Search Results (33)

The effects of 1-N-naphthylphthalamic acid (NPA) applied as an aqueous solution on uncooled grape hyacinth (Muscari armeniacum) bulbs were investigated, focusing on histological measurements and the determination of various metabolites in developing roots. M. armeniacum bulbs were kept for a defined number of days in distilled water (control) or aqueous NPA solutions, and then 2 cm sections of root tips were taken for histological measurements. Longitudinal and cross sections were taken in these root pieces, followed by measurements of their basic parts and microscopic images. Determinations of polar compounds by GC/MS and phenolic metabolites by HPLC/MS/MS were carried out in freeze-dried root samples. NPA inhibited the growth of the roots and caused swelling of their elongation parts, as well as changes in the dimensions of other parts of the roots and disruption of the gravitropic direction of their growth. However, NPA did not affect leaf growth and the amino acid, organic acid, and major carbohydrate content in the roots, but increased the level of unknown saccharides, probably oligofructans. The decrease in the contents of many phenolic compounds observed in our study under the influence of NPA may indicate that this could be one of the symptoms/causes of root growth disorders. In turn, the reduction in polyphenol levels may have been related to an increase in the number and length of root hairs. Full article

Background: The Arabidopsis FCS-LIKE ZINC FINGER (FLZ) family proteins play crucial roles in responses to various biotic and abiotic stresses, but the functions of many family members remain uncharacterized. Methods: In this study, we investigated the function of FLZ12, a member of the FLZ family, using a reverse genetic approach. Results: We found that overexpression of FLZ12 impaired root hair development, as evidenced by marked reductions in both root hair length and number under normal growth conditions. However, deprivation of phosphate could partially restore root hair formation, although it still impeded root hair elongation. Notably, FLZ12-overexpressing lines exhibited greatly enhanced tolerance to iron deficiency, with seedlings exhibiting more vigorous and robust growth compared to wild-type plants. In contrast, knockout of FLZ12 resulted in slight impact on seedling development. Further analysis revealed that FLZ12 accumulation was increased in vascular tissues of plants subjected to iron starvation, and the protein was predominantly localized within the nucleus. Conclusions: Integrating these findings with existing evidence, we propose that FLZ12 functions as a translational regulator through interacting with other proteins, playing dual roles in root hair development and iron-deficiency responses in Arabidopsis. These findings provide new insights into the FLZ-domain-containing proteins and offer molecular strategies to enhance iron uptake efficiency in crops, highlighting FLZ12 as a promising candidate for future breeding efforts. Full article

The novel plant hormone strigolactones (SL) are involved significantly in plant growth and development. Its key members SMXL6, 7, 8 can modulate SL signal reception and response negatively and can regulate plant branching remarkably. There are relatively scarce studies of cotton SMXL gene family, and this study was carried out to clarify the role of GbSMXL8 in cotton fiber development. Phylogenetic analysis identified 48 cotton SMXL genes, which were divided into SMXL-I (SMXL 1, 2), SMXL-II (SMXL 3) and SMXL-III (SMXL6, 7, 8) groups. The results of the cis-element analysis indicated that the SMXL gene could respond to hormones and the environment to modulate cotton growth process. A candidate gene GbSMXL8 was screened out based on the expression difference in extreme varieties of Gossypium barbadense. Tissue-specific analysis indicated that GbSMXL8 was mainly expressed in roots, 20D, 25D, and 35D and was involved in SL signaling pathways. In vitro ovule culture experiments showed that exogenous SLs (GR24) could promote the fiber elongation of G. barbadense, and GbSMXL8 expression was increased after GR24 treatment, indicating that GbSMXL8 was specifically responsive to GR24 in regulating fiber growth. GbSMXL8 knockout resulted in creased length and number of epidermal hairs and the length of fiber, indicating the interference role of GbSMXL8 gene with the development of cotton fiber. The GbSMXL8 transgenic plant was detected with a higher chlorophyll content and photosynthetic rate than those of the control plant, producing a direct impact on plant growth, yield, and biomass accumulation. GbSMXL8 gene knockout could increase plant height, accelerate growth rate, and lengthen fiber length. Intervening GbSMXL8 may mediate cotton growth, plant type formation and fiber elongation. In conclusion, the present study uncovers the function of GbSMXL8-mediated SL signal in cotton, providing theoretical insight for future breeding of new cotton varieties. Full article

Bacteria associated with plants, whether rhizospheric, epiphytic, or endophytic, play a crucial role in plant productivity and health by promoting growth through complex mechanisms known as plant growth promoters. This study aimed to isolate, characterize, identify, and evaluate the potential of endophytic bacteria from the resurrection plant Selaginella lepidophylla in enhancing plant growth, using Arabidopsis thaliana ecotype Col. 0 as a model system. Plant growth-promotion parameters were assessed on the bacterial isolates; this assessment included the quantification of indole-3-acetic acid, phosphate solubilization, and biological nitrogen fixation, a trehalose quantification, and the siderophore production from 163 endophytic bacteria isolated from S. lepidophylla. The bacterial genera identified included Agrobacterium, Burkholderia, Curtobacterium, Enterobacter, Erwinia, Pantoea, Pseudomonas, and Rhizobium. The plant growth promotion in A. thaliana was evaluated both in Murashige Skoog medium, agar-water, and direct seed inoculation. The results showed that the bacterial isolates enhanced primary root elongation and lateral root and root hair development, and increased the fresh and dry biomass. Notably, three isolates promoted early flowering in A. thaliana. Based on these findings, we propose the S. lepidophylla bacterial isolates as ideal candidates for promoting growth in other agriculturally important plants. Full article

Alfin-like proteins (ALs) form a plant-specific transcription factor (TF) gene family involved in the regulation of plant growth and development, and abiotic stress response. In this study, 30 ALs were identified in Brassica napus ecotype ‘Zhongshuang 11’ genome (BnaALs), and unevenly distributed on 15 chromosomes. Structural characteristic analysis showed that all of the BnaALs contained two highly conserved domains: the N terminal DUF3594 domain and the C-terminal PHD-finger domain. The BnaALs were classified into four groups (Group I-IV), supported by conserved intron–exon and protein motif structures in each group. The allopolyploid event between B. oleracea and B. rapa ancestors and the small-scale duplication events in B. napus both contributed to the large BnaALs expansion. The promoter regions of BnaALs contained multiple abiotic stress cis-elements. The BnaALs in I-IV groups were mainly expressed in cotyledon, petal, root, silique, and seed tissues, and the duplicated gene pairs shared highly similar expression patterns. RNA-seq and RT-qPCR analysis showed that BnaALs were obviously induced by low nitrogen (LN) and low phosphorus (LP) treatments in roots. Overexpressing BnaAL02 and BnaAL28 in Arabidopsis demonstrated their functions in response to LN and LP stresses. BnaAL28 enhanced primary roots’ (PRs) length and lateral roots’ (LRs) number under LP and LN conditions, where BnaAL02 can inhibit LR numbers under the two conditions. They can promote root hair (RH) elongation under LP conditions; however, they suppressed RH elongation under LN conditions. Our result provides new insight into the functional dissection of this family in response to nutrient stresses in plants. Full article

GhPEL48_Dt, a Pectate lyase (PEL, EC4.2.2.2), is a crucial enzyme involved in cell-wall modification and pectin degradation. Studies have shown that the GhPEL48_Dt also plays a significant role in cotton-fiber development; however, the specific function and regulatory mechanism of GhPEL48_Dt in cotton-fiber development are still not fully understood. Here, we found that the histone deacetylase inhibitor-Trichostatin A significantly reduces the transcript levels of GhPEL48_Dt and its enzyme activity. Further, silencing of GhPEL48_Dt significantly inhibits the initiation and elongation of cotton fibers by promoting pectin degradation, and the heterologous expression of GhPEL48_Dt promotes the development of trichomes and root hairs in Arabidopsis, which suggests that GhPEL48_Dt plays a positive and conserved role in single cell i.e., fiber, root hair, and leaf trichome development. Collectively, this paper provides a comprehensive analysis of the fundamental characteristics and functions of GhPEL48_Dt in fiber development, including the regulatory role of histone acetylation on GhPEL48_Dt, which contributes to the understanding of pectin degradation pathways and establishes a theoretical foundation for elucidating its regulatory mechanism. Full article

Potassium (K) is an essential nutrient for the growth and development of plants. Root hairs are the main parts of plants that absorb K⁺. The regulation of plant root hair growth in response to a wide range of environmental stresses is crucially associated with the dynamics of actin filaments, and the thick actin bundles at the apical and sub-apical regions are essential for terminating the rapid elongation of root hair cells. However, the dynamics and roles of actin filaments in root hair growth in plants’ response to low K⁺ stress are not fully understood. Here, we revealed that root hairs grow faster and longer under low K⁺ stress than the control conditions. Compared to control conditions, the actin filaments in the sub-apex of fast-growing wild-type root hairs were longer and more parallel under low K⁺ stress, which correlates with an increased root hair growth rate under low K⁺ stress; the finer actin filaments in the sub-apex of the early fully grown Col-0 root hairs under low K⁺ stress, which is associated with low K⁺ stress-induced root hair growth time. Further, Arabidopsis thaliana actin bundling protein Villin1 (VLN1) and Villin4 (VLN4) was inhibited and induced under low K⁺ stress, respectively. Low K⁺ stress-inhibited VLN1 led to decreased bundling rate and thick bundle formation in the early fully grown phase. Low K⁺ stress-induced VLN4 functioned in keeping long filaments in the fast-growing phase. Furthermore, the analysis of genetics pointed out the involvement of VLN1 and VLN4 in the growth of root hairs under the stress of low potassium levels in plants. Our results provide a basis for the dynamics of actin filaments and their molecular regulation mechanisms in root hair growth in response to low K⁺ stress. Full article

Weeds are a serious threat to crop production, and the utilization of secondary metabolites of phytopathogenic fungi is considered to be an effective method of weed control. In this study, eight compounds were isolated and purified from the mycelium and fermentation broth extracts of Bipolaris cookei SYBL03. The compounds (1–8), except 2 and 6, are reported for the first time from this genus. The herbicidal activities of compounds 1–8 were studied by evaluating their effects on the seed germination and seedling growth of monocotyledonous and dicotyledonous weeds. The results indicated that compound 7 (Cyclo-N-methylphenylalanyltryptophenyl, cNMPT) exhibited a concentration-dependent dual effect on the growth of weed seedlings and selective herbicidal activity against dicotyledonous weeds. We further investigated the morphological and physiological responses of roots of Amaranthus retroflexus, a dicotyledonous weed, to compound 7. Some changes were found in seedlings grown in 400 μg/mL compound 7 solution for 96 h, such as shortening and swelling of elongation zone cells, reduced number and length of root hairs, damage and wrinkling of the root surface, occurrence of electrolyte leakage, and an increase in ethylene content. These results suggest that compound 7 may exert herbicidal activity by causing stress to weed seedlings. Increased ethylene production could be involved in the response of plants to compound 7. Full article

The nematode family Aphelenchoididiae is considered fungal-feeding, predatory, or root hair feeders. Some members of this family are universally present in agricultural landscapes and are an integral part of soil health and conservation studies. In the present soil nematode biodiversity survey, we detected four species of the genera Aphelenchus, Aphelenchoides, and Robustodorus. Because fungal-feeding nematodes from southern Alberta have not previously been reported, we conducted a detailed morphological and molecular investigation, identifying these species as Aphelenchus avenae, Aphelenchoides limberi, Aphelenchoides prairiensis n. sp. and Robustodorus paramegadorus n. sp. The first two species we document as new records from southern Alberta, whereas A. prairiensis n. sp. and R. paramegadorus n. sp. we describe in detail as new taxa. Briefly, A. prairiensis n. sp. is an amphimictic species having 4 lateral lines; hemispherical anteriorly flattened lip region; delicate stylet and swelling-like stylet knobs; excretory pore at the posterior edge of nerve ring. Female tail conical, gradually tapering towards a truncated end with single mucro. Spicule 23.0 (20.0–25.0) µm long having elongated rounded condylus, small, blunt conical rostrum, and lamina that gradually tapers towards the rounded distal end; three pairs of caudal papillae were present on the male tail. Robustodorus paramegadorus n. sp., is a parthenogenetic species with 3 lines in the lateral fields; lip region rounded, anteriorly flattened; stylet robust, with knobs rounded to bean-shaped; excretory pore located posterior to nerve ring; reproductive components were quite indiscernible with a short 24.0 (18.0–27.0) µm post-vulval uterine sac; tail conical, ending with pointed to wedge-shaped tip. We performed molecular characterizations for each species and constructed phylogenetic trees to study the phylogenetic relationship of these aphelenchid species. The discovery of A. prairiensis n. sp. and R. paramegadorus n. sp. indicates that soil nematode diversity is relatively unexplored in southern Alberta. The findings of this study will significantly enhance the identification processes and may contribute towards future soil health and biodiversity efforts. Full article

The tap water that we normally use contains certain concentrations of free residual chlorine to kill microorganisms and viruses and make it safe for use. Water containing free residual chlorine not only dries out our hair and skin but can also cause irritation and itching in some people—especially those with sensitive skin or reduced skin barrier function. We investigated the effects of free residual chlorine on cultured dorsal root ganglion neurons and cultured epidermal keratinocytes. First, we measured neurite length in cultured rat dorsal root ganglion neurons. Next, to evaluate the effects of chlorine on semaphorin 3A (Sema3A) and nerve growth factor (NGF) levels in cultured human epidermal keratinocytes, we used an enzyme-linked immunosorbent assay to measure NGF in the supernatant and polymerase chain reaction and Western blot to determine Sema3A and NGF levels. Chlorine elongated the neurite length and increased the number of projections in cultured rat dorsal root ganglion neurons. Although there were no changes in NGF mRNA or protein levels in the supernatant of cultured human epidermal keratinocytes in the presence of chlorine, Sema3A mRNA and protein levels decreased, and the ratio of Sema3A to NGF was also reduced. Full article

Ethylene, a gaseous phytohormone, is emerging as a central player in the intricate web of plant developmental processes from germination to senescence under optimal and stressed conditions. The presence of ethylene has been noted in different plant parts, including the stems, leaves, flowers, roots, seeds, and fruits. This review aims to provide a comprehensive overview of the regulatory impact of ethylene on pivotal plant developmental processes, such as cell division and elongation, senescence, abscission, fruit and flower development, root hair formation, chloroplast maturation, and photosynthesis. The review also encompasses ethylene biosynthesis and signaling: a snapshot of the regulatory mechanisms governing ethylene production. Understanding of the impact of ethylene’s regulatory functions on plant developmental processes has significant implications for agriculture, biotechnology, and our fundamental comprehension of plant biology. This review underscores the potential of ethylene to revolutionize plant development and crop management. Full article

(1) Background: Root hairs are specialized structures involved in water and plant nutrient uptake. They elongate from epidermal cells following a complex developmental program. ß-cyanoalanine synthase (CAS), which is mainly involved in hydrogen cyanide (HCN) detoxification in Arabidopsis thaliana, plays a role in root hair elongation, as evidenced by the fact that cas-c1 mutants show a severe defect in root hair shape. In addition to root hairs, CAS C1 is expressed in the quiescent center and meristem. (2) Methods: To identify its role in root hair formation, we conducted single-cell proteomics analysis by isolating root hair cells using Fluorescence-activated Cell Sorting (FACS) from wild-type and cas-c1 mutants. We also analyzed the presence of S-cyanylation, a protein post-translational modification (PTM) mediated by HCN and affecting cysteine residues and protein activity in proteins of wild type and cas-c1 mutants. (3) Results and Conclusions: We have found that the cas-c1 mutation has no visible effect on quiescent center or meristem root tissue, in both control and nutrient-deprivation conditions. We have identified more than 3900 proteins in root hairs and we have found that several proteins involved in root hair development, related to the receptor kinase FERONIA signaling and DNA methylation, are modified by S-cyanylation. Full article

MicroRNAs are a class of endogenous, non-coding, small-RNA molecules with important functions in plant development and stress response processes. Root systems are important because they allow plants to absorb nutrients and water from the soil and are fundamental for anchoring the plant and responding to environmental signals. However, the roles of miRNAs underlying root development remain poorly investigated in potato. In this research, small-RNA sequencing was performed to thoroughly detect underlying miRNAs and their roles in regulating root development between the early root (ER) stage and the mature root (MR) stage of potato roots. A total of 203 known and 137 novel miRNAs were obtained, and 64 differentially expressed miRNAs (DEMs) were identified between the ER and MR stages. The expression patterns of 12 DEMs were also determined via qRT-PCR. In addition, a mixed degradome library was constructed from the ER and the MR stages to identify the targets of the identified miRNAs, and 2400 target genes were verified to be the targets of 131 miRNAs. Based on target annotation, we identified that nine target genes of six DEMs were probably involved in potato root development, and eight targets of six DEMs were validated via 5’-RLM-RACE assays. These targets may participate in root development by regulating cell proliferation, root cultures (PGSC0003DMT400013837), root meristem growth (PGSC0003DMT400079970), root morphogenesis (PGSC0003DMT400040282), post-embryonic root development (PGSC0003DMT400021612), root hair elongation (PGSC0003DMT400034518), cell wall repair (PGSC0003DMT400074930), and auxin polar transport (PGSC0003DMT400079970), and by negatively regulating cell proliferation (PGSC0003DMT400009997) and cell growth (PGSC0003DMT400003464). The qRT-PCR analysis indicated that most miRNAs have opposing expression patterns to their targets. It is widely accepted that potato root development is regulated by miRNAs, among which stu-miR8006-p5-1ss9AT is substantially down-regulated during root development. We show here that the suppression of stu-miR8006-p5-1ss9AT led to an alteration in the potato root architecture and that it targeted auxin induction in the root culture protein 12-encoding gene that is potentially involved in the regulation of root development. In addition, the suppression of stu-miR8006-p5-1ss9AT led to a significant alteration in the potato root architecture. Altogether, our results might provide some useful insights into stu-miR8006-p5-1ss9AT and the crucial role that it plays in potato root development; they could also facilitate the molecular genetic breeding of potato. Full article

A bioassay study was conducted to determine the differences in the susceptibility of selected crops to simulated imazethapyr residues based on morphological and anatomical parameters. Sugar beet, white mustard, and rapeseed oil were found to be the most sensitive based on ED₅₀ values for the root length and the root fresh weight. Corn and sunflower were less sensitive, and wheat was the least sensitive. The measured anatomical parameters confirmed the different sensitivities of the tested plants, as evidenced by a shortening of the meristem and elongation zones, a reduction in the distance between the root tip and the absorption zone, and the distance between the root tip and the point where the primordium of the lateral root appears. An imazethapyr residue level equivalent to ED₂₀ (for root length) did not cause serious morphological changes in the less sensitive plants, nor did it cause significant changes in the length of the root cap, the beginning of the root absorption zone (root hair region), the beginning of lateral root formation (i.e., the permanent region), and the number of root primordia per root length. Therefore, ED₂₀ could be proposed as an acceptable residue level (ARL) or herbicide residue level at which these plants can be safely sown. Full article

Strigolactones (SLs) are a class of plant hormones and rhizosphere communication signals of great interest. They perform diverse biological functions including the stimulation of parasitic seed germination and phytohormonal activity. However, their practical use is limited by their low abundance and complex structure, which requires simpler SL analogues and mimics with maintained biological function. Here, new, hybrid-type SL mimics were designed, derived from Cinnamic amide, a new potential plant growth regulator with good germination and rooting-promoting activities. Bioassay results indicated that compound 6 not only displayed good germination activity against the parasitic weed O. aegyptiaca with an EC₅₀ value of 2.36 × 10⁻⁸ M, but also exhibited significant inhibitory activity against Arabidopsis root growth and lateral root formation, as well as promoting root hair elongation, similar to the action of GR24. Further morphological experiments on Arabidopsis max2-1 mutants revealed that 6 possessed SL-like physiological functions. Furthermore, molecular docking studies indicated that the binding mode of 6 was similar to that of GR24 in the active site of OsD14. This work provides valuable clues for the discovery of novel SL mimics. Full article