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BMC Plant Biology Jun 2024Light deficit in shaded environment critically impacts the growth and development of turf plants. Despite this fact, past research has predominantly concentrated on...
BACKGROUND
Light deficit in shaded environment critically impacts the growth and development of turf plants. Despite this fact, past research has predominantly concentrated on shade avoidance rather than shade tolerance. To address this, our study examined the photosynthetic adjustments of Bermudagrass when exposed to varying intensities of shade to gain an integrative understanding of the shade response of C4 turfgrass.
RESULTS
We observed alterations in photosynthetic pigment-proteins, electron transport and its associated carbon and nitrogen assimilation, along with ROS-scavenging enzyme activity in shaded conditions. Mild shade enriched Chl b and LHC transcripts, while severe shade promoted Chl a, carotenoids and photosynthetic electron transfer beyond Q (ET/RC, φE, Ψ). The study also highlighted differential effects of shade on leaf and root components. For example, Soluble sugar content varied between leaves and roots as shade diminished SPS, SUT1 but upregulated BAM. Furthermore, we observed that shading decreased the transcriptional level of genes involving in nitrogen assimilation (e.g. NR) and SOD, POD, CAT enzyme activities in leaves, even though it increased in roots.
CONCLUSIONS
As shade intensity increased, considerable changes were noted in light energy conversion and photosynthetic metabolism processes along the electron transport chain axis. Our study thus provides valuable theoretical groundwork for understanding how C4 grass acclimates to shade tolerance.
Topics: Photosynthesis; Cynodon; Acclimatization; Plant Leaves; Electron Transport; Gene Expression Regulation, Plant; Nitrogen; Plant Roots; Plant Proteins; Chlorophyll
PubMed: 38902617
DOI: 10.1186/s12870-024-05242-x -
The Science of the Total Environment Jun 2024Soil contamination by heavy metals represents an important environmental and public health problem of global concern. Biocrust-forming cyanobacteria offer promise for...
Soil contamination by heavy metals represents an important environmental and public health problem of global concern. Biocrust-forming cyanobacteria offer promise for heavy metal immobilisation in contaminated soils due to their unique characteristics, including their ability to grow in contaminated soils and produce exopolysaccharides (EPS). However, limited research has analysed the representativeness of cyanobacteria in metal-contaminated soils. Additionally, there is a lack of studies examining how cyanobacteria adaptation to specific environments can impact their metal-binding capacity. To address this research gap, we conducted a study analysing the bacterial communities of cyanobacteria-dominated biocrusts in a contaminated area from South Sardinia (Italy). Additionally, by using two distinct approaches, we isolated three Nostoc commune strains from cyanobacteria-dominated biocrust and we also evaluated their potential to immobilise heavy metals. The first isolation method involved acclimatizing biocrust samples in liquid medium while, in the second method, biocrust samples were directly seeded onto agar plates. The microbial community analysis revealed Cyanobacteria, Bacteroidota, Proteobacteria, and Actinobacteria as the predominant groups, with cyanobacteria representing between 13.3 % and 26.0 % of the total community. Despite belonging to the same species, these strains exhibited different growth rates (1.1-2.2 g L of biomass) and capacities for EPS production (400-1786 mg L). The three strains demonstrated a notable ability for metal immobilisation, removing up to 88.9 % of Cu, 86.2 % of Pb, and 45.3 % of Zn from liquid medium. Cyanobacteria EPS production showed a strong correlation with the removal of Cu, indicating its role in facilitating metal immobilisation. Furthermore, differences in Pb immobilisation (40-86.2 %) suggest possible environmental adaptation mechanisms of the strains. This study highlights the promising application of N. commune strains for metal immobilisation in soils, offering a potential bioremediation tool to combat the adverse effects of soil contamination and promote environmental sustainability.
PubMed: 38897475
DOI: 10.1016/j.scitotenv.2024.174020 -
International Journal of Molecular... Jun 2024(maize) is a staple food, feed, and industrial crop. Heat stress is one of the major stresses affecting maize production and is usually accompanied by other stresses,...
(maize) is a staple food, feed, and industrial crop. Heat stress is one of the major stresses affecting maize production and is usually accompanied by other stresses, such as drought. Our previous study identified a heterotrimer complex, ZmNF-YA1-YB16-YC17, in maize. ZmNF-YA1 and ZmNF-YB16 were positive regulators of the drought stress response and were involved in maize root development. In this study, we investigated whether ZmNF-YA1 confers heat stress tolerance in maize. The mutant and overexpression lines were used to test the role of ZmNF-YA1 in maize thermotolerance. The mutant was more temperature-sensitive than the wild-type (WT), while the overexpression lines showed a thermotolerant phenotype. Higher malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation were observed in the mutant, followed by WT and overexpression lines after heat stress treatment, while an opposite trend was observed for chlorophyll content. RNA-seq was used to analyze transcriptome changes in and its wild-type control W22 in response to heat stress. Based on their expression profiles, the heat stress response-related differentially expressed genes (DEGs) in compared to WT were grouped into seven clusters via -means clustering. Gene Ontology (GO) enrichment analysis of the DEGs in different clades was performed to elucidate the roles of ZmNF-YA1-mediated transcriptional regulation and their contribution to maize thermotolerance. The loss function of led to the failure induction of DEGs in GO terms of protein refolding, protein stabilization, and GO terms for various stress responses. Thus, the contribution of ZmNF-YA1 to protein stabilization, refolding, and regulation of abscisic acid (ABA), ROS, and heat/temperature signaling may be the major reason why overexpression enhanced heat tolerance, and the mutant showed a heat-sensitive phenotype.
Topics: Zea mays; Heat-Shock Response; Thermotolerance; Gene Expression Regulation, Plant; Plant Proteins; Reactive Oxygen Species; Mutation; CCAAT-Binding Factor; Gene Expression Profiling; Transcriptome; Plants, Genetically Modified
PubMed: 38892463
DOI: 10.3390/ijms25116275 -
International Journal of Molecular... May 2024Breeding salt-tolerant crops is necessary to reduce food insecurity. Prebreeding populations are fundamental for uncovering tolerance alleles from wild germplasm. To...
Breeding salt-tolerant crops is necessary to reduce food insecurity. Prebreeding populations are fundamental for uncovering tolerance alleles from wild germplasm. To obtain a physiological interpretation of the agronomic salt tolerance and better criteria to identify candidate genes, quantitative trait loci (QTLs) governing productivity-related traits in a population of recombinant inbred lines (RIL) derived from were reanalyzed using an SNP-saturated linkage map and clustered using QTL meta-analysis to synthesize QTL information. A total of 60 out of 85 QTLs were grouped into 12 productivity MQTLs. Ten of them were found to overlap with other tomato yield QTLs that were found using various mapping populations and cultivation conditions. The MQTL compositions showed that fruit yield was genetically associated with leaf water content. Additionally, leaf Cl and K contents were related to tomato productivity under control and salinity conditions, respectively. More than one functional candidate was frequently found, explaining most productivity MQTLs, indicating that the co-regulation of more than one gene within those MQTLs might explain the clustering of agronomic and physiological QTLs. Moreover, MQTL1.2, MQTL3 and MQTL6 point to the root as the main organ involved in increasing productivity under salinity through the wild allele, suggesting that adequate rootstock/scion combinations could have a clear agronomic advantage under salinity.
Topics: Quantitative Trait Loci; Salt Tolerance; Solanum; Chromosome Mapping; Phenotype; Polymorphism, Single Nucleotide; Plant Breeding; Genetic Linkage; Genes, Plant
PubMed: 38892245
DOI: 10.3390/ijms25116055 -
International Journal of Molecular... May 2024Winter plants acclimate to frost mainly during the autumn months, through the process of cold acclimation. Global climate change is causing changes in weather patterns...
Winter plants acclimate to frost mainly during the autumn months, through the process of cold acclimation. Global climate change is causing changes in weather patterns such as the occurrence of warmer periods during late autumn or in winter. An increase in temperature after cold acclimation can decrease frost tolerance, which is particularly dangerous for winter crops. The aim of this study was to investigate the role of brassinosteroids (BRs) and BR analogues as protective agents against the negative results of deacclimation. Plants were cold-acclimated (3 weeks, 4 °C) and deacclimated (1 week, 16/9 °C d/n). Deacclimation generally reversed the cold-induced changes in the level of the putative brassinosteroid receptor protein (BRI1), the expression of BR-induced , and the expression of , which is involved in BR signal transduction. The deacclimation-induced decrease in frost tolerance in oilseed rape could to some extent be limited by applying steroid regulators. The deacclimation in plants could be detected using non-invasive measurements such as leaf reflectance, chlorophyll a fluorescence, and gas exchange monitoring.
Topics: Brassinosteroids; Acclimatization; Cold Temperature; Brassica napus; Gene Expression Regulation, Plant; Seasons; Plant Proteins; Plant Leaves
PubMed: 38892204
DOI: 10.3390/ijms25116010 -
International Journal of Molecular... May 2024Rice ( L.) is an important social-economic crop, and rice seedlings are easily affected by salt stress. Chitosan oligosaccharide (COS) plays a positive role in promoting...
Rice ( L.) is an important social-economic crop, and rice seedlings are easily affected by salt stress. Chitosan oligosaccharide (COS) plays a positive role in promoting plant growth and development. To gain a better understanding of the salt tolerance mechanism of rice under the action of COS, Nipponbare rice seedlings were selected as the experimental materials, and the physiological and biochemical indexes of rice seedlings in three stages (normal growth, salt stress and recovery) were measured. Unlabelled quantitative proteomics technology was used to study differential protein and signaling pathways of rice seedlings under salt stress, and the mechanism of COS to improve rice tolerance to salt stress was elucidated. Results showed that after treatment with COS, the chlorophyll content of rice seedlings was 1.26 times higher than that of the blank group (CK). The root activity during the recovery stage was 1.46 times that of the CK group. The soluble sugar in root, stem and leaf increased by 53.42%, 77.10% and 9.37%, respectively. The total amino acid content increased by 77% during the stem recovery stage. Furthermore, the malondialdehyde content in root, stem and leaf increased by 21.28%, 26.67% and 32.69%, respectively. The activity of oxide dismutase (SOD), peroxidase (POD) and oxygenase (CAT) were increased. There were more differentially expressed proteins in the three parts of the experimental group than in the CK group. Gene Ontology (GO) annotation of these differentially expressed proteins revealed that the experimental group was enriched for more entries. Then, through the Kyoto Encyclopedia of Genes and Genomes (KEGG), the top ten pathways enriched with differentially expressed proteins in the two groups (COS and CK groups) were utilized, and a detailed interpretation of the glycolysis and photosynthesis pathways was provided. Five key proteins, including phosphofructokinase, fructose bisphosphate aldolases, glycer-aldehyde-3-phosphate dehydrogenase, enolase and pyruvate kinase, were identified in the glycolysis pathway. In the photosynthesis pathway, oxygen evolution enhancement proteins, iron redox proteins and ferredoxin-NADPH reductase were the key proteins. The addition of COS led to an increase in the abundance of proteins, a response of rice seedlings to salt stress. COS helped rice seedlings resist salt stress. Furthermore, using COS as biopesticides and biofertilizers can effectively increase the utilization of saline-affected farmland, thereby contributing to the alleviating of the global food crisis.
Topics: Oryza; Chitosan; Seedlings; Salt Tolerance; Oligosaccharides; Proteome; Plant Proteins; Proteomics; Gene Expression Regulation, Plant; Chlorophyll
PubMed: 38892141
DOI: 10.3390/ijms25115953 -
International Journal of Molecular... May 2024Salinity stress has a great impact on crop growth and productivity and is one of the major factors responsible for crop yield losses. The K-homologous (KH) family...
Salinity stress has a great impact on crop growth and productivity and is one of the major factors responsible for crop yield losses. The K-homologous (KH) family proteins play vital roles in regulating plant development and responding to abiotic stress in plants. However, the systematic characterization of the family in rice is still lacking. In this study, we performed genome-wide identification and functional analysis of family genes and identified a total of 31 genes in rice. According to the homologs of genes in , we constructed a phylogenetic tree with 61 genes containing 31 genes in and 30 genes in and separated them into three major groups. In silico tissue expression analysis showed that the genes are constitutively expressed. The qRT-PCR results revealed that eight genes responded strongly to salt stresses, and exhibited the strongest decrease in expression level, which was selected for further study. We generated the mutant via the CRISPR/Cas9 genome-editing method. Further stress treatment and biochemical assays confirmed that mutant was more salt-sensitive than Nip and the expression of several key salt-tolerant genes in was significantly reduced. Taken together, our results shed light on the understanding of the family and provide a theoretical basis for future abiotic stress studies in rice.
Topics: Oryza; Salt Stress; Gene Expression Regulation, Plant; Plant Proteins; Phylogeny; Multigene Family; Salt Tolerance; Arabidopsis; Stress, Physiological
PubMed: 38892138
DOI: 10.3390/ijms25115950 -
International Journal of Molecular... May 2024Saline and alkaline stresses limit plant growth and reduce crop yield. Soil salinization and alkalization seriously threaten the sustainable development of agriculture...
Saline and alkaline stresses limit plant growth and reduce crop yield. Soil salinization and alkalization seriously threaten the sustainable development of agriculture and the virtuous cycle of ecology. Biofertilizers made from plant growth-promoting rhizobacteria (PGPR) not only enhance plant growth and stress tolerance, but also are environmentally friendly and cost-effective. There have been many studies on the mechanisms underlying PGPRs enhancing plant salt resistance. However, there is limited knowledge about the interaction between PGPR and plants under alkaline-sodic stress. To clarify the mechanisms underlying PGPR's improvement of plants' tolerance to alkaline-sodic stress, we screened PGPR from the rhizosphere microorganisms of local plants growing in alkaline-sodic land and selected an efficient strain, AD13-4, as the research object. Our results indicate that the strain AD13-4 can produce various growth-promoting substances to regulate plant endogenous hormone levels, cell division and differentiation, photosynthesis, antioxidant capacity, etc. Transcriptome analysis revealed that the strain AD13-4 significantly affected metabolism and secondary metabolism, signal transduction, photosynthesis, redox processes, and plant-pathogen interactions. Under alkaline-sodic conditions, inoculation of the strain AD13-4 significantly improved plant biomass and the contents of metabolites (e.g., soluble proteins and sugars) as well as secondary metabolites (e.g., phenols, flavonoids, and terpenoids). The 16S rRNA gene sequencing results indicated that the strain AD13-4 significantly affected the abundance and composition of the rhizospheric microbiota and improved soil activities and physiochemical properties. Our study provides theoretical support for the optimization of saline-alkali-tolerant PGPR and valuable information for elucidating the mechanism of plant alkaline-sodic tolerance.
Topics: Rhizosphere; Soil Microbiology; Medicago sativa; Bacillus; Alkalies; Microbiota; Stress, Physiological; Salt Tolerance; Soil
PubMed: 38891975
DOI: 10.3390/ijms25115785 -
International Journal of Molecular... May 2024AP2/ERF transcription factor genes play an important role in regulating the responses of plants to various abiotic stresses, such as cold, drought, high salinity, and...
AP2/ERF transcription factor genes play an important role in regulating the responses of plants to various abiotic stresses, such as cold, drought, high salinity, and high temperature. However, less is known about the function of oil palm AP2/ERF genes. We previously obtained 172 AP2/ERF genes of oil palm and found that the expression of was significantly up-regulated under salinity, cold, or drought stress conditions. In the present study, the sequence characterization and expression analysis for were conducted, showing that it was transiently over-expressed in L. The results indicated that transgenic tobacco plants over-expressing could have a stronger tolerance to salinity stress than wild-type tobacco plants. Compared with wild-type plants, the over-expression lines showed a significantly higher germination rate, better plant growth, and less chlorophyll damage. In addition, the improved salinity tolerance of transgenic plants was mainly attributed to higher antioxidant enzyme activities, increased proline and soluble sugar content, reduced HO production, and lower MDA accumulation. Furthermore, several stress-related marker genes, including , , , , , , and , were significantly up-regulated in transgenic tobacco plants subjected to salinity stress. Overall, over-expression of the gene significantly enhanced salinity stress tolerance in transgenic tobacco plants. This study lays a foundation for further exploration of the regulatory mechanism of the gene in conferring salinity tolerance in oil palm.
Topics: Nicotiana; Plants, Genetically Modified; Plant Proteins; Salt Tolerance; Gene Expression Regulation, Plant; Salt Stress; Stress, Physiological; Arecaceae; Germination
PubMed: 38891808
DOI: 10.3390/ijms25115621 -
BMC Plant Biology Jun 2024Nitrogen (N) availability is crucial in regulating plants' abiotic stress resistance, particularly at the seedling stage. Nevertheless, plant responses to N under...
BACKGROUND
Nitrogen (N) availability is crucial in regulating plants' abiotic stress resistance, particularly at the seedling stage. Nevertheless, plant responses to N under salinity conditions may vary depending on the soil's NH to NO ratio.
METHODS
In this study, we investigated the effects of different NH:NO ratios (100/0, 0/100, 25/75, 50/50, and 75/25) on the growth and physio-biochemical responses of soybean seedlings grown under controlled and saline stress conditions (0-, 50-, and 100-mM L NaCl and NaSO, at a 1:1 molar ratio).
RESULTS
We observed that shoot length, root length, and leaf-stem-root dry weight decreased significantly with increased saline stress levels compared to control. Moreover, there was a significant accumulation of Na, Cl, hydrogen peroxide (HO), and malondialdehyde (MDA) but impaired ascorbate-glutathione pools (AsA-GSH). They also displayed lower photosynthetic pigments (chlorophyll-a and chlorophyll-b), K ion, K/Na ratio, and weakened O-HO-scavenging enzymes such as superoxide dismutase, catalase, peroxidase, monodehydroascorbate reductase, glutathione reductase under both saline stress levels, while reduced ascorbate peroxidase, and dehydroascorbate reductase under 100-mM stress, demonstrating their sensitivity to a saline environment. Moreover, the concentrations of proline, glycine betaine, total phenolic, flavonoids, and abscisic acid increased under both stresses compared to the control. They also exhibited lower indole acetic acid, gibberellic acid, cytokinins, and zeatine riboside, which may account for their reduced biomass. However, NH:NO ratios caused a differential response to alleviate saline stress toxicity. Soybean seedlings supplemented with optimal ratios of NH:NO (T3 = 25:75 and T = 4 50:50) displayed lower Na and Cl and ABA but improved K and K/Na, pigments, growth hormones, and biomass compared to higher NH:NO ratios. They also exhibited higher O-HO-scavenging enzymes and optimized HO, MDA, and AsA-GSH pools status in favor of the higher biomass of seedlings.
CONCLUSIONS
In summary, the NH and NO ratios followed the order of 50:50 > 25:75 > 0:100 > 75:25 > 100:0 for regulating the morpho-physio-biochemical responses in seedlings under SS conditions. Accordingly, we suggest that applying optimal ratios of NH and NO (25/75 and 50:50) can improve the resistance of soybean seedlings grown in saline conditions.
Topics: Glycine max; Seedlings; Antioxidants; Plant Growth Regulators; Salt Tolerance; Nitrates; Ammonium Compounds; Salt Stress; Ions
PubMed: 38890574
DOI: 10.1186/s12870-024-05294-z