Photosynthetic contribution and characteristics of cucumber stem and petiole

2021 ◽  
Author(s):  
Weike Sun ◽  
Ning Ma ◽  
Hongyu Huang ◽  
Jingwei Wei ◽  
Si Ma ◽  
...  
Keyword(s):  
Photosynthetic Rate ◽  
Leaf Blade ◽  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Total Carbon ◽  
Photochemical Quenching ◽  
Gene Expressions ◽  
Chlorophyll Metabolism ◽  
Chlorophyll Contents ◽  
Stomata Size

Abstract Background Photosynthesis of plant non-leaf blade green tissue has been studied in some plants, but the photosynthesis characteristics of stem and petiole are poorly understood. Cucurbitaceous plants are climbing plants, and have a large biomass of stem and petiole. Understanding the photosynthetic contribution of cucumber stem and petiole to growth and the underlying molecular mechanisms are important for the regulation of growth in cucumber production. Results Here, the photosynthetic capacity of cucumber stem and petiole were proved by 14CO2 uptake. The total carbon fixation of stem and petioles is around 4% to that of one leaf blade in cucumber seedling stage, while the proportion of carbon accumulated in stem and petioles redistributed to sink organs (root and growing point) is increased obviously under leaf less condition. Photosynthetic properties of cucumber stem and petiole were studied using a combination of electron microscopy, chlorophyll fluorescence imaging and isotope tracer to compare with leaf blade using two genotype of cucumber (dark green and light green stems). Compare with leaf blade, chlorophyll contents of cucumber stem and petiole are lower, and accompanying with lower chloroplast number, lower stoma number, but with higher thylakoid grana lamella number and larger stomata size. The total photosynthetic rate of stem and petiole is equivalent to 6 ~ 8% of one leaf blade, but the respiration rates were simiar in all the three tissues, which shown an almost 0 net photosynthetic rate in stems and petioles, and with lower non-photochemical quenching (NPQ). Transcriptome analysis showed that compared with leaf blade, there are significantly different gene expressions in photosynthesis, porphyrin and chlorophyll metabolism, photosynthetic antenna proteins and carbon fixation in stem and petiole. Although with lower Rubisco expression level in stem and petiole, Rubisco and PEPC enzyme activities were both higher in stem and petiole than in leaf blade, suggesting the photosynthetic and respiratory mechanisms in stem and petiole are different from those in leaf blade. Conclusions In this study, we confirmed the photosynthetic contribution to growth of cucumber stem and petiole, and shown their similar photosynthetic pattern in tissue anatomy, molecular biology and physiology.

scholarly journals Photosynthetic contribution and characteristics of cucumber stems and petioles

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Weike Sun ◽  
Ning Ma ◽  
Hongyu Huang ◽  
Jingwei Wei ◽  
Si Ma ◽  
...  
Keyword(s):  
Gene Expression ◽  
Leaf Blade ◽  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Total Carbon ◽  
Chlorophyll Metabolism ◽  
Chl A ◽  
Chlorophyll Contents ◽  
Dark Green ◽  
Photosynthetic Antenna

Abstract Background Photosynthesis in the green leafless blade tissues or organs of plants has been studied in some plants, but the photosynthetic characteristics of stems and petioles are poorly understood. Cucurbitaceous plants are climbing plants that have substantial stem and petiole biomass. Understanding the photosynthetic contribution of cucumber stems and petioles to their growth and the underlying molecular mechanisms are important for the regulating of growth in cucumber production. Results In this study, the photosynthetic capacity of cucumber stems and petioles were determined by 14CO2 uptake. The total carbon fixed by the stems and petioles was approximately 4% of that fixed by one leaf blade in the cucumber seedling stage, while the proportion of the carbon accumulated in the stems and petioles that redistributed to sink organs (roots and shoot apexes) obviously increased under leafless conditions. The photosynthetic properties of cucumber stems and petioles were studied using a combination of electron microscopy and isotope tracers to compare these properties of stems and petioles with those of leaf blade using two genotypes of cucumber (dark green and light green). Compared with those of the leaf blades, the chlorophyll contents of the cucumber stems and petioles were lower, and the stems and petioles had lower chloroplast numbers and lower stoma numbers but higher thylakoid grana lamella numbers and larger stoma sizes. The Chl a/b ratios were also decreased in the petioles and stems compared with those in the leaf blades. The total photosynthetic rates of the stems and petioles were equivalent to 6 ~ 8% of that of one leaf blade, but the respiration rates were similar in all the three organs, with an almost net 0 photosynthetic rate in the stems and petioles. Transcriptome analysis showed that compared with the leaf blades, the stems and petioles has significantly different gene expression levels in photosynthesis, porphyrin and chlorophyll metabolism; photosynthetic antenna proteins; and carbon fixation. PEPC enzyme activities were higher in the stems and petioles than in the leaf blades, suggesting that the photosynthetic and respiratory mechanisms in stems and petioles are different from those in leaf blade, and these results are consistent with the gene expression data. Conclusions In this study, we confirmed the photosynthetic contribution to the growth of cucumber stems and petioles, and showed their similar photosynthetic patterns in the terms of anatomy, molecular biology and physiology, which were different from those of cucumber leaf blades.

scholarly journals Evaluation of Photosynthetic Characters and Regulation Pattern of Photosynthesis Associated Gene in Two Mulberry Varieties

2021 ◽  
Vol 25 (04) ◽  
pp. 863-872
Author(s):  
Yong Li
Keyword(s):  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Metabolic Pathways ◽  
Carbon Fixation ◽  
Expression Patterns ◽  
Photochemical Efficiency ◽  
High Yield ◽  
Photochemical Quenching ◽  
Chlorophyll Metabolism ◽  
Photosynthetic Organisms

Photosynthetic characteristics and expression patterns of the photosynthesis-related genes in the high-yield mulberry variety E’Sang 1 (E1) and normal mulberry variety Husang 32 (H32) were investigated in this study. The observation of daily variation of photosynthesis in E1 and H32 indicated that the peak of net photosynthetic rate(Pn)inE1 variety was significantly higher than that inH32 (P <0.05). Meanwhile, the Pn-PAR and Pn-Ci responses of E1 and H32 were evaluated, and the results showed that the carboxylation efficiency and compensation saturation point were much higher in E1 rather thanH32. Importantly, the photosystem II actual photochemical efficiency and photochemical quenching coefficient in the leaves of E1 were significantly higher than those in H32 (P<0.05). Also, the activity of RuBP in E1 was higher than that in H32 (P >0.05). Based on the RNA-seq data, a total of 3,356 differentially expressed genes (DEGs) were detected among different time points between E1 and H32. Of these, 1,136 DEGs were involved in the metabolic pathways, including three main photosynthesis-related metabolic pathways (i.e., carbon fixation in photosynthetic organisms, carbon metabolism, and porphyrin and chlorophyll metabolism). Meanwhile, 10 novel DEGs related to photosynthesis were detected, and four potential key genes of them could account for the differences in net photosynthetic rate and yield betweenH32 and E1.This study could provide important insights into the molecular breeding of mulberry varieties with high photosynthetic efficiency and contribute to understanding the genetic mechanism of photosynthesis.© 2021 Friends Science Publishers

scholarly journals Balancing energy supply during photosynthesis - a theoretical perspective

2018 ◽  
Author(s):  
Anna Matuszyńska ◽  
Nima P. Saadat ◽  
Oliver Ebenhöh
Keyword(s):  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Supply And Demand ◽  
Theoretical Perspective ◽  
Photosynthetic Electron Transport ◽  
C3 Plants ◽  
Photochemical Quenching ◽  
Dark Light ◽  
Dynamic Description

The photosynthetic electron transport chain (PETC) provides energy and redox equivalents for carbon fixation by the Calvin-Benson-Bassham (CBB) cycle. Both of these processes have been thoroughly investigated and the underlying molecular mechanisms are well known. However, it is far from understood by which mechanisms it is ensured that energy and redox supply by photosynthesis matches the demand of the downstream processes. Here, we deliver a theoretical analysis to quantitatively study the supply-demand regulation in photosynthesis. For this, we connect two previously developed models, one describing the PETC, originally developed to study non-photochemical quenching, and one providing a dynamic description of the photosynthetic carbon fixation in C3 plants, the CBB Cycle. The merged model explains how a tight regulation of supply and demand reactions leads to efficient carbon fixation. The model further illustrates that a stand-by mode is necessary in the dark to ensure that the carbon fixation cycle can be restarted after dark-light transitions, and it supports hypotheses, which reactions are responsible to generate such mode in vivo.

scholarly journals Physiological and transcriptome analyses of photosynthesis and chlorophyll metabolism in variegated Citrus (Shiranuhi and Huangguogan) seedlings

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bo Xiong ◽  
Xia Qiu ◽  
Shengjia Huang ◽  
Xiaojia Wang ◽  
Xu Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Chlorophyll Biosynthesis ◽  
Expression Patterns ◽  
Sequencing Error ◽  
Sequencing Data ◽  
Chlorophyll Metabolism ◽  
Regulatory Pathways ◽  
Chlorophyll Contents ◽  
Kegg Pathways ◽  
And Function

Abstract Citrus species are among the most economically important fruit crops. Physiological characteristics and molecular mechanisms associated with de-etiolation have been partially revealed. However, little is known about the mechanisms controlling the expression and function of genes associated with photosynthesis and chlorophyll biosynthesis in variegated citrus seedlings. The lower biomass, chlorophyll contents, and photosynthetic parameter values recorded for the variegated seedlings suggested that chlorophyll biosynthesis was partially inhibited. Additionally, roots of the variegated seedlings were longer than the roots of green seedlings. We obtained 567.07 million clean reads and 85.05 Gb of RNA-sequencing data, with more than 94.19% of the reads having a quality score of Q30 (sequencing error rate = 0.1%). Furthermore, we detected 4,786 and 7,007 differentially expressed genes (DEGs) between variegated and green Shiranuhi and Huangguogan seedlings. Thirty common pathways were differentially regulated, including pathways related to photosynthesis (GO: 0015979) and the chloroplast (GO: 0009507). Photosynthesis (44 and 63 DEGs), photosynthesis-antenna proteins (14 and 29 DEGs), and flavonoid biosynthesis (16 and 29 DEGs) pathways were the most common KEGG pathways detected in two analyzed libraries. Differences in the expression patterns of PsbQ, PetF, PetB, PsaA, PsaN, PsbP, PsaF, Cluster-2274.8338 (ZIP1), Cluster-2274.38688 (PTC52), and Cluster-2274.78784 might be responsible for the variegation in citrus seedlings. We completed a physiological- and transcriptome-level comparison of the Shiranuhi and Huangguogan cultivars that differ in terms of seedling variegation. We performed mRNA-seq analyses of variegated and green Shiranuhi and Huangguogan seedlings to explore the genes and regulatory pathways involved in the inhibition of chlorophyll biosynthesis and decreases in Chl a and Chl b contents. The candidate genes described herein should be investigated in greater detail to further characterize variegated citrus seedlings.

scholarly journals Comparative Transcriptomic Analysis Provides Novel Insights into the Blanched Stem of Oenanthe javanica

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2484
Author(s):  
Sunjeet Kumar ◽  
Xinfang Huang ◽  
Gaojie Li ◽  
Qun Ji ◽  
Kai Zhou ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Agricultural Field ◽  
Chlorophyll Metabolism ◽  
Photosynthetic Organisms ◽  
And Control ◽  
Indole 3 Acetic Acid ◽  
Comparative Transcriptomic Analysis ◽  
Water Dropwort

In the agricultural field, blanching is a technique used to obtain tender, sweet, and delicious water dropwort stems by blocking sunlight. The physiological and nutritional parameters of blanched water dropwort have been previously investigated. However, the molecular mechanism of blanching remains unclear. In the present study, we investigated transcriptomic variations for different blanching periods in the stem of water dropwort (pre, mid, post-blanching, and control). The results showed that many genes in pathways, such as photosynthesis, carbon fixation, and phytohormone signal transduction as well as transcription factors (TFs) were significantly dysregulated. Blanched stems of water dropwort showed the higher number of downregulated genes in pathways, such as photosynthesis, antenna protein, carbon fixation in photosynthetic organisms, and porphyrin and chlorophyll metabolism, which ultimately affect the photosynthesis in water dropwort. The genes of hormone signal transduction pathways (ethylene, jasmonic acid, brassinosteroid, and indole-3-acetic acid) showed upregulation in the post-blanched water dropwort plants. Overall, a higher number of genes coding for TFs, such as ERF, BHLH, MYB, zinc-finger, bZIP, and WRKY were overexpressed in blanched samples in comparison with the control. These genes and pathways participate in inducing the length, developmental processes, pale color, and stress tolerance of the blanched stem. Overall, the genes responsive to blanching, which were identified in this study, provide an effective foundation for further studies on the molecular mechanisms of blanching and photosynthesis regulations in water dropwort and other species.

scholarly journals Physiological and Transcriptome Analysis Reveals the Differences in Nitrate Content Between Lamina and Midrib of Flue-Cured Tobacco

2021 ◽  
Author(s):  
Yuqing Feng ◽  
Yuanyuan Zhao ◽  
Yafei Li ◽  
Jun Zhou ◽  
Yujing Li ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
High Capacity ◽  
Carotenoid Biosynthesis ◽  
Nitrate Content ◽  
Nitrate Accumulation ◽  
N Content ◽  
Chlorophyll Metabolism ◽  
Tobacco Specific Nitrosamines

Abstract Nitrate is an important precursor of tobacco-specific nitrosamines (TSNAs) and remarkable difference in nitrate accumulation between lamina and midrib of flue-cured tobacco has long been observed. However, the physiological and molecular mechanisms underpinning this difference remain poorly understood. In this study, physiological and genetic factors impacting nitrate accumulation were identified in pot experiments using flue-cured tobacco K326 with contrasting nitrate content between lamina and midrib. The results showed that three times higher of NO3-N content was observed in midrib than that in lamina, along with lower pigment, NH4-N content, NRA, SSA and GSA in midrib. Transcriptome analysis revealed that expression of genes involved in porphyrin and chlorophyll metabolism, carotenoid biosynthesis, photosynthesis-antenna proteins, photosynthesis, carbon fixation in photosynthetic organisms, starch and sucrose metabolism, nitrogen metabolism and biosynthesis of amino acids were significantly lower in midrib than in lamina. qRT-PCR results showed that the expression level of nitrate transporter genes LOC107782967, LOC107806749, LOC107775674, LOC107829632, LOC107799198, LOC107768465 decreased by 2.74, 1.81, 49.5, 3.5, 2.64 and 2.96 folds while LOC107789301 increased by 8.23 folds in midrib but not in lamina. Reduced chlorophyll content might result in low carbohydrate formation which is the source of energy and carbon skeleton supply, then the low capacity of nitrogen reduction, assimilation and transportation, and the poor ability of nitrate reallocation but high capacity of accumulation might lead to nitrate accumulation in midrib. The results laid the foundation for reducing nitrate content and TSNA formation in tobacco midribs and their products.

scholarly journals Lincomycin-Induced Transcriptional Alterations in the Green Alga Raphidocelis subcapitata

2020 ◽  
Vol 10 (23) ◽  
pp. 8565
Author(s):  
Qiang Zhang ◽  
Yi Bai ◽  
Zhi Chen ◽  
Jiezhang Mo ◽  
Yulu Tian ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Algal Growth ◽  
Nucleotide Metabolism ◽  
Chlorophyll Metabolism ◽  
Treatment Groups ◽  
Raphidocelis Subcapitata ◽  
Genes Encoding ◽  
Transcriptional Alterations ◽  
Coa Reductase

Lincomycin (LIN), as a waterborne contaminant, may pose a threat to algal health and may affect the provision of ecosystem services. In addition, the molecular mechanisms of lincomycin in algae are still unknown. Here, we attempted to use the transcriptome analysis to elucidate for the first time the potential impact of LIN at an environmentally relevant concentration on the algal growth, and verify the hypothesis that lincomycin can disrupt algal protein synthesis by combining with its subunits of ribosome at high-LIN level. In this study, 7-day growth inhibition tests and RNA-seq sequencing were conducted in Raphidocelis subcapitata (R. subcapitata) in response to a LIN at the concentrations of 0.5 µg L−1 (low), 5 µg L−1 (medium), and 400 µg L−1 (high) treatment groups. A negligible influence on algal growth and merely 21 (21 up- and 0 downregulated) differentially expressed genes (DEGs) was observed at low concentration of LIN, and medium groups showed a 13.4% inhibition and 92 (64 up- and 48 downregulated) DEGs, while high-LIN dosing caused 65.4% reduction in algal growth and 2514 (663 up- and 1851 downregulated) DEGs. In 0.5 and 5 µg L−1 groups, LIN upregulated the genes in the process of photosynthesis consisting of photosynthesis-antenna proteins, and porphyrin and chlorophyll metabolism pathways, suggesting that photosynthesis at low LIN exposure was more sensitive than algal growth. Whereas DEGs in the 400 µg L−1 group were mostly enriched in carbohydrate, carbon fixation in photosynthetic organisms, and nucleotide metabolism pathways. Furthermore, genes involved in detoxification processes were nearly downregulated in high-LIN group. In addition, genes encoding the antioxidant enzymes in the peroxisome pathway such as superoxide dismutase (sod2), peroxin-2 (pex2), 2,4-dienoyl-CoA reductase ((3E)-enoyl-CoA-producing) (decr2) were upregulated, which are responsible for deleting extra intracellular reactive oxygen species (ROS) caused by LIN to protect algal health, suggesting the occurrence of oxidative stress. Taken together, this is the first meticulous study unraveling the molecular mechanism of antibiotics in algae.

High Altitude hypoxia

2020 ◽  
Vol 17 ◽  
Author(s):  
Asma Babar ◽  
Kifayatullah Mengal ◽  
Abdul Hanan Babar ◽  
Shixin Wu ◽  
Mujahid Ali Shah ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
High Altitude ◽  
Molecular Mechanisms ◽  
Strong Association ◽  
Haemoglobin Concentration ◽  
Metabolic Reprogramming ◽  
Molecular Networks ◽  
Whole Genome ◽  
Gene Expressions ◽  
Transcriptional Responses

: The world highest and largest altitude area is called the Qinghai-Tibetan plateau (QTB), which harbors unique animal and plant species. Mammals that inhabit the higher altitude regions have adapted well to the hypoxic conditions. One of the main stressors at high altitude is hypoxia. Metabolic responses to hypoxia play important roles in cell survival strategies and some diseases. However, the homeostatic alterations that equilibrate variations in the demand and supply of energy to maintain organismal function in a prolonged low O2 environment persist partly understood, making it problematic to differentiate adaptive from maladaptive responses in hypoxia. Tibetans and yaks are two perfect examples innate to the plateau for high altitude adaptation. By the scan of the whole-genome, EPAS1 and EGLN1 were identified as key genes associated with sustained haemoglobin concentration in high altitude mammals for adaptation. The yak is a much more ancient mammal which has existed on QTB longer than humans, it is, therefore, possible that natural selection represented a diverse group of genes/pathways in yaks. Physiological characteristics are extremely informative in revealing molecular networks associated with inherited adaptation, in addition to the whole-genome adaptive changes at the DNA sequence level. Gene-expression can be changed by a variety of signals originating from the environment, and hypoxia is the main factor amongst them. The hypoxia-inducible factors (HIF-1α and EPAS1/HIF-2α) are the main regulators of oxygen in homeostasis which play a role as maestro regulators of adaptation in hypoxic reaction of molecular mechanisms. (Vague) The basis of this review is to present recent information regarding the molecular mechanism involved in hypoxia that regulates candidate genes and proteins. Many transcriptional responses toward hypoxia are facilitated by HIFs that change the number of gene expressions and help in angiogenesis, erythropoiesis, metabolic reprogramming and metastasis. HIFs also activate several signals highlighting a strong association between hypoxia, the misfolded proteins’ accumulation in the endoplasmic reticulum in stress and activation of unfolded protein response (UPR). It was observed that at high-altitude, pregnancies yield a low birth weight ∼100 g per1000 m of the climb. (Vague) It may involve variation in the events of energy-demanding, like protein synthesis. Prolonged hypobaric hypoxia causes placental ER stress, which in turn, moderates protein synthesis and reduces proliferation. Further, Cardiac hypertrophy by cytosolic Ca2+ raises and Ca2+/calmodulin, calcineurin stimulation, NF-AT3 pathway might be caused by an imbalance in Sarcoplasmic reticulum ER Ca2, might be adaptive in beginning but severe later.

scholarly journals Progress in understanding the role of lncRNA in programmed cell death

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Na Jiang ◽  
Xiaoyu Zhang ◽  
Xuejun Gu ◽  
Xiaozhuang Li ◽  
Lei Shang
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Molecular Mechanisms ◽  
Membrane Receptors ◽  
Gene Expressions ◽  
Apoptosis Pathway ◽  
Stem Cell Pluripotency ◽  
Extrinsic Apoptosis ◽  
Related Proteins ◽  
Cycle Regulation

AbstractLong non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides but not translated into proteins. LncRNAs regulate gene expressions at multiple levels, such as chromatin, transcription, and post-transcription. Further, lncRNAs participate in various biological processes such as cell differentiation, cell cycle regulation, and maintenance of stem cell pluripotency. We have previously reported that lncRNAs are closely related to programmed cell death (PCD), which includes apoptosis, autophagy, necroptosis, and ferroptosis. Overexpression of lncRNA can suppress the extrinsic apoptosis pathway by downregulating of membrane receptors and protect tumor cells by inhibiting the expression of necroptosis-related proteins. Some lncRNAs can also act as competitive endogenous RNA to prevent oxidation, thereby inhibiting ferroptosis, while some are known to activate autophagy. The relationship between lncRNA and PCD has promising implications in clinical research, and reports have highlighted this relationship in various cancers such as non-small cell lung cancer and gastric cancer. This review systematically summarizes the advances in the understanding of the molecular mechanisms through which lncRNAs impact PCD.

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