Stages Of Root Formation Research Articles

Spatiotemporal regulation of dental pulpal innervation in the rat.

The dental pulp is a highly innervated tissue transmitting pain-related sensations in the tooth. Consequently, understanding the intricacies of its innervation mechanism in odontogenesis is crucial for gaining insights into dental pain and developing dental pain-modulating agents. This study examined neuroregulatory molecules such as neurotrophic factors (nerve growth factor [NGF], brain-derived neurotrophic factor [BDNF], neurotrophin-4 [NTF-4], and neurturin [NRTN]) and neuroinhibitory factors (slit2, ephrin isoforms and netrin-1) in developing rat teeth with follicles. NGF, BDNF and NRTN transcriptions showed time-dependent upregulation, particularly during the root formation stage. In contrast, NTF-4 mRNA was highly expressed at the cap stage, but became downregulated over time. Slit2 and ephrin-B2 expression was distinct at the cap stage and then downregulated in a time-dependent manner. Ephrin-A5 and netrin-1 expression did not significantly change. Immunofluorescence analysis revealed a robust expression of both ephrin-B2 and slit2 in the outer and inner dental epithelia of the enamel organ, a non-neurogenic tissue, during the cap stage of 3rd molar germs. In contrast, BDNF was predominantly localized in dental papilla cells and odontoblasts during the root formation stage. These results suggest that neuroregulatory molecules, such as BDNF, slit2 and ephrin-B2, may be important in identifying therapeutic targets for modulating dental pulp pain.

Adventitious rooting in response to long-term cold: a possible mechanism of clonal growth in alpine perennials.

Arctic alpine species experience extended periods of cold and unpredictable conditions during flowering. Thus, often, alpine plants use both sexual and asexual means of reproduction to maximize fitness and ensure reproductive success. We used the arctic alpine perennial Arabis alpina to explore the role of prolonged cold exposure on adventitious rooting. We exposed plants to 4°C for different durations and scored the presence of adventitious roots on the main stem and axillary branches. Our physiological studies demonstrated the presence of adventitious roots after 21 weeks at 4°C saturating the effect of cold on this process. Notably, adventitious roots on the main stem developing in specific internodes allowed us to identify the gene regulatory network involved in the formation of adventitious roots in cold using transcriptomics. These data and histological studies indicated that adventitious roots in A. alpina stems initiate during cold exposure and emerge after plants experience growth promoting conditions. While the initiation of adventitious root was not associated with changes of DR5 auxin response and free endogenous auxin level in the stems, the emergence of the adventitious root primordia was. Using the transcriptomic data, we discerned the sequential hormone responses occurring in various stages of adventitious root formation and identified supplementary pathways putatively involved in adventitious root emergence, such as glucosinolate metabolism. Together, our results highlight the role of low temperature during clonal growth in alpine plants and provide insights on the molecular mechanisms involved at distinct stages of adventitious rooting.

Interspecies co-expression analysis of lateral root development using inducible systems in rice, Medicago, and Arabidopsis.

Lateral roots are crucial for plant growth and development, making them an important target for research aiming to improve crop yields and food security. However, their endogenous ontogeny and, as it were, stochastic appearance challenge their study. Lateral Root Inducible Systems (LRIS) can be used to overcome these challenges by inducing lateral roots massively and synchronously. The combination of LRISs with transcriptomic approaches significantly advanced our insights in the molecular control of lateral root formation, in particular for Arabidopsis. Despite this success, LRISs have been underutilized for other plant species or for lateral root developmental stages later than the initiation. In this study, we developed and/or adapted LRISs in rice, Medicago, and Arabidopsis to perform RNA-sequencing during time courses that cover different developmental stages of lateral root formation and primordium development. As such, our study provides three extensive datasets of gene expression profiles during lateral root development in three different plant species. The three LRISs are highly effective but timing and spatial distribution of lateral root induction vary among the species. Detailed characterization of the stages in time and space in the respective species enabled an interspecies co-expression analysis to identify conserved players involved in lateral root development, as illustrated for the AUX/IAA and LBD gene families. Overall, our results provide a valuable resource to identify potentially conserved regulatory mechanisms in lateral root development, and as such will contribute to a better understanding of the complex regulatory network underlying lateral root development.

Selenium nanoparticles promote adventitious rooting without callus formation at the base of passion fruit cuttings via hormonal homeostasis changes

Callus formation at the cutting base is an interesting and common phenomenon in cuttings; however, little is known of histology and hormonal dynamics during the adventitious root formation (AR) and callusing stages of cuttings, also the relationship between them, were the aims of this study. The results showed that all SeNPs selenium nanoparticles (SeNPs) concentrations (1.0; 3.0; 5.0; 7.0 and 9.0 mg/L) and control (-) which is AR stimulants-free showed an impact AR formation without callusing in passion fruit cuttings. Meanwhile, regardless of the callus accumulation induced by cortex cell proliferation at cutting base that promoted by 2.5 mg/L IBA-control (+), no ARs differentiated from callus but rather from vascular cambium cells. It implies callus formation is not an obligatory trigger/signal for AR formation. Interestingly, SeNPs regulate IAA, Kin, zeatin, GA3 and ABA levels that peak during the S1 phase (S1-induction root/callus founder cells) consequent an increase in GA3/IAA, GA3/CKs, GA3/ABA ratios and a decrease in CKs/ABA ratio causing early vascular differentiation and of cambial derivatives behavioral modification, when crosstalk further regulates responses during AR-forming cellular reprogramming. On the other hand, callus induced by IBA impeded AR formation and growth traits due to increased endogenous 2ip, IAA/CKs and decreased GA3/IAA ratio during S1. Furthermore, the sustained high maintenance IAA/CKs and IAA/ABA ratios during S1-S3 (S3-massive rooting phase) favor callusing. SeNPs derived-plantlets without accumulate callus exhibited higher survival rate and superior growth during acclimatization stage compared with those controls, emphasizing that callusing was detrimental to passion fruit cuttings.

Unveiling dental age patterns in a Chinese population: A study in Surabaya using the Demirjian method

Tooth development can serve as a means to estimate an individual's chronological age, which is crucial in dental treatment planning and understanding individual growth patterns. Demirjian et al. devised a technique to assess dental maturity in Caucasians by evaluating crown and root formation stages on dental radiographs. This study aims to evaluate the suitability of Demirjian's method for age assessment among Chinese children (aged 9-15 years). The present study involved 30 panoramic radiographs of outpatients (15 males and 15 females, aged 9-15 years) at the Dental Hospital Universitas Airlangga, Surabaya. The information, including the sex and chronological age of each subject, was recorded, and the dental age was estimated using the Demirjian method. Statistical analysis was conducted using IBM SPSS Statistics version 23.0. The results indicated that male subjects exhibited a slight overestimation of dental age by 0.34 years, whereas female subjects showed a slight underestimation of 0.51 years, with no statistically significant difference (p>0.05). In conclusion, this study suggests that the Demirjian method effectively estimates the dental age of Chinese children in Surabaya. Further research with larger sample sizes and diverse populations is recommended to enhance the method's validity.

Lateral Root Initiation in Cucumber (Cucumis sativus): What Does the Expression Pattern of Rapid Alkalinization Factor 34 (RALF34) Tell Us?

In Arabidopsis, the small signaling peptide (peptide hormone) RALF34 is involved in the gene regulatory network of lateral root initiation. In this study, we aimed to understand the nature of the signals induced by RALF34 in the non-model plant cucumber (Cucumis sativus), where lateral root primordia are induced in the apical meristem of the parental root. The RALF family members of cucumber were identified using phylogenetic analysis. The sequence of events involved in the initiation and development of lateral root primordia in cucumber was examined in detail. To elucidate the role of the small signaling peptide CsRALF34 and its receptor CsTHESEUS1 in the initial stages of lateral root formation in the parental root meristem in cucumber, we studied the expression patterns of both genes, as well as the localization and transport of the CsRALF34 peptide. CsRALF34 is expressed in all plant organs. CsRALF34 seems to differ from AtRALF34 in that its expression is not regulated by auxin. The expression of AtRALF34, as well as CsRALF34, is regulated in part by ethylene. CsTHESEUS1 is expressed constitutively in cucumber root tissues. Our data suggest that CsRALF34 acts in a non-cell-autonomous manner and is not involved in lateral root initiation in cucumber.

Effects of Different Growth Hormones on Rooting and Endogenous Hormone Content of Two Morus alba L. Cuttings

This study aimed to explore the effects of different concentrations of indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and indene-naphthaleneacetic acid (ABT-1) on the rooting and dynamic changes of the endogenous hormone content of Australian Mulberry (vegetable Mulberry) and Kirin mulberry (Fruit Mulberry) hardwood cuttings. As exhibited by the results, the rooting process of both vegetable mulberry and fruit mulberry could be divided into three stages, namely the initiation stage (1–18 days), the callus formation stage (18–28 days), and the adventitious root formation and elongation stage (28–48 days). The two treatments with 1000 mg·L−1 ABT-1 and 500 mg·L−1 ABT-1 achieved the highest rooting efficiencies of vegetable mulberry and fruit mulberry, significantly higher than those of other treatments (p < 0.01), with average rooting rates of 63.3% and 68.7%, and rooting efficiency indices of 25.3 and 34.3, respectively. During the rooting process, the contents of endogenous IAA and zeatin riboside (ZR) and the ratios of IAA/ABA and IAA/ZR presented a trend of decreasing before increasing, while the abscisic acid (ABA) and jasmonic acid (JA) contents exhibited a trend of increasing before decreasing, and the gibberellin (GA3), strigolactone (SL), and IBA contents showed a continuous decreasing trend. Hence, ABT-1 was effective in inducing the synthesis of IAA, IBA, JA, and SL, reducing the contents of ABA, ZR, and GA3, and promoting the rooting of vegetable mulberry and fruit mulberry cuttings. For fruit mulberry and vegetable mulberry cuttings, the optimal concentrations of ABT-1 were 500 mg·L−1 and 1000 mg·L−1, respectively, demonstrating applicability for the efficient propagation of Morus alba L. cuttings.

Three Dimensional Analysis of Root Development and Bone Formation in an Immature Non Vital Permanent Molar Using Regenerative Endodontic Procedure: A Case Report

The Regenerative Endodontic Procedure (REP) is one of the latest biological procedures for successfully treating immature non vital teeth. Treating non vital immature teeth in children with associated bone resorption poses a challenge. In the present case, a 10- year-old male patient presented with an immature pulpally involved right permanent first molar, exhibiting a periapical radiolucency measuring 2×3.2×10.5 mm (distal root) and 4.4×5.2×10.5 mm (mesial root). The molar was non-surgically treated using a minimally invasive REP approach, aiming for anatomical healing and root completion. Mineral Trioxide Aggregate (MTA) was applied over a blood clot used as a scaffold. The radiolucency decreased significantly to a size of 0.9×1.3×0.2 mm (distal root) and 1×0.4×0.2 mm (mesial root). Continuous root formation was also observed, resulting in complete resolution of the Apical Bone Defect (ABD). The mesial and distal roots progressed from Nolla stage 8 (2/3rd of root formation) to Nolla stage 9 (root formation complete) over a twelve-month period. Three-dimensional (3D) analysis was employed to explain pathosis and the healing of lesions from every aspect. The present case demonstrates that REP may be the treatment of choice for managing non vital immature permanent posterior teeth with severe ABD in a paediatric patients, particularly when the surgical approach is contraindicated due to the presence of other developing structures. Furthermore, long-term follow-up is required, and the type of healing and root completion may vary depending on the stage of root formation, disinfection, and coronal seal achieved.

MICORPROPAGATION OF VIBURNUM OPULUS (ROSEUM) BY USING SINGLE NODES

The present study was carried out to investigate the micropropagation of viburnum opulus (Roseum) by using single nodes with axillary buds excised from soft cuttings using full strength MS salts, 30g.l-1 sucrose, 7g.l-1 Agar and different concentrations of plant growth regulators in culture medium. Results of the experiment at initiation stage revealed that the culture of single nodes of viburnum on a medium containing 4 mg.l-1 BA gave the highest number of shoots (2.21 shoots/explant). Concerning the interaction, a nutrient medium containing (2 mg.l-1 BA+ 0.4 mg.l-1 IAA) gave the highest values of mean number of shoots, leaves and length of new shoots (1.61 shoots/explant, 2.01 leaves/explant, 1.61 cm respectively). At shoot multiplication stage, the addition of 2.0 mg.l-1 from both BA and kinetin gave the highest number of shoots per explant estimated at 2.65 and 3.31 shoots/explant respectively at root formation stage; the interaction treatment of full MS salt strength with the use of 0 .5 mg.l-1 NAA gave the highest rooting percentage reaching 85.5 %. The highest number of roots (18 roots/ explant) was recorded as well from the combined treatment of full MS salt strength with the use of 0.5 mg.l-1 NAA. While the longest roots (6.65 cm) were recorded from the interaction treatment of half salt strength and 0.50 mg.l-1 IBA..

Effects of applying peanut shell and its biochar on the microbial activity and community structure of dryland red soil

Due to its soil formation process, dryland red soil has certain characteristics that are unfavorable for crop growth, including acidity, fineness, plate structures, and erosivity. The use of large amounts of fertilizer can decrease fertility and biodiversity and increase acidification, thereby seriously restricting the sustainable utilization of dryland red soil resources. Therefore, there is an urgent need for techniques that improve the crop quality and yield in dryland red soil areas. Returning crop waste to fields as fertilizer is a promising approach to sustainable agriculture. In the present study, the effects of applying peanut shell and an associated biochar product to dryland red soil were investigated, with a focus on soil microbial activity and community structure. Field experiments were conducted in Jiangxi Province, southern China, in 2020, in field plots of sweet potato crops. Seven treatments were set up according to the principle of equal carbon return to farmland: Control: (conventional fertilization); S1, S2, S3 (peanut shell application of 3000, 4500 and 6000 kg hm-2, respectively); and BC1, BC2, BC3 (peanut shell biochar application of 1000, 1500 and 2000 kg hm-2, respectively). The application of peanut shell and its biochar improved soil basal respiration, with the greatest increase relative to controls of 161.06% found in treatment S3 at the root harvest stage. The most obvious increase in microbial biomass carbon content due to biochar application was 206.50% in treatment BC2 at the root harvest stage. The application of peanut shell and its biochar increased the phospholipid fatty acid (PLFA) contents of total soil microorganisms and different microbial groups. The maximum increases in the PLFA contents of total soil microorganisms, gram-positive bacteria, and gram-negative bacteria occurred at the early root formation stage in treatment BC2, which were 112.16%, 102.52%, and 115.64%, respectively. Both peanut shell and biochar increased the PLFA contents of soil actinomycetes, arbuscular mycorrhizal fungi (AMF), and other fungi to certain extents. The soil actinomycetes PLFAs increased by 120.08% at the early root formation stage in BC2, while the AMF PLFAs increased by 79.44% at the seedling stage in S2. This study provides theoretical and practical guidance for the comprehensive utilization of peanut shell and the implementation of circular agriculture in dryland red soil regions. It also provides a scientific basis for improving the fertility of dryland red soil.

Identification of the HAK gene family reveals their critical response to potassium regulation during adventitious root formation in apple rootstock

Adventitious root formation is a bottleneck during vegetative proliferation. Potassium (K+) is an essential macronutrient for plants. K+ accumulation from the soil and its distribution to the different plant organs is mediated by K+ transporters named K+ transporter (KT), K+ uptake (KUP), or high-affinity K+ (HAK). This study aimed to identify members of the HAK gene family in apples and to characterize the effects of K+ supply on adventitious root formation and on the expression of HAK genes and the genes that putatively control auxin transport, signaling, and cell fate during adventitious root formation. In this study, 34 HAK genes (MdHAKs) were identified in the apple (Malus × domestica ‘Golden Delicious’) genome. A phylogenetic analysis divided MdHAKs into four clusters (I, II, III, and IV), comprising 16, 1, 4, and 13 genes, respectively. The syntenic relationships revealed that 62.5% of the total MdHAK genes arise from genomic duplication events. Chromosome location, domain structure, motif analysis, and physico-chemical characteristics were subsequently investigated. Furthermore, the application of K+ indicated the emergence of adventitious roots at 8 d and produced more adventitious roots at 16 d than the K+-free control (CK) treatment. In addition, various MdHAKs showed root-specific expression in B9 apple rootstock stem cuttings and enhanced expression during the initiation and emergence stages of adventitious root formation in response to K+ treatment. Additionally, K+ treatment enhanced the expression levels of MdPIN1, MdPIN2, and MdAUX1. Further data indicated that a higher expression of MdWOX11, MdLBD16, and MdLBD29 and of cell cycle-related genes contributed to the auxin-stimulated adventitious root formation in response to K+.

Results of orthodontic treatment of permanent upper incisors intrusive luxation: a clinical case

Relevance. Dental trauma prevalence is high among children. Treatment of intrusive luxation, where the choice of treatment technique depends on the root formation stage, is of particular interest.Clinical case description. The article presents the treatment results of an 8-year-old patient with mixed dentition. The patient was diagnosed with an intrusive luxation of teeth 1.1, 2.1, soft tissue contusion, and fracture of the maxillary alveolar process.Thirteen days after the injury, we started the orthodontic treatment with a bracket system (ROTH 018 Micro-Sprint) placed on the upper teeth, controlled by cone-beam computed tomography (CBCT). Arches and elastics were consecutively changed during the treatment. In nine and a half months, teeth 1.1 and 2.1 were extruded. Functional and aesthetic parameters were restored. We assessed stability of the obtained result 18 months after the start of orthodontic treatment.Conclusion. The intrusive luxation treatment planning calls for a thorough history and diagnosis data comparison. The choice of non-surgical treatment without tooth extraction requires informing the patient about possible complications, treatment difficulties and long-term follow-up observation. The successful treatment outcome needs comprehensive patient management by a multidisciplinary team of a maxillofacial surgeon, pediatric dentist, orthodontist and other related specialists, if necessary.

The Application of Nitrogen Source in Regulating Lignin Biosynthesis, Storage Root Development and Yield of Sweet Potato

The understanding of the effects of nitrogen sources on lignin synthesis in sweet potato during storage root formation is limited. In this study, we investigated the effects of different nitrogen source on sweet potato storage root formation and development, as well as lignin synthesis in potential storage roots. The sweet potato cultivars Shangshu 19 and Jixu 23 were used in field experiments in 2019 and 2020. Three treatments were tested: (a) no nitrogen fertilizer application (control); (b) 60 kg hm−2 ammonium nitrogen; and (c) 60 kg hm−2 amide nitrogen. The results indicate that during sweet potato storage root formation, ammonium nitrogen significantly enhanced root activity compared to that of the control. The ammonium nitrogen treatment promoted IbEXP1 and inhibited Ibkn1 and Ibkn2 expression during the early stages of storage root formation, then increased gibberellic acid and decreased zeatin riboside content, enhanced phenylalanine ammonia lyase and peroxidase activities, and promoted lignin synthesis in potential storage roots. The opposite effects of ammonium nitrogen treatment on gene expression, hormone contents, and enzyme activity were observed in the late stages of storage root formation. Relative to the control, the ammonium nitrogen treatment significantly increased the number of storage roots during canopy closure. The ammonium nitrogen treatment produced the highest storage root yield and number of storage roots per plant. These results indicated that the ammonium nitrogen can inhibit root lignin synthesis, then promote storage root formation and increase the yield of sweet potato.

Patterns of permanent incisor, canine and molar development in modern humans, great apes and early fossil hominins

ObjectiveThe objectives of this study were to quantify the variation in coincident stages of incisor, canine and molar eruption and tooth formation in modern humans and great apes and then to ask if any early fossil hominins showed a dental development pattern beyond the human range and/or clearly typical of great apes. DesignFour stages of eruption and 18 stages of tooth development were defined and then scored for each developing tooth on radiographs of 159 once-free-living subadult great apes and on orthopantomographs of 4091 dental patients aged 1–23 years. From original observations, and from published images of eleven early fossil hominins, we then scored formation stages of permanent incisors when M1 was at root formation stage R¼-R½ and R¾-RC. ResultsIncisor and canine eruption/development was delayed in great apes relative to molar development when compared with humans but there was overlap in almost all anterior tooth stages observed. Molar crown initiation was generally advanced in great apes and delayed in humans but again, we observed overlap in all stages in both samples. Only two fossil hominin specimens (L.H.–3 from Laetoli, Tanzania and KNM-KP 34725 from Kanapoi, Kenya) showed delayed incisor development relative to M1 beyond any individuals observed in the human sample. ConclusionsFor certain tooth types, the distribution of formation stages in our samples showed evidence of generally advanced or delayed development between taxa. However, it would rarely if ever be possible to allocate an individual to one taxon or another on this basis.

Endodontic pulp revitalization in traumatized necrotic immature permanent incisors: Early failures and long-term outcomes-A longitudinal cohort study.

AimThis prospective cohort study evaluates clinical and radiographical outcomes of endodontic pulp revitalization (PR) of traumatized necrotic incisors.MethodologyPulp revitalization was performed in 75 traumatized necrotic immature incisors from 71 patients. The radiographic outcome measures were continued root formation (width and length), root resorption, apex closure, periapical index, and root development stage. The clinical outcome measures were percussion pain, palpation pain, pathological tooth mobility, swelling, sinus tract, ankylosis, crown discolouration, response to pulp sensitivity test, and subjective pain. Treatment outcomes were categorized as a success based on the absence of clinical symptoms and when radiographic evidence was present for apical healing and continued root development. The performed statistical tests were repeated measures anova, pairwise comparisons of interactions (t‐test), McNemar's test, and linear regression model.ResultsIn 45 of 75 teeth (60%), PR was successful with the resolution of clinical and radiographic signs and continued root development. PR failed due to the absence of bleeding (n = 19) and persistent infection (n = 11). PR showed statistically significant increases in root length (11%), and dentinal wall thickness (30%), root maturation (pre‐operative 3.38 [CI 1.88; 4.88]; post‐operative 4.04, [CI 2.56; 5.52]) apical closure (71.4%), healing of pre‐operative apical periodontitis (100%), and healing of pre‐operative inflammatory root resorptions (100%). Three predictive variables for continued root maturation were identified – root development stage at entry (p = .0001, β 0.649), [CI 0.431; 0.867], trauma to the soft tissues (p = .026, β −0.012), [CI −0.0225; −0.015], and pre‐operative dentinal wall thickness (p = .009, β −0.001); [CI −0.001; 0.0001].ConclusionsOur findings indicate that PR provides satisfactory clinical and radiographical outcomes in traumatized necrotic incisors. The failed cases were related to lack of bleeding and persistent infections, indicating that new techniques are needed to improve the predictability of PR.

Radiographic study of the rhizogenesis in Brazilian adolescents and its contribution to dental age estimation

When applied to the examination of the living, methods for dental age estimation are based on clinical (visual or direct) or radiographic (radiographic or indirect) analyses. Two-dimensional (2D) techniques, such as panoramic radiography, or three-dimensional (3D) imaging modalities, such as cone-beam computed tomography, enable the visualization of multiple anatomical structures simultaneously. The development of each structure contributes to the age estimation process by providing age information. This study tested the performance of age information from rhizogenesis for age estimation. The sample consisted of panoramic radiographs of 568 female (n = 284) and male (n = 284) individuals, aged between 12 and 17.99 years. Tooth development was classified according to Demirjian et al. (1973) technique, and the age was calculated with the method of Willems et al. (2001). The average chronological age of each individual was compared with the estimated dental age, allowing the quantification of the error of the method for each age group at intervals of one year each. For both sexes, there was an overestimation of the chronological age in the age group of 12 |— 14.99 years, while age was underestimated in the age group of 16 |— 17.99 years (p < 0.0001). Statistically significant differences between sexes were observed in the age group of 15 |— 17.99 years (p < 0.05). The increasing error of the method in the late stages of root formation suggests that age information from the scarce remaining apical development of the permanent dentition may not be appropriate enough for sufficiently accurate forensic examinations.

PUCHI represses early meristem formation in developing lateral roots of Arabidopsis thaliana.

Lateral root organogenesis is a key process in the development of a plant’s root system and its adaptation to the environment. During lateral root formation, an early phase of cell proliferation first produces a four-cell-layered primordium, and only from this stage onwards is a root meristem-like structure, expressing root stem cell niche marker genes, being established in the developing organ. Previous studies reported that the gene regulatory network controlling lateral root formation is organized into two subnetworks whose mutual inhibition may contribute to organ patterning. PUCHI encodes an AP2/ERF transcription factor expressed early during lateral root primordium development and required for correct lateral root formation. To dissect the molecular events occurring during this early phase, we generated time-series transcriptomic datasets profiling lateral root development in puchi-1 mutants and wild types. Transcriptomic and reporter analyses revealed that meristem-related genes were expressed ectopically at early stages of lateral root formation in puchi-1 mutants. We conclude that, consistent with the inhibition of genetic modules contributing to lateral root development, PUCHI represses ectopic establishment of meristematic cell identities at early stages of organ development. These findings shed light on gene network properties that orchestrate correct timing and patterning during lateral root formation.

Transcriptome Analysis and Genes Function Verification of Root Development of Paeonia suffruticosa under Sandy Loam Cultivation

Relatively poor in vitro rooting has limited the large-scale commercial production of tree peony. In this study, on the basis of transcriptome sequencing, differentially expressed genes and the associated metabolic pathways were identified in tree peony roots at different stages of root formation under sandy loam cultivation. A total of 31.63 Gb raw data were generated and 120,188 unigenes (mean length of 911.98 bp) were annotated according to six databases (NR, NT, GO, KEGG, COG, and Swiss-Prot). Analyses of the ungerminated root primordium period, induced root primordium period, and root formation period detected 8,232, 6,907, and 10,687 differentially expressed genes related to 133, 132, and 133 metabolic pathways, respectively. Two significantly differentially expressed genes (Unigene13430_All and CL10096.Contig1_All) were associated with the auxin pathway. The full-length Unigene13430_All coding sequence (843 bp) encoded 280 amino acids, whereas the full-length CL10096.Contig1_All coding sequence (1,470 bp) encoded 489 amino acids. Unigene13430_All and CL10096.Contig1_All were identified as IAA gene family members and were respectively named PsIAA27 and PsARF19. The qRT-PCR analysis and functional verification indicated that the expressions of PsARF19 and PsIAA27 in tree peony seedlings, cuttings and grafted seedlings were significant different. PsARF19 promoted root development, it might be a regulatory gene related to the formation of tree peony roots, while PsIAA27 inhibited lateral root development, and it might be involved in controlling auxin sensitivity during root formation. The results of this study may form the basis of future investigations on the mechanism mediating peony root formation. The transcriptome data will be an excellent resource for researchers interested in characterizing the rooting-related tree peony genes.

Differential expression pattern of novel MADS-box genes in early root formation and differentiation of sweet potato

MADS-box genes are important transcription factors affecting overall development, but their role in sweet potato [Ipomoea batatas (L.) Lam.] has not been fully studied. This study isolated six novel MADS-box genes (IbSOC1, IbFUL1, IbAGL6, IbSVP1, IbSVP2, and IbSVP3) from sweet potato [Ipomoea batatas (L.) Lam. cv. Annouimo] during the early root differentiation stage using the de novo transcriptome assembly sequencing method. At the early root differentiation (between 0 and 3 days after transplanting), the IbSOC1, IbFUL1, and IbSVP2 genes decreased rapidly, whereas the IbSVP3 gene decreased gradually. In the early stages of root formation (0–30 days), the levels of IbSVP1 and IbSVP3 expression were steady, but the levels of IbSOC1 expression decreased gradually. The expression of six novel genes was also conducted in the tuberous root formation stage (30–90 days), and the IbSVP3 gene increased significantly according to the formation of the tuberous root. Six novel MADS-box genes that were believed to influence the entire root formation of sweet potato were isolated from the sweet potato. This study provides a genetic basis for further research on sweet potato root formation and development.

Transcriptomic and Anatomic Profiling Reveal Etiolation Promotes Adventitious Rooting by Exogenous Application of 1-Naphthalene Acetic Acid in Robinia pseudoacacia L.

The process of etiolation contributes significantly to vegetative propagation and root formation of woody plants. However, the molecular interaction pattern of different factors for etiolated adventitious root development in woody plants remains unclear. In the present study, we explored the changes at different etiolation stages of adventitious root formation in Robinia pseudoacacia. Histological and transcriptomic analyses were performed for the etiolated lower portion of hypocotyls to ascertain the adventitious root responses. We found that the dark-treated hypocotyls formed roots earlier than the control. Exogenous application of NAA (0.3 mg/L) stimulated the expressions of about 310 genes. Among these, 155 were upregulated and 155 were downregulated. Moreover, differentially expressed genes (DEGs) were significantly enriched in multiple pathways, including the biosynthesis of secondary metabolites, metabolic pathway, plant hormone signal transduction, starch and sucrose metabolism, phenylpropanoid biosynthesis, and carbon metabolism. These pathways could play a significant role during adventitious root formation in etiolated hypocotyls. The findings of this study can provide novel insights and a foundation for further studies to elucidate the connection between etiolation and adventitious root formation in woody plants.