Root Elongation Research Articles

Synthetically derived BiAux modulates auxin co-receptor activity to stimulate lateral root formation.

The root system plays an essential role in plant growth and adaptation to the surrounding environment. The root clock periodically specifies lateral root prebranch sites (PBS), where a group of pericycle founder cells (FC) is primed to become lateral root founder cells and eventually give rise to lateral root primordia or lateral roots (LRs). This clock-driven organ formation process is tightly controlled by modulation of auxin content and signaling. Auxin perception entails the physical interaction of TRANSPORT INHIBITOR RESPONSE 1 (TIR1) or AUXIN SIGNALING F-BOX (AFBs) proteins with AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) repressors to form a co-receptor system. Despite the apparent simplicity, the understanding of how specific auxin co-receptors are assembled remains unclear. We identified the compound bis-methyl auxin conjugated with N-glucoside, or BiAux, in Arabidopsis (Arabidopsis thaliana) that specifically induces the formation of PBS and the emergence of LR, with a slight effect on root elongation. Docking analyses indicated that BiAux binds to F-box proteins, and we showed that BiAux function depends on TIR1 and AFB2 F-box proteins and AUXIN RESPONSE FACTOR 7 activity, which is involved in FC specification and LR formation. Finally, using a yeast (Saccharomyces cerevisiae) heterologous expression system, we showed that BiAux favors the assemblage of specific co-receptors subunits involved in LR formation and enhances AUXIN/INDOLE-3-ACETIC ACID 28 protein degradation. These results indicate that BiAux acts as an allosteric modulator of specific auxin co-receptors. Therefore, BiAux exerts a fine-tune regulation of auxin signaling aimed to the specific formation of LR among the many development processes regulated by auxin.

Allelopathic Effects of Ageratum conyzoides Root Exudates on Germinability of Selected Crops: A Comparative Analysis

This study investigates the allelopathic effects of aqueous root exudate extracts of Ageratum conyzoides on the germination, shoot length, and root length of various agricultural crops. The study reveals how different species respond uniquely to varying concentrations, uncovering complex dynamics in crop-allelopathic interactions. The germination analysis reveals distinct sensitivities among the tested crops. C. sativus demonstrates resilience, displaying minimal germination reduction even at higher exudate concentrations. C. arietinum exhibits moderate susceptibility, while Z. mays emerge as the most sensitive crop, displaying a profound reduction in germination. L. esculentum and P. vulgaris also exhibit sensitivity, with adverse impacts on germination rates. A. esculentus consistently shows reduced germination rates with increasing exudate concentrations. Shoot length dynamics show that all crops experience greatest elongation without A. conyzoides root exudates, suggesting inhibition of growth by these exudates. Shoot growth declines with higher exudate concentrations across most crops, with varying sensitivities. C. sativus consistently decreases, while C. arietinum, Z. mays, and P. vulgaris show concentration-dependent inhibition. S. lycopersicum significantly reduces shoot elongation, and A. esculentus remains consistently sensitive. Root length patterns further elucidate the allelopathic effects. Responses vary across species and concentrations. A. esculentus roots thrive at lower concentrations but decline at higher ones. S. lycopersicum shows initial reduction, significant decline, followed by recovery. Z. mays and C. arietinum exhibit fluctuating responses. P. vulgaris consistently grows, while C. sativus persistently displays reduced root elongation. These findings highlight the complex and species-specific allelopathic interactions between A. conyzoides and agricultural crops, emphasizing the need for a comprehensive understanding of these dynamics for effective crop management in A. conyzoides-infested areas.

Identification and characterization of candidate genes for primary root length in Asiatic cotton (Gossypium arboreum L.).

One major gene controlling primary root length (PRL) in Gossypium arboreum is identified and this research provides a theoretical basis for root development for cotton. Primary root elongation is an essential process in plant root system structure. Here, we investigated the primary root length (PRL) of 215 diploid cotton (G. arboreum) accessions at 5, 8, 10, 15days after sowing. A Genome-wide association study was performed for the PRL, resulting in 49 significant SNPs associated with 32 putative candidate genes. The SNP with the strongest signal (Chr07_8047530) could clearly distinguish the PRLs between accessions with two haplotypes. GamurG is the only gene that showed higher relative expression in the long PRL genotypes than the short PRL genotypes, which indicated it was the most likely candidate gene for regulating PRL. Moreover, the GamurG-silenced cotton seedlings showed a shorter PRL, while the GamurG-overexpressed Arabidopsis exhibited a significantly longer PRL. Our findings provide insight into the regulation mechanism of cotton root growth and will facilitate future breeding programs to optimize the root system structure in cotton.

Reshaped DNA methylation cooperating with homoeolog-divergent expression promotes improved root traits in synthesized tetraploid wheat.

Polyploidization is a major event driving plant evolution and domestication. However, how reshaped epigenetic modifications coordinate gene transcription to generate phenotypic variations during wheat polyploidization is currently elusive. Here, we profiled transcriptomes and DNA methylomes of two diploid wheat accessions (SlSl and AA) and their synthetic allotetraploid wheat line (SlSlAA), which displayed elongated root hair and improved root capability for nitrate uptake and assimilation after tetraploidization. Globally decreased DNA methylation levels with a reduced difference between subgenomes were observed in the roots of SlSlAA. DNA methylation changes in first exon showed strong connections with altered transcription during tetraploidization. Homoeolog-specific transcription was associated with biased DNA methylation as shaped by homoeologous sequence variation. The hypomethylated promoters showed significantly enriched binding sites for MYB, which may affect gene transcription in response to root hair growth. Two master regulators in root hair elongation pathway, AlCPC and TuRSL4, exhibited upregulated transcription levels accompanied by hypomethylation in promoter, which may contribute to the elongated root hair. The upregulated nitrate transporter genes, including NPFs and NRTs, also are significantly associated with hypomethylation, indicating an epigenetic-incorporated regulation manner in improving nitrogen use efficiency. Collectively, these results provided new insights into epigenetic changes in response to crop polyploidization and underscored the importance of epigenetic regulation in improving crop traits.

Pseudomonas putida configures Arabidopsis root architecture through modulating the sensing systems for phosphate and iron acquisition

Iron (Fe) and phosphate (Pi) are two essential nutrients that are poorly available in the soil and should be supplemented either as fertilizers or organic amendments to sustain crop production. Currently, determining how rhizosphere bacteria contribute to plant mineral nutrient acquisition is an area of growing interest regarding its potential application in agriculture. The aim of this study was to investigate the influence of root colonization by Pseudomonas putida for Arabidopsis growth through Fe and Pi nutritional signaling. We found that root colonization by the bacterium inhibits primary root elongation and promotes the formation of lateral roots. These effects could be related to higher expression of two Pi starvation-induced genes and AtPT1, the major Pi transporter in root tips. In addition, P. putida influenced the accumulation of Fe in the root and the expression of different elements of the Fe uptake pathway. The loss of function of the protein ligase BRUTUS (BTS), and the bHLH transcription factors POPEYE (PYE) and IAA-LEUCINE RESISTANT3 (ILR3) compromised the root branching stimulation triggered by bacterial inoculation while the leaf chlorosis in the fit1 and irt1–1 mutant plants grown under standard conditions could be bypassed by P. putida inoculation. The WT and both mutant lines showed similar Fe accumulation in roots. P. putida repressed the expression of the IRON-REGULATED TRANSPORTER 1 (IRT1) gene suggesting that the bacterium promotes an alternative Fe uptake mechanism. These results open the door for the use of P. putida to enhance nutrient uptake and optimize fertilizer usage by plants.

The MYC2–PUB22–JAZ4 module plays a crucial role in jasmonate signaling in tomato

Jasmonates (JAs), a class of lipid-derived stress hormones, play a crucial role across an array of plant physiological processes and stress responses. Although JA signaling is thought to rely predominantly on the degradation of specific JAZ proteins by SCFCOI1, it remains unclear whether other pathways are involved in the regulation of JAZ protein stability. Here, we report that PUB22, a plant U-box type E3 ubiquitin ligase, plays a critical role in the regulation of plant resistance against Helicoverpa armigera and other JA responses in tomato. Whereas COI1 physically interacts with JAZ1/2/5/7, PUB22 physically interacts with JAZ1/3/4/6. PUB22 ubiquitinates JAZ4 to promote its degradation via the 26S proteasome pathway. Importantly, we observed that pub22 mutants showreduced resistance to H. armigera, whereas jaz4 single mutants and jaz1 jaz3 jaz4 jaz6 quadruple mutants have enhanced resistance. The hypersensitivity of pub22 mutants to herbivores could be partially rescued by JAZ4 mutation. Moreover, we found that expression of PUB22 can be transcriptionally activated by MYC2, thus forming a positive feedback circuit in JA signaling. We noticed that the PUB22–JAZ4 module also regulates other JA responses, including defense against B. cinerea, inhibition of root elongation, and anthocyanin accumulation. Taken together, these results indicate that PUB22 plays a crucial role in plant growth and defense responses, together with COI1-regulated JA signaling, by targeting specific JAZs.

Morpho-Anatomical Modulation of Seminal Roots in Response to Water Deficit in Durum Wheat (Triticum turgidum var. durum).

The productivity of durum wheat in Mediterranean regions is greatly reduced by water deficits that vary in intensity and time of occurrence. The development of more tolerant cultivars is the main solution for fighting these stresses, but this requires prior study of their mechanisms. The involvement of the root system in drought avoidance is of major importance. It is in this context that the present work attempts to establish the impact of morpho-anatomical remodeling of seminal roots on dehydration avoidance at the javelina stage in five durum wheat genotypes grown under three water regimes, 100%, 60% and 30% of field capacity (FC). In the last two treatments, which were applied by stopping irrigation, moisture was concentrated mainly in the depths of the substrate cylinders and was accompanied by greater root elongation compared with the control. The elongation reached rates of 20 and 22% in the ACSAD 1231 genotype and 12 and 13% in the Waha genotype, in the 60% FC and 30% FC treatments respectively. The seminal roots anatomy was also modified by water deficit in all genotypes but to different degrees. The diameter of vessels in the late metaxylem vessels was reduced, reaching 17.3 and 48.2% in the Waha genotype in the 60% FC and 30% FC treatments, respectively. The water deficit also increased the number of vessels in the early metaxylem, while reducing the diameter of its conducting vessels. ACSAD 1361 and Langlois genotypes stood out with the highest rates of diameter reduction. The morpho-anatomical transformations of the roots contributed effectively to the plants' absorption of water and, consequently, to the maintenance of a fairly high relative water content, approaching 80%.

Genome-wide analysis of PvMADS in common bean and functional characterization of PvMADS31 in Arabidopsis thaliana as a player in abiotic stress responses.

Changing climatic conditions with rising temperatures and altered precipitation patterns pose significant challenges to agricultural productivity, particularly for common bean crops. Transcription factors (TFs) are crucial regulators that can mitigate the impact of biotic and abiotic stresses on crop production. The MADS-box TFs family has been implicated in various plant physiological processes, including stress-responsive mechanisms. However, their role in common bean and their response to stressful conditions remain poorly understood. Here, we identified 35 MADS-box gene family members in common bean, with conserved MADS-box domains and other functional domains. Gene duplication events were observed, suggesting the significance of duplication in the evolutionary development of gene families. The analysis of promoter regions revealed diverse elements, including stress-responsive elements, indicating their potential involvement in stress responses. Notably, PvMADS31, a member of the PvMADS-box gene family, demonstrated rapid upregulation under various abiotic stress conditions, including NaCl, polyethylene glycol, drought, and abscisic acid (ABA) treatments. Transgenic plants overexpressing PvMADS31 displayed enhanced lateral root development, root elongation, and seed germination under stress conditions. Furthermore, PvMADS31 overexpression in Arabidopsis resulted in improved drought tolerance, likely attributed to the enhanced scavenging of ROS and increased proline accumulation. These findings suggest that PvMADS31 might play a crucial role in modulating seed germination, root development, and stress responses, potentially through its involvement in auxin and ABA signaling pathways. Overall, this study provides valuable insights into the potential roles of PvMADS-box genes in abiotic stress responses in common bean, offering prospects for crop improvement strategies to enhance resilience under changing environmental conditions.

Acceleration of Composting by Addition of Clinker to Tea Leaf Compost

The disposal of tea leaves discarded in the tea beverage market and clinker from coal-fired power plants has an impact on the environment; however, there are no reported cases of their combination for composting. Therefore, this study evaluated the effect of adding clinker from a coal-fired power plant to compost based on tea leaves, an organic waste product, on the composting rate and quality. The tea leaves-only compost was designated as Clinker 0%, and composts with 20% (w/w), 40% (w/w), and 60% (w/w) tea leaves supplemented with clinker were designated as Clinker 20, 40, and 60%, respectively. Each mixed material was placed in a 35 L polypropylene container with a lid and allowed to compost for 95 days. The composting rate was evaluated by the chemical oxygen demand (COD) in hot water extract and plant tests using juvenile komatsuna (Brassica rapa var. perviridis). The addition of clinker reduced the COD at the beginning of composting by 52.0, 74.3, and 86.7% in Clinker 20, 40, and 60%, respectively, compared to Clinker 0%. Furthermore, root elongation one month after composting was inhibited by Clinker 0% (60.1% relative to distilled water), but not by the addition of clinker (91.7–102.7% relative to distilled water). This suggests that the addition of clinker to tea leaf compost may accelerate composting.

Auxin acts upstream of nitric oxide to regulate cell wall xyloglucan and its aluminium-binding capacity in Arabidopsis thaliana.

Auxin acts upstream of NO through NOA and XXT5 pathways to regulate the binding capacity of the root cell wall to Al. In our previous study, we identified an unknown mechanism by which 1-naphthaleneacetic acid (NAA) decreased the fixation of aluminum (Al) in the cell wall. Here, we observed that external application of the nitric oxide (NO) donor S-nitrosoglutathion (GSNO) increased the inhibition of Al on root elongation. Further analysis indicated that GSNO could induce Al accumulation in the roots and root cell walls, which is consistent with lower xyloglucan content. In comparison to the Columbia-0 (Col-0) wild type (WT), endogenous NO-reduced mutants noa1 (NOA pathway) and nia1nia2 (NR pathway) were more resistant to Al, with lower root Al content, higher xyloglucan content, and more Al accumulation in the root cell walls. By contrast, the xxt5 mutant with reduced xyloglucan content exhibited an Al-sensitive phenotype. Interestingly, Al treatment increased the endogenous auxin and NO levels, and the auxin levels induced under Al stress further stimulated NO production. Auxin application reduced Al retention in hemicellulose and decreased the xyloglucan content, similar to the effects observed with GSNO. In yucca and aux1-7 mutants, exogenous application of NO resulted in responses similar to those of the WT, whereas exogenous auxin had little effect on the noa1 mutant under Al stress. In addition, as auxin had similar effects on the nia1nia2 mutant and the WT, exogenous auxin and NO had little effect on the xxt5 mutant under Al stress, further confirming that auxin acts upstream of NO through NOA and XXT5 pathways to regulate the binding capacity of the root cell wall to Al.

Fibroblast growth factor signalling regulates the development of tooth root.

Fibroblast growth factor (FGF) signalling plays a crucial role in the morphogenesis of multiple tissues including teeth. While the role of the signal has been studied in tooth crown development, little is known about root development. Of several FGF ligands involved in hard tissue formation, we suggest that FGF18 regulates the development of murine tooth roots. We implanted FGF18-soaked heparin beads into the lower first molar tooth buds at postnatal day 6 (P6), followed by transplantation under the kidney capsule. After 3 weeks, FGF18 significantly facilitated root elongation and periodontal tissue formation compared to the control. Insitu hybridisation showed that Fgf18 transcripts were initially localised in the dental pulp along Hertwig's epithelial root sheath at P6 and P10 and subsequently in the dental follicle cells at P14. Fgf receptors were expressed in various dental tissues during these stages. Invitro analysis using the dental pulp stem cells revealed that FGF18 inhibited cell proliferation and decreased expression levels of osteogenic markers, Runx2, Alpl and Sp7. Consistently, after 1 week of kidney capsule transplantation, FGF18 application did not induce the expression of Sp7 and Bsp, but upregulated Periostin in the apical region of dental mesenchyme in the grafted molar. These findings suggest that FGF18 facilitates molar root development by regulating the calcification of periodontal tissues.

Proteomic profiling of an extreme halophyte Schrenkiella parvula with accelerated root elongation under mild salt stress.

Increased salinity in soil is one of the impacts of climate change and a major problem for crop cultivation. Halophytes have the ability to survive in hypersaline environments, and investigating their adaptation mechanisms is effective in imparting salt tolerance to plants. Recently, we discovered a strategy by the extreme halophyte Schrenkiella parvula to promote primary root elongation, a morpho-physiological response that may be given to have access to groundwater sources, while reducing meristem DNA replication, root hair development, and biomass at moderate salinities around 100 mM NaCl. However, when NaCl concentration exceeds 200 mM, seedling root elongation is inhibited, and seedlings change to respond to severe stress induced by salinity. To understand the interesting physiological and molecular mechanisms underlying primary root elongation at moderate salinity, we performed a proteomic analysis using two-dimensional gel electrophoresis and MALDI-TOF MS. Ultimately, a total of 300 different proteins were identified, of which 20 showed significant increases and 25 showed significant decreases at 100 mM NaCl. Among the increased proteins, proteins responding to abiotic stress such as glutathione transferases were found, and among the decreased proteins, proteins involved in glycolysis, purine nucleotide synthesis, and protein synthesis were found. Accumulation levels of proline, an osmotic regulator that inhibits root growth, were lower in S. parvula than in A. thaliana. On the other hand, interestingly, the expression levels of fructose-bisphosphate aldolase, sucrose phosphatase, and α-subunit of acetyl-CoA carboxylase increased. In addition, increases in P5CDH, an enzyme in the proline catabolism process, and decreases in GLN and GDH in glutamate synthesis in S. parvula suggest that these may lead to a fine-tuning of proline content. For annexins, a family of calcium-binding and membrane-bound proteins that regulate plant tolerance, moderate salt treatment showed a significant decrease in SpANN7, a non-significant downtrend for SpANN2, but no change for SpANN1. These findings suggest that the 100 mM NaCl does not create a serious stress for S. parvula. We also performed gene expression analysis of these altered proteins between S. parvula and A. thaliana. Taken together, in S. parvula roots, 100 mM NaCl partially induced the redox homeostasis system, stress response, and proline-mediated osmoregulation, moderately suppressing carbon metabolism, nucleotide, and protein synthesis to accelerate primary root elongation.

Cone Beam Computed Tomography (CBCT) Aid in the Management of Apical Root Resorption of Impacted Maxillary Canines and Physiologically Erupted Maxillary Canines after Orthodontic Treatment

The aim of this study is to evaluate the effects of orthodontic traction, by means of light and controlled forces, on root length in impacted maxillary canines and physiologically erupted maxillary canines. Disinclusion of impacted maxillary canines is a frequent procedure in orthodontics due to their higher incidence of impaction. The effects of orthodontic traction, by means of light and controlled forces, can lead to a resorption of the root length in impacted and physiologically erupted teeth. Therefore, apical root resorption is a common phenomenon that must be taken into consideration. Apical root resorption measurements were taken using pre-treatment CBCTs and pre-treatment and post-treatment digital panoramic radiographs of 52 patients who underwent fixed-appliance treatment by using light and controlled orthodontic forces. The experimental group consisted of 26 patients with one impacted maxillary canine. The control group consisted of 26 patients without any impaction. Apical root resorption was calculated from root lengths before and after orthodontic treatment. In the experimental group, impacted canines with incomplete apical formation underwent root elongation, while impacted canines with completed root formation went through apical root resorption. The latter showed a slightly greater apical root resorption (0.2 mm) compared to the control group (95% confidence interval; p = 0.04). The extent of root resorption of impacted canines was significantly higher than that of physiologically erupted ones. However, this differential resorption did not compromise the structural and functional integrity of the involved teeth. The orthodontic treatment performed with light and controlled forces is, therefore, a procedure to be considered acceptable and safe.

Exploring the synergistic effects of goethite intercalated coal in the presence of humic acids for enhanced growth of Sinapis alba

BackgroundIron oxide mineral–humic complexes serve as a reservoir of bioavailable Fe for plants, releasing metal ligands and providing Fe–humic complexes directly usable by plant Fe-uptake mechanisms. In this study, we synthesized and characterized goethite α-FeOOH (G) nanoparticles (NPs) intercalated in coal (GC) to estimate the bioactivity effect of humic acids (HA). The synthesized GC NPs were characterized by X-ray diffraction, scanning electron microscopy (SEM), Mössbauer spectroscopy, N2 adsorption–desorption Brunauer–Emmett–Teller (BET) specific surface area, zeta potential, hydrodynamic particle diameter, iron ions release, and a phytoassay method of root elongation using the higher plant Sinapis alba.ResultsX-ray diffraction revealed that G was the primary phase in both GC and GC–HA complexes. Mössbauer spectroscopy analysis identified a goethite-doped Fe2+-in the GC samples. The intercalation of G into the coal matrix increased the specific surface area of GC, enhancing its HA sorption capacity. In addition, GC–HA demonstrated superior plant growth stimulation compared to HA and GC alone, indicating its role in colloidal stability. In contrast to GC, GC–HA exhibited a more consistent and time-dependent release of Fe3+ and Fe2+. This sustained Fe release from GC–HA, coupled with the formation of Fe3+ and more bioavailable (soluble) Fe2+ humic complexes is a promising result in terms of iron nanofertilizers production.ConclusionsThe use of goethite nanoparticles intercalated within a coal matrix and subsequently complexed with HA contributes to prolonged phytoactivity by employing slowly released nutrient additives within the coal mesoporous matrix.Graphical

Phototropin2 3’UTR overlaps with the AT5G58150 gene encoding an inactive RLK kinase

BackgroundThis study examines the biological implications of an overlap between two sequences in the Arabidopsis genome, the 3’UTR of the PHOT2 gene and a putative AT5G58150 gene, encoded on the complementary strand. AT5G58150 is a probably inactive protein kinase that belongs to the transmembrane, leucine-rich repeat receptor-like kinase family. Phot2 is a membrane-bound UV/blue light photoreceptor kinase. Thus, both proteins share their cellular localization, on top of the proximity of their loci.ResultsThe extent of the overlap between 3’UTR regions of AT5G58150 and PHOT2 was found to be 66 bp, using RACE PCR. Both the at5g58150 T-DNA SALK_093781C (with insertion in the promoter region) and 35S::AT5G58150-GFP lines overexpress the AT5G58150 gene. A detailed analysis did not reveal any substantial impact of PHOT2 or AT5G58150 on their mutual expression levels in different light and osmotic stress conditions. AT5G58150 is a plasma membrane protein, with no apparent kinase activity, as tested on several potential substrates. It appears not to form homodimers and it does not interact with PHOT2. Lines that overexpress AT5G58150 exhibit a greater reduction in lateral root density due to salt and osmotic stress than wild-type plants, which suggests that AT5G58150 may participate in root elongation and formation of lateral roots. In line with this, mass spectrometry analysis identified proteins with ATPase activity, which are involved in proton transport and cell elongation, as putative interactors of AT5G58150. Membrane kinases, including other members of the LRR RLK family and BSK kinases (positive regulators of brassinosteroid signalling), can also act as partners for AT5G58150.ConclusionsAT5G58150 is a membrane protein that does not exhibit measurable kinase activity, but is involved in signalling through interactions with other proteins. Based on the interactome and root architecture analysis, AT5G58150 may be involved in plant response to salt and osmotic stress and the formation of roots in Arabidopsis.

Metabolic Adaptations in Rapeseed: Hemin-Induced Resilience to NaCl Stress by Enhancing Growth, Photosynthesis, and Cellular Defense Ability.

This study aimed to investigate whether presoaking with hemin (5 μmol·L-1) could alleviate NaCl stress during rapeseed seedlings' growth and its role in the regulation of photosynthesis. In this experiment, 'HUAYOUZA 62 (HYZ 62)' and 'HUAYOUZA 158R (158R)' were used as materials for pot experiments to study the morphology, photosynthetic characteristics, antioxidant activity, and osmoregulatory factors of seedlings under different salt concentrations, as well as the regulatory effects of hemin-presoaked seeds. Our findings revealed that, compared the control, NaCl stress inhibited the growth of two rapeseed varieties, decreased the seedling emergence rate, and increased the content of malondialdehyde (MDA), the electrolyte leakage rate (EL) and antioxidant enzyme activity. Hemin soaking alleviated the adverse effects of salt stress and increased plant height, root elongation and dry matter accumulation. Compared with all NaCl treatments, hemin significantly enhanced photosynthetic indexes, including a percent increase of 12.99-24.36% and 5.39-16.52% in net photosynthetic rate (Pn), 17.86-48.08% and 8.6-23.44% in stomatal conductivity (Gs), and 15.42-37.94% and 11.09-19.08% in transpiration rate (Tr) for HYZ62 and 158R, respectively. Moreover, hemin soaking also increased antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), reducing the malondialdehyde, and thus resulting in the alleviation of oxidative damage caused by NaCl stress. Furthermore, hemin stimulated the formation of soluble protein, which effectively regulated the osmo-protective qualities. The current findings strongly elucidate that hemin soaking could effectively alleviate the negative impacts of NaCl stress by regulating the morphological, photosynthetic, and antioxidant traits. This study provides a new idea regarding the effect of Hemin on the salt tolerance of rapeseed, and provides a basis for the practical application of Hemin in saline-alkali soil to improve the salt tolerance of cultivated rapeseed.

Alkaline Invertase 2 positively modulates cold adaptive of Camellia sinensis and enhances freezing and salt tolerance in transgenic Arabidopsis thaliana

Alkaline/neutral invertase (A/N-Inv) is a type of hydrolases that irreversibly hydrolyze sucrose into glucose and fructose, thus participating in the plant morphogenesis and stress responses. In tea plant, a putative A/N-Inv gene, CsINV2, mediated the abiotic stress responses of tea plant, but the detailed molecular mechanism has not been elucidated yet. In this study, CsINV2 was verified as an alkaline invertase that can split sucrose into glucose and fructose in vitro, which showed the optimal catalytic activity at 45 °C and pH 8 conditions. Besides, the high transcription of CsINV2 contributed to improving the cold adaptation of tea plant, while silencing of CsINV2 reduced cold adaptive of tea plant. Overexpression of CsINV2 improved freezing tolerance of transgenic Arabidopsis by improving A/N-Inv activity, glucose content, hexose/sucrose ratio, and also via a feedback regulation pathway. Meanwhile, overexpression of CsINV2 promoted gemination rate and root elongation of transgenic Arabidopsis under salt stress condition. Finally, a cold-induced transcription factor CsAHL17 was confirmed to interact with the promoter of CsINV2, silencing of CsAHL17 reduced the transcription of CsINV2 both under 25 °C and 4 °C conditions. In summary, it can draw a conclusion that CsINV2 regulates the cold resistance of tea plant by influencing the contents of different soluble sugar components under the regulation of CsAHL17. This study will further promote the understanding to the role of invertase in tea plants.

Upregulation of Wheat Heat Shock Transcription Factor TaHsfC3-4 by ABA Contributes to Drought Tolerance.

Drought stress can seriously affect the yield and quality of wheat (Triticum aestivum). So far, although few wheat heat shock transcription factors (Hsfs) have been found to be involved in the stress response, the biological functions of them, especially the members of the HsfC (heat shock transcription factor C) subclass, remain largely unknown. Here, we identified a class C encoding gene, TaHsfC3-4, based on our previous omics data and analyzed its biological function in transgenic plants. TaHsfC3-4 encodes a protein containing 274 amino acids and shows the basic characteristics of the HsfC class. Gene expression profiles revealed that TaHsfC3-4 was constitutively expressed in many tissues of wheat and was induced during seed maturation. TaHsfC3-4 could be upregulated by PEG and abscisic acid (ABA), suggesting that this Hsf may be involved in the regulation pathway depending on ABA in drought resistance. Further results represented that TaHsfC3-4 was localized in the nucleus but had no transcriptional activation activity. Notably, overexpression of TaHsfC3-4 in Arabidopsis thaliana pyr1pyl1pyl2pyl4 (pyr1pyl124) quadruple mutant plants complemented the ABA-hyposensitive phenotypes of the quadruple mutant including cotyledon greening, root elongation, seedling growth, and increased tolerance to drought, indicating positive roles of TaHsfC3-4 in the ABA signaling pathway and drought tolerance. Furthermore, we identified TaHsfA2-11 as a TaHsfC3-4-interacting protein by yeast two-hybrid (Y2H) screening. The experimental data show that TaHsfC3-4 can indeed interact with TaHsfA2-11 in vitro and in vivo. Moreover, transgenic Arabidopsis TaHsfA2-11 overexpression lines exhibited enhanced drought tolerance, too. In summary, our study confirmed the role of TaHsfC3-4 in response to drought stress and provided a target locus for marker-assisted selection breeding to improve drought tolerance in wheat.

Phytotoxic phenols from the needles of Cedrus deodara

During the course of screening for anti-seed germination phytochemicals, the methanol fraction of the Cedrus deodara fresh needles showed potent activity. Bioactivity-guided fractionation led to the isolation of thirty-eight phenolic compounds. Four ones were identified as previously undescribed including (7S,8S)-3-methoxy-9′-acetoxy-3′,7-epoxy-8,4′-oxyneoligna-4,9-diol (7), (7S,8R)-dihydro-3′-hydroxy-8-acetoxymethyl-7-(4-hydroxy-3-methoxy-phenyl)-1′-benzofuranpropanol (10), (8S)-4,9,9′-trihydroxy-3,3′-dimethoxy-8,4′-oxyneolignan (11) and (7S,8S)-4,7,9′-trihydroxy-3,3′-dimethoxy-9-acetoxy-8,4′-oxyneolignan (16), respectively. The potential phytotoxic effects of these compounds on the seed germination and root elongation of Arabidopsis thaliana were evaluated by the filter paper assay developed in our laboratory. Bioassay results indicated that caffeic acid (36) displayed most significant inhibitory activities against the seed germination and root elongation of A. thaliana, stronger than those of the commercial herbicides acetochlor and glyphosate at the same concentration of 200 μg/mL. Ditetrahydrofuran lignan (1), dihydrochalcone (25), and eight simple phenols (28, 29, 31, 33–35, 37 and 38) completely inhibited the seed germination of A. thaliana at the concentration of 400 μg/mL, which were as active as acetochlor. Dihydroflavone (21) and the simple phenols 32–34 displayed stronger inhibitory effects on the root elongation of A. thaliana than that of glyphosate. The inhibitory effects of these active compounds on the seed germination and root elongation of Amaranthus tricolor and Lactuca sativa were evaluated as well. The phytotoxic activity of 11, 16, 22, 25, 31, 34, 37 and 38 were detected for the first time. In addition, the structure-activity relationships of the same class of these phytochemicals were discussed.

In-vivo and in-silico studies to identify toxicity mechanisms of permethrin with the toxicity-reducing role of ginger.

In this study, the toxic effects of permethrin on Allium cepa L. and the protective role of Zingiber officinale rhizome extract (Zoex) were investigated. In this context, 6 different groups were formed. While the control group was treated with tap water, the groups II and III were treated with 10µg/mL and 20µg/mL Zoex, respectively, and the group IV was treated with 100µg/L permethrin. The protective effect of Zoex against permethrin toxicity was studied as a function of dose, and groups V and VI formed for this purpose were treated with 10µg/mL Zoex + 100µg/L permethrin and 20µg/mL Zoex + 100µg/L permethrin, respectively. After 72h of germination, cytogenetic, biochemical, physiological, and anatomical changes in meristematic cells of A. cepa were studied. As a result, permethrin application decreased the mitotic index (MI) and increased the frequency of micronuclei (MN), and chromosomal abnormalities. The increase in malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) and the decrease in glutathione (GSH) indicate that permethrin causes oxidative damage. Compared to the control group, a 68.5% decrease in root elongation (p < 0.05) and an 81.8% decrease (p < 0.05) in weight gain were observed in the permethrin-treated group. It was found that the application of Zoex together with permethrin resulted in regression of all detected abnormalities, reduction in the incidence of anatomical damage, MN and chromosomal aberrations, and improvement in MI rates. The most significant improvement was observed in group VI treated with 20µg/mL Zoex, and Zoex was also found to provide dose-dependent protection. The toxicity mechanism of permethrin was also elucidated by molecular docking and spectral studies. From the data obtained during the study, it was found that permethrin has toxic effects on A. cepa, a non-target organism, while Zoex plays a protective role by reducing these effects.