Micropylar Region Research Articles

Ultrastructure of the Eggs, Larvae, and Pupae of Hyphantria cunea (Lepidoptera: Erebidae)

Hyphantria cunea is a widespread pest that causes significant issues in forestry and agriculture, with a far-reaching global impact. However, ultramorphological studies of H. cunea, especially in terms of ultramorphological changes, are far from in-depth. Therefore, we investigated the ultrastructure of its eggs, larvae, and pupae using scanning electron microscopy, focusing on ultrastructural changes in larvae across different instars. The eggs have rough surfaces, and the micropylar region consists of rosette cells. The larval head chaetotaxy is symmetrically arranged, and there are three types of sensilla on the antennae and mouthparts. The abdominal and anal prolegs feature a uniordinal heteroideus midband of crochets. The pupal abdomen has ten segments; in females, the genital slit (Fgs) is located at the anterior edge of abdominal segment VIII, while in males, the genital slit (Mgs) is situated in the middle of abdominal segment IX. First-instar larvae exhibit only primary setae, and secondary setae emerge in the second instar. As the larvae mature, the head, thoracic legs, and abdominal and anal prolegs all become larger overall. The surface of the verrucae is initially smooth, with microtrichia appearing from the fourth instar onwards, and the setae on the verrucae gradually increase in size. These findings provide additional features for larval species identification and contribute to the morphological study of H. cunea.

Eight hydroxyproline-O-galactosyltransferases play essential roles in female reproductive development

In angiosperms, ovules give rise to seeds upon fertilization. Thus, seed formation is dependent on both successful ovule development and tightly controlled communication between female and male gametophytes. During establishment of these interactions, cell walls play a pivotal role, especially arabinogalactan-proteins (AGPs). AGPs are highly glycosylated proteins decorated by arabinogalactan side chains, representing 90 % of the AGP molecule. AGP glycosylation is initiated by a reaction catalysed by hydroxyproline-O-galactosyltransferases (Hyp-GALTs), specifically eight of them (GALT2–9), which add the first galactose to Hyp residues. Five Hyp-GALTs (GALT2, 5, 7, 8 and 9) were previously described as essential for AGP functions in pollen and ovule development, pollen-pistil interactions, and seed morphology. In the present work, a higher order Hyp-GALT mutant (23456789) was studied, with a high degree of under-glycosylated AGPs, to gain deeper insight into the crucial roles of these eight enzymes in female reproductive tissues. Notably, the 23456789 mutant demonstrated a high quantity of unfertilized ovules, displaying abnormal callose accumulation both at the micropylar region and, sometimes, throughout the entire embryo sac. Additionally, this mutant displayed ovules with abnormal embryo sacs, had a disrupted spatiotemporal distribution of AGPs in female reproductive tissues, and showed abnormal seed and embryo development, concomitant with a reduction in AGP-GlcA levels. This study revealed that at least three more enzymes exhibit Hyp-O-GALT activity in Arabidopsis (GALT3, 4 and 6), and reinforces the crucial importance of AGP carbohydrates in carrying out the biological functions of AGPs during plant reproduction.

Rare eggshell structure in Odonata: Lindenia tetraphylla (Van der Linden) (Anisoptera: Gomphidae).

Lindenia tetraphylla (Van der Linden, 1825) eggs exhibit an egg structure that is very rare in other Gomphidae species. They have a well-developed surface reticulation structure. The anterior pole of the egg has a small, rounded micropylar area consisting of seven orifices arranged radially around a central area. The posterior pole has a sessile, truncated cone that carries 55-65 coiled filaments. The filament structure found at the posterior pole of the egg has been observed in the gomphid species Lestinogomphus africanus (Fraser, 1926), Ictinogomphus australis (Selys, 1873), and I. rapax (Rambur, 1842). However, L. tetraphylla eggs differ from these species in both morphology and filament structure. This study provides a detailed analysis of the ultrastructure of L. tetraphylla eggs using scanning electron microscopy, and the functional and taxonomic significance of the eggshell are discussed. RESEARCH HIGHLIGHTS: The aim of this study is to examine the ultrastructure of the L. tetraphylla eggshell, emphasizing its function and taxonomic value. In this context, the general morphology of the egg, the reticulations on its surface, the micropylar region and micropylar structure, and the posterior filament coil were examined. In this study, the ultrastructure of L. tetraphylla egg was examined for the first time using scanning electron microscopy (SEM). As a result of the examination, it was detected for the first time that the posterior filament coil, which is rarely seen in odonate eggs, is also present in L. tetraphylla eggs. By comparing the L. tetraphylla egg with the eggs of I. ferox, I. rapax, I. australis, and L. africanus species, which are similar in terms of the posterior filament coil, the features that distinguish the L. tetraphylla egg.

Late stages of megagametophytogenesis: Archegonial development in Zamiaceae

The anatomy of the neck cells and the structure of the archegonium during the central cell growth as a stage in the ontogeny of the archegonium that occurs before fertilization is described and compared for Ceratozamia tenuis and Zamia furfuracea. Two neck cells are reported for both species with anatomical features that suggest they participate in the fertilization process. It is postulated that this stage is characterized by a profusely vacuolated cytoplasm from which a large central vacuole becomes prominent. This vacuole plays an important role in pushing the huge egg cell nucleus along with conspicuous smaller vacuoles of the central cell towards the micropylar region. It then presses and pushes the two globose neck cells with their respective subtending surface cells apart and towards the archegonial chamber. There are no significant differences between the development and structure of archegonial neck complexes in the two species studied.

Type II arabinogalactans initiated by hydroxyproline-O-galactosyltransferases play important roles in pollen-pistil interactions.

Arabinogalactan-proteins (AGPs) are hydroxyproline-rich glycoproteins containing a high sugar content and are widely distributed in the plant kingdom. AGPs have long been suggested to play important roles in sexual plant reproduction. The synthesis of their complex carbohydrates is initiated by a family of hydroxyproline galactosyltransferase (Hyp-GALT) enzymes which add the first galactose to Hyp residues in the protein backbone. Eight Hyp-GALT enzymes have been identified so far, and in the present work a mutant affecting five of these enzymes (galt2galt5galt7galt8galt9) was analyzed regarding the reproductive process. The galt25789 mutant presented a low seed set, and reciprocal crosses indicated a significant female gametophytic contribution to this mutant phenotype. Mutant ovules revealed abnormal callose accumulation inside the embryo sac and integument defects at the micropylar region culminating in defects in pollen tube reception. In addition, immunolocalization and biochemical analyses allowed the detection of a reduction in the amount of glucuronic acid in mutant ovary AGPs. Dramatically low amounts of high-molecular-weight Hyp-O-glycosides obtained following size exclusion chromatography of base-hydrolyzed mutant AGPs compared to the wild type indicated the presence of underglycosylated AGPs in the galt25789 mutant, while the monosaccharide composition of these Hyp-O-glycosides displayed no significant changes compared to the wild-type Hyp-O-glycosides. The present work demonstrates the functional importance of the carbohydrate moieties of AGPs in ovule development and pollen-pistil interactions.

Response to Zhang et al., 'do egg cell-secreted aspartic proteases promote gamete attachment?'

In angiosperms, the molecular mechanism controlling polytubey/polyspermy block and fertilization recovery was not unraveled until recently (Zhong et al., 2022), which can be described as follows: Five pollen tube-expressed RALF peptide ligands, perceived by the receptor complex composed of three receptors FER/ANJ/HERK1 at the septum, establish the polytubey block at the septum so that only one pollen tube is allowed to emerge from the septum to target the ovule for fertilization. Pollen tube rupture releases the two sperm cells and fertilization is completed within 20 minutes. This article is protected by copyright. All rights reserved.

New insights on the expression patterns of specific Arabinogalactan proteins in reproductive tissues of Arabidopsis thaliana.

Arabinogalactan proteins (AGPs) are hydroxyproline-rich glycoproteins containing a high proportion of carbohydrates, widely distributed in the plant kingdom and ubiquitously present in land plants. AGPs have long been suggested to play important roles in plant reproduction and there is already evidence that specific glycoproteins are essential for male and female gametophyte development, pollen tube growth and guidance, and successful fertilization. However, the functions of many of these proteins have yet to be uncovered, mainly due to the difficulty to study individual AGPs. In this work, we generated molecular tools to analyze the expression patterns of a subgroup of individual AGPs in different Arabidopsis tissues, focusing on reproductive processes. This study focused on six AGPs: four classical AGPs (AGP7, AGP25, AGP26, AGP27), one AG peptide (AGP24) and one chimeric AGP (AGP31). These AGPs were first selected based on their predicted expression patterns along the reproductive tissues from available RNA-seq data. Promoter analysis using β-glucuronidase fusions and qPCR in different Arabidopsis tissues allowed to confirm these predictions. AGP7 was mainly expressed in female reproductive tissues, more precisely in the style, funiculus, and integuments near the micropyle region. AGP25 was found to be expressed in the style, septum and ovules with higher expression in the chalaza and funiculus tissues. AGP26 was present in the ovules and pistil valves. AGP27 was expressed in the transmitting tissue, septum and funiculus during seed development. AGP24 was expressed in pollen grains, in mature embryo sacs, with highest expression at the chalazal pole and in the micropyle. AGP31 was expressed in the mature embryo sac with highest expression at the chalaza and, occasionally, in the micropyle. For all these AGPs a co-expression analysis was performed providing new hints on its possible functions. This work confirmed the detection in Arabidopsis male and female tissues of six AGPs never studied before regarding the reproductive process. These results provide novel evidence on the possible involvement of specific AGPs in plant reproduction, as strong candidates to participate in pollen-pistil interactions in an active way, which is significant for this field of study.

Seed Geometric Morphometrics of Neottioid Orchids

This study aims to investigate orchid seed variation between some representatives of Neottieae, C. rubra, L. abortivum, Neottia nidus-avis, and N. (Listera) ovata, naturally distributed in our country by using geometric morphometric analyses based on 2-dimensional landmarks. For this purpose, a total of 95 specimens were evaluated. The results of ANOVA, PCA, and discriminant analyses showed significant shape and size differences between the species. Size differences were statically significant among all species except for that between C. rubra and N. ovata. Based on PCA, shape differences were most prominent in the chalazal and micropylar regions of the seed as well as the whole seed width. Discriminant analysis was also statistically significant and cross-validation scores were a highly powerful to distinguish the species with scores ranging from 60% to 88%. Regression analyses also showed highly significant allometric effect of the size on shape with a similar trend across species. Based on current results, geometric morphometric analysis is promising in the study of morphological variation within plant parts. The present study is also significant in terms of the widespread use of such studies in the field of botany, especially in the context of systematic or functional morphology.

The Effect of Scarification Treatments and Seed Moisture Content on the Hardseededness of ‘Taitung No.1’ Winged Bean (Psophocarpus tetragonolobus) Seeds

Seeds of some winged bean varieties have low germination due to the presence of water-impermeable hardseeds. Seeds of ‘Taitung No.1’ winged bean had only 31% germination because the remaining 69% of seeds had a water-impermeable seedcoat. Sandpaper abrasion and sulfuric acid immersion for 15 and 25 min effectively removed hardseededness of the seeds, resulting in more than 89% germination. As seed moisture content (MC) decreased from 14.8% to 7%, the percentage of seeds with a water-impermeable seedcoat increased. Seed lots with 14.8%, 11%, 9%, and 7% MC had 7%, 38%, 56%, and 78% of hardseeds, respectively, on day 7 in the germination test. It was found that the hilum was responsible for water loss from the whole seed, and the seedcoats began to become water-impermeable at 12% MC. The lens and micropylar regions were initial water entry sites in the Vaseline-blocking experiment.

Fine structure of micropylar regions of Cobitis hankugensis, Iksookimia longicorpa and their unisexual natural hybrids.

Iksookimia longicorpa and Cobitis hankugensis are two species of fish distributed only on the Korean Peninsula. They have a unique reproductive ecology that naturally hybridizes into three widely known unisexual types, maintaining populations of almost all females. In this study, the fine structure of the micropyles of I. longicorpa, C. hankugensis and their hybrids was analyzed to find out how egg-sperm interaction, a common interspecies isolation mechanism, is possible between heterogeneous species. Analysis of 30 eggs from five females of each species revealed that all had one funnel-shaped micropylar region and a manhole-shaped micropyle canal. With the exception of C. hankugensis, which had no spiral grooves or ridges, the rest had counterclockwise spiral grooves and ridges on the micropylar region. All five species, however, showed identical groove patterns for the micropyle canal. The egg size was the largest in HL (one from the C. hankugensis locus with one from the I. longicorpa locus) and the smallest in C. hankugensis. In the hybrids, the HL type had the largest egg and HHL (two from the C. hankugensis locus with one from the I. longicorpa locus) type the smallest. For the diameter of the micropylar region and micropyle canal, the diploid I. longicorpa, C. hankugensis and HL were smaller than those of the triploid. In addition, as the ratio of the canal diameter to the eggs was lower in I. longicorpa than in C. hankugensis, it was confirmed that I. longicorpa has a relatively small micropyle canal compared with C. hankugensis.

Pericarp histogenesis and histochemistry during fruit development in Butia capitata (Arecaceae).

Palm fruits show great structural complexity, and in-depth studies of their development are still scarce. This work aimed to define the developmental stages of the fruit of the neotropical palm Butia capitata and to characterize the ontogenesis of its pericarp. Biometric, anatomical, and histochemical evaluations were performed on pistillate flowers and developing fruits. The whole fruit develops in three phases: (I) histogenesis (up to 42days after anthesis - DAA), when the topographic regions of the pericarp are defined; (II) pyrene maturation (42 to 70 DAA), when the sclerified zone of the pericarp is established; and (III) mesocarp maturation (70 to 84 DAA), when reserve deposition is completed. During pericarp ontogenesis (i) the outer epidermis and the outer mesophyll of the ovary give origin to the exocarp (secretory epidermis, collenchyma, parenchyma, sclerenchyma, and vascular bundles); (ii) the median ovarian mesophyll develops into the mesocarp, with two distinct topographical regions; (iii) the inner ovarian epidermis originates the endocarp; and in the micropylar region, it differentiates into the germination pore plate, a structure that protects the embryo and controls germination. (iv) Most of the inner region of the mesocarp fuses with the endocarp and, both lignified, give rise to the stony pyrene; (v) in the other regions of the mesocarp, carbohydrates and lipids are accumulated in a parenchyma permeated with fiber and vascular bundles. The development of the B. capitata pericarp presents high complexity and a pattern not yet reported for Arecaceae, which supports the adoption of the Butia-type pyrenarium fruit class.

Seasonality and the control of longevity and dormancy in macaúba palm diaspores

The persistence of diaspores in soil seed banks (SB) will depend on their ability to remain viable (longevity) without germinating (dormancy). Changes in longevity and dormancy are governed by interactions between both intrinsic and environmental factors, and which determine the dynamics of SB. Our understanding of those dynamics will be important for the commercial propagation and conservation of natural populations, but remains incipient for tropical species. We evaluated the effects of climatic seasonality on the longevity and dormancy of diaspores of the neotropical oleaginous macaúba palm (Acrocomia aculeata). Pyrenes (seeds enveloped by the endocarp) of the species were kept in simulated SB under nursery conditions for two years. Morphological, biomechanical, cytological and physiological evaluations were carried out, every 90 days. The longevity of macaúba pyrenes is related to the maintenance of the structural protection of the embryo, tolerance to water deficits, and the control of oxidative stress. Dormancy level is reduced by changes in the biomechanics of the micropylar region: the gradual weakening of resistance tissues (the operculum and germination pore plate) and the increasing growth force of the embryo. Diaspores gradually become competent at perceiving environmental stimuli (especially high temperatures), which favors germination during windows of climatic opportunity in the late austral spring and early summer. Diaspores persisting in the SB contribute to the resilience of natural populations and will be important to the management and enrichment of areas where the species is exploited through extractivism.

The identification of type I MADS box genes as the upstream activators of an endosperm-specific invertase inhibitor in Arabidopsis

BackgroundNuclear endosperm development is a common mechanism among Angiosperms, including Arabidopsis. During nuclear development, the endosperm nuclei divide rapidly after fertilization without cytokinesis to enter the syncytial phase, which is then followed by the cellularized phase. The endosperm can be divided into three spatial domains with distinct functions: the micropylar, peripheral, and chalazal domains. Previously, we identified two putative small invertase inhibitors, InvINH1 and InvINH2, that are specifically expressed in the micropylar region of the syncytial endosperm. In addition, ectopically expressing InvINH1 in the cellularized endosperm led to a reduction in embryo growth rate. However, it is not clear what are the upstream regulators responsible for the specific expression of InvINHs in the syncytial endosperm.ResultsUsing protoplast transient expression system, we discovered that a group of type I MADS box transcription factors can form dimers to activate InvINH1 promoter. Promoter deletion assays carried out in the protoplast system revealed the presence of an enhancer region in InvINH1 promoter, which contains several consensus cis-elements for the MADS box proteins. Using promoter deletion assay in planta, we further demonstrated that this enhancer region is required for InvINH1 expression in the syncytial endosperm. One of the MADS box genes, AGL62, is a key transcription factor required for syncytial endosperm development. Using promoter-GFP reporter assay, we demonstrated that InvINH1 and InvINH2 are not expressed in agl62 mutant seeds. Collectively, our data supports the role of AGL62 and other type I MADS box genes as the upstream activators of InvINHs expression in the syncytial endosperm.ConclusionsOur findings revealed several type I MADS box genes that are responsible for activating InvINH1 in the syncytial endosperm, which in turn regulates embryo growth rate during early stage of seed development.

Intact funiculus in mature harvested seeds of field pea (Pisum sativum L.): preliminary investigation and possible implications

AbstractA seed remains attached to mother plant through funiculus which is the only means of communication between seed and mother plant. In general, the funiculus is detached from seeds at maturity while harvesting and threshing. However, out of about 950 accessions of fieldpea (Pisum sativum) screened at ICAR‐Indian Institute of Pulses Research, Kanpur, India, eight accessions were identified to have intact funiculus in matured and harvested seed. The role of intact funiculus after maturity and harvesting is not yet known. This article summarizes the results of a preliminary investigation on the effect of presence of funiculus on mature harvested seeds of fieldpea on water uptake, as the region underneath the funiculus (hilum–micropylar region) is known to be actively involved in water imbibition by seed. We also propose the possible implications (positive and negative) of incorporation of such trait in high yielding cultivars. The preliminary investigation suggested that the presence of funiculus in harvested seeds has a significant but negative role in rate of water uptake, as the seeds of all eight accessions imbibed more water when funiculus was removed. Such an effect on water uptake, which triggers many physiological metabolisms of dry seed, could have an effect on rate and final germination, dormancy, seed shattering, and cooking time. Also, such genotypes are expected to perform better under high initial moisture and/or flood situation like rice (Oryza sativa) fallows.

Isolation of Egg and Sperm Cells from Bauhinia blakeana

Isolated sperm cells and egg cells provide useful materials for the study of fertilization in higher plants, under controlled conditions, in the absence of somatic tissue. Viable egg cells from Bauhinia blakeana were isolated using enzymatic digestion and mechanical dissection. Ovules were digested with enzymes for 40–50 min and then transferred to a solution without enzymes for dissection. The three cells of the egg apparatus (i.e., the egg cell and two synergids) were released from a cut ovule by pushing the micropylar region of the ovule with a dissecting needle. Typically, 7–10 egg cells were isolated within 1 h. B. blakeana pollen is bicellular and contains only a vegetative and generative cell at anthesis. Sperm cells were isolated using an in vivo–in vitro method. The isolation of B. blakeana egg and sperm cells potentially provides a basis for in vitro fertilization of this woody dicotyledonous plant and materials for molecular biological investigations of fertilization mechanisms.

Battenispermum hirsutum gen. et sp. nov., a new Early Cretaceous seed from Portugal with chlamydospermous organisation

A new genus and species, Battenispermum hirsutum, is described from the Early Cretaceous mesofossil flora of Catefica, Portugal. The new taxon is based on five ovulate structures with up to three seeds surrounded by an outer cup formed from partly fused bracts. The seeds are small, about 2.4–3.3 mm long and 1.0–1.6 mm wide, orthotropous with a chlamydospermous organisation. The nucellus is surrounded by a thin integument, a sclerenchymatic inner seed envelope and an additional outer envelope of four bracts, fused for most of their length. The seeds are three- or four-angled in transverse section and elliptical in lateral view with the free tips of the outer envelope forming short, apical projections around the micropyle. The outer surface of the inner seed envelope is almost smooth, while the abaxial surfaces of both inner and outer bracts of the compound ovulate structures are covered by a dense indumentum of long and stiff trichomes. Battenispermum hirsutum clearly belongs to the chlamydospermous BEG complex (Bennettitales-Erdtmanithecales-Gnetales), but it is distinguished from all previously described fossils by the presence of two distinct seed envelopes, a feature otherwise known only for extant Gnetum. The seeds of Battenispermum hirsutum differ, from those of extant Gnetum in other features, including the much simpler micropylar region.

Enzyme activity in the micropylar region of Melanoxylon brauna Schott seeds during germination under heat stress conditions

Abstract: Recent studies indicate that global temperatures will rise substantially in the 21st century, leading to the extinction of several plant species, as plant metabolism and germination are greatly affected by temperature. Melanoxylon brauna, a tree species native to the Atlantic Forest that occurs from northeastern to southeastern Brazil, is one of the many species threatened by global warming. Despite the economic and ecological importance of M. brauna, studies investigating the influence of heat stress on seed germination and biochemical responses are still incipient. This study aimed to evaluate enzyme activity in the micropylar region of M. brauna seeds during germination under heat stress conditions. Endo-β-mannanase, α-galactosidase, polygalacturonase, pectin methylesterase, pectin lyase, total cellulase, 1,3-β-glucosidase, and 1,4-β-glucosidase activities were determined in micropyles of seeds imbibed for 24, 48 and 72 h at 25, 35 and 45 °C. Seed germination was highest at 25 °C. Endo-β-mannanase activity was not detected under any of the experimental conditions, but imbibition temperature had a significant effect on the activity of all other enzymes.

Deterioration of ovary plays a key role in heat stress-induced spikelet sterility in sorghum.

In sorghum (Sorghum bicolor [L.] Moench), the impact of heat stress during flowering on seed set is known, but mechanisms that lead to tolerance are not known. A diverse set of sorghum genotypes was tested under controlled environment and field conditions to ascertain the impact of heat stress on time-of-day of flowering, pollen viability, and ovarian tissue. A highly conserved early morning flowering was observed, wherein >90% of spikelets completed flowering within 30 min after dawn, both in inbreds and hybrids. A strong quantitative impact of heat stress was recorded before pollination (reduced pollen viability) and post pollination (reduced pollen tube growth and linear decline in fertility). Although viable pollen tube did reach the micropylar region, 100% spikelet sterility was recorded under 40/22°C (day/night temperatures), even in the tolerant genotype Macia. Heat stress induced significant damage to the ovarian tissue near the micropylar region, leading to highly condensed cytoplasmic contents and disintegrated nucleolus and nucleus in the susceptible genotype RTx430. Whereas, relatively less damages to ovarian cell organelles were observed in the tolerant genotype Macia under heat stress. Integrating higher tolerance in female reproductive organ will help in effective utilization of the early morning flowering mechanism to enhance sorghum productivity under current and future hotter climate.

Gyretes Brullé (Coleoptera: Gyrinidae) from Brazil: Morphology of eggs and early instars.

Taxonomic information regarding Gyrinidae is mostly based on adults, especially due to the difficulty in collecting immatures and assigning them to a particular species. Association between immatures and adults is sometimes difficult because closely related species can be found in the same habitat. To solve this problem a feasible technique is rearing under laboratory conditions. However, this method is challenging because larval survival rate is usually low, and emulation of natural conditions is difficult. Molecular techniques, especially the use of the COI gene, have been applied to identify species and to associate different life stages. However, in some species groups this marker has not been successful in distinguishing closely related species. The objectives of this study are to describe the egg and the first two instars of Gyretes nubilus Ochs, 1965 and the egg of G. minax Ochs, 1967 and to evaluate the utility of COI to associate immatures and adults. The association of these immature stages with adults was done either rearing adults under laboratory conditions or by using DNA sequence data (COI), corroborating the utility of this molecular marker to associate immature and adults in Gyretes. These immature stages are described, including chaetotaxic analysis of larvae for the first time for the genus Gyretes Brullé, 1835. The eggs are described based on scanning electron microscopy. The eggs are similar to those of other Gyrinidae genera in having a micropylar region in the anterior pole and a longitudinal fissure, and by the absence of an aeropyle, but they differ mainly in characters related to chorionic structure and reticulation. Larvae of Gyretes can be distinguished from those of the other Neotropical Gyrinidae genera by a combination of several characters, including the frontoclypeal seta FR3 short, presence of three conspicuous additional setae on lateral region of parietal (contiguous to stemmata), and posterior margin of lacinia smooth, with apex not indented.

Jasmonic acid and ethylene are involved in the accumulation of osmotin in germinating tomato seeds

The expression of SlNP24 encoding osmotin was studied in germinating tomato seeds Solanum lycopersicum L. cv. Moneymaker. The results show that the accumulation of the transcripts of SlNP24 and its potential upstream regulator TERF1 encoding an ethylene response factor was induced by ethylene and methyl jasmonate in germinating tomato seeds. There was no effect of gibberellins on the expression of the genes studied. The expression of SlNP24 was localized in the micropylar region of the endosperm of tomato seeds. The promoter of tomato osmotin was active in the endosperm cells of transgenic Arabidopsis thaliana seeds, which contain reporter genes under control of SlNP24 promoter. The activity of SlNP24 promoter in A. thaliana reporter line seeds was visible when the expression of its ortholog gene in A. thaliana (AtOMS34) was observed. The mechanism of induction and a possible role of NP24 in germinating tomato seeds are discussed.