scholarly journals Expression of cyanobacterial genes enhanced CO2 assimilation and biomass production in transgenic Arabidopsis thaliana

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11860
Author(s):  
Anum Zeb Abbasi ◽  
Misbah Bilal ◽  
Ghazal Khurshid ◽  
Charilaos Yiotis ◽  
Iftikhar Zeb ◽  
...  

Background Photosynthesis is a key process in plants that is compromised by the oxygenase activity of Rubisco, which leads to the production of toxic compound phosphoglycolate that is catabolized by photorespiratory pathway. Transformation of plants with photorespiratory bypasses have been shown to reduce photorespiration and enhance plant biomass. Interestingly, engineering of a single gene from such photorespiratory bypasses has also improved photosynthesis and plant productivity. Although single gene transformations may not completely reduce photorespiration, increases in plant biomass accumulation have still been observed indicating an alternative role in regulating different metabolic processes. Therefore, the current study was aimed at evaluating the underlying mechanism (s) associated with the effects of introducing a single cyanobacterial glycolate decarboxylation pathway gene on photosynthesis and plant performance. Methods Transgenic Arabidopsis thaliana plants (GD, HD, OX) expressing independently cyanobacterial decarboxylation pathway genes i.e., glycolate dehydrogenase, hydroxyacid dehydrogenase, and oxalate decarboxylase, respectively, were utilized. Photosynthetic, fluorescence related, and growth parameters were analyzed. Additionally, transcriptomic analysis of GD transgenic plants was also performed. Results The GD plants exhibited a significant increase (16%) in net photosynthesis rate while both HD and OX plants showed a non-significant (11%) increase as compared to wild type plants (WT). The stomatal conductance was significantly higher (24%) in GD and HD plants than the WT plants. The quantum efficiencies of photosystem II, carbon dioxide assimilation and the chlorophyll fluorescence-based photosynthetic electron transport rate were also higher than WT plants. The OX plants displayed significant reductions in the rate of photorespiration relative to gross photosynthesis and increase in the ratio of the photosynthetic electron flow attributable to carboxylation reactions over that attributable to oxygenation reactions. GD, HD and OX plants accumulated significantly higher biomass and seed weight. Soluble sugars were significantly increased in GD and HD plants, while the starch levels were higher in all transgenic plants. The transcriptomic analysis of GD plants revealed 650 up-regulated genes mainly related to photosynthesis, photorespiratory pathway, sucrose metabolism, chlorophyll biosynthesis and glutathione metabolism. Conclusion This study revealed the potential of introduced cyanobacterial pathway genes to enhance photosynthetic and growth-related parameters. The upregulation of genes related to different pathways provided evidence of the underlying mechanisms involved particularly in GD plants. However, transcriptomic profiling of HD and OX plants can further help to identify other potential mechanisms involved in improved plant productivity.

2020 ◽  
Author(s):  
Alejandra B Garcia ◽  
Hannah Locke ◽  
Kerri M Crawford

Abstract Aims Linkages formed through aquatic-terrestrial subsidies can play an important role in structuring communities and mediating ecosystem functions. Aquatic-terrestrial subsidies may be especially important in nutrient-poor ecosystems, such as the freshwater sand dunes surrounding Lake Michigan. Adult midges emerge from Lake Michigan in the spring, swarm to mate, and die. Their carcasses form mounds at the base of plants, where they may increase plant productivity through their nutrient inputs. However, the effect of aquatic-terrestrial subsidies on plant productivity could depend on other biotic interactions. In particular, soil microbes might play a key role in facilitating the conversion of nutrients to plant-available forms or competing for the nutrients by plants. Methods In a greenhouse experiment, we tested how carcasses from lake-emergent midges (Chironomidae) and soil microbes independently and interactively influenced the performance of a common dune grass, Calamovilfa longifolia. To determine whether midges influenced abiotic soil properties, we measured how midge additions influenced soil nutrients and soil moisture. Important findings Midges greatly increased plant biomass, while soil microbes influenced the magnitude of this effect. In the absence of soil microbes plant biomass was 7 times greater with midges than without midges. However, in the presence of soil microbes, plant biomass was only 3 times greater. The effect of midges might be driven by their nutrient inputs into the soil, as midges contained 100 times more N, 10 times more P, and 150 times more K than dune soils did. Our results suggest that soil microbes may be competing with plants for these nutrients. In sum, we found that midges can be an important aquatic-terrestrial subsidy that produces strong, positive effects on plant productivity along the shorelines of Lake Michigan, but that the impact of aquatic-terrestrial subsidies must be considered within the context of the complex interactions that take place within ecological communities.


2016 ◽  
Vol 5 (07) ◽  
pp. 4694 ◽  
Author(s):  
Viliana Vasileva ◽  
Anna Ilieva

In pot trial the biochemical composition and phosphorus use efficiency of birdsfoot trefoil, sainfoin and subterranean clover grown pure and in mixtures with perennial ryegrass in the next ratios were studied in the Institute of Forage Crops, Pleven, Bulgaria: birdsfoot trefoil + perennial ryegrass (50:50%); sainfoin + perennial ryegrass (50:50%); subterranean clover + perennial ryegrass (50:50%); birdsfoot trefoil + subterranean clover + perennial ryegrass (33:33:33%); sainfoin + subterranean clover + perennial ryegrass (33:33:33%). The highest crude protein content was found in the aboveground mass of birdsfoot trefoil (19.17%) and sainfoin (19.30%). The water soluble sugars contents in mixtures was found higher compared to the pure grown legumes. Birdsfoot trefoil showed the highest phosphorus use efficiency for plant biomass accumulation and nodules formation. In mixtures the phosphorus use efficiency was found be higher as compared to the same in pure grown legumes.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Guiomar Martín ◽  
Yamile Márquez ◽  
Federica Mantica ◽  
Paula Duque ◽  
Manuel Irimia

Abstract Background Alternative splicing (AS) is a widespread regulatory mechanism in multicellular organisms. Numerous transcriptomic and single-gene studies in plants have investigated AS in response to specific conditions, especially environmental stress, unveiling substantial amounts of intron retention that modulate gene expression. However, a comprehensive study contrasting stress-response and tissue-specific AS patterns and directly comparing them with those of animal models is still missing. Results We generate a massive resource for Arabidopsis thaliana, PastDB, comprising AS and gene expression quantifications across tissues, development and environmental conditions, including abiotic and biotic stresses. Harmonized analysis of these datasets reveals that A. thaliana shows high levels of AS, similar to fruitflies, and that, compared to animals, disproportionately uses AS for stress responses. We identify core sets of genes regulated specifically by either AS or transcription upon stresses or among tissues, a regulatory specialization that is tightly mirrored by the genomic features of these genes. Unexpectedly, non-intron retention events, including exon skipping, are overrepresented across regulated AS sets in A. thaliana, being also largely involved in modulating gene expression through NMD and uORF inclusion. Conclusions Non-intron retention events have likely been functionally underrated in plants. AS constitutes a distinct regulatory layer controlling gene expression upon internal and external stimuli whose target genes and master regulators are hardwired at the genomic level to specifically undergo post-transcriptional regulation. Given the higher relevance of AS in the response to different stresses when compared to animals, this molecular hardwiring is likely required for a proper environmental response in A. thaliana.


2019 ◽  
Vol 59 (3) ◽  
pp. 535-547 ◽  
Author(s):  
Julieta A Rosell

Abstract Most biological structures carry out multiple functions. Focusing on only one function to make adaptive inferences overlooks that manifold selection pressures and tradeoffs shape the characteristics of a multifunctional structure. Focusing on single functions can only lead to a partial picture of the causes underlying diversity and the evolutionary origin of the structure in question. I illustrate this discussion using bark as a study case. Bark comprises all the tissues surrounding the xylem in woody plants. Broadly, bark includes an inner and mostly living region and an outer, dead one. Of all plant structures, bark has the most complex anatomical structure and ontogenetic origin involving two (and often three) different meristems. Traditionally, the wide diversity in bark traits, mainly bark thickness, has been interpreted as the result of the selective pressures imposed by fire regime. However, recent research has shown that explanations based on fire regime cannot account for salient patterns of bark variation globally including the very strong inner bark thickness–stem diameter scaling, which is likely due to metabolic needs, and the very high intracommunity variation in total, inner, and outer bark thickness, and in inner:outer proportions. Moreover, explanations based on fire disregard that in addition to fire protection, bark carries out several other crucial functions for plants including translocation of photosynthates; storage of starch, soluble sugars, water, and other compounds; protection from herbivores, pathogens, and high temperatures; wound closure, as well as mechanical support, photosynthesis, and likely being involved in xylem embolism repair. All these functions are crucial for plant performance and are involved in synergistic (e.g., storage of water and insulation) and trade-off relationships (e.g., protection from fire vs photosynthetic activity). Focusing on only one of these functions, protection from fire has provided an incomplete picture of the selective forces shaping bark diversity and has severely hindered our incipient understanding of the functional ecology of this crucial region of woody stems. Applying a multifunctional perspective to the study of bark will allow us to address why we observe such high intracommunity variation in bark traits, why some bark trait combinations are ontogenetically impossible or penalized by selection, how bark is coordinated functionally with other plant parts, and as a result, to understand how bark contributes to the vast diversity of plant ecological strategies across the globe.


1999 ◽  
Vol 22 (2) ◽  
pp. 159-167 ◽  
Author(s):  
E. S. JENKINS ◽  
W. PAUL ◽  
M. CRAZE ◽  
C. A. WHITELAW ◽  
A. WEIGAND ◽  
...  

2018 ◽  
Vol 115 (45) ◽  
pp. E10778-E10787 ◽  
Author(s):  
Chia Pao Voon ◽  
Xiaoqian Guan ◽  
Yuzhe Sun ◽  
Abira Sahu ◽  
May Ngor Chan ◽  
...  

Matching ATP:NADPH provision and consumption in the chloroplast is a prerequisite for efficient photosynthesis. In terms of ATP:NADPH ratio, the amount of ATP generated from the linear electron flow does not meet the demand of the Calvin–Benson–Bassham (CBB) cycle. Several different mechanisms to increase ATP availability have evolved, including cyclic electron flow in higher plants and the direct import of mitochondrial-derived ATP in diatoms. By imaging a fluorescent ATP sensor protein expressed in livingArabidopsis thalianaseedlings, we found that MgATP2−concentrations were lower in the stroma of mature chloroplasts than in the cytosol, and exogenous ATP was able to enter chloroplasts isolated from 4- and 5-day-old seedlings, but not chloroplasts isolated from 10- or 20-day-old photosynthetic tissues. This observation is in line with the previous finding that the expression of chloroplast nucleotide transporters (NTTs) inArabidopsismesophyll is limited to very young seedlings. Employing a combination of photosynthetic and respiratory inhibitors with compartment-specific imaging of ATP, we corroborate the dependency of stromal ATP production on mitochondrial dissipation of photosynthetic reductant. Our data suggest that, during illumination, the provision and consumption of ATP:NADPH in chloroplasts can be balanced by exporting excess reductants rather than importing ATP from the cytosol.


Author(s):  
Vasil Atanasov ◽  
Lisa Fürtauer ◽  
Thomas Nägele

Diurnal and seasonal changes of abiotic environmental factors shape plant performance and distribution. Changes of growth temperature and light intensity may vary significantly on a diurnal, but also on a weekly or seasonal scale. Hence, acclimation to a changing temperature and light regime is essential for plant survival and propagation. In the present study, we analyzed photosynthetic CO2 assimilation and metabolic regulation of the central carbohydrate metabolism in two natural accessions of Arabidopsis thaliana originating from Russia and south Italy during exposure to heat and a combination of heat and high light. Our findings indicate that it is hardly possible to predict photosynthetic capacities to fix CO2 under combined stress from single stress experiments. Further, capacities of hexose phosphorylation were found to be significantly lower in the Italian than in the Russian accession which could explain an inverted sucrose-to-hexose ratio. Together with the finding of significantly stronger accumulation of anthocyanins under heat/high light these observations indicate a central role of hexokinase activity in stabilization of photosynthetic capacities within a changing environment.


2021 ◽  
Vol 20 (1) ◽  
pp. 71-80
Author(s):  
Anousheh Zakeri ◽  
Ramazan-Ali Khavari-Nejad ◽  
Sara Saadatmand ◽  
Fatemeh Nouri Kootanaee ◽  
Rouzbeh Abbaszadeh

The effects of magnetic waves as natural environmental factors on the Earths are not well known on plant growth and development. The present study was carried out to evaluate the effects of static magnetic field (SMF) treatment (4 and 6 mT for 30 and 120 min per day) for eight days on the biomass production, proline contents and total soluble sugar, phenolic compounds, accumulation of H2O2 and MDA along with activity of antioxidant enzymes in lemon balm seedlings. Our results showed that SMF treatments, especially 6 mT and 120 min duration, increased the plant biomass, proline contents, phenolic compounds, H2O2 and MDA accumulation, and reduced the contents of total soluble sugars. The SMF application also increased the activity of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) enzymes compared to untreated seedlings. Our results suggest that SMF treatments induces the antioxidant defense system in the lemon balm seedlings and, by changing the plant metabolism, improves the early vigor of seedlings.


2004 ◽  
Vol 109 (7) ◽  
pp. 1512-1518 ◽  
Author(s):  
M. Labra ◽  
C. Vannini ◽  
F. Grassi ◽  
M. Bracale ◽  
M. Balsemin ◽  
...  

2020 ◽  
Vol 47 (5) ◽  
pp. 454
Author(s):  
Jian Li ◽  
Tian Chen ◽  
Fengzhen Huang ◽  
Penghui Dai ◽  
Fuxiang Cao ◽  
...  

Serious seed abortion of dove tree (Davidia involucrate Baill.) is one of the critical factors leading to the low fecundity of this species. Seed abortion is a complicated process and various factors have been verified to synergistically determine the fate of seeds. To reveal the mechanism of seed abortion in D. involucrata, we performed transcriptome analysis in normal and abortive seeds of D. involucrata. According to the transcriptome data, we noticed that most of the genes encoding a MYB transcription factor were predominantly expressed in abortive seeds. Among these, a gene named DiMYB1 was selected and its function was validated in this study. Overexpression of DiMYB1 resulted in obviously reduced viability of transgenic seeds and seedlings, and caused a significantly higher seed abortion rate. The vegetative growth of transgenic plants was hindered, resulting in an earlier flowering time. In addition, colour changes occurred in transgenic plants. Some transgenic sprouts, stems and pods appeared purple instead of green in colour. Our finding demonstrated that DiMYB1 participates in multiple plant developmental processes, especially in seed development in Arabidopsis thaliana (L.) Heynh., which indicated the similar role of this gene in D. involucrata.


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