Bud Growth Research Articles

Identification of Key Genes Related to Dormancy Control in Prunus Species by Meta-Analysis of RNAseq Data.

Bud dormancy is a genotype-dependent mechanism observed in Prunus species in which bud growth is inhibited, and the accumulation of a specific amount of chilling (endodormancy) and heat (ecodormancy) is necessary to resume growth and reach flowering. We analyzed publicly available transcriptome data from fifteen cultivars of four Prunus species (almond, apricot, peach, and sweet cherry) sampled at endo- and ecodormancy points to identify conserved genes and pathways associated with dormancy control in the genus. A total of 13,018 genes were differentially expressed during dormancy transitions, of which 139 and 223 were of interest because their expression profiles correlated with endo- and ecodormancy, respectively, in at least one cultivar of each species. The endodormancy-related genes comprised transcripts mainly overexpressed during chilling accumulation and were associated with abiotic stresses, cell wall modifications, and hormone regulation. The ecodormancy-related genes, upregulated after chilling fulfillment, were primarily involved in the genetic control of carbohydrate regulation, hormone biosynthesis, and pollen development. Additionally, the integrated co-expression network of differentially expressed genes in the four species showed clusters of co-expressed genes correlated to dormancy stages and genes of breeding interest overlapping with quantitative trait loci for bloom time and chilling and heat requirements.

Assessment of bud fruitfulness of three grapevine varieties grown in northwest Portugal

Assessing bud fruitfulness (fertility) before budburst can provide useful information for determining the yield potential for the following growing season and allows the number of buds per vine to be adjusted according to the productive potential of each season. The present study aims to assess bud fruitfulness and the incidence of necrotic buds using different analysis techniques in three spur pruned (cordon) grapevine white varieties planted in the Vinhos Verdes Demarcated Region (VVDR), NW Portugal. The first two dormant buds and cane samples were collected before winter pruning in December 2016 and 2017 from three (Vitis vinifera L.) varieties (Alvarinho, Fernão-Pires and Loureiro) in two different VVDR sub-regions. The fruitfulness and the incidence of bud necrosis were determined using anatomical bud analysis and by forcing bud growth under controlled environmental conditions. Additional analyses were performed to determine the total soluble sugars and starch in cane samples on node and internode regions. There were significant differences in fruitfulness among varieties over the two growing seasons (2016/2017 and 2017/2018). The Fernão-Pires variety showed the highest bud fruitfulness for the two first buds of the three varieties. Total soluble sugars and starch content were influenced by the site, variety and position on the cane. A year-to-year variation was observed, with a decrease in bud necrosis and an increase in the fruitfulness indices and carbohydrates content from 2016/2017 to 2017/2018. To our knowledge, no previous studies combining anatomical and forced bud growth techniques have been carried out on these three white varieties.

NADES Compounds Identified in Hypoxis hemerocallidea Corms during Dormancy.

Soaking Hypoxis hemerocallidea corms in distilled water improved the propagation and development of cormlets, suggesting the potential leaching-out of inhibitory chemical compounds. To investigate the presence of inhibitory compounds, nuclear magnetic resonance (NMR) spectral data of the leachate from dormant H. hemerocallidea corms were obtained using a 600 MHz 1H-NMR spectrometer. The 1H-NMR analysis led to the identification of choline, succinate, propylene glycol, and lactose, as inhibitory compounds. These four chemical compounds are part of the “Natural Deep Eutectic Solvents” (NADES) that protect plant cells during stress periods, each of which has the potential to inhibit bud growth and development. These compounds are supposedly leached out of the corms during the first rain under natural conditions, possibly accompanied by changes in the ratios of dormancy-breaking phytohormones and inhibitory compounds, to release bud dormancy. The identified chemical compounds heralded a novel frontier in the vegetative propagation of H. hemerocallidea as a medicinal plant, and for its enhanced sustainable uses.

Soil water and solute transport in an Andosol apple orchard including the dormancy period in a snowy cold region

Early spring corresponds to the snowmelt season in apple orchards of the northern hemisphere. This has a significant effect on the initial growth of shoots and flower buds of apple trees. Understanding the soil environment of the orchard during the non-growth period as monitored by farmers is important for managing year-round apple production. However, the details of mass transport, such as that of soil water and solute, during the non-growing season in the Andosols remain unclear. This study conducted soil environment monitoring in an Andosol apple orchard in Aomori Prefecture, Japan, during the non-growing season in winter to examine the year-round changes in the soil environment, using a field monitoring system that is necessary for understanding the soil environment. Volumetric water content, soil bulk electrical conductivity, and soil temperature were measured, and the cumulative changes in total soil moisture (ΣΔTSM) were calculated from the monitored volumetric water content. Results showed that although ΣΔTSM tended to increase (i.e., dry out) annually with periodicity, the variation was small compared to that of apple orchards with gravelly brown forest soil. These results could significantly influence fertilization management of apple orchard soil during the summer drought season and early spring when the roots of apple trees begin taking up nutrients. In particular, it was revealed that if sufficient nutrients remain in the soil pore water in early spring, the negative impact of excessive fertilization on the surrounding environment can be reduced. Therefore, this study constitutes an innovative step in the implementation of field monitoring system to understand the details of mass transport in the Andosol apple orchard soil.

Effect of Different Type Light and Growing Medium on the Growth and Flowering of Two Cultivars of Carnation (Dianthus caryophyllus L.)

This study was carried out in the greenhouse of the Horticulture Department Nursery, College of Agriculture Engineering Sciences, Duhok University, Kurdistan region, Iraq, for the period from 1st Aug 2020 to 1st Mar 2021, to study the effect of five supplemental light (control, natural light, Incandescent 14, Incandescent 18, mixed 14, mixed 18) hours daily and three growing medium (river soil, river soil + 30% local compost, river soil + 60% local compost) on some vegetative growth and flowering of two cultivars of carnation plant. The best results (fewest days) for the number of days from planting to bud emergence, visible flower colour, and anthesis were obtained when the plants were exposed to mixed light colours or incandescent lamps for a 14-hour treatment, Also this treatments were significantly superior in the other characteristics like plant height, flower length and flower diameter compared to the control. Medium with 60% local compost significantly increased all the studied characteristics compared with other mediums. The Ormea (Red) cultivar was significantly superior to the Moonlight cultivar in all studies of characteristics and was early in day numbers for bud emergence, visible flower colour, and anthesis. All second interactions between the investigated factors had a significant influence in all studied characteristics. In addition, the triple interaction between the three factors had a significant impact on all characteristics, including the least days or fewest days to flower anthesis of the Ormea cultivar when planted on medium containing 60% local compost under incandescent 14h, which took 101.80 days compared 176.27 days, with an early reach of 74.47 days for the control. The Moonlight (white) cultivar required the fewest days, 128.93 days, for a medium containing 60% compost under mixed 14h, which needed 123.93 days, compared to the control, which required 195.87 days with an early flowering rate of 71.94 days.

FRUITFULL is involved in double fruit formation at high temperature in sweet cherry

Sweet cherry (Prunus avium L.) is sensitive to high temperature during pistil development, but the spatial and temporal variability of high temperature and the molecular mechanism of its impact on the formation of double pistils are little known. An analysis of historical and projected climate data was conducted to characterize the spatial and temporal variability of high temperature from June to September at 5 stations in main sweet cherry growing regions of China and a warmer reference site. Several high temperature indices were developed to quantify heat frequency, intensity and duration during pistil development based on observed and projected maximum temperatures. The risk of high temperature was projected to increase under two Representative Concentration Pathways for 2035–2065 and 2070–2100, and the increasing rate was higher in the south station than the north except for Yantai city. Furthermore, to explore the mechanism of double fruit formation at high temperature, we investigated the regulation of FRUITFULL (FUL) during the growth of floral buds in sweet cherry. We identified a AP1/ FUL family gene FUL from sweet cherry, which was grouped with PpCAL, PpMADS6 from Prunus persica, ParFUL from Prunus armeniaca, PyeCAL from Prunus yedoensis, and PdCAL, PdAGL8 from Prunus dulcis by phylogenetic tree analysis. The seasonal expression level of PavFUL was higher in the high multi-pistil rate cultivar during summer stage and enhanced by high temperature. Moreover, overexpression of PavFUL led to multi-silique formation and early flowering in Arabidopsis. In addition, Y2H and BiFC assays revealed that PavFUL interacted with other MADS-box proteins, including PavLFY, PavSOC1, PavAP1, and PavSEP, to co-regulate the flowering and multi-silique formation. Our findings will help decipher the possible mechanism of high temperature-mediated double fruit via affecting FUL and other MADS-box genes in molecular level for tree fruit species.

Phenology analysis growing and degree days of flower bud growth in three Dianthus caryophyllus L. varieties under greenhouse conditions

The production of carnations (Dianthus caryophyllus L.) in Colombia is a very important economic activity. Therefore, predicting harvests is vital for the market. The phenological behavior and growth of carnations during the flowering season in the cultivars Idilio, Ilusion, and Moon light were determined in greenhouse using a functional growth analysis. This research was based on the phenological stages and accumulation of growing degree day (GDD), relating the temperature in terms of thermal time with the development of flower buds from the rice point phenological stage to cut-off point 5. There were eight stages of carnation flower bud development; rice, pea, chickpea, barrel, star, bullet, cut point 3, and cut point 5. The fresh and dry mass of the flower buds in the three varieties presented a simple sigmoid growth pattern that was adjusted to a logistic model. There were three growth phases: phase 1, which was from the pea stage to barrel stage with accumulation of 380.7 GDD in the Idilio cultivar, 381.5 GDD for ‘Ilusion’, and 361.6 GDD for ‘Moon light’. Phase 2 ended with the bullet stage, where the accumulation was 294.4 GDD, 397.7 GDD, and 293.5 GDD for ‘Idilio’, ‘Ilusion’ and ‘Moon light’, respectively. In phase 3, ‘Idilio’ accumulated 108.9 GDD, ‘Ilusion’ had 110.8 GDD, and ‘Moon light’ showed 99.9 GDD. Moon light was the earliest cultivar, and Ilusion was the latest variety.

Growth and Flowering of Saffron (Crocus sativus L.) with Three Corm Weights under Different LED Light Qualities

• Saffron (Crocus sativus L.) is referred ‘red gold’ worldwide as it is the most expensive spice. • The cultivation of saffron has been limited due to low flower yields. • Light emitting diode (LED) emits monochromatic light, which can improve crop quality and yield. • The effects of LED supplementation on growth and flowering of saffron ( Crocus sativus ) with three corm weights were studied. • Monochromatic red light significantly promoted saffron growth and increase stigmas yields with three corm weights. Saffron ( Crocus sativus L.) is a flowering plant whose dried stigma is an expensive and well-known spice. The major goal in saffron cultivation is to improve flower quality and yield. The present research aimed to understand the influence of LED light quality on the growth and flowering of saffron and provide valuable guidance to explore modern techniques to promote flower and stigma yield. The growth characteristics, flowering characteristics, hormone and nutrient content, and stigma quality and value were determined at three different corm weights (20–25 g, 25–30 g, 30–35 g per corm) under six LED light qualities [white (control, CK); monochromatic blue light (B); monochromatic red light (R); red and blue light at 1:2 ratio (R1B2); red and blue light at 1:1 ratio (R1B1); red and blue light at 2:1 ratio (R2B1)]. Monochromatic red light reduced corm biomass loss, accelerated apical bud growth, enhanced flower size and number, and advanced flowering. Monochromatic red light significantly increased the indole-3-acetic acid (IAA), soluble protein (SP), and zeatin riboside (ZR) levels in the mature corms compared with CK. Besides, red light demonstrated the highest hormone and nutrient content for the 30–35 g corm weight. Furthermore, monochromatic red light improved stigma yield (total dry weight), total crocin production, and the practical value ratio of saffron. The present study's observations indicate that monochromatic red light promoted saffron growth, advanced flowering, and increased stigma yield by regulating the corm phytohormones and enzyme activity. The study provides valuable guidance to explore modern techniques to promote saffron flower and stigma yield.

Leaf cytokinin accumulation promotes potato growth in mixed nitrogen supply by coordination of nitrogen and carbon metabolism

The source and sink balance determines crop growth, which is largely modulated by nitrogen (N) supplies. The use of mixed ammonium and nitrate as N supply can improve plant growth, however mechanisms involving the coordination of carbon and N metabolism are not well understood. Here, we investigated potato plants responding to N forms and confirmed that, compared with sole nitrate supply, mixed N (75 %/25 % nitrate/ammonium) enhanced leaf area, photosynthetic activity and N metabolism and accordingly resulted in outgrowth of stolons and shoot axillary buds. Cytokinin transportation in xylem sap and local cytokinin synthesis in leaves were up-regulated in mixed-N-treated potato plants relative to sole nitrate provision; and exogenous application of 6-benzylaminopurine in addition to sole nitrate restored leaf area, photosynthetic capacity and N content in leaves to the similar as those under mixed-N treatment. Partial defoliation, an effective method to enhance the sink strength, induced more cytokinin content in leaflets under two treatments relative to their respective controls and ultimately resulted in larger photosynthesis capacity and leaf area. These results suggest that mixed-N-enhanced plant growth through the coordination of carbon and N metabolism largely depends on the signal molecule cytokinin modulated by N supplies.

A mismatch in the emergence of Torymus sinensis may affect the effectiveness of this biocontrol agent?

The biocontrol agent Torymus sinensis Kamijo is considered as one of the most successful examples of classical biological control programs. This parasitoid represented a feasible option to obtain sufficient, sustainable, and long-term control of the Asian chestnut gall wasp (ACGW), Dryocosmus kuriphilus Yasumatsu. Recently, an unusual presence of galls was recorded in a few chestnut orchards of Northern Italy, although T. sinensis was released in previous years. We hypothesized that the increase in infestation rate over the years was related to a mismatch in the parasitoid/host phenology, resulting in a decrease in biocontrol effectiveness. Investigations were performed in the five-year period 2018–2022 in six chestnut orchards, selected according to the ACGW infestation level, and divided in two categories: non-critical sites (negligible presence of ACGW galls) and critical sites (high presence of galls with suppression of bud growth). We evaluated T. sinensis’s parasitism rate and phenology by dissecting chestnut galls, comparing non-critical sites versus critical sites. Temperatures were monitored in all the orchards with data loggers. In non-critical sites the parasitism rate by T. sinensis was stable and/or growing in all years, accounting from 77% to 99% (i.e., total number of T. sinensis divided by total number of larval chambers). Conversely, the parasitism rate in critical sites experienced a severe decline, reaching values under 50% in all sites in 2021–2022. Specifically, parasitism on average was reduced by 44% when comparing 2019 versus 2022. The dissection of the galls recorded in non-critical sites in winter (February) highlighted that on average most T. sinensis were larvae and immature pupae (about 70%). Conversely, in critical sites most of the individuals were black mature pupae (76%), with presence of newly formed adults (12%). In 2019–2022, the mean temperature recorded in critical sites was 2.72 °C and 2.34 °C higher in January and February respectively, when compared to non-critical sites. Moreover, in critical sites the early emergence of the biocontrol agent (late February-early March) was recorded when current-year ACGW fresh galls were not available. No variation in the phenological cycle of the ACGW was ever observed, in all sites and years. Our results suggest that the asynchrony between T. sinensis and the ACGW heavily affected the role of the released agent in the suppression of the pest’s outbreaks. Future studies are needed to clarify whether this event is increasing in relevance, also in a climate change perspective.

Annual dynamic variation of seven active components of Lonicera japonica in leaf growth and pruning periods

Pruning branches and leaves is the measure to stimulate the growth of Lonicera japonica flower buds, and consequently, the resources of pruned leaves are inevitably and seriously wasted in production. High-performance liquid chromatography(HPLC) was applied for content determination of seven active ingredients(chlorogenic acid, galuteolin, isochlorogenic acids A, B, and C, secologanic acid, and secoxyloganin) in L. japonica leaves from March to November. The results showed that the tillering removed from the trunk of L. japonica in March, the leaves pruned from May to July, and the leaves after the first frost date in November were rich in active ingredients, which deserved further exploitation and utilization. The total content(TC) of active ingredients in pruned L. japonica leaves in early March was the highest. The content of active ingredients in L. japonica leaves increased significantly after the first frost date, which was close to that in the bud tillers pruned in early and middle March. After the first frost date, L. japonica leaves are incapable of photosynthesis, and the harvesting of L. japonica leaves does not affect the physiological activities of the tree. In addition to huge resources, the content of active ingredients is high during this period, which is the best harvesting period of L. japonica leaves.

The Role of Transcription Factors in the Regulation of Plant Shoot Branching.

Transcription factors, also known as trans-acting factors, balance development and stress responses in plants. Branching plays an important role in plant morphogenesis and is closely related to plant biomass and crop yield. The apical meristem produced during plant embryonic development repeatedly produces the body of the plant, and the final aerial structure is regulated by the branching mode generated by axillary meristem (AM) activities. These branching patterns are regulated by two processes: AM formation and axillary bud growth. In recent years, transcription factors involved in regulating these processes have been identified. In addition, these transcription factors play an important role in various plant hormone pathways and photoresponses regulating plant branching. In this review, we start from the formation and growth of axillary meristems, including the regulation of hormones, light and other internal and external factors, and focus on the transcription factors involved in regulating plant branching and development to provide candidate genes for improving crop architecture through gene editing or directed breeding.

OsSPL14 acts upstream of OsPIN1b and PILS6b to modulate axillary bud outgrowth by fine-tuning auxin transport in rice.

As a multigenic trait, rice tillering can optimize plant architecture for the maximum agronomic yield. SQUAMOSA PROMOTER BINDING PROTEIN-LIKE14 (OsSPL14) has been demonstrated to be necessary and sufficient to inhibit rice branching, but the underlying mechanism remains largely unclear. Here, we demonstrated that OsSPL14, which is cleaved by miR529 and miR156, inhibits tillering by fine-tuning auxin transport in rice. RNA interference of OsSPL14 or miR529 and miR156 overexpression significantly increased the tiller number, whereas OsSPL14 overexpression decreased the tiller number. Histological analysis revealed that the OsSPL14-overexpressing line had normal initiation of axillary buds but inhibited outgrowth of tillers. Moreover, OsSPL14 was found to be responsive to indole-acetic acid and 1-naphthylphthalamic acid, and RNA interference of OsSPL14 reduced polar auxin transport and increased 1-naphthylphthalamic acid sensitivity of rice plants. Further analysis revealed that OsSPL14 directly binds to the promoter of PIN-FORMED 1b (OsPIN1b) and PIN-LIKE6b (PILS6b) to regulate their expression positively. OsPIN1b and PILS6b were highly expressed in axillary buds and proved involved in bud outgrowth. Loss of function of OsPIN1b or PILS6b increased the tiller number of rice. Taken together, our findings suggested that OsSPL14 could control axillary bud outgrowth and tiller number by activating the expression of OsPIN1b and PILS6b to fine-tune auxin transport in rice.

Melatonin Mediates Axillary Bud Outgrowth by Improving Nitrogen Assimilation and Transport in Rice.

Melatonin plays an important role in plant resistance to biotic and abiotic stresses. However, whether melatonin is involved in the regulation of plant architecture, such as the formation of axillary bud outgrowth or tillering, in rice remains unknown. Here, we found that different concentrations of melatonin influenced axillary bud outgrowth in rice, and moderate melatonin concentrations also alleviated the inhibition of axillary bud outgrowth in the presence of high concentrations of basic amino acids lysine and arginine. Furthermore, transcriptome analysis demonstrated that genes involved in nitrogen metabolism and phytohormone signal transduction pathways may affect axillary bud outgrowth, which is regulated by melatonin. We determined that the differentially expressed genes glutamine synthetase OsGS2 and amino acid transporter OsAAP14, which are involved in nitrogen metabolism and are regulated by melatonin and basic amino acids, were the key regulators of axillary bud outgrowth in rice. In addition, we validated the functions of OsGS2 and OsAAP14 using rice transgenic plants with altered axillary bud outgrowth and tillers. Taken together, these results suggest that melatonin mediates axillary bud outgrowth by improving nitrogen assimilation and transport in rice.

How Strigolactone Shapes Shoot Architecture.

Despite its central role in the control of plant architecture, strigolactone has been recognized as a phytohormone only 15 years ago. Together with auxin, it regulates shoot branching in response to genetically encoded programs, as well as environmental cues. A central determinant of shoot architecture is apical dominance, i.e., the tendency of the main shoot apex to inhibit the outgrowth of axillary buds. Hence, the execution of apical dominance requires long-distance communication between the shoot apex and all axillary meristems. While the role of strigolactone and auxin in apical dominance appears to be conserved among flowering plants, the mechanisms involved in bud activation may be more divergent, and include not only hormonal pathways but also sugar signaling. Here, we discuss how spatial aspects of SL biosynthesis, transport, and sensing may relate to apical dominance, and we consider the mechanisms acting locally in axillary buds during dormancy and bud activation.

Transmembranous and enchondral osteogenesis in transplants of rat limb buds cultivated in serum- and protein-free culture medium.

Cartilage differentiates in rat limb buds cultivated in a chemically defined protein‐free medium in the same manner as in the richer serum‐supplemented medium. We aimed to investigate the remaining differentiation potential of pre‐cultivated limb buds by subsequent transplantation in vivo. Rat front (FLBs) and hind‐limb buds (HLBs) were isolated from Fischer rat dams at the 14th gestation day (GD 14) and cultivated at the air‐liquid interface in Eagle's Minimum Essential Medium (MEM) alone; with 5 μM of 5‐azacytidine (5azaC) or with rat serum (1:1). Overall growth was measured seven times during the culture by an ocular micrometre. After 14 days, explants were transplanted under the kidney capsule of adult males. Growth of limb buds was significantly lower in all limb buds cultivated in MEM than in those cultivated with serum. In MEM with 5azaC, growth of LBs was significantly lower only on day 3 of culture. Afterwards, it was higher throughout the culture period, although a statistically significant difference was assessed only for HLBs. In transplants, mixed structures developed with the differentiated transmembranous bone, cartilage with enchondral ossification, bone‐marrow, sebaceous gland, and hair that have never been found in vitro. Nerves differentiated only in transplants precultivated in the serum‐supplemented medium. We conclude that pre‐cultivation of LBs in a chemically defined protein‐free medium does not restrict osteogenesis and formation of epidermal appendages but is restrictive for neural tissue. These results are important for understanding limb development and regenerative medicine strategies.

Strigolactones and Cytokinin Interaction in Buds in the Control of Rice Tillering.

Shoot branching is among the most crucial morphological traits in rice (Oryza sativa L.) and is physiologically modulated by auxins, cytokinins (CKs), and strigolactones (SLs) cumulatively in rice. A number of studies focused on the interplay of these three hormones in regulating rice tiller extension. The present study primarily aimed at determining the impact of different treatments, which were used to regulate rice tiller and axillary bud development on node 2 at the tillering stage and full heading stage, respectively. Transcription levels of several genes were quantified through qRT-PCR analysis, and an endogenous auxin and four types of CKs were determined through LC-MS/MS. Both nutrient deficiency and exogenous SL supply were found to inhibit rice tiller outgrowth by reducing the CK content in the tiller buds. Furthermore, supplying the inhibitor of both exogenous SLs and endogenous SL synthesis could also affect the expression level of OsCKX genes but not the OsIPT genes. Comparison of OsCKX gene expression pattern under exogenous SL and CK supply suggested that the induction of OsCKX expression was most likely via a CK-induced independent pathway. These results combined with the expression of CK type-A RR genes in bud support a role for SLs in regulating bud outgrowth through the regulation of local CK levels. SL functioned antagonistically with CK in regulating the outgrowth of buds on node 2, by promoting the OsCKX gene expression in buds.

Knockdown of PagSAP11 Confers Drought Resistance and Promotes Lateral Shoot Growth in Hybrid Poplar (Populus alba × Populus tremula var. glandulosa)

Plants have evolved defense mechanisms to overcome unfavorable climatic conditions. The growth and development of plants are regulated in response to environmental stress. In this study, we investigated the molecular and physiological characteristics of a novel gene PagSAP11 in hybrid poplar (Populus alba × Populus tremula var. glandulosa) under drought stress. PagSAP11, a stress-associated protein (SAP) family gene, encodes a putative protein containing an A20 and AN1 zinc-finger domain at its N- and C-termini, respectively. Knockdown of PagSAP11 transgenic poplars (SAP11-Ri) enhanced their tolerance to drought stress compared with wild type plants. Moreover, the RNAi lines showed increased branching of lateral shoots that led to a gain in fresh weight, even when grown in the living modified organism (LMO) field. In SAP11-Ri transgenic plants, the expression levels of genes involved in axillary bud outgrowth and cell proliferation such as DML10, CYP707A and RAX were increased while the DRM gene which involved in bud dormancy was down-regulated. Taken together, these results indicate that PagSAP11 represents a promising candidate gene for engineering trees with improved stress tolerance and growth during unfavorable conditions.

The Semaphorin 3A-AKT axis-mediated cell proliferation in salivary gland morphogenesis and adenoid cystic carcinoma pathogenesis

We recently demonstrated that Semaphorin 3 A (Sema3A), the expression of which is negatively regulated by Wnt/β-catenin signaling, promotes odontogenic epithelial cell proliferation, suggesting the involvement of Sema3A in tooth germ development. Salivary glands have a similar developmental process to tooth germ development, in which reciprocal interactions between the oral epithelium and adjacent mesenchyme proceeds via stimulation with several growth factors; however, the role of Sema3A in the development of salivary glands is unknown. There may thus be a common mechanism between epithelial morphogenesis and pathogenesis; however, the role of Sema3A in salivary gland tumors is also unclear. The current study investigated the involvement of Sema3A in submandibular gland (SMG) development and its expression in adenoid cystic carcinoma (ACC) specimens. Quantitative RT-PCR and immunohistochemical analyses revealed that Sema3A was expressed both in epithelium and in mesenchyme in the initial developmental stages of SMG and their expressions were decreased during the developmental processes. Loss-of-function experiments using an inhibitor revealed that Sema3A was required for AKT activation-mediated cellular growth and formation of cleft and bud in SMG rudiment culture. In addition, Wnt/β-catenin signaling decreased the Sema3A expression in the rudiment culture. ACC arising from salivary glands frequently exhibits malignant potential. Immunohistochemical analyses of tissue specimens obtained from 10 ACC patients showed that Sema3A was hardly observed in non-tumor regions but was strongly expressed in tumor lesions, especially in myoepithelial neoplastic cells, at high frequencies where phosphorylated AKT expression was frequently detected. These results suggest that the Sema3A-AKT axis promotes cell growth, thereby contributing to morphogenesis and pathogenesis, at least in ACC, of salivary glands.

Cultivated strawberry HANABA TARANU: a tale of transcription factors, raging hormones, and asexual reproduction

Cultivated strawberry <scp><i>HANABA TARANU</i></scp>: a tale of transcription factors, raging hormones, and asexual reproduction