scholarly journals Temporal Distinction between Male and Female Floral Organ Development in Nicotiana tabacum cv. Xanthi (Solanaceae)

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 127
Author(s):  
Hongli Chang ◽  
Fengjie Sun
Keyword(s):  
Nicotiana Tabacum ◽  
Molecular Mechanisms ◽  
Pollen Grains ◽  
Floral Organ ◽  
Evolutionary Mechanisms ◽  
Tetrad Stage ◽  
Flower Primordia ◽  
Future Studies ◽  
Carpel Development ◽  
Solid Foundation

Early floral developmental investigations provide crucial evidence for phylogenetic and molecular studies of plants. The developmental and evolutionary mechanisms underlying the variations in floral organs are critical for a thorough understanding of the diversification of flowers. Ontogenetic comparisons between anthers and pistil within single flowers were characterized over time in Nicotiana tabacum cv. Xanthi. The ages of 42 tobacco flower or flower primordia were estimated using corolla growth analysis. Results showed that the protodermal layer in carpel primordia contributes to carpel development by both anticlinal and periclinal divisions. Periclinal divisions in the hypodermal layer of the placenta were observed around 4.8 ± 1.3 days after the formation of early carpel primordia (ECP) and ovule initiation occurred 10.0 ± 0.5 days after ECP. Meiosis in anthers and ovules began about 8.9 ± 1.1 days and 14.4 ± 1.3 days after ECP, respectively. Results showed an evident temporal distinction between megasporogenesis and microsporogenesis. Flower ages spanned a 17-day interval, starting with flower primordia containing the ECP and anther primordia to the tetrad stage of meiosis in megasporocytes and the bicellular stage in pollen grains. These results establish a solid foundation for future studies in order to identify the developmental and molecular mechanisms responsible for the mating system in tobacco.

scholarly journals Abortion Categories and Characteristics of Acarpous Crape Myrtle Floral Organs

2019 ◽  
Vol 144 (6) ◽  
pp. 387-393
Author(s):  
Wei Zhou ◽  
Xiaoming Wang ◽  
Jianhua Chen ◽  
Liangming Chen ◽  
Zhongquan Qiao ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Embryo Sac ◽  
Floral Organ ◽  
Flowering Period ◽  
Pollen Abortion ◽  
Future Studies ◽  
Egg Apparatus ◽  
Landscape Plant ◽  
Single Flower ◽  
Cell Contour

Lagerstroemia indica (crape myrtle) is a popular Chinese landscape plant with a long flowering period that contributes to its gorgeous flowers and high ornamental value, which motivate L. indica breeding. We found a wild acarpous individual of L. indica that did not bear seeds after flowering and had a significantly longer flowering period than fructiferous L. indica. This study identified differences in floral organ morphology, and stamen and pistil structure between fructiferous and acarpous L. indica through observation, paraffin sectioning, and scanning electron microscopy (SEM). The flowering time of each acarpous L. indica inflorescence lasts as long as 18 to 25 days. When a single flower withers, it falls from the pedicel without any fruit. The abortion in the floral organ of acarpous L. indica is characterized by sterile and undehisced anthers, pollen abortion, and deformed and irregularly arranged filament cells. Acarpous L. indica features short and loosely arranged papilla cells in the stigma, a flat style and narrow stylar canal, loosely arranged epidermal cells, and no obvious nuclei. No embryo sac cavity is found in acarpous L. indica ovules. In some nucelli, the egg apparatus structure can be observed indistinctly but without cell contour. In others, the egg apparatus structure is completely absent, and only flocculent tissue is observed. This study may provide a theoretical foundation for future studies on the molecular mechanisms of the mutations in acarpous L. indica.

Mesophyll conductance: the leaf corridors for photosynthesis

2020 ◽  
Vol 48 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Jorge Gago ◽  
Danilo M. Daloso ◽  
Marc Carriquí ◽  
Miquel Nadal ◽  
Melanie Morales ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Main Role ◽  
Mesophyll Conductance ◽  
Future Studies ◽  
Cell Structures ◽  
Leaf Tissues ◽  
Change Framework ◽  
Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

scholarly journals Divergence of a genomic island leads to the evolution of melanization in a halophyte root fungus

2021 ◽  
Author(s):  
Zhilin Yuan ◽  
Irina S. Druzhinina ◽  
John G. Gibbons ◽  
Zhenhui Zhong ◽  
Yves Van de Peer ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Genomic Island ◽  
Population Genomics ◽  
Growth Yield ◽  
Fixation Index ◽  
Nucleotide Polymorphisms ◽  
Evolutionary Mechanisms ◽  
Melanin Biosynthesis ◽  
Two Populations

AbstractUnderstanding how organisms adapt to extreme living conditions is central to evolutionary biology. Dark septate endophytes (DSEs) constitute an important component of the root mycobiome and they are often able to alleviate host abiotic stresses. Here, we investigated the molecular mechanisms underlying the beneficial association between the DSE Laburnicola rhizohalophila and its host, the native halophyte Suaeda salsa, using population genomics. Based on genome-wide Fst (pairwise fixation index) and Vst analyses, which compared the variance in allele frequencies of single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs), respectively, we found a high level of genetic differentiation between two populations. CNV patterns revealed population-specific expansions and contractions. Interestingly, we identified a ~20 kbp genomic island of high divergence with a strong sign of positive selection. This region contains a melanin-biosynthetic polyketide synthase gene cluster linked to six additional genes likely involved in biosynthesis, membrane trafficking, regulation, and localization of melanin. Differences in growth yield and melanin biosynthesis between the two populations grown under 2% NaCl stress suggested that this genomic island contributes to the observed differences in melanin accumulation. Our findings provide a better understanding of the genetic and evolutionary mechanisms underlying the adaptation to saline conditions of the L. rhizohalophila–S. salsa symbiosis.

Parallel molecular mechanisms for enzyme temperature adaptation

Science ◽  
2021 ◽  
Vol 371 (6533) ◽  
pp. eaay2784
Author(s):  
Margaux M. Pinney ◽  
Daniel A. Mokhtari ◽  
Eyal Akiva ◽  
Filip Yabukarski ◽  
David M. Sanchez ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Interaction Networks ◽  
Temperature Adaptation ◽  
Mechanistic Studies ◽  
Sequence Analyses ◽  
Evolutionary Mechanisms ◽  
Ketosteroid Isomerase ◽  
Physical Mechanisms ◽  
Bacterial Enzyme ◽  
Enzyme Families

The mechanisms that underly the adaptation of enzyme activities and stabilities to temperature are fundamental to our understanding of molecular evolution and how enzymes work. Here, we investigate the molecular and evolutionary mechanisms of enzyme temperature adaption, combining deep mechanistic studies with comprehensive sequence analyses of thousands of enzymes. We show that temperature adaptation in ketosteroid isomerase (KSI) arises primarily from one residue change with limited, local epistasis, and we establish the underlying physical mechanisms. This residue change occurs in diverse KSI backgrounds, suggesting parallel adaptation to temperature. We identify residues associated with organismal growth temperature across 1005 diverse bacterial enzyme families, suggesting widespread parallel adaptation to temperature. We assess the residue properties, molecular interactions, and interaction networks that appear to underly temperature adaptation.

scholarly journals PSYCHOGEOGRAPHICAL EXPERIENCE BETWEEN THE SELF AND THE PLACE

2022 ◽  
Vol 7 (1) ◽  
pp. 243-263
Author(s):  
Mohd Fadhli Shah Khaidzir ◽  
Ruzy Suliza Hashim ◽  
Noraini Md. Yusof
Keyword(s):  
Critical Role ◽  
Critical Factor ◽  
The Self ◽  
Future Research ◽  
Future Studies ◽  
Place Meaning ◽  
Solid Foundation ◽  
Self Discovery ◽  
Attachment Place

Background and Purpose: The absence of psychogeographical awareness is a critical factor contributing to the lackadaisical attitudes towards the place and its environment. As a result, it enables an individual to fully experience a location, both physically and intellectually, while also gaining a feeling of self-discovery and self-realisation.   Methodology: The purpose of this study was to examine the responses of a group of individuals who participated in a field observation. 40 participants from a Malaysian university's foundation level were brought to Malacca to experience the environment's geographical scenery at their own leisure. The survey data was then manually transcribed and analysed in accordance with the study's aim.   Findings: Interactions with individuals and observation of features in the countryside and urban surroundings enabled participants to go on a psychogeographical journey that influenced their way of thinking and behaving. All participants felt that the journey had influenced their experiences and perspectives on their thinking and behaviour, highlighting the critical role of this notion in establishing the connection between place and self.   Contributions:  The findings of this study provide a solid foundation for future research in the field of psychogeography. The data may be used as a baseline for future studies to determine whether a comparable impact exists in other locations, with or without significant features like those found in Malacca.   Keywords: Psychogeography, place attachment, place meaning, self-discovery, Malacca.   Cite as: Khaidzir, M. F. S., Hashim, R. S., & Md. Yusof, N. (2022). Psychogeographical experience between the self and the place.  Journal of Nusantara Studies, 7(1), 243-263. http://dx.doi.org/10.24200/jonus.vol7iss1pp243-263

scholarly journals Transcriptome-Wide Analyses Provide Insights into Development of the Hedychium Coronarium Flower, Revealing Potential Roles of PTL

2020 ◽  
Author(s):  
Tong Zhao ◽  
Alma Piñeyro-Nelson ◽  
Qianxia Yu ◽  
Xiaoying Hu ◽  
Huanfang Liu ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Flower Development ◽  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Floral Organ ◽  
Mrna In Situ Hybridization ◽  
Hedychium Coronarium ◽  
Organ Identity

Abstract Background:The flower of Hedychium coronarium possesses highly specialized floral organs: a synsepalous calyx, petaloid staminodes and a labellum. The formation of these organs is controlled by two gene categories: floral organ identity genes and organ boundary genes, which may function individually or jointly during flower development. Although the floral organogenesis of H. coronarium has been studied at the morphological level, the underlying molecular mechanisms involved in its floral development still remain poorly understood. In addition, previous works analyzing the role of MADS-box genes in controlling floral organ specification in some Zingiberaceae did not address the molecular mechanisms involved in the formation of particular organ morphologies that emerge later in flower development, such as the synsepalous calyx formed through intercalary growth of adjacent sepals. Results:Here, we used comparative transcriptomics combined with Real-time quantitative PCR and mRNA in situ hybridization to investigate gene expression patterns of ABC-class genes in H. coronarium flowers, as well as the homolog of the organ boundary gene PETAL LOSS (HcPTL). qRT-PCR detection showed that HcAP3 and HcAG were expressed in both the petaloid staminode and the fertile stamen. mRNA in situ hybridization showed that HcPTL was expressed in developing meristems, including cincinnus primordia, floral primordia, common primordia and almost all new initiating floral organ primordia.Conclusions:Our studies found that stamen/petal identity or stamen fertility in H. coronarium was not necessarily correlated with the differential expression of HcAP3 and HcAG. We also found a novel spatio-temporal expression pattern for HcPTL mRNA, suggesting it may have evolved a lineage-specific role in the morphogenesis of the Hedychium flower. Our study provides a new transcriptome reference and a functional hypothesis regarding the role of a boundary gene in organ fusion that should be further addressed through phylogenetic analyzes of this gene, as well as functional studies.

The orexin system: a potential player in the pathophysiology of absence epilepsy?

2021 ◽  
Vol 19 ◽  
Author(s):  
Roberta Celli ◽  
Gilles Van Luijtelaar
Keyword(s):  
Somatosensory Cortex ◽  
Molecular Mechanisms ◽  
Recent Literature ◽  
Absence Epilepsy ◽  
Experimental Animals ◽  
Future Studies ◽  
Protein Levels ◽  
System A ◽  
Cortical Circuit

Background : Absence epilepsy is characterized by the presence of spike-and-wave discharges (SWDs) at the EEG generated within the cortico-thalamo-cortical circuit. The molecular mechanisms involved in the pathophysiology of absence epilepsy are only partially known. WAG/Rij rats older than 2-3 months develop spontaneous SWDs, and they are sensitive to anti-absence medications. Hence, WAG/Rij rats are extensively used as a model for absence epilepsy with predictive validity. Objective : To examine the possibility that the orexin system, which supports the wake status in experimental animals and humans, plays a role in the pathophysiology of absence seizures. Methods : The perspective grounds its method on recent literature along with measurements of orexin receptor type-1 (OX1) protein levels in the thalamus and somatosensory cortex of WAG/Rij rats and non-epileptic Wistar control rats at two ages (25 days and 6-7 months). OX1 protein levels were measured by immunoblotting. Results : The analysis of the current literature suggests that the orexin system might be involved in the pathophysiology of absence epilepsy and might be targeted by therapeutic intervention. Experimental data are in line with this hypothesis showing that OX1 protein levels were reduced in the thalamus and somatosensory cortex of symptomatic WAG/Rij rats (6-7 months of age) with respect to non-epileptic controls, whereas these differences were not seen in pre-symptomatic, 25 days-old WAG/Rij rats. Conclusions : This might pave the way to future studies on the involvement of the orexinergic system in the pathophysiology of SWDs associated with absence epilepsy and its comorbidities.

scholarly journals Potential Pathways and Genes Involved in Lac Synthesis and Secretion in Kerria chinensis (Hemiptera: Kerriidae) Based on Transcriptomic Analyses

Insects ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 430
Author(s):  
Weiwei Wang ◽  
Pengfei Liu ◽  
Qin Lu ◽  
Xiaofei Ling ◽  
Jinwen Zhang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Expression Profiles ◽  
Future Studies ◽  
Natural Resin ◽  
Beneficial Insect ◽  
Excellent Adhesion ◽  
The Military ◽  
Secretion Rates

Lac is a type of natural resin secreted by lac insects and is widely used in the military and other industries because of its excellent adhesion and insulation properties. The main ingredients of lac are lactones and lactides, which are formed from hydroxy fatty acids and sesquiterpene esters. In this study, we measured lac secretion rates by the insect Kerria chinensis at different developmental stages and identified lac secretion-minimum and lac secretion-active stages of the insect. We then analyzed transcriptomes of lac secretion-minimum and lac secretion-active stages of the insect. Based on expression profiles of genes in different stages of the insect, we identified pathways and genes that are potentially involved in lac synthesis and secretion in K. chinensis. Our study lays a foundation for future studies to reveal the molecular mechanisms and pathways of lac synthesis and secretion in this beneficial insect.

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