Development Of Male Organs Research Articles

Cellular sex throughout the organism underlies somatic sexual differentiation

Sex chromosomes underlie the development of male or female sex organs across species. While systemic signals derived from sex organs prominently contribute to sex-linked differences, it is unclear whether the intrinsic presence of sex chromosomes in somatic tissues has a specific function. Here, we use genetic tools to show that cellular sex is crucial for sexual differentiation throughout the body in Drosophila melanogaster. We reveal that every somatic cell converts the intrinsic presence of sex chromosomes into the active production of a sex determinant, a female specific serine- and arginine-rich (SR) splicing factor. This discovery dismisses the mosaic model which posits that only a subset of cells has the potential to sexually differentiate. Using cell-specific sex reversals, we show that this prevalence of cellular sex drives sex differences in organ size and body weight and is essential for fecundity. These findings demonstrate that cellular sex drives differentiation programs at an organismal scale and highlight the importance of cellular sex pathways in sex trait evolution.

The Impact of Maternal Hypothyroidism during Pregnancy on Minipuberty in Boys.

Minipuberty is a period of increased reproductive axis activity in infancy, which seems to be implicated in the postnatal development of male genital organs. Impaired thyroid function during pregnancy is associated with an increased risk of prenatal, perinatal, and postnatal complications. The aim of this study was to investigate whether the presence of hypothyroidism during pregnancy modulates the course of male minipuberty. We compared three matched groups of male infants: sons of women with hypothyroidism uncontrolled or poorly controlled during pregnancy (group A), male offspring of women treated over the entire pregnancy with adequate doses of levothyroxine (group B), and sons born to women with no evidence of thyroid disease (group C). Salivary levels of testosterone, androstenedione, dehydroepiandrosterone sulfate, estradiol, progesterone, and 17-hydroxyprogesterone, as well as urine concentrations of FSH and LH, were assessed once a month in the first 6 months of life, and once every two months between months 6 and 12. Gonadotropin and testosterone levels during the first 6 months of life were lower in group A than in groups B and C. Differences in testosterone and gonadotropin levels were accompanied by similar differences in penile length and testicular volume. Concentrations of the remaining hormones did not differ between the study groups. The obtained results suggest that untreated or undertreated maternal thyroid hypofunction in pregnancy has an inhibitory effect on postnatal activation of the hypothalamic-pituitary-testicular axis and genital organ development in their male offspring.

Minipuberty in Sons of Women with Low Vitamin D Status during Pregnancy.

Minipuberty is a transient phase of reproductive axis activation during the first several months of life, playing an important role in the development of reproductive organs in boys. Low 25-hydroxyvitamin D levels during pregnancy are associated with an increased risk of neonatal complications. An inadequate gestational vitamin D status is hypothesized to affect the postnatal activation of the hypothalamic-pituitary-gonadal axis. The purpose of our study was to assess whether a low vitamin D status during pregnancy determines the course of minipuberty in boys. The study included three groups of male infants born to women with different vitamin D statuses: sons of women with vitamin D deficiency (group 1), sons of women with vitamin D insufficiency (group 2), and male offspring of females with normal 25-hydroxyvitamin D levels (group 3 (the reference group)). Concentrations of testosterone, androstenedione, dehydroepiandrosterone sulfate, estradiol, progesterone, and 17-hydroxyprogesterone in saliva, as well as concentrations of gonadotropins in urine, were assayed monthly from postnatal months 1 to 6, and once every 2 months in the second half of the first year of life. Additionally, at each visit, penile length and testicular volume were assessed. Concentrations of testosterone, FSH, and LH, as well as penile length and testicular volume, were greater in group 1 than in groups 2 and 3. In turn, group 2 was characterized by higher FSH levels and a greater testicular volume than group 3. Peak concentrations of LH and testosterone were observed earlier in group 1 than in the remaining groups. The obtained results suggest that a low vitamin D status during pregnancy may have a stimulatory impact on reproductive axis activity and on the early postnatal development of male genital organs, correlating with the severity of hypovitaminosis D.

Testosterone modulates atrazine-induced cytotoxicity in testicular cell lines

Testosterone greatly influences healthy growth and development of male sex organs. Testosterone has been demonstrated to possess antioxidant and anti-cytotoxic effects in cells. The present study examine the protective effect of testosterone on ATZ-induced cytotoxicity using TM3 Leydig and TM4 Sertoli cell lines as testicular in vitro models. TM3 Leydig and TM4 Sertoli cell lines were treated with atrazine (ATZ) 232 μM with varying concentrations of testosterone (0.1. 1, 10, 20 nM) for 6 h, 12 h and 48 h. Administration of testosterone increased the viability of the cell lines for 12 h and 48 h exposure compared to ATZ values (p< 0.005). Furthermore, testosterone reduced TM3 cell and TM4 cell GSH levels. Exogenous testosterone intake minimizes cell death and GSH levels in testicular cell lines exposed to ATZ. However, the lowest dose of testosterone attenuates the ATZ-induced increase of GSH levels in both TM3 and TM4 cells (p< 0.005).

Expression of the Homeobox Proteins Dlx-5 and TLX1 During the Development of Cat Testis

Recent studies have shown that homeobox proteins play an important role in the formation and development of tissues and organs in the embryonic period. In our study, the distribution of Dlx-5 and TLX proteins, which are members of the homeobox family, in the testis, epididymis and ductus deferens ducts of some cat breeds were investigated. For this purpose, in the study, 18 testes younger than six months (immature) and older than one year (mature) were examined under a light microscope using an immunohistochemical method (indirect streptavidin-biotin complex). While it was determined that Dlx-5 and TLX1 proteins were expressed at varying levels in cells in immature and mature cat testicles, epithelial cells of ductus epididymis and ductus deferens, and smooth muscle cells of ductus deferens, no differences were observed between cat breeds. Dlx-5 immunoreactivity was more intense in the testes, epididymis and deferens ducts of immature and mature compared to TLX1. These results suggested that both proteins play important roles in the development of male feline genital organs and in the secretion and differentiation of cells, and also further observation of Dlx-5 expression suggested that this protein may be more effective than TLX1 in testicular development and physiological processes.

ARR17 controls dioecy in Populus by repressing B-class MADS-box gene expression.

The number of dioecious species for which the genetic basis of sex determination has been resolved is rapidly increasing. Nevertheless, the molecular mechanisms downstream of the sex determinants remain largely elusive. Here, by RNA-sequencing early-flowering isogenic aspen (Populus tremula) lines differing exclusively for the sex switch gene ARR17, we show that a narrowly defined genetic network controls differential development of female and male flowers. Although ARR17 encodes a type-A response regulator supposedly involved in cytokinin (CK) hormone signalling, clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9-mediated arr17 knockout only affected the expression of a strikingly small number of genes, indicating a specific role in the regulation of floral development rather than a generic function in hormone signalling. Notably, the UNUSUAL FLORAL ORGANS (UFO) gene, encoding an F-box protein acting as a transcriptional cofactor with LEAFY (LFY) to activate B-class MADS-box gene expression, and the B-class gene PISTILLATA (PI), necessary for male floral organ development, were strongly de-repressed in the arr17 CRISPR mutants. Our data highlight a CK-independent role of the poplar response regulator ARR17 and further emphasize the minimal differences between female and male individuals.This article is part of the theme issue ‘Sex determination and sex chromosome evolution in land plants’.

Morphological analysis and stage determination of anther development in Sorghum [Sorghum bicolor (L.) Moench

Main ConclusionThe characteristics of sorghum anthers at 18 classified developmental stages provide an important reference for future studies on sorghum reproductive biology and abiotic stress tolerance of sorghum pollen.Sorghum (Sorghum bicolor L. Moench) is the fifth-most important cereal crop in the world. It has relatively high resilience to drought and high temperature stresses during vegetative growing stages comparing to other major cereal crops. However, like other cereal crops, the sensitivity of male organ to heat and drought can severely depress sorghum yield due to reduced fertility and pollination efficiency if the stress occurs at the reproductive stage. Identification of the most vulnerable stages and the genes and genetic networks that differentially regulate the abiotic stress responses during anther development are two critical prerequisites for targeted molecular trait selection and for enhanced environmentally resilient sorghum in breeding using a variety of genetic modification strategies. However, in sorghum, anther developmental stages have not been determined. The distinctive cellular characteristics associated with anther development have not been well examined. Lack of such critical information is a major obstacle in the studies of anther and pollen development in sorghum. In this study, we examined the morphological changes of sorghum anthers at cellular level during entire male organ development processes using a modified high-throughput imaging variable pressure scanning electron microscopy and traditional light microscopy methods. We divided sorghum anther development into 18 distinctive stages and provided detailed description of the morphological changes in sorghum anthers for each stage. The findings of this study will serve as an important reference for future studies focusing on sorghum physiology, reproductive biology, genetics, and genomics.

Immunoexpression of androgen receptor in genital tissues of male BALB/c mice

Aim: Androgens are hormones that are essential for the differentiation and development of male genital organs, preserving their structural features and maintaining their functions. These hormones exert their effects on target tissues mainly through androgen receptors (AR). The aim of this study was to determine the AR immunoexpression pattern in the genital tissues of male mice. Materials and Methods: A total of 6 BALB/c male mice were anesthetized with ether, and the genital tissues, which were quickly removed from the body, were fixed in Bouin’s solution for 18 hours. Tissues that underwent routine histological procedures after fixation were embedded in paraffin. Tissue sections cut with a thickness of 5 µm from paraffin blocks were taken on a slide and examined by staining with immunohistochemical methods. Results: AR-positive immunostaining in the testis was observed only in somatic cells such as Sertoli, peritubular myoid cells, and Leydig cells. Germ cells were AR-negative. In the caput epididymis, ductus deferens, and seminal vesicle, AR positive immunoexpression was observed in stromal cells, especially epithelial cells. Although AR-positive staining was observed in some of the epithelial and stromal cells in these organs, some of them were AR-negative. Conclusion: In the current study, it was determined that the AR expression pattern in the genital tissues of male BALB/c mice was similar to that in other species, although there were minor differences. The findings support the hypothesis that androgens exert their effects in testis mainly through somatic cells, and their effects in other genital tissues through epithelial cells, and the fact that androgens/ARs are essential for maintaining the structures and functions of male genital organs.

Spatiotemporal regulation and roles of reproductive phasiRNAs in plants.

Since co-suppression was discovered as a pioneer silencing phenomenon of RNA interference (RNAi) in petunia in 1990, many types of small RNAs have been identified in the RNAi pathway among various eukaryotes. In plants, a large number of 21- or 24-nucleotide (nt) phased small interfering RNAs (phasiRNAs) are produced via processing of long RNA precursors by Dicer-like proteins. However, the roles of phasiRNAs remain largely unknown. The development of imaging technology and RNA profiling has clarified the spatiotemporal regulation of phasiRNAs, and subsequently the different functions of 21-nt trans-acting phasiRNAs and 24-nt cis-regulatory phasiRNAs during male organ development. This review focuses on the biogenesis, diversification, spatiotemporal expression pattern and function of phasiRNAs in plants.

Developmental expression patterns of toolkit genes in male accessory gland of Drosophila parallels those of mammalian prostate.

ABSTRACTConservation of genetic toolkits in disparate phyla may help reveal commonalities in organ designs transcending their extreme anatomical disparities. A male accessory sexual organ in mammals, the prostate, for instance, is anatomically disparate from its analogous, phylogenetically distant counterpart – the male accessory gland (MAG) – in insects like Drosophila. It has not been ascertained if the anatomically disparate Drosophila MAG shares developmental parallels with those of the mammalian prostate. Here we show that the development of Drosophila mesoderm-derived MAG entails recruitment of similar genetic toolkits of tubular organs like that seen in endoderm-derived mammalian prostate. For instance, like mammalian prostate, Drosophila MAG morphogenesis is marked by recruitment of fibroblast growth factor receptor (FGFR) – a signalling pathway often seen recruited for tubulogenesis – starting early during its adepithelial genesis. A specialisation of the individual domains of the developing MAG tube, on the other hand, is marked by the expression of a posterior Hox gene transcription factor, Abd-B, while Hh-Dpp signalling marks its growth. Drosophila MAG, therefore, reveals the developmental design of a unitary bud-derived tube that appears to have been co-opted for the development of male accessory sexual organs across distant phylogeny and embryonic lineages.This article has an associated First Person interview with the first author of the paper.

Chromosome-level assembly of the brown planthopper genome with a characterized Y chromosome.

Hundreds of insect genome sequences have been reported; however, most sequencing projects have not determined the sex chromosomes, and no Y chromosomes from a heterometabolous insect have been identified and characterized to date. The brown planthopper (Nilaparvata lugens Stål) is the most economically damaging pest to rice and is also an ideal research subject for paddy ecology and functional genomics. We previously assembled a draft female genome mainly using second-generation sequencing technologies, with a contig N50 of only 24kb, due to the large size and excessive repetitive regions in the N.lugens genome. Here, we utilize third-generation sequencing technologies and Hi-C data to generate a high-quality male N.lugens assembly with a contig N50 of 1.01Mb, a scaffold N50 of 69.96Mb and more than 95.6% of the assembled bases located on 16 chromosomes. Fourteen autosomes and two sex chromosomes (X+Y) were identified, filling in the gap related to the Y chromosome in heterometabolous insects. A total of 18,021 protein-coding genes and 6423 long-noncoding RNAs were predicted with full-length cDNA sequencing data. All 315 of the Y chromosome genes (Y-genes) were derived from autosomal and X-chromosome duplications. Large-scale RNA interference (RNAi) experiments were conducted against the N.lugens Y-genes, demonstrating that 7 Y-genes were essential for normal BPH development or male organ development, suggesting the importance of Y-genes. The first identified Y chromosome in heterometabolous insects will help gain more insight into sex determination, fertility and chromosome evolution.

Comparative RNA-Seq analysis reveals genes associated with masculinization in female Cannabis sativa

Main conclusionUsing RNA profiling, we identified several silver thiosulfate-induced genes that potentially control the masculinization of female Cannabis sativa plants.Genetically female Cannabis sativa plants normally bear female flowers, but can develop male flowers in response to environmental and developmental cues. In an attempt to elucidate the molecular elements responsible for sex expression in C. sativa plants, we developed genetically female lines producing both female and chemically-induced male flowers. Furthermore, we carried out RNA-Seq assays aimed at identifying differentially expressed genes responsible for male flower development in female plants. The results revealed over 10,500 differentially expressed genes, of which around 200 potentially control masculinization of female cannabis plants. These genes include transcription factors and other genes involved in male organ (i.e., anther and pollen) development, as well as genes involved in phytohormone signalling and male-biased phenotypes. The expressions of 15 of these genes were further validated by qPCR assay confirming similar expression patterns to that of RNA-Seq data. These genes would be useful for understanding predisposed plants producing flowers of both sex types in the same plant, and help breeders to regulate the masculinization of female plants through targeted breeding and plant biotechnology.

Comparative Transcriptomics Analysis and Functional Study Reveal Important Role of High-Temperature Stress Response Gene GmHSFA2 During Flower Bud Development of CMS-Based F1 in Soybean.

High-temperature (HT) is one of the most important environmental factors that negatively impact the yield of some soybean cytoplasmic male sterility (CMS)-based hybrid (F1) combinations. The response of soybean to HT, especially at the male organ development stage, is poorly understood. To investigate the molecular mechanisms of the response from soybean CMS-based F1 male organ to HT, a detailed transcriptomics analysis was performed during flower bud development of soybean HT-tolerant and HT-sensitive CMS-based F1 combinations (NF1 and YF1) under normal-temperature and HT conditions. Obvious HT damage was observed by subjecting YF1 with HT, such as indehiscent anthers and decreased pollen fertility, whereas the male fertility of NF1 was normal. In total, 8,784 differentially expressed genes (DEGs) were found to respond to HT stress, which were mainly associated with anther/pollen wall development, carbohydrate metabolism and sugar transport, and auxin signaling. The quantitative real-time PCR (qRT-PCR) analysis and substance content detection also revealed that HT caused male fertility defects in YF1 by altering pectin metabolism, auxin, and sugar signaling pathways. Most importantly, the sugar signaling-PIF-auxin signaling pathway may underlie the instability of male fertility in YF1 under HT. Furthermore, HT induced the expression of heat shock factor (HSF) and heat shock protein (HSP) gene families. Overexpression of GmHSFA2 in Arabidopsis can promote the expression of HT protective genes (such as HSP20) by binding to the HSE motifs in their promoters, so as to improve the HT tolerance during flowering. Our results indicated that GmHSFA2 acted as a positive regulator, conferring HT tolerance improvement in soybean CMS-based F1. GmHSFA2 may be directly involved in the activation of male fertility protection mechanism in the soybean CMS-based F1 under HT stress.

The MYB transcription factor Baymax1 plays a critical role in rice male fertility.

Key message Rice male fertility gene Baymax1, isolated through map-based cloning, encodes a MYB transcription factor and is essential for rice tapetum and microspore development.Abstract The mining and characterization of male fertility gene will provide theoretical and material basis for future rice production. In Arabidopsis, the development of male organ (namely anther), usually involves the coordination between MYB (v-myb avian myeloblastosis viral oncogene homolog) and bHLH (basic helix-loop-helix) members. However, the role of MYB proteins in rice anther development remains poorly understood. In this study, we isolated and characterized a male sterile mutant (with normal vegetative growth) of Baymax1 (BM1), which encodes a MYB protein. The bm1 mutant exhibited slightly lagging meiosis, aborted transition of the tapetum to a secretory type, premature tapetal degeneration, and abnormal pollen exine formation, leading to ultimately lacks of visible pollens in the mature white anthers. Map-based cloning, complementation and targeted mutagenesis using CRISPR/Cas9 technology demonstrated that the mutated LOC_Os04g39470 is the causal gene in bm1. BM1 is preferentially expressed in rice anthers from stage 5 to stage 10. Phylogenetic analysis indicated that rice BM1 and its homologs in millet, maize, rape, cabbage, and pigeonpea are evolutionarily conserved. BM1 can physically interacts with bHLH protein TIP2, EAT1, and PHD (plant homeodomain)-finger member TIP3, respectively. Moreover, BM1 affects the expression of several known genes related to tapetum and microspore development. Collectively, our results suggest that BM1 is one of key regulators for rice male fertility and may serve as a potential target for rice male-sterile line breeding and hybrid seed production.

Dietary methoprene treatment promotes rapid development of reproductive organs in male Queensland fruit fly

Methoprene supplements added to diets of yeast hydrolysate and sugar promote early expression of sexual behaviour and mating in male Queensland fruit fly (Bactrocera tryoni; ‘Q-fly’) and show promise as a pre-release treatment for sterile insect technique programs. Currently it is not known whether the early mating behaviour of methoprene-treated male Q-flies is only behavioural or is coupled with accelerated development of reproductive organs. Accordingly, the present study investigates whether incorporation of methoprene into diets of yeast hydrolysate and sugar (1:3) or sugar alone, accelerate development of testes, ejaculatory apodeme, and accessory glands in male Q-flies and ovaries in females. All organs increased in size as the flies aged and matured, and development rate of all organs was far greater when the flies were provided yeast hydrolysate in addition to sugar. Incorporation of methoprene into diets containing yeast hydrolysate was found to strongly accelerate development of testes and ejaculatory apodeme, but not accessory glands, in males. In the absence of yeast hydrolysate, methoprene treatment had only a modest effect on male organ development. In contrast to males, development of ovaries in female Q-flies did not respond to dietary methoprene supplements, regardless of whether they were fed yeast hydrolysate and sugar or sugar alone. These findings of diet-dependent effects of methoprene supplements on reproductive organs are a close match to previous studies investigating effects of methoprene supplements on mating behaviour. Overall, methoprene supplements substantially enhance the positive effects of protein rich adult diet on the early expression of sexual behaviour and accelerate development of reproductive organs in male, but not female, Q-flies. Methoprene supplements added to pre-release diets of yeast hydrolysate and sugar show promise as a means of accelerating reproductive development of Q-flies released in sterile insect technique programs, and may also bias operational sex ratio in favour of males.

Rice Male Gamete Expression Database (RMEDB): A Web Resource for Functional Genomic Studies of Rice Male Organ Development

Oryza sativa (rice) is an economically important crop, which is valued as a staple food source and as genetic model for cereals. Rice production needs to increase substantially to meet the growing global demand. Genetic studies have indicated that anther and pollen development genes can be used as targets to improve yield. Although several genes related to male organ developmental pathways have been characterized, the complete signaling network remains unclear. We used publicly available anther and pollen development transcriptome datasets to identify candidates for functional genomics studies. In addition, we newly generated RNA-Seq data for anther, anther wall and pollen samples with leaf sheath as control to provide the expression data for genes that are not covered by microarray technologies in rice. We constructed a platform, the rice male gamete expression database (RMEDB), comprising microarray and RNA-Seq based 188 transcriptome samples across diverse rice tissues and developmental stages of O. sativa japonica and O. sativa indica. Meta-expression analysis identified genes expressed at specific stages of anther or pollen developments. The functionalities in RMEDB database ( http://ricephylogenomics-khu.org/RMEDB/home.php ) can serve to identify candidates in male organ development for functional genomic studies of rice.

Unisexual flower initiation in the monoecious Quercus suber L.: a molecular approach.

Several plant species display a temporal separation of the male and female flower organ development to enhance outbreeding; however, little is known regarding the genetic mechanisms controlling this temporal separation. Quercus suber is a monoecious oak tree with accentuated protandry: in late winter, unisexual male flowers emerge adjacent to the swollen buds, whereas unisexual female flowers emerge in the axils of newly formed leaves formed during spring (4-8weeks after male flowering). Here, a phylogenetic profiling has led to the identification of cork oak homologs of key floral regulatory genes. The role of these cork oak homologs during flower development was identified with functional studies in Arabidopsis thaliana. The expression profile throughout the year of flower regulators (inducers and repressors), in leaves and buds, suggests that the development of male and female flowers may be preceded by separated induction events. Female flowers are most likely induced during the vegetative flush occurring in spring, whereas male flowers may be induced in early summer. Male flowers stay enclosed within the pre-dormant buds, but complete their development before the vegetative flush of the following year, displaying a long period of anthesis that spans the dormant period. Our results portray a genetic mechanism that may explain similar reproductive habits in other monoecious tree species.

Is Testosterone Replacement Safe in Men with Cardiovascular Disease?

Testosterone is an anabolic hormone that is responsible for the development of male sex organs. It also increases muscle mass and fortifies bone density. In addition to being responsible for primary sexual characteristics at birth and puberty (development and changes of sexual organs such as uterus, vagina, penis, and testes), testosterone is also involved in maintaining secondary sexual characteristics. Patients with low testosterone who are symptomatic should be treated with testosterone replacement therapy (TRT) once the diagnosis has been confirmed. The goal of treatment is to improve the symptoms including the physical, sexual, and cognitive health with the aim being to keep the testosterone in the mid-normal limit of the reference range. Male hypogonadism has been increasingly diagnosed and treated in elderly males since the last decade. A proportionate increase in the prescription of testosterone has been seen as well. The relationship of testosterone levels with cardiovascular (CV) outcomes is challenging and has shown conflicting results. Moreover, in patients with established CV disease, those with high CV risk factors including diabetes, or those with significant risk factors for atherosclerotic CV disease (ASCVD), the benefits of TRT should be weighed against the risks of replacement. Risks and benefits of TRT should be discussed with every patient prior to starting or restarting the procedure.

The persimmon genome reveals clues to the evolution of a lineage-specific sex determination system in plants.

Most angiosperms bear hermaphroditic flowers, but a few species have evolved outcrossing strategies, such as dioecy, the presence of separate male and female individuals. We previously investigated the mechanisms underlying dioecy in diploid persimmon (D. lotus) and found that male flowers are specified by repression of the autosomal gene MeGI by its paralog, the Y-encoded pseudo-gene OGI. This mechanism is thought to be lineage-specific, but its evolutionary path remains unknown. Here, we developed a full draft of the diploid persimmon genome (D. lotus), which revealed a lineage-specific whole-genome duplication event and provided information on the architecture of the Y chromosome. We also identified three paralogs, MeGI, OGI and newly identified Sister of MeGI (SiMeGI). Evolutionary analysis suggested that MeGI underwent adaptive evolution after the whole-genome duplication event. Transformation of tobacco plants with MeGI and SiMeGI revealed that MeGI specifically acquired a new function as a repressor of male organ development, while SiMeGI presumably maintained the original function. Later, a segmental duplication event spawned MeGI’s regulator OGI on the Y-chromosome, completing the path leading to dioecy, and probably initiating the formation of the Y-chromosome. These findings exemplify how duplication events can provide flexible genetic material available to help respond to varying environments and provide interesting parallels for our understanding of the mechanisms underlying the transition into dieocy in plants.

Suhu Tinggi Berpengaruh Negatif pada Perkembangan Polen Cabai (Capsicum annum L.) cv. Tanjung-2

The development of male reproductive organ in plants is seriously affected by the adverse abiotic stresses. In this study, we investigated pollen development, particularly at microsporogenesis and micro gametogenesis stages of chili pepper (Capsicum annuum) cv. Tanjung-2 upon exposure with high temperature (day/night = 36/33°C). For this objective, anther of different flower sizes ranging from <2.5 mm; 3-4.5 mm; 4.5-7 mm; to 7-11 mm from treated and non-treated plants were collected. The results revealed that the early microsporogenesis stage was highly sensitive to high temperature indicated by a low progression of cells into subsequent process in meiotic division. This result was followed by the inhibition of tetrad formation up to 2%. Consequently, plant produced smaller microscpores and pollens with thin exin that resulted in the decreased pollen viability to 90%. In conclusion, high temperature has negative impact on the development of male reproductive program in chili pepper, including microsporogenesis and micro gametogenesis. Extending approach should be allocated to overcome this problem so that such environmental stress would not decrease the productivity of chili pepper. Keywords: Capsicum annuum, high temperature, microgametogenesis, microsporogenesis