Hormonal and stress induction of the gene encoding common bean acetyl-coenzyme A carboxylase

Effects of the Rhizosphere Fungus Cunninghamella bertholletiae on the Solanum lycopersicum Response to Diverse Abiotic Stresses

This study examined the efficiency of fungal strain (Cunninghamella bertholletiae) isolated from the rhizosphere of Solanum lycopersicum to reduce symptoms of salinity, drought and heavy metal stresses in tomato plants. In vitro evaluation of C. bertholletiae demonstrated its ability to produce indole-3-Acetic Acid (IAA), ammonia and tolerate varied abiotic stresses on solid media. Tomato plants at 33 days’ old, inoculated with or without C. bertholletiae, were treated with 1.5% sodium chloride, 25% polyethylene glycol, 3 mM cadmium and 3 mM lead for 10 days, and the impact of C. bertholletiae on plant performance was investigated. Inoculation with C. bertholletiae enhanced plant biomass and growth attributes in stressed plants. In addition, C. bertholletiae modulated the physiochemical apparatus of stressed plants by raising chlorophyll, carotenoid, glucose, fructose, and sucrose contents, and reducing hydrogen peroxide, protein, lipid metabolism, amino acid, antioxidant activities, and abscisic acid. Gene expression analysis showed enhanced expression of SlCDF3 and SlICS genes and reduced expression of SlACCase, SlAOS, SlGRAS6, SlRBOHD, SlRING1, SlTAF1, and SlZH13 genes following C. bertholletiae application. In conclusion, our study supports the potential of C. bertholletiae as a biofertilizer to reduce plant damage, improve crop endurance and remediation under stress conditions.

An Arabidopsis mutant deficient in phosphatidylinositol-4-phosphate kinases ß1 and ß2 displays altered auxin-related responses in roots

Phosphatidylinositol 4-kinases (PI4Ks) are the first enzymes that commit phosphatidylinositol into the phosphoinositide pathway. Here, we show that Arabidopsis thaliana seedlings deficient in PI4Kβ1 and β2 have several developmental defects including shorter roots and unfinished cytokinesis. The pi4kβ1β2 double mutant was insensitive to exogenous auxin concerning inhibition of root length and cell elongation; it also responded more slowly to gravistimulation. The pi4kß1ß2 root transcriptome displayed some similarities to a wild type plant response to auxin. Yet, not all the genes displayed such a constitutive auxin-like response. Besides, most assessed genes did not respond to exogenous auxin. This is consistent with data with the transcriptional reporter DR5-GUS. The content of bioactive auxin in the pi4kß1ß2 roots was similar to that in wild-type ones. Yet, an enhanced auxin-conjugating activity was detected and the auxin level reporter DII-VENUS did not respond to exogenous auxin in pi4kß1ß2 mutant. The mutant exhibited altered subcellular trafficking behavior including the trapping of PIN-FORMED 2 protein in rapidly moving vesicles. Bigger and less fragmented vacuoles were observed in pi4kß1ß2 roots when compared to the wild type. Furthermore, the actin filament web of the pi4kß1ß2 double mutant was less dense than in wild-type seedling roots, and less prone to rebuilding after treatment with latrunculin B. A mechanistic model is proposed in which an altered PI4K activity leads to actin filament disorganization, changes in vesicle trafficking, and altered auxin homeostasis and response resulting in a pleiotropic root phenotypes.

Influence of Nutrient (NPK) Factors on Growth, and Pharmacodynamic Component Biosynthesis of Atractylodes chinensis: An Insight on Acetyl-CoA Carboxylase (ACC), 3-Hydroxy-3-Methylglutaryl-CoA Reductase (HMGR), and Farnesyl Pyrophosphate Synthase (FPPS) Signaling Responses

In the planting of crops, especially medicinal plants, formula fertilization is important for improving the utilization rate of elements, soil quality, crop yield, and quality. Therefore, it is important to study targeted fertilizer application schemes for sustainable agricultural development and environmental protection. In this study, an L9(34) orthogonal design was used to conduct a field experiment to study the effects of NPK combined application on the growth and pharmacodynamic component biosynthesis of Atractylodes chinensis (DC.) Koidz. Results showed that after applying a base fertilizer at the seedling stage (late May), topdressing at the vegetative stage (late June) and fruit stage (late August) was beneficial to the growth and development of A. chinensis. The high concentrations of phosphorus were conducive to the accumulation of yield and effective components, and the best harvest time was after late October. Principal component analysis (PCA) showed that the comprehensive score of T6 treatment was the highest, indicating that the optimal fertilization scheme for the high yield and high quality of A. chinensis was (N2P3K1): N 180, P2O5 225, and K2O 105 kg⋅ha-1. A signaling response analysis showed that during the growth and development of A. chinensis, the T6 fertilization scheme had clear effects on the activity and gene expression of the key enzymes acetyl-CoA carboxylase (ACC) and farnesyl pyrophosphate synthase (FPPS). Under the T4 [(N2P1K2): N 180, P2O5 75, and K2O 210 kg⋅ha-1] fertilization scheme, the activity and gene expression of the key enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) were higher. Moreover, ACC was closely related to the synthesis of the polyacetylene component atractylodin, and FPPS played an important regulatory role in the synthesis of sesquiterpene components atractylenolide II, β-eudesmol, and atractylon. In summary, the high phosphorus fertilization scheme T6 could notably increase the yield of A. chinensis, and promote the accumulation of polyacetylene and sesquiterpene volatile oils by increasing the expression of ACC and FPPS. Therefore, we postulate that the precise application of nutrients (NPK) plays a vital role in the yield formation and quality regulation of A. chinensis.

Fab Advances in Fabaceae for Abiotic Stress Resilience: From 'Omics' to Artificial Intelligence

Legumes are a better source of proteins and are richer in diverse micronutrients over the nutritional profile of widely consumed cereals. However, when exposed to a diverse range of abiotic stresses, their overall productivity and quality are hugely impacted. Our limited understanding of genetic determinants and novel variants associated with the abiotic stress response in food legume crops restricts its amelioration. Therefore, it is imperative to understand different molecular approaches in food legume crops that can be utilized in crop improvement programs to minimize the economic loss. 'Omics'-based molecular breeding provides better opportunities over conventional breeding for diversifying the natural germplasm together with improving yield and quality parameters. Due to molecular advancements, the technique is now equipped with novel 'omics' approaches such as ionomics, epigenomics, fluxomics, RNomics, glycomics, glycoproteomics, phosphoproteomics, lipidomics, regulomics, and secretomics. Pan-omics-which utilizes the molecular bases of the stress response to identify genes (genomics), mRNAs (transcriptomics), proteins (proteomics), and biomolecules (metabolomics) associated with stress regulation-has been widely used for abiotic stress amelioration in food legume crops. Integration of pan-omics with novel omics approaches will fast-track legume breeding programs. Moreover, artificial intelligence (AI)-based algorithms can be utilized for simulating crop yield under changing environments, which can help in predicting the genetic gain beforehand. Application of machine learning (ML) in quantitative trait loci (QTL) mining will further help in determining the genetic determinants of abiotic stress tolerance in pulses.

Trichoderma Applications on Strawberry Plants Modulate the Physiological Processes Positively Affecting Fruit Production and Quality

Many Trichoderma spp. are successful plant beneficial microbial inoculants due to their ability to act as biocontrol agents with direct antagonistic activities to phytopathogens, and as biostimulants capable of promoting plant growth. This work investigated the effects of treatments with three selected Trichoderma strains (T22, TH1, and GV41) to strawberry plants on the productivity, metabolites and proteome of the formed fruits. Trichoderma applications stimulated plant growth, increased strawberry fruit yield, and favored selective accumulation of anthocyanins and other antioxidants in red ripened fruits. Proteomic analysis of fruits harvested from the plants previously treated with Trichoderma demonstrated that the microbial inoculants highly affected the representation of proteins associated with responses to stress/external stimuli, nutrient uptake, protein metabolism, carbon/energy metabolism and secondary metabolism, also providing a possible explanation to the presence of specific metabolites in fruits. Bioinformatic analysis of these differential proteins revealed a central network of interacting molecular species, providing a rationale to the concomitant modulation of different plant physiological processes following the microbial inoculation. These findings indicated that the application of Trichoderma-based products exerts a positive impact on strawberry, integrating well with previous observations on the molecular mechanisms activated in roots and leaves of other tested plant species, demonstrating that the efficacy of using a biological approach with beneficial microbes on the maturing plant is also able to transfer advantages to the developing fruits.

Plant hormone induced enrichment of Chlorella sp. omega-3 fatty acids

BACKGROUND

Omega-3 fatty acids have various health benefits in combating against neurological problems, cancers, cardiac problems and hypertriglyceridemia. The main dietary omega-3 fatty acids are obtained from marine fish. Due to the pollution of marine environment, recently microalgae are considered as the promising source for the omega-3 fatty acid production. However, the demand and high production cost associated with microalgal biomass make it necessary to implement novel strategies in improving the biomass and omega-3 fatty acids from microalgae.

RESULTS

Four plant hormones zeatin, indole acetic acid (IAA), gibberellic acid (GBA) and abscisic acid (ABA) were investigated for their effect on the production of biomass and lipid in isolated Chlorella sp. The cells showed an increase of the biomass and lipid content after treatments with the plant hormones where the highest stimulatory effect was observed in ABA-treated cells. On the other hand, IAA showed the highest stimulatory effect on the omega-3 fatty acids content, eicosapentaenoic acid (EPA) (23.25%) and docosahexaenoic acid (DHA) (26.06%). On the other hand, cells treated with ABA had highest lipid content suitable for the biodiesel applications. The determination of ROS markers, antioxidant enzymes, and fatty acid biosynthesis genes after plant hormones treatment helped elucidate the mechanism underlying the improvement in biomass, lipid content and omega-3 fatty acids. All four plant hormones upregulated the fatty acid biosynthesis genes, whereas IAA particularly increased omega-3-fatty acids as a result of the upregulation of omega-3 fatty acid desaturase.

CONCLUSIONS

The contents of omega-3 fatty acids, the clinically important compounds, were considerably improved in IAA-treated cells. The highest lipid content obtained from ABA-treated biomass can be used for biodiesel application according to its biodiesel properties. The EPA and DHA enriched ethyl esters are an approved form of omega-3 fatty acids by US Food and Drug Administration (FDA) which can be utilized as the therapeutic treatment for the severe hypertriglyceridemia.

Responsive Proteins in Wheat Cultivars with Contrasting Nitrogen Efficiencies under the Combined Stress of High Temperature and Low Nitrogen

Productivity of wheat (Triticumaestivum) is markedly affected by high temperature and nitrogen deficiency. Identifying the functional proteins produced in response to these multiple stresses acting in a coordinated manner can help in developing tolerance in the crop. In this study, two wheat cultivars with contrasting nitrogen efficiencies (N-efficient VL616 and N-inefficient UP2382) were grown in control conditions, and under a combined stress of high temperature (32 °C) and low nitrogen (4 mM), and their leaf proteins were analysed in order to identify the responsive proteins. Two-dimensional electrophoresis unravelled sixty-one proteins, which varied in their expression in wheat, and were homologous to known functional proteins involved in biosynthesis, carbohydrate metabolism, energy metabolism, photosynthesis, protein folding, transcription, signalling, oxidative stress, water stress, lipid metabolism, heat stress tolerance, nitrogen metabolism, and protein synthesis. When exposed to high temperature in combination with low nitrogen, wheat plants altered their protein expression as an adaptive means to maintain growth. This response varied with cultivars. Nitrogen-efficient cultivars showed a higher potential of redox homeostasis, protein stability, osmoprotection, and regulation of nitrogen levels. The identified stress-responsive proteins can pave the way for enhancing the multiple-stress tolerance in wheat and developing a better understanding of its mechanism.

Proteomic analyses provide new insights into the responses of Pinus massoniana seedlings to phosphorus deficiency

Phosphorus is an essential macronutrient for plant growth and development. Plants can respond defensively to phosphorus deficiency by modifying their morphology and metabolic pathways via the differential expression of low phosphate responsive genes. To better understand the mechanisms by which the Masson pine (Pinus massoniana) adapts to phosphorus deficiency, we conducted comparative proteomic analysis using an elite line exhibiting high tolerance to phosphorus deficiency. The selected seedlings were treated with 0.5 mM KH2PO4 (control), 0.01 mM KH2PO4 (P1), or 0.06 mM KH2PO4 (P2) for 48 days. Total protein samples were separated via 2DE. A total of 98 differentially expressed proteins, which displayed at least 1.7-fold change expression compared to the control levels (p ≤ 0.05), were identified by MALDI-TOF/TOF MS. These phosphate starvation responsive proteins were implicated in photosynthesis, defense, cellular organization, biosynthesis, energy metabolism, secondary metabolism, signal transduction etc. Therefore, these proteins might play important roles in facilitating internal phosphorus homeostasis. Additionally, the obtained data may be useful for the further characterization of gene function and may provide a foundation for a more comprehensive understanding of the adaptations of the Masson pine to phosphorus-deficient conditions.

Sethoxydim treatment inhibits lipid metabolism and enhances the accumulation of anthocyanins in rape (Brassica napus L.) leaves

Cyclohexanediones (e.g., sethoxydim) are known to be inhibitors of plastid acetyl-CoA carboxylase (ACCase) of monocotyledonous plants and provoke plant death. When rape leaves were treated with 10(-3) M sethoxydim, growth rate, chlorophyll and lipid contents were reduced, but plant resisted to herbicide. [1-(14)C] Acetate labelling showed that lipid synthesis was affected by sethoxydim, probably through inhibition of chloroplast homomeric ACCase activity, and the fatty acid synthase activity (FAS) was reduced because of malonyl-CoA deficiency. In contrast, sethoxydim treatment provoked an increase in phenylalanine ammonia lyase (PAL) activity with an accumulation of cinnamic acid, naringenin and anthocyanins. The accumulation of anthocyanins seems to reduce the damaging effect of the herbicide stress. Thus, in plant cell, the flux of carbon seems to be oriented towards protective mechanisms, and the two ACCases could have an important role in this orientation.

Overexpression of a putative Arabidopsis BAHD acyltransferase causes dwarfism that can be rescued by brassinosteroid

Plant growth and development are ensured through networks of complex regulatory schemes. Genetic approaches have been invaluable in dissecting these regulatory pathways. This study reports the isolation of a semi-dominant dwarf mutant designated abnormal shoot1-1 dominant (abs1-1D) through an Arabidopsis T-DNA activation tagging mutant screen. It was shown that the overexpression of a novel BAHD family acyltransferase gene, ABS1/At4g15400, was the cause of the dwarf phenotype in abs1-1D. Overexpression of ABS1 led to many phenotypic features reminiscent of brassinosteroid (BR) deficient or signalling mutants, and it was shown that exogenously applied BR could effectively rescue the dwarf phenotype of abs1-1D. Furthermore, genetic analyses indicated that abs1-1D interacted, in different ways, with the BR-deficient mutant det2-1, the constitutive BR response mutant bes1-D and the photomorphogenic mutant phyB-1. Moreover, ABS1 expression was activated by BR treatment or in a bes1-D mutant background. Genome-wide transcriptome profiling of abs1-1D revealed clear reprogramming of metabolic pathways, and it was demonstrated that BR biosynthesis genes were activated in abs1-1D and that the flavonoid biosynthesis pathway was repressed in abs1-1D, as well as in det2-1. This work provides new insights into the possible involvement of BAHD acyltransferase in the regulation of plant growth and development, and indicates a possible role of ABS1 in maintaining BR homeostasis.

Genome-Wide Characterization of ISR Induced in Arabidopsis thaliana by Trichoderma hamatum T382 Against Botrytis cinerea Infection

In this study, the molecular basis of the induced systemic resistance (ISR) in Arabidopsis thaliana by the biocontrol fungus Trichoderma hamatum T382 against the phytopathogen Botrytis cinerea B05-10 was unraveled by microarray analysis both before (ISR-prime) and after (ISR-boost) additional pathogen inoculation. The observed high numbers of differentially expressed genes allowed us to classify them according to the biological pathways in which they are involved. By focusing on pathways instead of genes, a holistic picture of the mechanisms underlying ISR emerged. In general, a close resemblance is observed between ISR-prime and systemic acquired resistance, the systemic defense response that is triggered in plants upon pathogen infection leading to increased resistance toward secondary infections. Treatment with T. hamatum T382 primes the plant (ISR-prime), resulting in an accelerated activation of the defense response against B. cinerea during ISR-boost and a subsequent moderation of the B. cinerea induced defense response. Microarray results were validated for representative genes by qRT-PCR. The involvement of various defense-related pathways was confirmed by phenotypic analysis of mutants affected in these pathways, thereby proving the validity of our approach. Combined with additional anthocyanin analysis data these results all point to the involvement of the phenylpropanoid pathway in T. hamatum T382-induced ISR.

The glossyhead1 allele of ACC1 reveals a principal role for multidomain acetyl-coenzyme A carboxylase in the biosynthesis of cuticular waxes by Arabidopsis

A novel mutant of Arabidopsis (Arabidopsis thaliana), having highly glossy inflorescence stems, postgenital fusion in floral organs, and reduced fertility, was isolated from an ethyl methanesulfonate-mutagenized population and designated glossyhead1 (gsd1). The gsd1 locus was mapped to chromosome 1, and the causal gene was identified as a new allele of Acetyl-Coenzyme A Carboxylase1 (ACC1), a gene encoding the main enzyme in cytosolic malonyl-coenzyme A synthesis. This, to our knowledge, is the first mutant allele of ACC1 that does not cause lethality at the seed or early germination stage, allowing for the first time a detailed analysis of ACC1 function in mature tissues. Broad lipid profiling of mature gsd1 organs revealed a primary role for ACC1 in the biosynthesis of the very-long-chain fatty acids (C(20:0) or longer) associated with cuticular waxes and triacylglycerols. Unexpectedly, transcriptome analysis revealed that gsd1 has limited impact on any lipid metabolic networks but instead has a large effect on environmental stress-responsive pathways, especially senescence and ethylene synthesis determinants, indicating a possible role for the cytosolic malonyl-coenzyme A-derived lipids in stress response signaling.

Candidate genes associated with bud dormancy release in blackcurrant (Ribes nigrum L.)

BACKGROUND

The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L.) in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak.

RESULTS

Using leaf bud tissue of blackcurrant, a cDNA library was generated as a source of blackcurrant ESTs for construction of a custom microarray, which was used to identify differential gene expression during dormancy release. Gene activity was lowest in early stages of dormancy, increasing to reach a maximum around the time of budbreak. Genes with significantly changing expression profiles were clustered and evidence is provided for the transient activity of genes previously associated with dormancy processes in other species. Expression profiling identified candidate genes which were mapped onto a blackcurrant genetic linkage map containing budbreak-related QTL. Three genes, which putatively encode calmodulin-binding protein, beta tubulin and acetyl CoA carboxylase respectively, were found to co-localise with budbreak QTL.

CONCLUSIONS

This study provides insight into the genetic control of dormancy transition in blackcurrant, identifying key changes in gene expression around budbreak. Genetic mapping of ESTs enabled the identification of genes which co-localise with previously-characterised blackcurrant QTL, and it is concluded that these genes have probable roles in release of dormancy and can therefore provide a basis for the development of genetic markers for future breeding deployment.