scholarly journals Molecular Control of Sporophyte-Gametophyte Ontogeny and Transition in Plants

2022 ◽  
Vol 12 ◽  
Author(s):  
Saurabh Pandey ◽  
Amir Bahram Moradi ◽  
Oleksandr Dovzhenko ◽  
Alisher Touraev ◽  
Klaus Palme ◽  
...  
Keyword(s):  
Doubled Haploids ◽  
Basic Research ◽  
Land Plants ◽  
Long Distance ◽  
Developmental Programs ◽  
Molecular Control ◽  
Evolutionary Origins ◽  
Male Gametes ◽  
Sporophytic Development ◽  
Alternation Of Generations

Alternation of generations between a sporophytic and gametophytic developmental stage is a feature common to all land plants. This review will discuss the evolutionary origins of these two developmental programs from unicellular eukaryotic progenitors establishing the ability to switch between haploid and diploid states. We will compare the various genetic factors that regulate this switch and highlight the mechanisms which are involved in maintaining the separation of sporophytic and gametophytic developmental programs. While haploid and diploid stages were morphologically similar at early evolutionary stages, largely different gametophyte and sporophyte developments prevail in land plants and finally allowed the development of pollen as the male gametes with specialized structures providing desiccation tolerance and allowing long-distance dispersal. Moreover, plant gametes can be reprogrammed to execute the sporophytic development prior to the formation of the diploid stage achieved with the fusion of gametes and thus initially maintain the haploid stage. Upon diploidization, doubled haploids can be generated which accelerate modern plant breeding as homozygous plants are obtained within one generation. Thus, knowledge of the major signaling pathways governing this dual ontogeny in land plants is not only required for basic research but also for biotechnological applications to develop novel breeding methods accelerating trait development.

scholarly journals Bio-inspired Fog Harvesting Materials: Basic Research and Bionic Potential Applications

2021 ◽  
Vol 18 (3) ◽  
pp. 501-533
Author(s):  
Kui Wan ◽  
Xuelian Gou ◽  
Zhiguang Guo
Keyword(s):  
Collection Efficiency ◽  
Basic Research ◽  
Development Trend ◽  
Water Mist ◽  
Long Distance ◽  
Biological Water ◽  
Water Collection ◽  
Transmission Area ◽  
Potential Applications ◽  
Water Transmission

AbstractWith the explosive growth of the world’s population and the rapid increase in industrial water consumption, the world’s water supply has fallen into crisis. The shortage of fresh water resources has become a global problem, especially in arid regions. In nature, many organisms can collect water from foggy water under harsh conditions, which provides us with inspiration for the development of new functional fog harvesting materials. A large number of bionic special wettable synthetic surfaces are synthesized for water mist collection. In this review, we introduce some water collection phenomena in nature, outline the basic theories of biological water harvesting, and summarize six mechanisms of biological water collection: increased surface wettability, increased water transmission area, long-distance water delivery, water accumulation and storage, condensation promotion, and gravity-driven. Then, the water collection mechanisms of three typical organisms and their synthesis are discussed. And their function, water collection efficiency, new developments in their biomimetic materials are narrated, which are cactus, spider and desert beetles. The study of multiple bionics was inspired by the discovery of Nepenthes’ moist and smooth peristome. The excellent characteristics of a variety of biological water collection structures, combined with each other, are far superior to other single synthetic surfaces. Furthermore, the main problems in the preparation and application of biomimetic fog harvesting materials and the future development trend of materials fog harvesting are prospected.

Haploidy and plant breeding

1981 ◽  
Vol 292 (1062) ◽  
pp. 499-507 ◽  
Keyword(s):  
Plant Breeding ◽  
Doubled Haploids ◽  
Chromosome Complement ◽  
Basic Research ◽  
Breeding Value ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Programmes ◽  
Dh Lines

A haploid is an organism that looks like a sporophyte, but has the chromosome complement of a reduced gamete. There are several ways in which haploids can occur or be induced in vivo : spontaneously, mostly associated with polyembryony, and through abnormal processes after crosses, like pseudogamy, semigamy, preferential elimination of the chromosomes of one parental species, and androgenesis. In the crops described, haploids are or are near to being used in basic research and plant breeding. The application of haploids in breeding self-pollinated crops is based on their potential for producing fully homozygous lines in one generation, which can be assessed directly in the field. Early generation testing of segregating populations is possible through haploids, because doubled haploids (DH) possess additive variance only. Haploids can also be applied in classical breeding programmes to make these more efficient through improved reliability of selection. The application of haploids in cross-pollinated crops is also based on a rapid production of DH-lines, which can be used as inbred lines for the production of hybrid varieties. By means of haploids all natural barriers to repeated selfing are bypassed. In autotetraploid crops there are two types of haploid. One cycle of haploidization leads to dihaploids; a second cycle produces monohaploids. The significance of dihaploids is in their greatly simplified genetics and breeding and in the possibility of estimation of the breeding value of tetraploid cultivars by assessing their dihaploids. The main drawback of dihaploids is their restriction to two alleles per locus. Also, after doubling, it is impossible to achieve tetra-allelism at many loci, the requirement for maximal performance of autotetraploid cultivars. Tetra-allelism can be obtained when improved dihaploids have a genetically controlled mechanism of forming highly heterozygous restitution gametes with the unreduced number of chromosomes. Monohaploids, after doubling or twice doubling, may lead to fully homozygous diploids and tetraploids. These are important for basic research, but not yet for practical application. Meiotic data of potato homozygotes at three ploidy levels are presented.

When SWEETs Turn Tweens: Updates and Perspectives

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Xueyi Xue ◽  
Jiang Wang ◽  
Diwakar Shukla ◽  
Lily S. Cheung ◽  
Li-Qing Chen
Keyword(s):  
Crop Yields ◽  
Sugar Transport ◽  
Basic Research ◽  
Biochemical Properties ◽  
Annual Review ◽  
Publication Date ◽  
Sugar Transporters ◽  
Evolutionary Origins ◽  
Plant Level ◽  
Dynamics Simulations

Sugar translocation between cells and between subcellular compartments in plants requires either plasmodesmata or a diverse array of sugar transporters. Interactions between plants and associated microorganisms also depend on sugar transporters. The sugars will eventually be exported transporter (SWEET) family is made up of conserved and essential transporters involved in many critical biological processes. The functional significance and small size of these proteins have motivated crystallographers to successfully capture several structures of SWEETs and their bacterial homologs in different conformations. These studies together with molecular dynamics simulations have provided unprecedented insights into sugar transport mechanisms in general and into substrate recognition of glucose and sucrose in particular. This review summarizes our current understanding of the SWEET family, from the atomic to the whole-plant level. We cover methods used for their characterization, theories about their evolutionary origins, biochemical properties, physiological functions, and regulation. We also include perspectives on the future work needed to translate basic research into higher crop yields. Expected final online publication date for the Annual Review of Plant Biology, Volume 73 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Vegetative and reproductive innovations of early land plants: implications for a unified phylogeny

2000 ◽  
Vol 355 (1398) ◽  
pp. 769-793 ◽  
Author(s):  
Karen Sue Renzaglia ◽  
R. Joel Duff ◽  
Daniel L. Nickrent ◽  
David J. Garbary
Keyword(s):  
Phylogenetic Signal ◽  
Phenotypic Variability ◽  
Land Plant ◽  
Land Plants ◽  
Total Evidence ◽  
Data Sets ◽  
Data Set ◽  
Plant Phylogeny ◽  
Male Gametes ◽  
Early Land

As the oldest extant lineages of land plants, bryophytes provide a living laboratory in which to evaluate morphological adaptations associated with early land existence. In this paper we examine reproductive and structural innovations in the gametophyte and sporophyte generations of hornworts, liverworts, mosses and basal pteridophytes. Reproductive features relating to spermatogenesis and the architecture of motile male gametes are overviewed and evaluated from an evolutionary perspective. Phylogenetic analyses of a data set derived from spermatogenesis and one derived from comprehensive morphogenetic data are compared with a molecular analysis of nuclear and mitochondrial small subunit rDNA sequences. Although relatively small because of a reliance on water for sexual reproduction, gametophytes of bryophytes are the most elaborate of those produced by any land plant. Phenotypic variability in gametophytic habit ranges from leafy to thalloid forms with the greatest diversity exhibited by hepatics. Appendages, including leaves, slime papillae and hairs, predominate in liverworts and mosses, while hornwort gametophytes are strictly thalloid with no organized external structures. Internalization of reproductive and vegetative structures within mucilage–filled spaces is an adaptive strategy exhibited by hornworts. The formative stages of gametangial development are similar in the three bryophyte groups, with the exception that in mosses apical growth is intercalated into early organogenesis, a feature echoed in moss sporophyte ontogeny. A monosporangiate, unbranched sporophyte typifies bryophytes, but developmental and structural innovations suggest the three bryophyte groups diverged prior to elaboration of this generation. Sporophyte morphogenesis in hornworts involves non–synchronized sporogenesis and the continued elongation of the single sporangium, features unique among archegoniates. In hepatics, elongation of the sporophyte seta and archegoniophore is rapid and requires instantaneous wall expandability and hydrostatic support. Unicellular, spiralled elaters and capsule dehiscence through the formation of four regular valves are autapomorphies of liverworts. Sporophytic sophistications in the moss clade include conducting tissue, stomata, an assimilative layer and an elaborate peristome for extended spore dispersal. Characters such as stomata and conducting cells that are shared among sporophytes of mosses, hornworts and pteridophytes are interpreted as parallelisms and not homologies. Our phylogenetic analysis of three different data sets is the most comprehensive to date and points to a single phylogenetic solution for the evolution of basal embryophytes. Hornworts are supported as the earliest divergent embryophyte clade with a moss/liverwort clade sister to tracheophytes. Among pteridophytes, lycophytes are monophyletic and an assemblage containing ferns, Equisetum and psilophytes is sister to seed plants. Congruence between morphological and molecular hypotheses indicates that these data sets are tracking the same phylogenetic signal and reinforces our phylogenetic conclusions. It appears that total evidence approaches are valuable in resolving ancient radiations such as those characterizing the evolution of early embryophytes. More information on land plant phylogeny can be found at: http://www.science.siu.edu/landplants/index.html.

Diversity of Sperm Cell Architecture in Ferns

2001 ◽  
Vol 7 (S2) ◽  
pp. 452-453
Author(s):  
Thomas H. Johnson ◽  
Steven J. Schmitt ◽  
Karen S. Renzaglia
Keyword(s):  
Phosphate Buffer ◽  
Vascular Plants ◽  
Sperm Cell ◽  
Electron Microscope Study ◽  
Osmium Tetroxide ◽  
Land Plants ◽  
Scanning Electron Microscope Study ◽  
Leptosporangiate Fern ◽  
Male Gametes ◽  
Cell Architecture

Among land plants, lower vascular plants produce the most elaborate of all male gametes. in order to characterize the degree of variability in sperm cell architecture among ferns, this scanning electron microscope study was undertaken on three highly disparate genera: Ceratopteris(a derived leptosporangiate fern) Angiopteris(a derived eusporangiate fern) and Psilotum(a putatively basal eusporangiate fern).Mature gametophytes were placed in 0.01M phosphate buffer (pH ca. 7.2) or distilled water until spermatozoids were released. Gametophyte portions were removed and the spermatozoid suspension fixed with 2% glutaraldehyde in 0.05M phosphate buffer. Post-fixation utilized 1% aqueous osmium tetroxide for lhr, followed by rinsing and dehydration in ethanol (10 min @ 25, 50, 75 and 100%). The dehydrated pellet was suspended in 100% hexamethyldisilazane, immediately centrifuged and the pellet deposited onto clean glass coverslips. Specimens were dried at 60°C, sputtered with ca. 350 A of palladium/gold and imaged in a Hitachi S570 SEM.

scholarly journals What are the evolutionary origins of stomatal responses to abscisic acid in land plants?

2017 ◽  
Vol 59 (4) ◽  
pp. 240-260 ◽  
Author(s):  
Frances C. Sussmilch ◽  
Timothy J. Brodribb ◽  
Scott A. M. McAdam
Keyword(s):  
Abscisic Acid ◽  
Land Plants ◽  
Evolutionary Origins ◽  
Stomatal Responses

scholarly journals Infrasound propagation in the Arctic

2021 ◽  
Author(s):  
D. Wilson ◽  
Vladimir Ostashev ◽  
Michael Shaw ◽  
Michael Muhlestein ◽  
John Weatherly ◽  
...  
Keyword(s):  
Sound Propagation ◽  
Ground Surface ◽  
Polar Vortex ◽  
Basic Research ◽  
Arctic Region ◽  
Initial Step ◽  
The Arctic ◽  
Equation Modeling ◽  
Katabatic Wind ◽  
Long Distance

This report summarizes results of the basic research project “Infrasound Propagation in the Arctic.” The scientific objective of this project was to provide a baseline understanding of the characteristic horizontal propagation distances, frequency dependencies, and conditions leading to enhanced propagation of infrasound in the Arctic region. The approach emphasized theory and numerical modeling as an initial step toward improving understanding of the basic phenomenology, and thus lay the foundation for productive experiments in the future. The modeling approach combined mesoscale numerical weather forecasts from the Polar Weather Research and Forecasting model with advanced acoustic propagation calculations. The project produced significant advances with regard to parabolic equation modeling of sound propagation in a windy atmosphere. For the polar low, interesting interactions with the stratosphere were found, which could possibly be used to provide early warning of strong stratospheric warming events (i.e., the polar vortex). The katabatic wind resulted in a very strong low-level duct, which, when combined with a highly reflective icy ground surface, leads to efficient long-distance propagation. This information is useful in devising strategies for positioning sensors to monitor environmental phenomena and human activities.

scholarly journals The genomic landscape of meiotic crossovers and gene conversions in Arabidopsis thaliana

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Erik Wijnker ◽  
Geo Velikkakam James ◽  
Jia Ding ◽  
Frank Becker ◽  
Jonas R Klasen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Average Length ◽  
Doubled Haploids ◽  
Gene Promoters ◽  
Sequence Motifs ◽  
Long Distance ◽  
Genomic Landscape ◽  
Significant Enrichment ◽  
Copy Number Changes ◽  
Gene Conversions

Knowledge of the exact distribution of meiotic crossovers (COs) and gene conversions (GCs) is essential for understanding many aspects of population genetics and evolution, from haplotype structure and long-distance genetic linkage to the generation of new allelic variants of genes. To this end, we resequenced the four products of 13 meiotic tetrads along with 10 doubled haploids derived from Arabidopsis thaliana hybrids. GC detection through short reads has previously been confounded by genomic rearrangements. Rigid filtering for misaligned reads allowed GC identification at high accuracy and revealed an ∼80-kb transposition, which undergoes copy-number changes mediated by meiotic recombination. Non-crossover associated GCs were extremely rare most likely due to their short average length of ∼25–50 bp, which is significantly shorter than the length of CO-associated GCs. Overall, recombination preferentially targeted non-methylated nucleosome-free regions at gene promoters, which showed significant enrichment of two sequence motifs.

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