Functional Plant Biology最新文献

Lysine is an amino acid that is essential for the growth and development of all organisms owing to its role in a plethora of critical biological functions and reactions. In plants, lysine is synthesised via five sequential enzyme-catalysed reactions collectively known as the diaminopimelate (DAP) pathway, whereas animals are reliant on their plant dietary intake to obtain lysine. Given that lysine is one of the most nutritionally limiting amino acids, several studies have focused on developing strategies to modulate the activity of DAP pathway enzymes to improve the nutritional value of crops. More recently, research has emerged on the potential of inhibiting DAP pathway enzymes for the development of herbicides with a novel mode of action. Over reliance on a small number of modes of action has led to a herbicide resistance crisis, necessitating the development of new modes of action to which no resistance exists. As such, the first herbicidal inhibitors of the DAP pathway have been developed, which target the first three enzymes in lysine biosynthesis. This review explores the structure, function, and inhibition of these enzymes, as well as highlighting promising avenues for the future development of new plant lysine biosynthesis inhibitors.

Alternaria blight (Alternaria burnsii ) causes significant economic losses due to defoliation, reduced yields, and poor-quality produce in various crops. Consequently, effective strategies for managing this disease are critical. In this study, the caffeoyl-CoA O-methyltransferase (PdCCoAOMT ) gene, which plays a key role in lignin biosynthesis and plant defense, was isolated from Populus deltoides and investigated for its potential to enhance resistance against A. burnsii , the causal agent of blight of various crop species. The PdCCoAOMT gene (741bp) was cloned, characterised, and expressed in the model plant Nicotiana tabacum via Agrobacterium -mediated transformation. Sequencing of the amplicon followed by BLAST analysis revealed 100% query coverage and 98.52% identity of CCoAOMT with the Populus tomentosa and Populus trichocarpa mRNA. Histochemical GUS staining of the putative transformed leaves displayed a distinct blue colour, predominantly in the veins. Gene expression analysis via real time quantitative PCR of 11 T1 plants showed the highest expression in T1 -6 plant. Overexpression of PdCCoAOMT gene showed a positive correlation with lignin deposition in the transformed plants compared to the control plants. A detached leaf assay for A. burnsii resistance demonstrated a significant negative correlation between lignin deposition and disease severity, suggesting that higher lignin accumulation in the leaf was associated with reduced disease symptoms. This highlights the effectiveness of the gene in mitigating the disease in the transformed tobacco plants. These findings suggest that PdCCoAOMT could be a valuable tool in developing crop varieties resistant to Alternaria blight, providing a promising strategy to combat this economically devastating pathogen.

The functioning of the photosynthetic electron transport chain and the proceeding of accompanying processes were studied in Arabidopsis thaliana plants acclimated during 2weeks to reduced (150ppm) or elevated (1000ppm) CO2 concentrations in air. Measured at ambient CO2 , the quantum yields of both photosystems were lower in plants acclimated to these CO2 concentrations as compared with control plants grown at ambient CO2 . The difference was more pronounced at the beginning of the illumination. It is discussed that this difference resulted from the difference in Rubisco content, which at both reduced and elevated CO2 in air was lower than in control plants. The quantum yield of regulated non-photochemical energy loss in photosystem II under both reduced and elevated CO2 was lower than in control plants. This correlated with reduced expression of the PsbS protein gene. H2 O2 content in the leaves increased during the first days of plant adaptation to 150ppm CO2 , but then decreased. The increase resulted from enhanced rates of both photorespiration and Mehler reaction, while the following decrease resulted from enhancing contents of ascorbate peroxidases in all cell compartments.

Enhancing nitrogen (N) use efficiency is important for a sustainable food production. Measuring shoot biomass and N pool across growth stages is critical to calculate N use efficiency, but relies on slow, costly and destructive sampling. This paper presents a non-destructive allometric approach developed for cereals; in this study, we assessed wheat (Triticum aestivum ) for crop shoot biomass and N pool. Our methodology considered tiller height and number, and the estimates of leaf chlorophyll content (SPAD) as non-destructive measures to predict shoot biomass and N pool by using a multiple linear and a non-linear regression (R 2 =0.71 and R 2 =0.89, respectively) on the data from 72 samples of 16 recombinant inbred spring wheat lines (RILs) field-grown in central Sweden during 2years with contrasting weather. Model parameters are estimated separately for different years to accommodate environmental variations between them. The regressions obtained were applied to estimate critical N use efficiency traits of 80 randomly selected wheat lines from the same RIL population. The method developed here provides a promising novel tool for the cost-effective estimation of critical N use efficiency parameters in cereals, with reduced destructive sampling, and a first step toward automated phenotyping for rapid N use efficiency assessment in cereal breeding populations.

Rapeseed (Brassica napus ) is one of the world's most important oilseed crops, supplying humans with oil products, nutritious feed for livestock, and natural resources for industrial applications. Due to immense population pressure, more seed production is needed for human consumption due to its high quality of food products. As a vital genetic resource, male sterility provides ease in hybrid seed production and heterosis breeding. Better utilization of male sterility requires understanding its mechanisms, mode of action, and genes involved to be characterized in detail. Cytoplasmic male sterility (CMS) has been reported in many plant species and is a maternally inherited trait that restricts viable pollen development and production. The mitochondrial genome is involved in the induction of male sterility, while the nuclear genome plays its role in the restoration. Presently, rapeseed has more than 10 CMS systems. Pol-CMS and Shaan2A are autoplasmic resources that arose via natural mutation, while Nap-CMS and Nsa-CMS are alloplasmic and were created by intergeneric hybridisation. In this review, we discuss the types of male sterility systems in rapeseed and provide comprehensive information on CMS in rapeseed with a particular focus and emphasis the types of CMS in rapeseed.

The phytochrome (phy) photoreceptors, comprising a small family of species, regulate plant development, being most active under red (R) and far-red (FR) light. One of the major phytochromes, phyA, is unique among the others: it mediates distinct photoreactions - the very low fluence responses (VLFR), the high irradiance responses (HIR), and the low fluence responses (LFR) characteristic of phyB. This functional diversity is likely to be connected with its heterogeneity: there are two native pools, possibly differing by serine phosphorylation at the N-terminus - phyA' mediating the VLFR and phyA″ responsible for the HIR and LFR. In this work, we investigated their nature by in vivo spectrofluorimetry, turning to the chlorophyll-less albino barley mutant. It was characterized both by the higher total phyA content and the proportion of phyA' in etiolated coleoptile tips. The lack of protochlorophyllide (PChlide) allowed characterization of phyA pools in primary leaves (of the mutant) - the phyA'/phyA″ proportion was the same as in the coleoptiles, whereas their content was substantially lower. phyA' in the mutant coleoptiles revealed less lability under light as compared with the wild type, suggesting that the mutation may affect the phyA's proteolytic system. A specific effect of FR light on phyA in coleoptiles was observed - a relatively fast (tens of minutes) conversion of phyA' into phyA″ that may be part of the complex process of plant light adaptation.

While the effects of plant growth-promoting rhizobacterium, Azospirillum , on abiotic stress tolerance in plants are widely reported, the mechanisms that underlie this process remain elusive. Surface lectins of strains A. brasilense Sp7 and A. baldaniorum Sp245 are capable of attaching to specific carbohydrates and ensure the binding of bacteria to the surface of the plant root. They exhibit multifunctionality, and the effects induced by lectins are dose-dependent. This work investigated mechanisms by which lectins improved drought tolerance in wheat (Triticum aestivum ) plants. In the roots of wheat seedlings under drought stress, lectins with varying intensities increased the activity of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT). Lectins caused a decrease in lipid peroxidation, but increased the content of secondary metabolites such as total phenolics and flavonoids. In the roots of stressed seedlings, lectins increased the total protein content and caused a dose-dependent change in the electrophoretic spectra of low molecular weight proteins. It was concluded that Azospirillum lectins, due to their ability to influence the metabolism of the host plant, are involved in adaptive changes in the roots of wheat seedlings. Lectins can regulate the relationship between bacteria and their hosts when soil and climatic factors change.

Shading plays an important role in determining nutrient content and yield fo wheat (Triticum aestivum ). However, the genetic mechanism underlying the effects of shading treatment on grain filling remains unclear. Therefore, we performed phenotypic and transcriptome analyses on wheat cv. ZY96-3 during grain development under normal and shaded conditions. Shading resulted in a significant decrease in grain size and 1000-grain weight. Correlation analysis revealed the strong effect of shading on the mean and maximum grain-filling rate and secondary grain-filling parameters R 2 and R 3 . And shading reduced starch content and starch-related enzyme activity (including granule-bound starch synthase and soluble starch synthase). Transcriptomic analyses showed that shading mainly affected pathways related to photosynthetic antenna proteins, carbon fixation in photosynthetic organisms, and starch and sucrose metabolism. Sixteen genes related to photosynthetic antenna protein and carbon fixation pathways were first upregulated and then downregulated; whereas all differentially expressed genes (PetC , Fd , LFNR1 , LFNR2 , PC , PsbO , PsaG , and PSB28 ) in the photosynthetic antenna protein pathway belonged to electron transport chain proteins. We found that shading treatment affects the physiological and molecular properties of grain development during the grain-filling stage. This study reveals new candidate genes (such as TaLFNR1-7A and TaFd-7A ) for breeding wheat varieties with high photosynthetic efficiency in regions with insufficient light intensity.

Fatty acid desaturases (FADs) represent a class of oxygen-dependent enzymes that dehydrogenate C-C bonds in fatty acids (FAs) producing unsaturated C=C bonds that markedly change the properties of lipid membranes, which is critical for protein and lipid diffusion, perception and transduction of environmental signals, cell division, etc . Membrane-located FADs (acyl-lipid FADs of plants and bacteria, as well as animal acyl-coenzyme A (CoA) FADs) are highly conserved from viruses to human. These enzymes are highly specific towards their acyl substrates, as well as towards the position and geometric configuration of the newly introduced cis double bonds. The regiospecificity of soluble Acyl-Carrier-Protein (ACP) Δ9-FADs was determined relative to the carboxyl end of the FA. Similar regiospecificity was suggested for acyl-lipid and acyl-CoA FADs Δ9-FADs. It was previously thought that acyl-lipid Δ12-FADs (also known as ω6-FADs) also count from the carboxyl terminus of an FA. However, heterologous expression and supplementation of model yeast or cyanobacterial strains with exogenous monounsaturated odd- and even-chain FAs revealed that plant and cyanobacterial acyl-lipid Δ12-FADs use neither end of the FA (Δ or ω) as a counting reference point; but count three carbons toward the methyl end from an existing double bond in the monoene precursors irrespective of FA chain length. Δ6-FADs appeared to 'count' from the carboxyl terminus. ω3-FADs that contribute to unsaturation of C16-C18 FAs of membrane lipids, in fact, are Δ15-FADs that also 'count' from the C-terminus of acyl chains. The exact knowledge of counting order is crucial for understanding the modes of FADs activities and for further construction of biochemical pathways for biosynthesis of polyunsaturated FAs.

The dependence of agriculture on water availability is an important premise justifying attempts to enhance water use efficiency for plant production. Photosynthetic efficiency, directly impacts biomass production, is dependent on both water availability and the quality and quantity of light. Understanding how these factors interact is crucial for improving crop yields. Many overlapping signalling pathways and functions of common bioactive molecules that shape plant responses to both water deficit and light have been identified and discussed in this review. Separate or combined action of these environmental factors include the generation of reactive oxygen species, biosynthesis of abscisic acid, stomatal functioning, chloroplast movement and alterations in the levels of photosynthetic pigments and bioactive molecules. Plant response to water deficit depends on light intensity and its characteristics, with differentiated impacts from UV, blue, and red light bands determining the strength and synergistic or antagonistic nature of interactions. Despite its significance, the combined effects of these environmental factors remain insufficiently explored. The findings highlight the potential for optimising horticultural production through controlled light conditions and regulated deficit irrigation. Future research should assess light and water manipulation strategies to enhance resource efficiency and crop nutritional value.