The pathogenic fungus Puccinia helianthi, which causes rust disease and significant economic loss, poses a serious threat to the Helianthus annuus crop. This study is the first to examine the ultrastructure of the spore stages of this rust, aiming to fill the gap in the understanding of Egyptian rusts. The present study aimed to explore the micromorphology and development of pycniospores and aeciospores of Puccinia helianthi on its host, using LM, SEM, and TEM. The immature pycnium grows subepidermally and is bordered by a peripheral layer of pseudoparenchymatous cells. Within the pycnium, uninuclear, compactly packed, and elongated pycniosporophores are formed. Pointed periphyses emerge at the highest point of the pycnium, where numerous pycniospores are produced. The primary pycniospores are then released from the pycniosporophores having an elliptical shape with a wrinkled surface. Aeciospores are produced at the edges of a distinct layer, the peridium with rhomboid-shaped peridial cells. A prosenchymatous stroma develops beneath the hymenium layer (aeciosporophores). Two main types of hyphae can distinguish in this stroma: vacuolated hyphae, at the base of the aecium, and non-vacuolated hyphae with dense, ribosome-rich cytoplasm, oil droplets, and glycogen. Each aeciospore divides to form a young aeciospore and an intercalary cell with elongated or hexagonal shapes and warts on the mature aeciospores. SEM examination reveals cog-like ornaments and refracting bodies on the surfaces of peridial cells and aeciospores. The ultrastructure of these two spore stages is more or less similar to that of other Puccinia species with some differences. The procedures used in this study will assist mycologists in rust identification, taxonomy, and microscopic characterization. In conclusion, this study will provide additional information to help understand the interaction between rusts and their hosts. Future research on ultracytochemical studies may provide insight into controlling these serious pathogens.

One of the main source of demise during the next ten years will be coronary heart disease and stroke, which are brought on by smoking (nicotine). To identify the percentage (%) of nicotine consumption by electrocatalytic sensor towards nicotine for target-specific prevent stroke, four uninuclear Ni[2+] complexes of substituted butanimidamide Schiff base ligands [H2L1-4] was prepared. All the complexes were thoroughly analyzed by using several spectroscopic techniques such as CHNS analysis, FT-IR, NMR ([1]H & [13]C) UV-Vis and NMR. The analyses showed tetradentate binding mode of ligand around nickel(II) metal ion leads to the structure of square planar with N2X2 (X = O, S) donor fashion. In addition, the well-defined nickel(II) complexes were utilized for oxidation of various alcohols such as cyclohexanol, and benzyl alcohol were produced to the assorted oxidized products with high yield respectively using greener co-oxidant (molecular oxygen). In addition, Nickel(II) complexes was further utilized as catalyst for aryl-aryl coupling reaction via Suzuki-Mayura method to obtain biphenyl compound. Furthermore, nickel(II) complexes were exploited for electrochemical detection of nicotine sensing in μM concentration.

Androgenetically-derived haploids can be obtained by inducing embryogenesis in microspores. Thus, full homozygosity is achieved in a single generation, oppositely to conventional plant breeding programs. Here, the metabolite profile of embryogenic microspores of Triticum aestivum was acquired and integrated with transcriptomic existing data from the same samples in an effort to identify the key metabolic processes occurring during the early stages of microspore embryogenesis. Primary metabolites and transcription profiles were identified at three time points: prior to and immediately following a low temperature pre-treatment given to uninuclear microspores, and after the first nuclear division. This is the first time an integrative -omics analysis is reported in microspore embryogenesis in T. aestivum. The key findings were that the energy produced during the pre-treatment was obtained from the tricarboxylic acid (TCA) cycle and from starch degradation, while starch storage resumed after the first nuclear division. Intermediates of the TCA cycle were highly demanded from a very active amino acid metabolism. The transcription profiles of genes encoding enzymes involved in amino acid synthesis differed from the metabolite profiles. The abundance of glutamine synthetase was correlated with that of glutamine. Cytosolic glutamine synthetase isoform 1 was found predominantly after the nuclear division. Overall, energy production was shown to represent a major component of the de-differentiation process induced by the pre-treatment, supporting a highly active amino acid metabolism.

Betula platyphylla, belonging to the cold-specialized lineage Betulaceae, exhibits a unique reproductive strategy where staminate catkins emerge in the first summer and undergo an overwintering process, culminating in flowering in the following year. However, the underlying regulatory mechanism remains unclear. In this study, we investigated the male germline development of B. platyphylla in four distinct stages: microsporocytes in Oct. (S1), uninuclear microspores from Dec. (S2) to Mar. of the following year (S3), and bicellular microspores in Apr. (S4). We performed RNA sequencing on mature pollen and the four stages of staminate catkins. Using weighted gene co-expression network analysis (WGCNA), we identified five highly correlated gene modules with distinct expression profiles. These modules exhibited strong correlations with sugar metabolism, cell cycle, flowering, and cell wall dynamics, highlighting their dynamic roles during male germline developmental stages. During the overwintering process, we observed that the expression of transcription factors such as BpDUO1 and BpAMS at the appropriate developmental stages, suggests their significant roles in male germline development. The expression patterns of BpFLC and BpFT suggest their potential involvement in temperature perception during male reproductive development. These findings offer valuable insights into the reproductive success of plants adapting to cold environments.

Animal and plant microRNAs (miRNAs) are essential for the spatio-temporal regulation of development. Together with this role, plant miRNAs have been proposed to target transposable elements (TEs) and stimulate the production of epigenetically active small interfering RNAs. This activity is evident in the plant male gamete containing structure, the male gametophyte or pollen grain. How the dual role of plant miRNAs, regulating both genes and TEs, is integrated during pollen development and which mRNAs are regulated by miRNAs in this cell type at a genome-wide scale are unknown. Here, we provide a detailed analysis of miRNA dynamics and activity during pollen development in Arabidopsis thaliana using small RNA and degradome parallel analysis of RNA end high-throughput sequencing. Furthermore, we uncover miRNAs loaded into the two main active Argonaute (AGO) proteins in the uninuclear and mature pollen grain, AGO1 and AGO5. Our results indicate that the developmental progression from microspore to mature pollen grain is characterized by a transition from miRNAs targeting developmental genes to miRNAs regulating TE activity.

In eukaryotes, coat protein complex II (COPII) vesicles mediate anterograde traffic from the endoplasmic reticulum to the Golgi apparatus. Compared to yeasts, plants have multiple COPII coat proteins; however, the functional diversity among them is less well understood. SEC31A and SEC31B are outer coat proteins found in COPII vesicles in Arabidopsis. In this study, we explored the function of SEC31A and compared it with that of SEC31B from various perspectives. SEC31A was widely expressed, but at a significantly lower level than SEC31B. SEC31A-mCherry and SEC31B-GFP exhibited a high co-localization rate in pollen, but a lower rate in growing pollen tubes. The sec31a single mutant exhibited normal growth. SEC31A expression driven by the SEC31B promoter rescued the pollen abortion and infertility observed in sec31b. A sec31asec31b double mutant was unavailable due to lethality of the sec31asec31b gametophyte. Transmission electron microscopy revealed that one quarter of male gametogenesis was arrested at the uninuclear microspore stage, while confocal laser scanning microscopy showed that 1/4 female gametophyte development was suspended at the functional megaspore stage in sec31a-1/+sec31b-3/+ plants. Our study highlights the essential role of SEC31A/B in gametogenesis and their interchangeable functions in pollen development.

The orchid reproductive strategy, including the formation of numerous tiny seeds, is achieved by the elimination of some stages in the early plant embryogenesis. In this study, we documented in detail the formation of the maternal tissues (the nucellus and integuments), the structures of female gametophyte (megaspores, chalazal nuclei, synergids, polar nuclei), and embryonic structures in Dendrobium nobile. The ovary is unilocular, and the ovule primordia are formed in the placenta before the pollination. The ovule is medionucellate: the two-cell postament and two rows of nucellar cells persist until the death of the inner integument. A monosporic eight-nucleated embryo sac is developed. After the fertilization, the most common central cell nucleus consisted of two joined but not fused polar nuclei. The embryogenesis of D. nobile is similar to the Caryophyllad-type, and it is characterized by the formation of all embryo cells from the apical cell (ca) of a two-celled proembryo. The only exception is that there is no formation of the radicle and/or cotyledons. The basal cell (cb) does not divide during the embryogenesis, gradually transforming into the uninuclear suspensor. Then the suspensor goes through three main stages: it starts with an unbranched cell within the embryo sac, followed by a branched stage growing into the integuments, and it ends with the cell death. The stage-specific development of the female gametophyte and embryo of D. nobile is discussed.

Propranolol (PRO) is widely detected in the aquatic environment and proved to be detrimental to multifarious aquatic organisms. In view of some virtues of sulfate radicals than hydroxyl radicals, advanced oxidation technologies that involve the activation of peroxymonosulfate (PMS) have stimulated wide-ranging research on the PRO removal. In this paper, a composite (C2NOMS-2) of amino-functionalized manganese octahedral molecular sieve (NOMS-2) and binuclear cobalt phthalocyanine (Co2CPc) was synthesized easily, and utilized as a catalyzer for PMS to degrade PRO in water. The apparent rate constants of PRO degradation by PMS with C2NOMS-2 as a catalyst was found to be higher than with NOMS-2, Co2CPc and the composite of uninuclear cobalt phthalocyanine (CoCPc) and NOMS-2. The catalytic ability of C2NOMS-2 was investigated under various reaction conditions: catalyst dosages (0.5-2.0 g/L), PMS doses (50-500 mg/L), initial pH (5-11), reaction temperature (20-35 °C), and natural water constituents (Cl-, HCO3-, and sodium huminate). Radical scavenging tests and electron paramagnetic resonance spectroscopy showed that 1O2 was the most critical reactive oxygen species, and conceivable mechanisms of PMS activation with C2NOMS-2 were proposed established on the curve estimation of high-resolution XPS spectra, revealing that the generation of reactive oxygen species was mainly resulted from the cycles of Mn3+/Mn4+, Co3+/Co2+ and surface lattice oxygen/surface adsorbed oxygen. The intermediate products of propranolol degradation were identified by LC-MS/MS. Cycling experiments and ion dissolution detection suggested that C2NOMS-2 could maintain satisfactory stability in an aqueous system.

In this study, we investigated the chromosome breakage caused by gametocidal (Gc) chromosome 3Ct and its interaction with the suppressor gene Igc1 (inhibitor of gametocidal gene 1) on wheat chromosome 3B. We demonstrated cytologically that patterns of 3Ct-induced chromosomal fragmentation in microspores differed from patterns observed for other Gc genes. Uninuclear microspores of the monosomic 3Ct addition line had high frequencies of micronuclei, possibly explaining its low fertility. Chromosome fragmentation was observed in prometaphase and metaphase of the first pollen mitosis in the monosomic 3Ct addition line. Patterns of chromosome fragmentation were different from those previously reported for Gc chromosomes 2S of Aegilops speltoides, 4Ssh of Ae. sharonensis and 2Ccy of Ae. cylindrica; many chromosome fragments were observed in prometaphase of the first pollen mitosis in the monosomic 3Ct addition plants. In anthers at the binuclear stage, many microspores at the uninuclear stage coexisted with normally developed microspores.

Mitogen-activated protein kinases (MAPKs) regulate diverse aspects of plant growth. However, their potential role in reproductive development remains elusive. Here, we discovered an unique role of SlMPK20, a plant-specific group D MAPK, in pollen development in tomato. RNAi-mediated suppression of SlMPK20 or its knockout using CRISPR/Cas9 significantly reduced or completely abolished pollen viability, respectively, with no effects on maternal fertility. Cell biology and gene expression analyses established that SlMPK20 exerts its role specifically at the uni-to-binucleate transition during microgametogenesis. This assertion is based on the findings that the transgenic pollen was largely arrested at the binucleate stage with the appearance of subcellular abnormality at the middle uninucleate microspore stage; and SlMPK20 mRNA and SlMPK20-GUS signals were localized in the tetrads, uninuclear microspores and binuclear pollen grains but not in microspore mother cells or mature pollen grains. Transcriptomic and proteomic analyses revealed that knockout of SlMPK20 significantly reduced the expression of a large number of genes controlling sugar and auxin metabolism and signaling in anthers. Finally, protein-protein interaction assays identified SlMYB32 as a putative target protein of SlMPK20. We conclude that SlMPK20 specifically regulates post-meiotic pollen development through modulating sugar and auxin metabolism and signaling.

Melatonin is a pleiotropic signal molecule that plays critical roles in regulating plant growth and development, as well as providing physiological protections against various environmental stresses. Nonetheless, the mechanisms for melatonin-mediated pollen thermotolerance remain largely unknown. In this study, we report that irrigation treatment with melatonin (20 µM) effectively ameliorated high temperature-induced inactivation of pollen and inhibition of pollen germination in tomato (Solanum lycopersicum) plants. Melatonin alleviated reactive oxygen species production in tomato anthers under high temperature by the up-regulation of the transcription and activities of several antioxidant enzymes. Transmission electron micrograph results showed that high temperature-induced pollen abortion is associated with a premature degeneration of the tapetum cells and the formation of defective pollen grains with degenerated nuclei at the early uninuclear microspore stage, whilst melatonin protected degradation of organelles by enhancing the expression of heat shock protein genes to refold unfolded proteins and the expression of autophagy-related genes and formation of autophagosomes to degrade denatured proteins. These findings suggest a novel function of melatonin to protect pollen activity under high temperature and support the potential effects of melatonin on reproductive development of plants.

The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a serious pest worldwide, transmitting Candidatus Liberibacter spp. (Alphaproteobacteria), the causative agents of a devastating citrus disease known as huanglongbing or greening disease. In a symbiotic organ called the bacteriome, D. citri possesses an organelle-like defensive symbiont, Candidatus Profftella armatura (Betaproteobacteria), and a nutritional symbiont, Ca. Carsonella ruddii (Gammaproteobacteria). Drastically reduced symbiont genomes and metabolic complementarity among the symbionts and D. citri indicate their mutually indispensable association. Moreover, horizontal gene transfer between the Profftella and Liberibacter lineages suggests ecological and evolutionary interactions between the bacteriome symbiont and the HLB pathogen. Using fluorescence in situ hybridization, we examined the behavior of Profftella and Carsonella during transovarial transmission and the development of D. citri. In the bacteriomes of sexually-mature female adults, symbionts transformed from an extremely elongated tubular form into spherical or short-rod forms, which migrated toward the ovary. The symbionts then formed mosaic masses, which entered at the posterior pole of the vitellogenic oocytes. After anatrepsis, Carsonella and Profftella migrated to the central and peripheral parts of the mass, respectively. Following the appearance of host nuclei, the mass cellularized, segregating Carsonella and Profftella in the central syncytium and peripheral uninucleate bacteriocytes, respectively. Subsequently, the uninucleate bacteriocytes harboring Profftella assembled at the posterior pole, while the syncytium, containing Carsonella, sat on the anterior side facing the germ band initiating katatrepsis. During dorsal closure, the syncytium was divided into uninuclear bacteriocytes, which surrounded the mass of bacteriocytes containing Profftella. Once fully surrounded, the bacteriocyte mass containing Profftella was fused into a syncytium. Prior to hatching, a pair of wing-like protrusions arose from both lateral sides of the bacteriome, which continued to grow throughout the nymphal stages. These findings provide a foundation for better understanding the intricate relationship between D. citri and its microbiota.

One hundred three out of 225 (45.8%) of the Red Sea fish Saurida tumbil were infected with microsporidian parasites. The infection was recorded as tumor-like masses (whitish macroscopic cysts) or xenomas often up to 2 cm in diameter and embedded in the peritoneal cavity. Generally, the infection was increased during winter 63.8% (86 out of 135) and fall to 18.9% (17 out of 90) in summer. Light microscopic study revealed that xenomas were encapsulated by a fibrous layer encircling numerous sporophorous vesicles filled with mature spores measuring 1.7 ± 0.6 (1.5-2.7 μm) × 1.5 ± 0.3 μm (1.2-1.8 μm) in size. Ultrastructural microscopic study showed the presence of smooth membranes of the sarcoplasmic reticulum forming a thick, amorphous coat surrounding various developmental stages of the parasite. The various recognizable stages of the parasite were uninuclear, binucleated, and multinucleated meronts followed by detachment of the plasmalemma of the sporont from the sporophorous vesicle producing sporoblasts. Mature spores consist of a spore coat and spore contents. The spore contents consist of the uninucleated sporoplasm and a posterior vacuole located at the posterior end. The polar tube consists of a straight shaft and a coiled region (26-32 coils) arranged in many rows along the inside periphery of the spore. The polaroplast consisted of an anterior region of closely and loosely packed membranes. Molecular analysis based on the small subunit rDNA gene was performed to determine the phylogenetic position of the present species. The percentage identity between this species and a range of other microsporidia predominantly from aquatic hosts demonstrated a high degree of similarity (>92%) with eight Pleistophora species. Comparison of the nucleotide sequences and divergence showed that the sequence of the present microsporidium was most similar to that of Pleistophora anguillarum (99.8% identity) differing in 13 nucleotide positions. So, the present species was recorded and phylogenetically positioned as a new species of Pleistophora.

Cochlosoma sp. infection was identified in a single case among 60 stunted diarrheic native turkey poults, Meleagris galopavo. A large number of the flagellated parasites was found free or within the intervillous spaces of the jejunum, ileum and cecum. Moderate enteritis was associated with the parasites. In TEM studies of the parasagittal sections of the parasite, a prominent ventral sucker like disc and flagella emerging from an opening on the ventrodorsal surface of the pyriform uninuclear parasite were found. The morphological characteristics of this protozoan match with those described for Cochlosoma anatis. The parasite could be considered as an intestinal pathogenic protozoan causing stunting and diarrhea in turkeys in Iran.