Functional Plant Biology最新文献

Many studies have shown that multidrug and toxic compound extrusion (MATE) is a new secondary transporter family that plays a key role in secondary metabolite transport, the transport of plant hormones and disease resistance in plants. However, detailed information on this family in Gleditsia sinensis has not yet been reported. In the present study, a total of 45 GsMATE protein members were identified and analysed in detail, including with gene classification, phylogenetic evaluation and conserved motif determination. Phylogenetic analysis showed that GsMATE proteins were divided into six subfamilies. Additionally, in order to understand these members’ regulatory roles in growth and development in G. sinensis, the GsMATEs expression profiles in different tissues and different developmental stages of thorn were examined in transcriptome data. The results of this study demonstrated that the expression of all MATE genes varies in roots, stems and leaves. Notably, the expression levels of GsMATE26, GsMATE32 and GsMATE43 differ most in the early stages of thorn development, peaking at higher levels than in later stages. Our results provide a foundation for further functional characterisation of this important class of transporter family in G. sinensis.

Drought is a major obstacle to the development of naked oat industry. This work investigated mechanisms by which exogenous Streptomyces albidoflavus T4 and Streptomyces rochei D74 improved drought tolerance in naked oat (Avena nuda) seedlings. Results showed that in the seed germination experiment, germination rate, radicle and hypocotyl length of naked oat seeds treated with the fermentation filtrate of T4 or D74 under PEG induced drought stress increased significantly. In the hydroponic experiment, the shoot and root dry weights of oat seedlings increased significantly when treated with the T4 or D74 fermentation filtrate under the 15% PEG induced drought stress (S15). Simultaneously, the T4 treatment also significantly increased the surface area, volume, the number of tips and the root activity of oat seedlings. Both T4 and D74 treatments elicited significant increases in proline and soluble sugar contents, as well as the catalase and peroxidase activities in oat seedlings. The results of comprehensive drought resistance capacity (CDRC) calculation of oat plants showed that the drought resistance of oat seedlings under the T4 treatment was better than that under the D74 treatment, and the effect was better under higher drought stress (S15). Findings of this study may provide a novel and effective approach for enhancing plant defenses against drought stress.

Reproductive development of fruiting trees, including mango (Mangifera indica L.), is limited by non-structural carbohydrates. Competition for sugars increases with cropping, and consequently, vegetative growth and replenishment of starch reserves may reduce with high yields, resulting in interannual production variability. While the effect of crop load on photosynthesis and the distribution of starch within the mango tree has been studied, the contribution of starch and sugars to different phases of reproductive development requires attention. This review focuses on mango and examines the roles of non-structural carbohydrates in fruiting trees to clarify the repercussions of crop load on reproductive development. Starch buffers the plant’s carbon availability to regulate supply with demand, while sugars provide a direct resource for carbon translocation. Sugar signalling and interactions with phytohormones play a crucial role in flowering, fruit set, growth, ripening and retention, as well as regulating starch, sugar and secondary metabolites in fruit. The balance between the leaf and fruit biomass affects the availability and contributions of starch and sugars to fruiting. Crop load impacts photosynthesis and interactions between sources and sinks. As a result, the onset and rate of reproductive processes are affected, with repercussions for fruit size, composition, and the inter-annual bearing pattern.

DNA binding proteins with one finger (Dof) transcription factors are essential for seed development and defence against various biotic and abiotic stresses in plants. Genomic analysis of Dof has not been determined yet in pitaya (Selenicereus undatus). In this study, we have identified 26 Dof gene family members, renamed as HuDof-1 to HuDof-26, and clustered them into seven subfamilies based on conserved motifs, domains, and phylogenetic analysis. The gene pairs of Dof family members were duplicated by segmental duplications that faced purifying selection, as indicated by the K_a/K_s ratio values. Promoter regions of HuDof genes contain many cis-acting elements related to phytohormones including abscisic acid, jasmonic acid, gibberellin, temperature, and light. We exposed pitaya plants to different environmental stresses and examined melatonin’s influence on Dof gene expression levels. Signifcant expression of HuDof-2 and HuDof-6 were observed in different developmental stages of flower buds, flowers, pericarp, and pulp. Pitaya plants were subjected to abiotic stresses, and transcriptome analysis was carried out to identify the role of Dof gene family members. RNA-sequencing data and reverse transcription quantitative PCR-based expression analysis revealed three putative candidate genes (HuDof-1, HuDof-2, and HuDof-8), which might have diverse roles against the abiotic stresses. Our study provides a theoretical foundation for functional analysis through traditional and modern biotechnological tools for pitaya trait improvement.

Continuous increasing leaf photosynthesis may enhance plant yield. As an evolutionary property, plants use less photosynthetic capacity than is theoretically possible. Plant nanobionics is a bioengineering field that improves plant functions using nanoparticles. We applied orange carbon dots (o-CDs) onto the foliage of green beans (Phaseolus vulgaris ) grown in hydroponics to improve their photosynthetic performance and CO2 assimilation. Photosynthesis parameters, photosynthetic pigments content, total phenolic content (TPC) and antioxidative activity (TAA) were measured. Results show that photosynthetic pigments remained unchanged, while photosynthesis was improved. Both o-CDs concentrations decreased TPC and TAA. The light response curve showed higher CO2 assimilation at both o-CDs concentrations, particularly at lower light intensity. Correlation analysis confirmed increased CO2 binding and assimilation at 1mg L-1 . This study demonstrated the potential of using o-CDs as a safe biostimulator through photosynthesis increase and CO2 assimilation without toxic effects on plants. This may stimulate yield increase that paves the way for their agricultural application.

The runner reed (Phragmites japonica ) is the dominant species on riverbanks, whereas the common reed (Phragmites australis ) thrives in continuously flooded areas. Here, we aimed to identify the key root anatomical traits that determine the different adaptative responses of the two Phragmites species to water-deficit and low-oxygen conditions. Growth measurements revealed that P . japonica tolerated high osmotic conditions, whereas P . australis preferred low-oxygen conditions. Root anatomical analysis revealed that the ratios of the cortex to stele area and aerenchyma (gas space) to cortex area in both species increased under low-oxygen conditions. However, a higher ratio of cortex to stele area in P . australis resulted in a higher ratio of aerenchyma to stele, which includes xylem vessels that are essential for water and nutrient uptakes. In contrast, a lower ratio of cortex to stele area in P . japonica could be advantageous for efficient water uptake under high-osmotic conditions. In addition to the ratio of root tissue areas, rigid outer apoplastic barriers composed of a suberised exodermis may contribute to the adaptation of P . japonica and P . australis to water-deficit and low-oxygen conditions, respectively. Our results suggested that root anatomical plasticity is essential for plants to adapt and respond to different soil moisture levels.

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-associated proteins are a class of transmembrane proteins involved in intracellular trafficking pathways. However, the functions of many SNARE domain-containing proteins remain unclear. We have previously identified a SNARE-associated gene in alfalfa (Medicago sativa ) KILLING ME SLOWLY1 (MsKMS1 ), which is involved in various abiotic stresses. In this study, we investigated the function of MsKMS1 in the seed germination of transgenic tobacco (Nicotiana tabacum ). Phylogenetic analysis showed that MsKMS1 was homologous to the SNARE-associated or MAPR component-related proteins of other plants. Germination assays revealed that MsKMS1 negatively regulated seed germination under normal, D-mannitol and abscisic acid-induced stress conditions, yet MsKMS1 -overexpression could confer enhanced heat tolerance in transgenic tobacco. The suppressive effect on germination in MsKMS1 -overexpression lines was associated with higher abscisic acid and salicylic acid contents in seeds. This was accompanied by the upregulation of abscisic acid biosynthetic genes (ZEP and NCED ) and the downregulation of gibberellin biosynthetic genes (GA20ox2 and GA20ox3 ). Taken together, these results suggested that MsKMS1 negatively regulated seed germination by increasing abscisic acid and salicylic acid contents through the expression of genes related to abscisic acid and gibberellin biosynthesis. In addition, MsKMS1 could improve heat tolerance during the germination of transgenic tobacco seeds.

The effect of drought stress on leaf physiology was studied in 10-month-old plants of Sindora siamensis . Plants were either placed in an open greenhouse (unhardening; UH) or in an open field (open field hardening; H) for 45days. Both the UH and H plants stopped receiving water (D) until the initial drought injury and then rewatered (R) until complete recovery. Results showed necrosis in the leaves of UH+D, while H+D showed wilting at Day 7 after drought. A greater degree of necrosis was found in UH+D+R but made complete recovery in H+D+R at Day 4 after rewatering. Drought stress resulted in decreased leaf area in H, and reduced leaf and stem water status, PSII efficiency, net photosynthetic rate, stomatal conductance and transpiration rate in both UH and H. It also resulted in an increase in water use efficiency in both UH and H. Electrolyte leakage and malondialdehyde contents in UH were markedly increased due to drought stress. These results suggest that unhardened young plants of Sindora exposed to drought exhibited enhanced stomata behaviour by minimising open stomata and transpiration, resulting in high efficiency of water usage. However, there was still membrane damage from lipid peroxidation, which caused necrosis. Open field hardened plants exposed to drought demonstrated reduced open stomata and transpiration, thereby preserving leaf and soil water status and enhancing water use efficiency. This may be a reduction in lipid peroxidation though an oxidative scavenging mechanism that causes a slight alteration in membrane stability and a slight necrosis.

Due to global warming and changes in precipitation patterns, many regions are prone to permanent drought. Rapeseed (Brassica napus ) is one of the main sources of edible oils worldwide, and its production and yield are affected by drought. In this study, gene expression alterations under drought stress are investigated with bioinformatics studies to examine evolutionary relations of conserved motifs structure and interactions among Calvin cycle and photorespiration pathways key genes in drought-tolerant (SLM046) and drought-sensitive (Hayola308) genotypes of rapeseed. Investigating the conservation and evolutionary relationships revealed high conservation in motifs of FBPase, PRK, GlyK and NADP-ME enzymes. The analysis of protein interactions showed the correlation between FTRC, FBPase1, PRKX1, GlyKX2 and NADP-ME4 genes. Furthermore, in rapeseed, for the GlyKX2 and NADP-ME4 genes, four microRNAs of the miR172 family and four members of the miR167 family were identified as post-transcriptional regulators, respectively. The expression of ferredoxin thioredoxin reductase, fructose-1,6-bisphosphatase genes, phosphoribulokinase, glycerate kinase and malic enzyme 4 genes in the two rapeseed genotypes were evaluated by real-time qPCR method under 72h of drought stress and methanol foliar application. As a result, the highest expression levels of FTRC, PRKX1, GlyKX2, NADP-ME4 and FBPase1 were observed in methanol foliar application on the SLM046 genotype at 24h. In contrast, in methanol foliar application on the Hayola308 genotype, the highest expression levels of FTRC, PRKX1, GlyKX2, NADP-ME4 and FBPase1 were observed 8h after the treatment. Our study illustrated that methanol foliar application enhanced plant tolerance under drought stress.