Changes of melatonin and its receptors in synchronizing turbot(Scophthalmus maximus)seasonal reproduction and maturation rhythm

In most fish,reproduction is seasonal or periodic under the suitable conditions.In turbot(Scophthalmus maximus)farms,one of the most economically important marine flatfish species,changes in daylength could cause changes in the spawning time.In this study,to characterize the regulation of reproductive physiology following light signals,three melatonin receptors(Mtnr)investigated in turbot were named sm Mtnr1,sm Mtnr2,and sm Mtnr1 c.Distinct expression profiles demonstrated that Mtnr m RNAs were concentrated in the brain(as detected in the hypothalamus(Hy)and mesencephalon(Me)),gonad and eye.The most abundant Mtnr1 and Mtnr2 m RNA expression levels were detected in the central nervous system at the beginning of the breeding season,suggesting that Mtnr1 and Mtnr2 may play vital roles in the regulation of turbot gonadal development.In addition,the melatonin profiles gradually increased and reached to the highest level at the spawning stage,indicating that melatonin is a potent hormone in the regulation of fish oocyte growth and maturation.The results of this study suggested that melatonin is the primary factor that transduces the light signal and regulates the physiological functions of turbot seasonal reproduction.Moreover,the results of this study may establish a foundation for further research seeking to identify fish melatonin receptors involved in the gonadal development and gamete maturation.

An Overview on Biological Markers in Reproductive and Developmental Toxicology: Concepts, Definitions and Use in Risk Assessment

Reproduction and development are complex couple-dependent processes. Risk assessment for these health outcomes requires the use of biomarkers to link exposures to disease. Biological markers of susceptability, external dose, internal dose, biologically effective dose, early or late biological responses, altered reproductive or developmental function, and reproductive or developmental disease are introduced. Using these biomarkers it is possible to define a biologically based risk assessment methodology for reproductive and developmental toxicity. Risk assessment for reproductive toxicity requires definition of male and female fecundity, couple-specific factors, spontaneous abortion, rate, and other factors. Using using sperm count as a biomarker for male fecundity, an example of a reproductive risk assessment using biomarkers is performed.

Effects of a soybean milk product on feto-neonatal development in rats

Since estrogenic pollutants and phytoestrogens can cause the disorder of the reproductive system, the effects of a soybean milk product（Vegemil^（？） containing 162 ppm isoflavones） on the feto-neonatal development, including male reproductive function, were investigated. Pregnant rats were fed the soybean milk（5% or 100% in drinking water）from gestational day（GD） 6 to parturition or to post-natal day（PND） 56. Specifically, the rats were divided into 4 groups： the control group（drinking water）, the GD5% group（5% soybean milk during only the GD period）, the GDPND5% group（5% soybean milk during the GD and PND periods）, and the GD-PND100% group（100% soybean milk instead of water during the GD and PND periods）. During the gestational, lactational, and developmental periods, the reproductive and developmental parameters of dams and offspring were observed. Feeding soybean milk did not affect the birth and physical development of both male and female offspring. At PND57, the weights of the testes and epididymides of F1 males significantly increased by feeding a high concentration of the soybean milk（GDPND100%）. In addition, feeding of the soybean milk during both the GD and PND periods（GD-PND5% and GDPND100%） enhanced the sperm counts and motility. The results indicate that soybean milk is safe for embryos,fetuses, and offspring, and improves the post-generational development of male reproductive function.

Cloning and Characterization of a Somatic Embryogenesis Receptor-Like Kinase Gene in Cotton (Gossypium hirsutum)

A novel gene, GhSERK1, was identified in cotton. It encoded a protein belonging to the somatic embryogenesis receptor- like kinase （SERK） family. The genomic sequence of GhSERK1 was 6 920 bp in length, containing a predicted transcriptional start site （TSS）. Its full-length cDNA was 2 502 bp, encoding a protein of 627 amino acids. Sequence analysis of GhSERK1 revealed high levels of similarity to other reported SERKs, as well as a conserved intron/exon structure that was unique to members of the SERK family. Expression analysis showed that GhSERK1 mRNA was present in all organs of cotton plants and at different developmental stages, but its transcripts were most abundant in reproductive organs. Compared with that of the male-fertile line, the level of GhSERK1 mRNA was lower in the anther of the male-sterile cotton line, in which the pollen development was defected. Taken together, these findings illustrated that the GhSERK1 play a critical role during the anther formation, and may also have a broad role in other aspects of plant development.

Transcriptome analysis of hsp18.3 functions and regulatory systems using RNA-sequencing in the red flour beetle,Tribolium castaneum

The red flour beetle, Tribolium castaneum, is a major agriculture pest of stored grain, cereal products and peanuts for human consumption. It is reported that heat shock protein 18.3 of T. castaneum（Tchsp18.3） plays a significant role in stress resistance, development and reproduction. However, the regulatory systems of Tchsp18.3 remain unknown. Therefore, we compared the global transcriptome profiles of RNA interference（RNAi）-treated larvae（ds-Tchsp18.3） and control larvae of T. castaneum using RNA sequencing. Overall, we obtained 14 154 435 sequence reads aligned with 13 299 genes. Additionally, 569 differentially expressed genes（DEGs） were identified from the ds-Tchsp18.3 and control groups, of which 246 DEGs were annotated in the 47 Gene Ontology（GO） functional groups and 282 DEGs were assigned to 147 Kyoto Encyclopedia of Genes and Genomes（KEGG） biological signaling pathways. The DEGs encoding viperin, dorsal, Hdd11, PGRP2, defensin1 and defensin2 were simultaneously related to immunity and stress responses, which suggests that cross-talk might exist between the immunity and stress responses of T. castaneum. The knockdown of Tchsp18.3 gene expression suppressed the antioxidant activity process, which most likely modulated the effects of Tchsp18.3 on development and reproduction. Furthermore, the DEGs, including Blimp-1, Gld, Drm, Kinesin-14, Pthr2, Delta（11）-like and EGF-like domain protein 2, were also associated with the development and reproduction of ds-Tchsp18.3 insects. Additionally, knockdown of Tchsp18.3 amplified the serine protease（SP） signaling pathway to further regulate stress responses and innate immunity as well as development and reproduction of the red flour beetles. These results provide valuable insight into the molecular regulatory mechanism of Tchsp18.3 involved in insect physiology and further facilitate the research of suitable and sustainable management for pest control.

Molecular regulation of tomato male reproductive development

The reproductive success of flowering plants,which directly affects crop yield,is sensitive to environmental changes.A thorough understanding of how crop reproductive development adapts to climate changes is vital for ensuring global food security.In addition to being a high-value vegetable crop,tomato is also a model plant used for research on plant reproductive development.Tomato crops are cultivated under highly diverse climatic conditions worldwide.Targeted crosses of hybrid varieties have resulted in increased yields and abiotic stress resistance;however,tomato reproduction,especially male reproductive development,is sensitive to temperature fluctuations,which can lead to aborted male gametophytes,with detrimental effects on fruit set.We herein review the cytological features as well as genetic and molecular pathways influencing tomato male reproductive organ development and responses to abiotic stress.We also compare the shared features among the associated regulatory mechanisms of tomato and other plants.Collectively,this review highlights the opportunities and challenges related to characterizing and exploiting genic male sterility in tomato hybrid breeding programs.

Population Development and Reproduction Health Education in Tibet

MY ancestors have lived in Lhasa, Tibet, for generations. I have personally witnessed the great changes in modern Tibetan society. The total population of the region has doubled since 1951. The Fourth National Census in 1990 revealed that the human fertility rate in the Tibet Autonomous Region was 27.60 per thousand, the natural population growth rate 18.40 per thousand, and the total fertility rate of women at childbearing age 4.22.

Sugar Input, Metabolism, and Signaling Mediated by Invertase： Roles in Development, Yield Potential, and Response to Drought and Heat

Invertase （INV） hydrolyzes sucrose into glucose and fructose, thereby playing key roles in primary metabolism and plant development. Based on their pH optima and sub-cellular locations, INVs are categorized into cell wall, cytoplasmic, and vacuolar subgroups, abbreviated as CWlN, CIN, and VlN, respectively. The broad importance and implications of INVs in plant development and crop productivity have attracted enormous interest to examine INV function and regulation from multiple perspectives. Here, we review some exciting advances in this area over the last two decades, focusing on （1） new or emerging roles of INV in plant development and regulation at the post-translational level through interaction with inhibitors, （2） cross-talk between INV-mediated sugar signaling and hormonal control of development, and （3） sugar- and INV-mediated responses to drought and heat stresses and their impact on seed and fruit set. Finally, we discuss major questions arising from this new progress and outline future directions for unraveling mechanisms underlying INV-mediated plant development and their potential applications in plant biotechnology and agriculture.

Lipid Metabolism: Critical Roles in Male Fertility and Other Aspects of Reproductive Development in Plants

Fatty acids and their derivatives are essential building blocks for anther cuticle and pollen wall formation.Disruption of lipid metabolism during anther and pollen development often leads to genic male sterility(GMS).To date,many lipid metabolism-related GMS genes that are involved in the formation of anther cuticle,pollen wall,and subcellular organelle membranes in anther wall layers have been identified and characterized.In this review,we summarize recent progress on characterizing lipid metabolism-related genes and their roles in male fertility and other aspects of reproductive development in plants.On the basis of cloned GMS genes controlling biosynthesis and transport of anther cutin,wax,sporopollenin,and tryphine\r\Arabidopsis,rice,and maize as well as other plant species,updated lipid metabolic networks underlying anther cuticle development and pollen wall formation were proposed.Through bioinformatics analysis of anther RNA-sequencing datasets from three maize inbred lines(Oh43,W23,and B73),a total of 125 novel lipid metabolism-related genes putatively involved in male fertility in maize were deduced.More,we discuss the pathways regulating lipid metabolism-related GMS genes at the transcriptional and post-transcriptional levels.Finally,we highlight recent findings on lipid metabolism-related genes and their roles in other aspects of plant reproductive development.A comprehensive understanding of lipid metabolism,genes involved,and their roles in plant reproductive development will facilitate the application of lipid metabolism-related genes in gene editing,haploid and callus induction,molecular breeding and hybrid seed production in crops.

Temporal and Spatial Requirement of EMF1 Activity for Arabidopsis Vegetative and Reproductive Development

EMBRYONIC FLOWER （EMF） genes are required to maintain vegetative development via repression of flower homeotic genes in Arabidopsis. Removal of EMF gene function caused plants to flower upon germination, producing abnormal and sterile flowers. The pleiotropic effect of ernfl mutation suggests its requirement for gene programs involved in diverse developmental processes. Transgenic plants harboring EMF1 promoter：：glucuronidase （GUS） reporter gene were generated to investigate the temporal and spatial expression pattern of EMF1. These plants displayed differential GUS activity in vegetative and flower tissues, consistent with the role of EMF1 in regulating multiple gene programs. EMFI：：GUS expression pattern in emf mutants suggests organ-specific auto-regulation. Sense- and antisense （as） EMF1 cDNA were expressed under the control of stage- and tissue-specific promoters in transgenic plants. Characterization of these transgenic plants showed that EMF1 activity is required in meristematic as well as differentiating tissues to rescue emf mutant phenotype. Temporal removal or reduction of EMF1 activity in the embryo or shoot apex of wild-type seedlings was sufficient to cause early flowering and terminal flower formation in adult plants. Such reproductive cell memory is reflected in the flower MADS-box gene activity expressed prior to flowering in these early flowering plants. However, temporal removal of EMF1 activity in flower meristem did not affect flower development. Our results are consistent with EMF1＇s primary role in repressing flowering in order to allow for vegetative growth.

Zebrafish as a possible bioindicator of organic pollutants with effects on reproduction in drinking waters

Organic contaminants can be detected at low concentrations in drinking water, raising concerns for human health, particularly in reproduction. In this respect, we attempted to use the zebrafish as a bioindicator to detect the possible presence of these substances in drinking water, aiming to define the most relevant parameters to detect these substances, which particularly affect the development and reproduction of zebrafish. To this end, batches of30 embryos with the chorion intact were cultured in drinking waters from different sources,throughout their full life-cycle up to 5 months, in 20 L tanks. Six replicates were performed in all water groups, with a total of 24 aquariums. Two generations（F0 and F1） were studied and the following parameters were tested： in the F0 generation, survival and abnormality rates evaluated at 5 dpf（days post-fertilization） and at 5 mpf（months post-fertilization）,the onset of spawning and the fertility rate from 3 mpf to 5 mpf, and the sex ratio and underdeveloped specimens at 5 mpf. Furthermore, in the F0 offspring（F1）, survival and abnormality rates were evaluated at 5 dpf and the hatching rate at 72 hpf. These results revealed that the hatching rate is the most sensitive parameter to distinguish different levels of effects between waters during the early life stages, whereas the rate of underdeveloped specimens is more suitable at later life stages. Regarding adult reproduction, fertility rate was the most sensitive parameter. The possible reversibility or accumulative nature of such effects will be studied in future work.

Nucleolar histone deacetylases HDT1,HDT2,and HDT3 regulate plant reproductive development

Nucleolus is a membrane-less organelle where ribosomes are assembled, and ribosomal RNAs(r RNAs)transcribed and processed. The assembled ribosomes composed of ribosomal proteins and r RNAs synthesize proteins for cell survival. In plants, the loss of nucleolar ribosomal proteins often causes gametophytically or embryonically lethality. The amount of r RNAs are under stringent regulation according to demand and partially switched off by epigenetic modifications. However, the molecular mechanism for the selective activation or silencing is still unclear, and the transcriptional coordination of r RNAs and ribosomal proteins is also unknown. Here, we report the critical role of three Arabidopsis nucleolar proteins HDT1,HDT2, and HDT3 in fertility and transcription of r DNAs and r RNA processing-related genes through histone acetylation. This study highlights the important roles of transcriptional repression of ribosome biogenesisrelated genes for plant reproductive development.

Receptor-like protein kinases in plant reproduction: Current understanding and future perspectives

Reproduction is a crucial process in the life span of flowering plants,and directly affects human basic requirements in agriculture,such as grain yield and quality.Typical receptor-like protein kinases(RLKs)are a large family of membrane proteins sensing extracellular signals to regulate plant growth,development,and stress responses.In Arabidopsis thaliana and other plant species,RLK-mediated signaling pathways play essential roles in regulating the reproductive process by sensing different ligand signals.Molecular understanding of the reproductive process is vital from the perspective of controlling male and female fertility.Here,we summarize the roles of RLKs during plant reproduction at the genetic and molecular levels,including RLK-mediated floral organ development,ovule and anther development,and embryogenesis.In addition,the possible molecular regulatory patterns of those RLKs with unrevealed mechanisms during reproductive development are discussed.We also point out the thought-provoking questions raised by the research on these plant RLKs during reproduction for future investigation.

DEVELOPMENT OF FEMALE REPRODUCTIVE ENDOCRINOLOGY IN CHINA

Female reproductive endocrinology plays an important role in obstetrics and gynecology, and is a component part of perinatology, family planning and geriatrics. It is closely linked with the physiological changes, disease conditions and health care in different reproductive stages of a woman’s life. Ovarian function consists of ovulation and hormonal secretion, which acts upon the uterine endometrium and other target organs and feeds back to the hypothalamus-pituitary unit. Thus, it is connected with other endocrine systems, cerebral cortex and the external environment. Whether the ovrian function is normal or not reflects itself clinically in the changes of menstrual cycle and reproductive status and may be evaluated by laboratory assays.

Rice functional genomics:decades'efforts and roads ahead

Rice(Oryza sativa L.)is one of the most important crops in the world.Since the completion of rice reference genome sequences,tremendous progress has been achieved in understanding the molecular mechanisms on various rice traits and dissecting the underlying regulatory networks.In this review,we summarize the research progress of rice biology over past decades,including omics,genome-wide association study,phytohormone action,nutrient use,biotic and abiotic responses,photoperiodic flowering,and reproductive development(fertility and sterility).For the roads ahead,cutting-edge technologies such as new genomics methods,high-throughput phenotyping platforms,precise genome-editing tools,environmental microbiome optimization,and synthetic methods will further extend our understanding of unsolved molecular biology questions in rice,and facilitate integrations of the knowledge for agricultural applications.