Standardization of a protocol for micropropagation of Eupatorium glandulosum L. an important medicinal plant

The presence of residual female fertility in most of the parthenocarpic banana accessions encourages the banana breeder to develop new hybrids through conventional breeding. Desirable trait can be fixed in the first generation of hybrid progenies, but the evaluation of these hybrids in field is the time-consuming process owing to non-availability of uniform suckers/planting material. This can be overcome by developing multiple shoots from single embryo in a short period of time through embryo culture. A protocol for in vitro multiplication of plantlets from zygotic embryos was standardized in seeded accessions. Multiple shoots from zygotic embryos were achieved up to 55.2% and 64.1% in seeded accessions of Musa acuminata and M. velutina respectively in medium supplemented with 17.76 µM of BAP. The Single shoot derived (only germination) from zygotic embryos was decapitated and the apical meristem were disturbed for further multiple shoot formation in media supplemented with 17.76 µM of BAP. Present studies revealed that in total 75% and 91% of the M. acuminata and M.velutina embryos were able to produce multiple shoot from single embryo by manipulating the media composition and decortications technique. The above protocol was applied for zygotic embryos obtained from controlled pollination (18 cross combinations) and open pollination (nine accessions) of various genomic groups (ABB, AAB, AA). The multiple shoots derived from zygotic embryos and plantlet germinated from zygotic embryos was examined for genetic fidelity analysis by SSR markers.

     

Sectional relationships in the genus <Emphasis Type="Italic">Musa</Emphasis> L. inferred from the PCR-RFLP of organelle DNA sequences

The objective of this study was to construct a molecular phylogeny of the genus Musa using restriction-site polymorphisms of the chloroplast (cpDNA) and mitochondrial DNA (mtDNA). Six cpDNA and two mtDNA sequences were amplified individually in polymerase chain reaction (PCR) experiments in 13 species representing the four sections of Musa. Ensete ventricosum (W.) Ch. was used as the outgroup. The amplified products were digested with ten restriction endonucleases. A total of 79 restriction-site changes were scored in the sample. Wagner parsimony using the branch and bound option defined two lines of evolution in Musa. One lineage comprised species of the sections Australimusa and Callimusa which have a basic number of x = 10 chromosomes, while most species of sections Eumusa and Rhodochlamys (x = 11) formed the other lineage. Musa laterita Cheesman (Rhodochlamys) had identical organellar genome patterns as some subspecies of the Musa acuminata Colla complex. The progenitors of the cultivated bananas, M. acuminata and Musa balbisiana Colla, were evolutionarily distinct from each other. Musa balbisiana occupied a basal position in the cladogram indicating an evolutionarily primitive status. The close phylogenetic relationship between M. laterita and M. acuminata suggests that species of the section Rhodochlamys may constitute a secondary genepool for the improvement of cultivated bananas.Communicated by H.F. Linskens     

Study of Resistance of Musa acuminata to Fusarium oxysporum using RAPD markers

Suckers collected from different populations of Musa acuminata ssp. malaccensis were found to be highly resistant to race 4 of Fusarium oxysporum f. sp. cubense (FOC) suggesting that local wild banana populations co-evolved with the pathogen. Seedlings from these wild banana plants segregated for resistance to the pathogen. The infected seedlings were characterized based on external and internal symptoms and the variable response to FOC was mainly due to the genetic factors. Using the technique of random amplified polymorphic DNA (RAPD), 96 major amplification products from 15 primers were identified. Only 10 out of 96 markers were monomorphic and shared among the seed progenies, whereas the remaining 86 were highly polymorphic. Three primers showed banding patterns specific to resistant or susceptible seedlings. These results showed the great potential of the wild Musa acuminata ssp. malaccensis as a source for banana improvement and also for the synthesis of segregating populations for linkage mapping, gene cloning and DNA markers related to FOC resistance.     

Synthesis of 2-(4-Hydroxyphenyl)naphthalene-1,8-dicarboxylic Anhydride,a Phytoalexin Isolated from Unripe Banana (Musa acuminata)

2-(4-Hydroxyphenyl)naphthalene-1,8-dicarboxylic anhydride, a component of the phytoalexin that has been isolated from the peel of unripe banana (Musa acuminata), was synthesized from 3-bromoacenaphthene.     

Plant regeneration from embryogenic suspension cultures of Musa acuminata cv. Mas (AA)

Embryogenic callus was established using immature male flower of Musa acuminata cv. Mas. After 5–6 months of culture, embryogenic callus was obtained at 21.75±11.9 from 750 immature male flower clusters with translucent somatic embryos proliferated from the whitish friable callus. It was observed that flower clusters ranging from 4 to 11 responded to form embryogenic callus and out of which 3–10 somatic embryos were formed per flower cluster. Embryogenic callus were obtained at a percentage of 10.00±0.3 on M1 medium initially supplemented with 18 M 2,4-dichlorophenoxyacetic acid (2,4-D) for 3 months and subsequently transferred to the same media with reduced 2,4-D (9 M) for the next 2–3 months. Embryos developed into translucent spheres and slightly torpedo shaped embryos in suspension cultures. Plantlets were obtained on medium M4 supplemented with 0.8M BA, at an average regeneration rate of 13.00±0.58.     

Identification of cytoplasmic ancestor gene-pools of <Emphasis Type="Italic">Musa acuminata</Emphasis> Colla and <Emphasis Type="Italic">Musa balbisiana</Emphasis> Colla and their hybrids by chloroplast and mitochondrial haplotyping

Cytoplasmically inherited characters such as resistance to viral and fungal diseases, determination of starch types, crop yield, resistance to low or high temperature often contribute to the advantageous phenotypic traits of plants. In the present study, our goal was to elucidate the genealogy of cytoplasmic genomes chloroplast and mitochondria in banana. Banana breeding is rather complicated because of the low fertility and mostly unknown origin of the edible cultivars, therefore, knowledge on the putative fertile ancestors of cytoplasmic genomes chloroplast and mitochondria would be beneficial for breeding programmes. Based on the established marker systems distinct species specific gene-pools could be identified for both chloroplast and mitochondrial genomes for Musa acuminata and Musa balbisiana wild types, respectively. Detailed analysis of the species specific chloroplast and mitochondrial gene-pools of M. acuminata and M. balbisiana revealed six chloroplast and seven mitochondrial gene-pools in the analysed accessions. Comparative analysis of the haplotypes revealed the presence of Primary Centers of origin for both chloroplast and mitochondrial genomes of both species supporting the idea of common origin of these genomes. Cytotypes representing combinations of M. acuminata chloroplast and mitochondrial gene-pools were identified in majority of the analysed hybrid cultivars. A single M. acuminata cytotype was present in the majority of the analysed cultivars, which combination was not detected in any of the wild types. On the other part a single balbisiana cytotype was identified participating in the formation of interspecies hybrids. The strong preference for the presence of certain cytoplasmic gene-pools in cultivars may indicate hundreds of years of natural as well as of farmers’ selection supplementing the phenotypic traits provided by the nuclear genome. Based on the present results the present day subspecies classification of M. acuminata is also discussed.     

First record of the emesine assassin bug genus Emesopsis (Heteroptera: Reduviidae) from Vietnam, with descriptions of two new species

The emesine assassin bug genus Emesopsis is reported from Vietnam for the first time and is briefly diagnosed, and two new species of the genus, E. longipilosa and E. albispinosa, are described. They were collected by beating dead, drooping leaves of the banana, Musa acuminata (Musaceae).     

Distribution of Lateral Root Primordia in Root Tips of Musa acuminata Colla

The distribution of lateral root primordia in Musa acuminatashows discrete elements of pattern, a major element of whichis the rather regular spacing of laterals along protoxylem-basedranks. There is some co-ordination of positions of lateralsin different ranks. Laterals are apparently not initiated ina single acropetal sequence within the root tip as a whole althoughthey are initiated in acropetal sequence within each rank. Musa acuminata, banana, roots, lateral roots     

Genetic Diversity of the Wild Banana Musa acuminata Colla in Malaysia as Evidenced by AFLP

Musa acuminata Colla (Musaceae), the wild progenitor of thecultivated banana, is highly variable in Malaysia and presentsseveral unresolved nomenclatural problems. AFLP was employedto distinguish among three subspecies of Musa acuminata(subsp.truncata and subsp. malaccensis from peninsular Malaysia andsubsp. microcarpa from Borneo) and to examine whether subsp.truncata is a distinct taxon. Eight primer combinations revealedmolecular markers specific for each of the three taxa. UPGMAcluster analysis showed the three taxa were distinct. Subspeciesmalaccensis which is endemic in peninsular Malaysia and subsp.microcarpa which is endemic in Borneo were found to be moresimilar to each other in their DNA patterns than they are tosubsp. truncata, which is endemic to peninsular Malaysia. Sincesubsp. truncata is genetically separate from subsp. malaccensisand subsp.microcarpa , it cannot be regarded as synonymous witheither of these subspecies. This paper sheds light on the nomenclatureof the three subspecies of Musa acuminata. Copyright 2001 Annalsof Botany Company Musa acuminata Colla, truncata, malaccensis, microcarpa, Musaceae, wild banana, genetic diversity, AFLP, DNA fingerprinting     

A BAC end view of the <Emphasis Type="Italic">Musa acuminata</Emphasis> genome

Background  

Musa species contain the fourth most important crop in developing countries. Here, we report the analysis of 6,252 BAC end-sequences, in order to view the sequence composition of the Musa acuminata genome in a cost effective and efficient manner.     

RFLP-based phylogeny of Musa species in Papua New Guinea

Summary Random genomic probes were used to detect restriction fragment length polymorphisms (RFLPs) in 26 accessions of Musa representing eight species from Papua New Guinea (PNG), M. textilis, M. jackeyi and one accession of Ensete. Ninety-eight phylogenetically informative characters were scored and analyzed cladistically and phenetically. Results generally agreed with previous morphology-based phylogenetic analyses. However, the closest wild relative of the edible M. fehi (fe'i banana) appears to be M. lolodensis. Musa angustigemma is sister species with M. boman and M. jackeyi and is distinct from M. peekelii, with which it is often united. Musa boman is unambiguously placed in section Australimusa. The diploid parthenocarpic landraces of section Musa unique to PNG are closely related to, but apparently distinct from, M. acuminata ssp. banksii. The evolution of the fe'i bananas and the M. acuminata-derived diploid landraces of PNG are discussed.     

Mechanisms of haplotype divergence at the <Emphasis Type="Italic">RGA08</Emphasis> nucleotide-binding leucine-rich repeat gene locus in wild banana <Emphasis Type="Italic">(Musa balbisiana)</Emphasis>

Background  

Comparative sequence analysis of complex loci such as resistance gene analog clusters allows estimating the degree of sequence conservation and mechanisms of divergence at the intraspecies level. In banana (Musa sp.), two diploid wild species Musa acuminata (A genome) and Musa balbisiana (B genome) contribute to the polyploid genome of many cultivars. The M. balbisiana species is associated with vigour and tolerance to pests and disease and little is known on the genome structure and haplotype diversity within this species. Here, we compare two genomic sequences of 253 and 223 kb corresponding to two haplotypes of the RGA08 resistance gene analog locus in M. balbisiana "Pisang Klutuk Wulung" (PKW).     

An easy and efficient protocol in the production of pflp transgenic banana against Fusarium wilt

This study describes an efficient protocol for Agrobacterium tumefaciens-mediated transformation of two subgroups of genotype AAA bananas (Musa acuminata cv. Pei Chiao and Musa acuminata cv. Gros Michel). Instead of using suspension cells, cauliflower-like bud clumps, also known as multiple bud clumps (MBC), were induced from sucker buds on MS medium containing N ⁶-Benzylaminopurine (BA), Thidiazuron (TDZ), and Paclobutrazol (PP333). Bud slices were co-cultivated with A. tumefaciens C58C1 or EHA105 that carry a plasmid containing Arabidopsis root-type ferredoxin gene (Atfd3) and a plant ferredoxin-like protein (pflp) gene, respectively. These two strains showed differences in transformation efficiency. The EHA105 strain was more sensitive in Pei Chiao, 51.3% bud slices were pflp-transformed, and 12.6% slices were Atfd3-transformed. Gros Michel was susceptible to C58C1 and the transformation efficiency is 4.4% for pflp and 13.1% for Atfd3. Additionally, gene integration of the putative pflp was confirmed by Southern blot. Resulting from the pathogen inoculation assay, we found that the pflp transgenic banana exhibited resistance to Fusarium oxysporum f. sp. cubense tropical race 4. This protocol is highly advantageous to banana cultivars that have difficulties in setting up suspension cultures for the purpose of quality improvement through genetic transformation. In addition, this protocol would save at least 6 months in obtaining explants for transformation and reduce labor for weekly subculture in embryogenic cell suspension culture systems.     

影响体胚发生途径香蕉(Musa spp.,AAB Group)植株再生的因素

香蕉品种‘Agbagaba'和‘Orishele'的胚性细胞悬浮系(ECS)在液体培养基中分别预培养1和2周后,将其接种在RD1和M3培养基上,于光照或黑暗条件下进行体胚的再生.从沉积细胞体积(SCV)为1 mL(1 mL SCV)的ECS获得的再生体胚数量因预培养时间、再生培养基的种类及培养条件的不同而异.植株的再生率及从1 mL SCV的ECS获得的再生植株数量也受上述体胚再生条件的间接影响.     

Relationship Between Lateral Root Primordia in Different Ranks

Comparisons with theoretical random distributions indicate thatthe longitudinal positional relationships between lateral rootsin different ranks are random in roots of Musa acuminata, Pistiastratiotes and i, species in which lateral root primordia arisein the root tip. In Potentilla palustris, where lateral rootprimordia arise further back in the root, there is a deficiencyof close spacings, which indicates that there is some interactionbetween ranks. Musa acuminata, Pistia stratiotes, Pontederia cordat, Potentilla palustris, roots, lateral roots, pattern     

SAMPL: A technique for somaclonal variation fingerprinting inMusa

SAMPL primers designed for genomic profiling in chickpea (Cicer arietinum L.) were tested for their applicability to fingerprinting of DNA of banana cultivars and soma-clonal variants. Most of the chickpea primers allowed amplification of genomic DNA of banana and detection of sequence polymorphisms within theMusa acuminata genome (A). Our results demonstrate that the highly resolving SAMPL technique is useful in banana genomics, especially for the distinction and characterization of commercially important cultivars and promising somaclonal variants containing the A genome.     

Increasing in vitro germination of Musa balbisiana seed

Seeds of Musa balbisiana were soaked in water for five days prior to excision of embryos. Embryos with their longitudinal axis laid flat and half-way embedded on agar-solidified medium produced the highest germination and the most desirable plantlet characteristics. Germination in vitro was 94% within 7 days compared to 50% after 54 days for greenhouse-sown seeds.     

Genome ancestry mosaics reveal multiple and cryptic contributors to cultivated banana

Hybridizations between closely related species commonly occur in the domestication process of many crops. Banana cultivars are derived from such hybridizations between species and subspecies of the Musa genus that have diverged in various tropical Southeast Asian regions and archipelagos. Among the diploid and triploid hybrids generated, those with seedless parthenocarpic fruits were selected by humans and thereafter dispersed through vegetative propagation. Musa acuminata subspecies contribute to most of these cultivars. We analyzed sequence data from 14 M. acuminata wild accessions and 10 M. acuminata‐based cultivars, including diploids and one triploid, to characterize the ancestral origins along their chromosomes. We used multivariate analysis and single nucleotide polymorphism clustering and identified five ancestral groups as contributors to these cultivars. Four of these corresponded to known M. acuminata subspecies. A fifth group, found only in cultivars, was defined based on the ‘Pisang Madu’ cultivar and represented two uncharacterized genetic pools. Diverse ancestral contributions along cultivar chromosomes were found, resulting in mosaics with at least three and up to five ancestries. The commercially important triploid Cavendish banana cultivar had contributions from at least one of the uncharacterized genetic pools and three known M. acuminata subspecies. Our results highlighted that cultivated banana origins are more complex than expected – involving multiple hybridization steps – and also that major wild banana ancestors have yet to be identified. This study revealed the extent to which admixture has framed the evolution and domestication of a crop plant.     

Evaluation of terrestrial plants extracts for uranium sorption and characterization of potent phytoconstituents

Sorption capacity of four plants (Funaria hygrometrica, Musa acuminata, Brassica juncea and Helianthus annuus) extracts/fractions for uranium, a radionuclide was investigated by EDXRF and tracer studies. The maximum sorption capacity, i.e., 100% (complete sorption) was observed in case of Musa acuminata extract and fractions. Carbohydrate, proteins, phenolics and flavonoids contents in the active fraction (having maximum sorption capacity) were also determined. Further purification of the most active fraction provided three pure molecules, mannitol, sorbitol and oxo-linked potassium oxalate. The characterization of isolated molecules was achieved by using FTIR, NMR, GC-MS, MS-MS, and by single crystal-XRD analysis. Of three molecules, oxo-linked potassium oxalate was observed to have 100% sorption activity. Possible binding mechanism of active molecule with the uranyl cation has been purposed.     

Micropropagation of Camptotheca acuminata decaisne from axillary buds, shoot tips, and seed embryos in a tissue culture system

Summary Micropropagation of the anti-cancer plant Camptotheca acuminata Decaisne from axillary buds and seed embryos was investigated. Axillary buds from greenhouse seedlings required a period of culture in media free of N⁶-benzyladenine (BA) before multiple shoot induction began. Direct induction of multiple shoots on BA-containing medium resulted in high mortality of the axillary buds. Multiple shoot induction from the greenhouse axillary buds was best achieved on B5 with 4.4 μM BA+0.5μM α-naphthaleneacetic acid, forming an average of three 2-mm tall shoots per bud in 8 wk. Elongation of these multiple shoots was successful at a lower BA level (0.22 μM) on B5 medium. Both in vitro and ex vitro rooting of the microcuttings was feasible with indole-3-butyric acid in the culture media, but ex vitro rooting led to high plantlet survival. Seed embryos were not ideal explants for multiple shoot induction. Shoot tips and axillary buds of in vitro-germinated seedlings showed an optimal multiple shoot formation on B5 with 8.9 μM BA, double the optimal BA level for greenhouse axillary buds. Using axillary buds to propagate C. acuminata plants in vitro is feasible for mass propagation of desired clonal lines high in camptothecin concentrations.