scholarly journals The Importance of Cytokinins during Reproductive Development in Arabidopsis and Beyond

2020 ◽  
Vol 21 (21) ◽  
pp. 8161
Author(s):  
Giada Callizaya Terceros ◽  
Francesca Resentini ◽  
Mara Cucinotta ◽  
Silvia Manrique ◽  
Lucia Colombo ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Functional Unit ◽  
Control Plant ◽  
Reproductive Development ◽  
Plant Reproduction ◽  
World Population ◽  
Plant Growth And Development ◽  
Seed Formation ◽  
Human Needs

Fertilization and seed formation are fundamental events in the life cycle of flowering plants. The seed is a functional unit whose main purpose is to propagate the plant. The first step in seed development is the formation of male and female gametophytes and subsequent steps culminate in successful fertilization. The detailed study of this process is highly relevant because it directly impacts human needs, such as protecting biodiversity and ensuring sustainable agriculture to feed the increasing world population. Cytokinins comprise a class of phytohormones that play many important roles during plant growth and development and in recent years, the role of this class of phytohormones during reproduction has become clear. Here, we review the role of cytokinins during ovule, pollen and seed formation at the genetic and molecular levels. The expansion of knowledge concerning the molecular mechanisms that control plant reproduction is extremely important to optimise seed production.

Cancer epidemiology and public health

2021 ◽  
pp. 17-42
Author(s):  
Paolo Boffetta ◽  
Zuo-Feng Zhang ◽  
Carlo La Vecchia
Keyword(s):  
Public Health ◽  
Risk Factors ◽  
Molecular Mechanisms ◽  
Cancer Epidemiology ◽  
Attributable Risk ◽  
World Population ◽  
The World ◽  
Near Future ◽  
Epidemiology And Public Health

Neoplasms continue to dominate globally as one of the major sources of human disease and death. There are multiple modifiable causes of cancer and understanding their attributable risk factors for each cancer is of importance. This chapter covers the role of cellular and molecular mechanisms as well as the experimental and epidemiological approaches as determinants of the main cancers. Even if major discoveries in the clinical management of cancer patients will be accomplished in the near future, the changes will mainly affect the affluent part of the world population. Promising approaches focused on prevention of the known causes, reducing its consequences, notably in resource-constrained settings are highlighted.

scholarly journals Mitigation of Salt Stress-Induced Inhibition of Plantago crassifolia Reproductive Development by Supplemental Calcium or Magnesium

2012 ◽  
Vol 40 (2) ◽  
pp. 58 ◽  
Author(s):  
Marius N. GRIGORE ◽  
Monica BOSCAIU ◽  
Josep LLINARES ◽  
Oscar VICENTE
Keyword(s):  
Salt Stress ◽  
Salt Marshes ◽  
Vegetative Growth ◽  
Reproductive Development ◽  
Protective Role ◽  
Similar Function ◽  
Seed Formation ◽  
Supplemental Calcium ◽  
Negative Effect

In Plantago crassifolia, a moderate halophyte characteristic of borders of salt marshes in the Mediterranean region, reproductivedevelopment is more sensitive to high soil salinity than vegetative growth. To investigate the possible role of calcium and magnesiumsalts in the responses of this species to salt stress, adult plants were submitted over a 2-month period to treatments with 300 mMNaCl-a concentration which affects, but does not completely inhibit seed formation in P. crassifolia-either alone or combined with lowconcentrations of CaCl2 (10 mM) or MgCl2 (20 mM). The NaCl treatment did not affect plant vegetative growth and had a stimulatingeffect on flowering. Yet almost half the spikes produced had aborted seeds, and the effect on seed number and quality-estimated bytheir mean weight and germination capacity-was obviously deleterious. Addition of calcium or magnesium chloride during the saltstresstreatment completely counteracted the negative effect of NaCl on the ‘reproductive success’ of the plants: the number, weightand germination frequency of the seeds were similar to that in the control, non-stressed plants. These results indicate that both divalentcations can suppress or mitigate the deleterious effects of salt stress. While this protective role is well established in the case of calcium,we provide here the first experimental evidence of a similar function for magnesium.

scholarly journals The Role of Light and Circadian Clock in Regulation of Leaf Senescence

2021 ◽  
Vol 12 ◽  
Author(s):  
Juhyeon Lee ◽  
Myeong Hoon Kang ◽  
Jung Yeon Kim ◽  
Pyung Ok Lim
Keyword(s):  
Circadian Clock ◽  
Leaf Senescence ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Control Plant ◽  
Structural Features ◽  
Clock Period ◽  
Environmental Signals

Leaf senescence is an integrated response of the cells to develop age information and various environmental signals. Thus, some of the genes involved in the response to environmental changes are expected to regulate leaf senescence. Light acts not only as the primary source of energy for photosynthesis but also as an essential environmental cue that directly control plant growth and development including leaf senescence. The molecular mechanisms linking light signaling to leaf senescence have recently emerged, exploring the role of Phytochrome-Interacting Factors (PIFs) as a central player leading to diverse senescence responses, senescence-promoting gene regulatory networks (GRNs) involving PIFs, and structural features of transcription modules in GRNs. The circadian clock is an endogenous time-keeping system for the adaptation of organisms to changing environmental signals and coordinates developmental events throughout the life of the plant. Circadian rhythms can be reset by environmental signals, such as light-dark or temperature cycles, to match the environmental cycle. Research advances have led to the discovery of the role of core clock components as senescence regulators and their underlying signaling pathways, as well as the age-dependent shortening of the circadian clock period. These discoveries highlight the close relationship between the circadian system and leaf senescence. Key issues remain to be elucidated, including the effect of light on leaf senescence in relation to the circadian clock, and the identification of key molecules linking aging, light, and the circadian clock, and integration mechanisms of various senescence-affecting signals at the multi-regulation levels in dynamics point of view.

scholarly journals Brassinosteroids: A Multifunctional Phytohormone of Plant Development and Stress Responses

2020 ◽  
pp. 174-196
Author(s):  
Jannela Praveena ◽  
Satyanarayan Dash ◽  
Laxmipreeya Behera ◽  
Gyana Ranjan Rout
Keyword(s):  
Plant Growth ◽  
Stress Responses ◽  
Growth And Development ◽  
Nutrient Deficiency ◽  
High Yield ◽  
Enzymatic Reactions ◽  
Plant Growth And Development ◽  
Nutrient Distribution ◽  
Seed Formation

Brassinosteroids (BRs) act as immune-modulators for generating plant growth and development. It regulated either activation or suppression of various key enzymatic reactions, activation of synthesis of protein, and generation of various defense modulating compounds for the plant kingdom. BRs play a vital role in regulating cellular differentiation, pollen development, fruit ripening, and quality seed formation.   BRs regulates the various physiological process including root growth during nutrient deficiency such as nitrogen, phosphorus, boron and tends to signal the nutrient distribution in the rhizosphere level for better growth and high yield in crop plants. This review highlighted the role of BRs in plant growth and development and stress response, understanding the BR pathway, the molecular mechanism of BR signaling in various tissues, crosstalk between BRs and other phytohormones, gene involves in the brassinosteroids signaling pathway, biosynthesis and  role of  BRs  in  biomass production and crop yield.

scholarly journals Epigenetics as a key link between psychosocial stress and aging: concepts, evidence, mechanisms

2019 ◽  
Vol 21 (4) ◽  
pp. 389-396 ◽  
Keyword(s):  
Psychosocial Stress ◽  
Molecular Mechanisms ◽  
Disease Risk ◽  
Accelerated Aging ◽  
World Population ◽  
Biochemical Processes ◽  
Complex Phenotypes ◽  
Underlying Mechanisms ◽  
Shed Light

Psychosocial stress—especially when chronic, excessive, or occurring early in life—has been associated with accelerated aging and increased disease risk. With rapid aging of the world population, the need to elucidate the underlying mechanisms is pressing, now more so than ever. Among molecular mechanisms linking stress and aging, the present article reviews evidence on the role of epigenetics, biochemical processes that can be set into motion by stressors and in turn influence genomic function and complex phenotypes, including aging-related outcomes. The article further provides a conceptual mechanistic framework on how stress may drive epigenetic changes at susceptible genomic sites, thereby exerting systems level effects on the aging epigenome while also regulating the expression of molecules implicated in aging-related processes. This emerging evidence, together with work examining related biological processes, begins to shed light on the epigenetic and, more broadly, molecular underpinnings of the long-hypothesized connection between stress and aging.

scholarly journals The Importance of Ion Homeostasis and Nutrient Status in Seed Development and Germination

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 504 ◽  
Author(s):  
María del Carmen Martínez-Ballesta ◽  
Catalina Egea-Gilabert ◽  
Encarnación Conesa ◽  
Jesús Ochoa ◽  
María José Vicente ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Seed Development ◽  
Molecular Mechanisms ◽  
Ion Homeostasis ◽  
Nutrient Status ◽  
Seed Vigor ◽  
Nutrient Deficiencies ◽  
Seed Formation ◽  
New Genes

Seed is the dissemination unit of plants initiating an important stage in the life cycle of plants. Seed development, comprising two phases: embryogenesis and seed maturation, may define the quality of sown seed, especially under abiotic stress. In this review we have focused on the recent advances in the molecular mechanisms underlying these complex processes and how they are controlled by distinct environmental factors regulating ion homeostasis into the seed tissues. The role of transporters affecting seed embryogenesis and first stages of germination as imbibition and subsequent radicle protrusion and extension were revised from a molecular point of view. Seed formation depends on the loading of nutrients from the maternal seed coat to the filial endosperm, a process of which the efflux is not clear and where different ions and transporters are involved. The clear interrelation between soil nutrients, presence of heavy metals and the ion capacity of penetration through the seed are discussed in terms of ion effect during different germination stages. Results concerning seed priming techniques used in the improvement of seed vigor and radicle emergence are shown, where the use of nutrients as a novel way of osmopriming to alleviate abiotic stress effects and improve seedlings yield is discussed. Novel approaches to know the re-translocation from source leaves to developing seeds are considered, as an essential mechanism to understand the biofortification process of certain grains in order to cope with nutrient deficiencies, especially in arid and semiarid areas. Finally, the role of new genes involved in hormone-dependent processes, oxidative response and water uptake into the seeds during their development or germination, have been described as plant mechanisms to deal with abiotic stresses.

scholarly journals The role of universal regulators of plant growth and development the DELLA proteins in the control of symbiosis

2019 ◽  
Vol 17 (1) ◽  
pp. 33-41
Author(s):  
Aleksandra V. Dolgikh ◽  
Elena A. Dolgikh
Keyword(s):  
Plant Growth ◽  
Growth And Development ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Direct Interaction ◽  
Plant Growth And Development ◽  
Della Proteins ◽  
Secondary Messengers ◽  
External Signals

The regulators of the gibberellin response, the DELLA proteins, are universal participants of signaling pathways that coordinate the processes of plant growth and development. This regulation is provided by the integration of external effect, as well as internal signals, such as a level of phytohormones and secondary messengers. Since DELLA proteins are extremely sensitive to increasing or decreasing of the gibberellic acid (GA) endogenous level, their direct interaction with transcription factors modulates the activity of the latter, and, consequently, the level of expression of target genes in response to external signals causing changes in the level of GA. However, the molecular mechanisms of the effect of DELLA proteins on the development of symbiosis remain poorly understood. The review analyzes classical and modern data on the functioning of DELLA proteins in plants.

scholarly journals Space Breeding: The Next-Generation Crops

2021 ◽  
Vol 12 ◽  
Author(s):  
Tapan Kumar Mohanta ◽  
Awdhesh Kumar Mishra ◽  
Yugal Kishore Mohanta ◽  
Ahmed Al-Harrasi
Keyword(s):  
Cosmic Radiation ◽  
Molecular Mechanisms ◽  
Space Environment ◽  
Genetic Mutations ◽  
Next Generation ◽  
Plant Growth And Development ◽  
Crop Varieties ◽  
Breeding Programmes ◽  
Major Factors

Since the beginning of space exploration, researchers have been exploring the role of microgravity, cosmic radiation, and other aspects of the space environment on plant growth and development. To create superior crop varieties and achieve noticeable success in the space environment, several types of research have been conducted thus far. Space-grown plants have been exposed to cosmic radiation and microgravity, which has led to the generation of crop varieties with diverse genotypes and phenotypes arising from different cellular, subcellular, genomic, chromosomal, and biochemical changes. DNA damage and chromosomal aberrations due to cosmic radiation are the major factors responsible for genetic polymorphism and the generation of crops with modified genetic combinations. These changes can be used to produce next-generation crop varieties capable of surviving diverse environmental conditions. This review aims to elucidate the detailed molecular mechanisms and genetic mutations found in plants used in recent space crop projects and how these can be applied in space breeding programmes in the future.

scholarly journals Autophagy is essential for optimal Fe translocation to seeds in Arabidopsis

2018 ◽  
Author(s):  
Mathieu Pottier ◽  
Jean Dumont ◽  
Céline Masclaux-Daubresse ◽  
Sébastien Thomine
Keyword(s):  
De Novo ◽  
Nutrient Recycling ◽  
Fine Tuning ◽  
World Population ◽  
Micronutrient Deficiencies ◽  
Nitrogen Remobilization ◽  
Seed Formation ◽  
Vegetative Organs ◽  
Step Mechanism

AbstractMicronutrient deficiencies affect a large part of the world population. They are mostly due to the consumption of grains with insufficient content of Fe or Zn. Both de novo uptake by roots and recycling from leaves may provide seeds with nutrients. Autophagy, which is a conserved mechanism for nutrient recycling in eukaryotes, was shown to be involved in nitrogen remobilization to seeds. Here, we have investigated the role of this mechanism in micronutrient translocation to seeds. We found that several Arabidopsis thaliana plants impaired in autophagy display defects in nutrient remobilization to seeds. In atg5-1 mutant, which is completely defective in autophagy, the efficiency of Fe translocation from vegetative organs to seeds was severely decreased even when Fe was provided during seed formation. Combining atg5-1 with sid2 mutation that counteracts premature senescence associated to autophagy deficiency and using 57Fe pulse labeling, we could propose a two-step mechanism in which iron taken up de novo during seed formation is first accumulated in vegetative organs and subsequently remobilized to seeds. Finally, we showed that translocations of zinc and manganese to seeds are also dependent on autophagy. Fine tuning autophagy during seed formation opens therefore new possibilities to improve micronutrient remobilization to seeds.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

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