried out in our laboratory we also mention possible biotechnology approaches envisaging EO improvement of some species of the genus.     

Gap characteristics and gap regeneration in a subalpine coniferous forest on Mt Ontake,central Honshu,Japan

Gap characteristics and gap regeneration were studied in three mature stands belonging to different community types in a subalpine coniferous forest on Mt Ontake, central Honshu, Japan. Gap disturbance regimes were remarkably similar among stands studied; percentage gap area to surveyed area, gap density and mean gap size were 7.3–8.5%, 17.8–20.0 ha⁻¹ and 40.8–42.5 m², respectively. The gap size class distributions were also similar and showed a strong positive skewness with a few large and many small gaps; gaps <40m² were most frequent and gaps >200m² were rare. Forty-five to 66% of gaps were due to the death of single canopy trees. Canopy trees more often died leaving standing dead wood (40–5.7%) or broken trunks (43–49%). Shade tolerantAbies mariesii andAbies veitchii, frequently, andTsuga diversifolia, less frequently, regenerated in gaps, from advance regenerations recruited before gap formation.Picea jezoensis var.hondoensis may regenerate in gaps, from new individuals recruited after gap formation. The breakage of denseSasa coverage and the mineral soils exposed by the uprooted plants that form gaps might provide regeneration opportunities for shade intolerantBetula. Of the important species limited to the ridge site,Chamaecyparis obtusa, frequently, andThuja standishii, infrequently, regenerated from plants alreadyin situ. Regeneration ofPinus parviflora was not seen. Based on the gap characteristics and gap regeneration behaviour of each species described, stand dynamics in each stand are discussed.     

A genetic linkage map for azuki bean [Vigna angularis (Willd.) Ohwi & Ohashi]

To make progress in genome analysis of azuki bean (Vigna angularis) a genetic linkage map was constructed from a backcross population of (V. nepalensis x V. angularis) x V.angularis consisting of 187 individuals. A total of 486 markers—205 simple sequence repeats (SSRs), 187 amplified fragment length polymorphisms (AFLPs) and 94 restriction fragment length polymorphisms (RFLPs) —were mapped onto 11 linkage groups corresponding to the haploid chromosome number of azuki bean. This map spans a total length of 832.1 cM with an average marker distance of 1.85 cM and is the most saturated map for a Vigna species to date. In addition, RFLP markers from other legumes facilitated finding several orthologous linkage groups based on previously published RFLP linkage maps. Most SSR primers that have been developed from SSR-enriched libraries detected a single locus. The SSR loci identified are distributed throughout the azuki bean genome. This moderately dense linkage map equipped with many SSR markers will be useful for mapping a range of useful traits such as those related to domestication and stress resistance. The mapping population will be used to develop advanced backcross lines for high resolution QTL mapping of these traits. O.K. Han, A. Kaga, T. Isemura have contributed equally to this paper.     

Subcellular distribution of selenium during uptake and its influence on mitochondrial oxidations in germinatingVigna radiata L

The metabolic significance of Se in plants is not well documented, though the presence of many selenoenzymes in bacteria and the essentiality of Se in higher animals is established. Since germination is an active process in plant growth and metabolism, the effect of Se was investigated in germinatingVigna radiata L, a nonaccumulating Sedeficient legume. Growth and protein were enhanced in seedlings supplemented with selenium (Se) as sodium selenite in the medium up to 1 μg/mL. The pattern of uptake of⁷⁵Se in the differentiating tissues and the subcellular distribution were investigated. The percentage of incorporation of⁷⁵Se was greater in the mitochondria at the lowest level (0.5 μg/mL) of Se supplementation compared to higher levels of Se exposure. Proteins precipitated from the postmitochondrial supernatant fractions, when separated by means of polyacrylamide gel electrophoresis (PAGE), indicated a major selenoprotein in the seedlings germinated at 2.0 μg/mL Se. In seedlings grown with supplemented Se, enhanced respiratory control ratio and succinate dehydrogenase activity were observed in the mitochondria of tissues, indicative of a role for Se in mitochondrial membrane functions.     

Influence of low-intensity magnetic fields on the development of satellite muscle cells of a newborn rat in primary culture

The influence of Earth magnetic field shielded down to 0.3 μT and static magnetic field (60–160 μT) on the proliferation and differentiation of satellite muscle cells in primary culture has been investigated. A stimulatory effect of static magnetic fields on the rate of the formation of massive multinucleate myotubes and an increase in the intracellular calcium concentration ([Ca²⁺] _i ) have been detected for magnetic fields of the microtesla range. On the other hand, it was shown that the reduction of earth magnetic fields to 0.3 μT leads to inhibition of proliferation and differentiation of skeletal muscle cells in primary culture. Since the formation of contractile myotubes during in vitro experiments is similar to the regeneration of skeletal muscle fibers under muscle damage in vivo, it may be concluded that weak magnetic fields have a strong effect on intracellular processes by influencing all phases of muscle fiber formation. It is necessary to take this fact into consideration when forecasting probable complications of skeletal muscle regeneration during long-term exposure of man to low-intensity magnetic fields and also for the potential use of low static magnetic fields as a tool to recover the affected myogenesis.     

Genome organization in dicots. II. Arabidopsis as a ’bridging species’ to resolve genome evolution events among legumes

Analysis of molecular linkage groups within the soybean (Glycine max L. Merr.) genome reveals many homologous regions, reflecting the ancient polyploidy of soybean. The fragmented arrangement of the duplicated regions suggests that extensive rearrangements, as well as additional duplications, have occurred since the initial polyploidization event. In this study we used comparisons between homoeologous regions in soybean, and the homologous regions in the related diploids Phaseolus vulgaris and Vigna radiata, to elucidate the evolutionary history of the three legume genomes. Our results show that there is not only conservation of large regions of the genomes but that these conserved linkage blocks are also represented twice in the soybean genome. To gain a better understanding of the process of genome evolution in dicots, molecular comparisons have been extended to another well-studied species, Arabidopsis thaliana. Interestingly, the conserved regions we identified in the legume species are also relatively conserved in Arabidopsis. Our results suggest that there is conservation of blocks of DNA between species as distantly related as legumes and brassicas, representing 90 million years of divergence. We also present evidence for an additional, presumably earlier, genome duplication in soybean. These duplicated regions were only recognized by using Arabidopsis as a ’bridging’ species in the genome comparisons. Received: 10 October 2000 / Accepted: 13 January 2001     

An efficient method for <Emphasis Type="Italic">in vitro</Emphasis> regeneration of leafy spurge (<Emphasis Type="Italic">Euphorbia esula</Emphasis> L.)

Leafy spurge (Euphorbia esula L.) is a perennial, invasive weed used as a model to study invasive plant behavior, because molecular tools (such as a deep expressed sequence tag database and deoxyribonucleic acid microarrays) have been developed for this species. However, the lack of effective in vitro regeneration and genetic transformation systems has hampered molecular approaches to study leafy spurge. In this study, we describe an efficient in vitro regeneration system. Three highly regenerative lines were selected by screening the in vitro regeneration capabilities of stem explants of 162 seedlings. The effects of various culture conditions on in vitro regeneration were then evaluated based on explant competence to form calluses and shoots. High rates of shoot regeneration can be obtained using a growth medium containing 1× woody plant basal medium and 1× Murashige and Skoog (MS) basal salts, 1× MS vitamins, 1.11 μM 6-benzylaminopurine, 1.97 μM indole-3-butyric acid, and 3% sucrose, pH 5.6–5.8. After 30 d culture, multiple shoots formed either directly from the stem or indirectly from the callus. This method is a requisite for the development of genetic transformation systems for leafy spurge and may be used to develop in vitro regeneration techniques for other species in the Euphorbiaceae.     

Regeneration and transformation in adult plants of Campanula species

Adult plants are known for recalcitrance when it comes to adventitious organ formation and regeneration. Methods used for regeneration in explants from seedlings of Campanula carpatica failed to work for explants from adult plants of the same species. The present investigation generated efficient regeneration methods for mature specimens of four species of Campanula, C. carpatica, C. haylodgensis, C. portenschlagiana and C. poscharskyana. Petiole explants from dark-grown in vitro shoot cultures grown from nodal cuttings of adult plants regenerated successfully (95%), while explants from light-grown in vitro shoot cultures and greenhouse-grown plants regenerated at 12% and zero percentage, respectively. Dark-treatment, along with media manipulation with plant growth regulators, further enhanced regenerative capacity of the explants. A MS-based medium containing 10mg l ⁻¹ TDZ and 0.25 mg l⁻¹ NAA was the most efficient regeneration medium. Transgenic shoots from C. carpatica (3%) and C. haylodgensis (1%) and transgenic callus from all species were produced using Agrobacterium tumefaciens, and transformation was confirmed by histochemical and Southern blot analyses. Protocols developed in this study may be useful for achieving efficient regeneration and transformation of recalcitrant adult plants.     

Differential effects of amino acid analogs on growth and heterocyst differentiation in two nitrogen-fixing blue-green algae

Effects of a few amino acid analogs on growth and heterocyst differentiation have been studied in two nitrogen-fixing species ofAnabaena. All the analogs except α-methyl-dl-aspartic acid inhibited growth. Exposure ofAnabaena doliolum, todl-5-fluorotryptophan anddl-p-fluorophenylalanine caused pronounced fragmentation of filaments into single cells. At low concentrations (0.01 mM), α-methyl-dl-aspartic acid stimulated growth of the strain ofA. doliolum as well as the strain of the second (unidentified)Anabaena species. Ethionine,dl-p-fluorophenylalanine,dl-5-fluorotryptophan, and canavanine blocked heterocyst differentiation, whereas α-methyl-dl-aspartic acid, α-methyl-dl-methionine,N-o-nitrophenylsulfenyl-l-tryptophan, norleucine, andS-2-aminoethyl-l-cysteine did not show any significant effect. Treatment with 7-azatryptophan,dl-β-hydroxynorvaline,l-methionine-dl-sulfoximine,l-methionine sulfone, and β-2-thienyl-dl-alanine led to a twofold increase in heterocyst frequency. Possible modes of action of the analogs in growth inhibition and changes in heterocyst frequency are discussed.     

Thidiazuron-induced high-frequency axillary and adventitious shoot regeneration in Vigna radiata (L.) Wilczek

Summary Prolific shoot regeneration was achieved in mungbean Vigna radiata (L.) Wilczek from 3-d-old in vitro cotyledonary node and hypocotyl explants from seedlings derived from mature seeds on Murashige and Skoog (MS) medium supplemented with thidiazuron (TDZ) (0.9 μM). An initial exposure to TDZ for 20 d and three successive transfers to fresh medium with reduced thidiazuron levels (0.09 μM) resulted in the regeneration of 104 shoots/explant from the cotyledon and 30 shoots/explant from the hypocotyl. Thidiazuron-associated abnormalities such as short compact shoots, fasciation and leaf growth in the form of rosettes were observed in shoots regenerated from hypocotyl explants. Both axillary and adventitious shoot formation from the explants were confirmed by histology. Through repectitive cycles of regeneration in the presence of TDZ, the number of shoots that could be obtained from the two explant classes within 80 d was significantly higher than with previous reports in mungbean