Female gametophyte and seed development in Musella lasiocarpa (Musaceae), a monotypic genus endemic to Southwestern China

2007 ◽  
Vol 85 (10) ◽  
pp. 964-975 ◽  
Author(s):  
Chun-Ying Xue ◽  
Hong Wang ◽  
De-Zhu Li
Keyword(s):  
Seed Development ◽  
Female Gametophyte ◽  
Wild Population ◽  
Embryo Sac ◽  
Single Species ◽  
Ex Situ ◽  
Southwestern China ◽  
Conservation Strategies ◽  
Female Sterility ◽  
Monotypic Genus

Musella is a monotypic genus composed of a single species, Musella lasiocarpa (Franch.) C.Y. Wu ex H.W. Li, endemic to Southwestern China. The genus status of Musella remains controversial. Musella had been placed first in Musa , then in Ensete , and back to Musa before its monotypic status was recognized. Musella was reported to be extinct in the wild and maintained through cultivation only via vegetative propagation through sprouting of rhizomes. In this study, female gametophyte and seed development of Musella are described to assess its systematic position and possible reasons why the wild population is now extinct. The ovules are anatropous, bitegmic, and crassinucellar. The micropyle is formed by both integuments. The megaspore mother cell undergoes meiotic division and forms a linear megaspore triad or more rarely, a T-shaped megaspore tetrad. The chalazal megaspore develops into a Polygonum type embryo sac. A nucellar pad forms, and a hypostase differentiates. Fertilization is porogamous. Endosperm formation is of the nuclear type. The zygote degenerates and so the process by which the embryo develops, if it does, remains unclear. An operculum, micropylar collar, and chalazal chamber form in mature seeds. The storage tissue is mainly endosperm containing large, compound starch grains and some perisperm. The seed coat has lignified exotestal cells, 25–30 cell layers of sclerotic mesotestal cells, and unspecialized endotesta cells; the tegment consists of two layers of longitudinally elongated cells. The seed is inviable. After comparison with the other Musaceae s. str. taxa using embryological and botanical features, we conclude that Musella should be a distinct genus. Female sterility in Musella may be the main reason why the wild population is extinct. Based on these findings, we propose conservation strategies for this endemic species, including habitat protection as well as ex-situ conservation.

scholarly journals Embryo and Endosperm Development Is Disrupted in the Female Gametophytic capulet Mutants of Arabidopsis

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1911-1925
Author(s):  
Paul E Grini ◽  
Gerd Jürgens ◽  
Martin Hülskamp
Keyword(s):  
Seed Development ◽  
Transgene Expression ◽  
Female Gametophyte ◽  
Higher Plants ◽  
Embryo Sac ◽  
Endosperm Development ◽  
Wild Type ◽  
Paternal Genome ◽  
Early Stages ◽  
Gametic Imprinting

Abstract The female gametophyte of higher plants gives rise, by double fertilization, to the diploid embryo and triploid endosperm, which develop in concert to produce the mature seed. What roles gametophytic maternal factors play in this process is not clear. The female-gametophytic effects on embryo and endosperm development in the Arabidopsis mea, fis, and fie mutants appear to be due to gametic imprinting that can be suppressed by METHYL TRANSFERASE1 antisense (MET1 a/s) transgene expression or by mutation of the DECREASE IN DNA METHYLATION1 (DDM1) gene. Here we describe two novel gametophytic maternal-effect mutants, capulet1 (cap1) and capulet2 (cap2). In the cap1 mutant, both embryo and endosperm development are arrested at early stages. In the cap2 mutant, endosperm development is blocked at very early stages, whereas embryos can develop to the early heart stage. The cap mutant phenotypes were not rescued by wild-type pollen nor by pollen from tetraploid plants. Furthermore, removal of silencing barriers from the paternal genome by MET1 a/s transgene expression or by the ddm1 mutation also failed to restore seed development in the cap mutants. Neither cap1 nor cap2 displayed autonomous seed development, in contrast to mea, fis, and fie mutants. In addition, cap2 was epistatic to fis1 in both autonomous endosperm and sexual development. Finally, both cap1 and cap2 mutant endosperms, like wild-type endosperms, expressed the paternally inactive endosperm-specific FIS2 promoter GUS fusion transgene only when the transgene was introduced via the embryo sac, indicating that imprinting was not affected. Our results suggest that the CAP genes represent novel maternal functions supplied by the female gametophyte that are required for embryo and endosperm development.

scholarly journals The mac1 Gene: Controlling the Commitment to the Meiotic Pathway in Maize

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 1009-1020 ◽  
Author(s):  
William F Sheridan ◽  
Nadezhda A Avalkina ◽  
Ivan I Shamrov ◽  
Tatyana B Batyea ◽  
Inna N Golubovskaya
Keyword(s):  
Female Gametophyte ◽  
Embryo Sac ◽  
Flowering Plants ◽  
Normal Female ◽  
Ovule Development ◽  
Partial Sterility ◽  
Embryo Sac Formation ◽  
Female Gametophyte Development ◽  
Normal Meiosis ◽  
Pleiotropic Mutation

Abstract The switch from the vegetative to the reproductive pathway of development in flowering plants requires the commitment of the subepidermal cells of the ovules and anthers to enter the meiotic pathway. These cells, the hypodermal cells, either directly or indirectly form the archesporial cells that, in turn, differentiate into the megasporocytes and microsporocytes. We have isolated a recessive pleiotropic mutation that we have termed multiple archesporial cells1 (macl) and located it to the short arm of chromosome 10. Its cytological phenotype suggests that this locus plays an important role in the switch of the hypodermal cells from the vegetative to the meiotic (sporogenous) pathway in maize ovules. During normal ovule development in maize, only a single hypodermal cell develops into an archesporial cell and this differentiates into the single megasporocyte. In macl mutant ovules several hypodermal cells develop into archesporial cells, and the resulting megasporocytes undergo a normal meiosis. More than one megaspore survives in the tetrad and more than one embryo sac is formed in each ovule. Ears on mutant plants show partial sterility resulting from abnormalities in megaspore differentiation and embryo sac formation. The sporophytic expression of this gene is therefore also important for normal female gametophyte development.

scholarly journals Cryopreservation of Woody Crops: The Avocado Case

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 934
Author(s):  
Chris O’Brien ◽  
Jayeni Hiti-Bandaralage ◽  
Raquel Folgado ◽  
Alice Hayward ◽  
Sean Lahmeyer ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Ex Situ Conservation ◽  
Plant Genetic Resources ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Recalcitrant Seed ◽  
In Vitro Storage ◽  
Germplasm Collections ◽  
Seed Crops

Recent development and implementation of crop cryopreservation protocols has increased the capacity to maintain recalcitrant seeded germplasm collections via cryopreserved in vitro material. To preserve the greatest possible plant genetic resources globally for future food security and breeding programs, it is essential to integrate in situ and ex situ conservation methods into a cohesive conservation plan. In vitro storage using tissue culture and cryopreservation techniques offers promising complementary tools that can be used to promote this approach. These techniques can be employed for crops difficult or impossible to maintain in seed banks for long-term conservation. This includes woody perennial plants, recalcitrant seed crops or crops with no seeds at all and vegetatively or clonally propagated crops where seeds are not true-to-type. Many of the world’s most important crops for food, nutrition and livelihoods, are vegetatively propagated or have recalcitrant seeds. This review will look at ex situ conservation, namely field repositories and in vitro storage for some of these economically important crops, focusing on conservation strategies for avocado. To date, cultivar-specific multiplication protocols have been established for maintaining multiple avocado cultivars in tissue culture. Cryopreservation of avocado somatic embryos and somatic embryogenesis have been successful. In addition, a shoot-tip cryopreservation protocol has been developed for cryo-storage and regeneration of true-to-type clonal avocado plants.

Genetic gap analysis of wildHordeumtaxa

2012 ◽  
Vol 10 (3) ◽  
pp. 242-253 ◽  
Author(s):  
Holly Vincent ◽  
Roland von Bothmer ◽  
Helmut Knüpffer ◽  
Ahmed Amri ◽  
Jan Konopka ◽  
...  
Keyword(s):  
Gap Analysis ◽  
Plant Genetic Resources ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Gene Pools ◽  
Barley Plant ◽  
Genetic Reserve ◽  
Set Up ◽  
Global Inventory

To facilitate the updating ofin situandex situconservation strategies for wild taxa of the genusHordeumL., a combined ecogeographic survey and gap analysis was undertaken. The analysis was based on the Global Inventory of Barley Plant Genetic Resources held by ICARDA plus additional datasets, resulting in a database containing 17,131 wildHordeumaccessions. The analysis concluded that a genetic reserve should be established in the Mendoza Province of Argentina, as this is the most species-rich area globally forHordeum. A network of reserves should also be set up across the Fertile Crescent in Israel, Palestine, Syria, Jordan, Lebanon and Turkey to provide effective conservation within the centres of diversity for gene pools 1B (Hordeum vulgaresubsp.spontaneum(C. Koch) Thell.) and 2 (Hordeum bulbosumL.). The majority of the species were deemed under-collected, so further collecting missions are required worldwide where possible. Althoughex situandin situconservation strategies have been developed, there needs to be further investigation into the ecological environments thatHordeumspecies occupy to ensure that any adaptive traits expressed are fully conserved. Additionally, studies are required to characterize existing collections and test the viability of rare species accessions held in genebanks to determine whether furtherex situcollections are required alongside the proposedin situconservation.

scholarly journals Co-occurring cryptic species pose challenges for conservation: a case study of the African dwarf crocodile (Osteolaemusspp.) in Cameroon

Oryx ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 584-590 ◽  
Author(s):  
Nicole L. Smolensky
Keyword(s):  
Cryptic Species ◽  
Conservation Status ◽  
Taxonomic Revision ◽  
Single Species ◽  
Conservation Strategies ◽  
Encounter Rates ◽  
Distribution Maps ◽  
Species Complexes ◽  
Threatened Taxa ◽  
Population Structures

AbstractThe conservation status of threatened taxa may be obfuscated by the detection of cryptic species complexes, in both vertebrate and invertebrate species. African dwarf crocodiles (Osteolaemusspp.) are hunted throughout their range but their conservation status is unknown. Few population assessments have been carried out and there has been a taxonomic revision of the number of species in the genus. The similar morphologies ofOsteolaemus tetraspisandOsteolaemus osbornipose a challenge for conservation in Cameroon, where they are still managed as a single species. Nocturnal spotlight surveys were conducted in three regions during August–November 2010 and December 2011–February 2012 to provide population assessments ofO. tetraspisandO. osborniand raise awareness of the two species in Cameroon. The mean encounter rates ofO. tetraspisandO. osborniwere 1.02 ± SD 1.34 (65 individuals in 39 surveys) and 0.61 ± SD 0.38 (three in four surveys) crocodiles per km, respectively. TheO. tetraspispopulation comprised juveniles predominantly and had a male-biased sex ratio. The fewO. osbornidetected comprised both adults and juveniles. Both species are threatened in Cameroon, based on low encounter rates, young population structures and the threats of habitat loss and hunting pressure. This study provides distribution maps and serves as a baseline to quantify population trends and inform conservation strategies.

scholarly journals In vitro performance in cotton plants with different genetic backgrounds: the case of Gossypium hirsutum in Mexico, and its implications for germplasm conservation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7017 ◽  
Author(s):  
Alejandra Hernández-Terán ◽  
Ana Wegier ◽  
Mariana Benítez ◽  
Rafael Lira ◽  
Tania Gabriela Sosa Fuentes ◽  
...  
Keyword(s):  
Gossypium Hirsutum ◽  
Biodiversity Conservation ◽  
Crop Production ◽  
Statistical Tests ◽  
Germplasm Conservation ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Wild Germplasm ◽  
Wild Cotton

One of the best ex situ conservation strategies for wild germplasm is in vitro conservation of genetic banks. The success of in vitro conservation relies heavily on the micropropagation or performance of the species of interest. In the context of global change, crop production challenges and climate change, we face a reality of intensified crop production strategies, including genetic engineering, which can negatively impact biodiversity conservation. However, the possible consequences of transgene presence for the in vitro performance of populations and its implications for biodiversity conservation are poorly documented. In this study we analyzed experimental evidence of the potential effects of transgene presence on the in vitro performance of Gossypium hirsutum L. populations, representing the Mexican genetic diversity of the species, and reflect on the implications of such presence for ex situ genetic conservation of the natural variation of the species. We followed an experimental in vitro performance approach, in which we included individuals from different wild cotton populations as well as individuals from domesticated populations, in order to differentiate the effects of domestication traits dragged into the wild germplasm pool via gene flow from the effects of transgene presence. We evaluated the in vitro performance of five traits related to plant establishment (N = 300): propagation rate, leaf production rate, height increase rate, microbial growth and root development. Then we conducted statistical tests (PERMANOVA, Wilcoxon post-hoc tests, and NMDS multivariate analyses) to evaluate the differences in the in vitro performance of the studied populations. Although direct causality of the transgenes to observed phenotypes requires strict control of genotypes, the overall results suggest detrimental consequences for the in vitro culture performance of wild cotton populations in the presence of transgenes. This provides experimental, statistically sound evidence to support the implementation of transgene screening of plants to reduce time and economic costs in in vitro establishment, thus contributing to the overarching goal of germplasm conservation for future adaptation.

scholarly journals Hue and cry for Fritillaria cirrhosa D.Don, a threatened medicinal plant in the Western Himalaya

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Manisha Mathela ◽  
Amit Kumar ◽  
Monika Sharma ◽  
Gurinderjit Singh Goraya
Keyword(s):  
Medicinal Plant ◽  
Population Decline ◽  
Plant Conservation ◽  
Western Himalaya ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Market Demand ◽  
Wild Populations ◽  
Threatened Medicinal Plant ◽  
Fritillaria Cirrhosa

AbstractThe unique Himalayan ecosystems are repositories to the wild populations of diverse flora and fauna. The high value medicinal and aromatic plant species (MAPs) are an example of the same. Since time immemorial, these MAPs have been traditionally used by the local inhabitants and have eventually developed a high market value all over the world. Increasing market demand engenders over-extraction of species, unsustainable collection further catalyses decline in wild populations. The current communication raises high conservation concern on the rapid population decline of Fritillaria cirrhosa D.Don in the Western Himalaya. Harvested and traded with a new trade name i.e., ‘Jangli lehsun’ probably to disguise common Allium species, the species is facing tremendous decline in wild populations due to its illegal harvesting and trade in Himachal Pradesh. Further, F. cirrhosa faces threat due to unorganized, over-extraction, unsustainable and premature harvesting of the bulbs, coupled with illegal hidden markets functioning parallelly. Considering that this valuable species is under multiple threats being a medicinally important plant, priority should be given for its conservation through in-situ such as identification of medicinal plant conservation areas and ex-situ methods for its propagation and multiplication. Further, to ensure the long-term conservation of Fritillaria cirrhosa, prioritized conservation strategies such as strengthening of the Biodiversity Management Committees, capacity building through awareness programs for the key stakeholders and sustainable harvesting would be the practical solution.

Further Studies of Lung Parasites (Nematoda) From Australian Marsupials.

1984 ◽  
Vol 32 (2) ◽  
pp. 283 ◽  
Author(s):  
DM Spratt
Keyword(s):  
New South ◽  
Single Species ◽  
Northern Territory ◽  
Trichosurus Vulpecula ◽  
Monotypic Genus ◽  
New Host ◽  
Phascolarctos Cinereus ◽  
Histological Sections ◽  
South Wales ◽  
Host Parasite

Seven new taxa in two families of metastrongyloid nematodes are described from the lungs of five host species belonging to the Dasyuridae, Phalangeridae and Macropodidae. Filaroides (Filaroides) athertonensis, sp. nov., (Filaroididae) is described from Thylogale stigmatica Gould in north Queensland. The following species of Marsupostrongylus Mackerras & Sandars, 1953, (Angiostrongylidae) are described as new: M. parallelus, sp. nov., from Satanellus hallucatus (Could) in the Northern Territory; M. pseudominesi, sp. nov., from Trichosurus vulpecula johnstonii (Ramsay) in north Queensland; M. vandiemeni, sp. nov., from macro pus rufogriseus rufogriseus (Desmarest) in Tasmania; and M. wallabiae, sp. nov., from Wallabia bicolor (Desmarest) and Macropus rufogriseus banksianus (Quoy & Gaimard) in New South Wales. To the formerly monotypic genus Filostrongylus Mackenas, 1955, (Angiostrongylidae) is added F. tridendriticus, sp. nov., described from Trichosurus vulpecula (Kerr) in Tasmania. The genus Cosmostrongylus (Angiostrongylidae) is described as new, with a single species C. conspectus, sp. nov., from Thylogale stigmatica Gould in north Queensland. Durikainema sp. (Muspiceoidea: Robertdollfusidae) is diagnosed in histological sections of the lungs of Phascolarctos cinereus (Goldfuss), Macropus agilis (Could) and M. giganteus Shaw. Keys to the genera of lung parasites and to all species of Filaroides, Marsupostrongylus and Filostrongylus known from Australian marsupials, new host and new geographic records of known taxa, and a host-parasite list of lung parasites of Australian marsupials, including those known only from histological sections of lung tissue, are provided.

scholarly journals Application of the MSAP Technique to Evaluate Epigenetic Changes in Plant Conservation

2020 ◽  
Vol 21 (20) ◽  
pp. 7459
Author(s):  
María Elena González-Benito ◽  
Miguel Ángel Ibáñez ◽  
Michela Pirredda ◽  
Sara Mira ◽  
Carmen Martín
Keyword(s):  
Dna Methylation ◽  
In Situ Conservation ◽  
Plant Conservation ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Regenerated Plants ◽  
Before And After ◽  
Methylation Patterns

Epigenetic variation, and particularly DNA methylation, is involved in plasticity and responses to changes in the environment. Conservation biology studies have focused on the measurement of this variation to establish demographic parameters, diversity levels and population structure to design the appropriate conservation strategies. However, in ex situ conservation approaches, the main objective is to guarantee the characteristics of the conserved material (phenotype and epi-genetic). We review the use of the Methylation Sensitive Amplified Polymorphism (MSAP) technique to detect changes in the DNA methylation patterns of plant material conserved by the main ex situ plant conservation methods: seed banks, in vitro slow growth and cryopreservation. Comparison of DNA methylation patterns before and after conservation is a useful tool to check the fidelity of the regenerated plants, and, at the same time, may be related with other genetic variations that might appear during the conservation process (i.e., somaclonal variation). Analyses of MSAP profiles can be useful in the management of ex situ plant conservation but differs in the approach used in the in situ conservation. Likewise, an easy-to-use methodology is necessary for a rapid interpretation of data, in order to be readily implemented by conservation managers.

scholarly journals Recent advances in understanding female gametophyte development

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 804 ◽  
Author(s):  
Debra J Skinner ◽  
Venkatesan Sundaresan
Keyword(s):  
Cell Fate ◽  
Female Gametophyte ◽  
Cell Communication ◽  
Embryo Sac ◽  
Cell Types ◽  
Egg Cell ◽  
Male Gametes ◽  
Reproductive Unit ◽  
Genetic Mechanisms ◽  
Female Gametophyte Development

The haploid female gametophyte (embryo sac) is an essential reproductive unit of flowering plants, usually comprising four specialized cell types, including the female gametes (egg cell and central cell). The differentiation of these cells relies on spatial signals which pattern the gametophyte along a proximal-distal axis, but the molecular and genetic mechanisms by which cell identities are determined in the embryo sac have long been a mystery. Recent identification of key genes for cell fate specification and their relationship to hormonal signaling pathways that act on positional cues has provided new insights into these processes. A model for differentiation can be devised with egg cell fate as a default state of the female gametophyte and with other cell types specified by the action of spatially regulated factors. Cell-to-cell communication within the gametophyte is also important for maintaining cell identity as well as facilitating fertilization of the female gametes by the male gametes (sperm cells).

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