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 Difference between Burley Tobacco and Flue-Cured Tobacco in Nitrate Accumulation and Chemical Regulation of Nitrate and TSNA Contents

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Yafei Li ◽  
Hongzhi Shi ◽  
Huijuan Yang ◽  
Jun Zhou ◽  
Jing Wang ◽  
...  
Keyword(s):  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Growth Period ◽  
Fast Growth ◽  
Nitrate Content ◽  
Maturity Stage ◽  
Nitrate Accumulation ◽  
Burley Tobacco ◽  
Tobacco Specific Nitrosamines ◽  
Growth Experiments

Tobacco-specific nitrosamines (TSNAs) are harmful carcinogens, with nitrate as a precursor of their formation. Nitrate content is considerably higher in burley tobacco than in flue-cured tobacco, but little has been reported on the differences between types of nitrate accumulation during development. We explored nitrate accumulation prior to harvest and examined the effects of regulatory substances aimed at decreasing nitrate and TSNA accumulation. In growth experiments, nitrate accumulation in burley and flue-cured tobacco initially increased but then declined with the highest nitrate content observed during a fast-growth period. When treating tobacco crops with molybdenum (Mo) during fast growth, nitrate reductase activity in burley tobacco increased significantly, but the NO3-N content decreased. These treatments also yielded significant reductions in NO3-N and TSNA contents. Therefore, we suggest that treatment with Mo during the fast-growth period and a Mo-Gfo (Mo-glufosinate) combination at the maturity stage is an effective strategy for decreasing nitrate and TSNAs during cultivation.

scholarly journals A Review of Environment Effects on Nitrate Accumulation in Leafy Vegetables Grown in Controlled Environments

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 732
Author(s):  
Zhonghua Bian ◽  
Yu Wang ◽  
Xiaoyan Zhang ◽  
Tao Li ◽  
Steven Grundy ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Molecular Mechanisms ◽  
Management Strategies ◽  
Leafy Vegetables ◽  
Future Research ◽  
Nitrate Content ◽  
Vegetable Production ◽  
Nitrate Accumulation ◽  
Potential Threat ◽  
Controlled Environments

Excessive accumulation of nitrates in vegetables is a common issue that poses a potential threat to human health. The absorption, translocation, and assimilation of nitrates in vegetables are tightly regulated by the interaction of internal cues (expression of related genes and enzyme activities) and external environmental factors. In addition to global food security, food nutritional quality is recognized as being of strategic importance by most governments and other agencies. Therefore, the identification and development of sustainable, innovative, and inexpensive approaches for increasing vegetable production and concomitantly reducing nitrate concentration are extremely important. Under controlled environmental conditions, optimal fertilizer/nutrient element management and environmental regulation play vital roles in producing vegetables with low nitrate content. In this review, we present some of the recent findings concerning the effects of environmental factors (e.g., light, temperature, and CO2) and fertilizer/nutrient solution management strategies on nitrate reduction in vegetables grown under controlled environments and discuss the possible molecular mechanisms. We also highlight several perspectives for future research to optimize the yield and nutrition quality of leafy vegetables grown in controlled environments.

scholarly journals Simultaneous changes in anthocyanin, chlorophyll, and carotenoid contents produce green variegation in pink–leaved ornamental kale

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yang Liu ◽  
Xin Feng ◽  
Yuting Zhang ◽  
Fuhui Zhou ◽  
Pengfang Zhu
Keyword(s):  
Molecular Mechanisms ◽  
Color Change ◽  
Anthocyanin Biosynthesis ◽  
Carotenoid Biosynthesis ◽  
Anthocyanin Content ◽  
Leaf Color ◽  
Chlorophyll Metabolism ◽  
Leaf Coloration ◽  
New Varieties ◽  
Ornamental Kale

Abstract Background Anthocyanin, chlorophyll, and carotenoid pigments are widely distributed in plants, producing various colors. Ornamental kale (Brassica oleracea var. acephala DC) which has colorful inner leaves is an ideal plant to explore how these three pigments contribute to leaf color. The molecular mechanisms of the coloration in ornamental kale could provide reference for exploring the mechanisms of pigmentation in other plants. Results In this study, we sequenced the transcriptome and determined the pigment contents of an unusual cultivar of ornamental kale with three different types of leaf coloration: pink (C3), light pink (C2), and variegated pink–green (C1). A total of 23,965 differentially expressed genes were detected in pairwise comparisons among the three types of leaves. The results indicate that Bo9g058630 coding dihydroflavonol 4–reductase (DFR) and Bo3g019080 coding shikimate O–hydroxycinnamoyltransferase (HCT) acted in anthocyanin biosynthesis in pink leaves. Bo1g053420 coding pheophorbidase (PPD) and Bo3g012430 coding 15–cis–phytoene synthase (crtB) were identified as candidate genes for chlorophyll metabolism and carotenoid biosynthesis, respectively. The transcription factors TT8, MYBL2, GATA21, GLK2, and RR1 might participate in triggering the leaf color change in ornamental kale. Anthocyanin content was highest in C3 and lowest in C1. Chlorophyll and carotenoid contents were lowest in C2 and highest in C1. Conclusions Based on these findings, we suspected that the decrease in anthocyanin biosynthesis and the increase in chlorophyll and carotenoid biosynthesis might be the reason for the leaf changing from pink to variegate pink–green in this unusual cultivar. Our research provides insight into the molecular mechanisms of leaf coloration in ornamental kale, contributing to a theoretical foundation for breeding new varieties.

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 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 Physiological and Transcripts Analyses Reveal the Mechanism by Which Melatonin Alleviates Heat Stress in Chrysanthemum Seedlings

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaojuan Xing ◽  
Yurong Ding ◽  
Jinyu Jin ◽  
Aiping Song ◽  
Sumei Chen ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Dry Weight ◽  
Carotenoid Biosynthesis ◽  
Antioxidant Enzyme Activities ◽  
Chlorophyll Metabolism ◽  
Heat Stress Response ◽  
Shock Proteins

Heat stress limits the growth and development of chrysanthemum seedlings. Although melatonin (MT) has been linked to the heat stress response in plants, research on the underlying molecular mechanisms is scarce. In this study, the regulatory networks of MT on heat stress in chrysanthemum seedlings were explored. Physiological measurements suggested that MT not only reduced malondialdehyde accumulation, hydrogen peroxide content, and superoxide anion free radical generation rate, but also significantly promoted osmotic regulation substance synthesis (proline and soluble protein), antioxidant accumulation (GSH and AsA), and the antioxidant enzyme activities (SOD, POD, CAT, and APX) in chrysanthemum leaves under heat stress. Furthermore, MT increased the fresh weight, dry weight, chlorophyll content, photosynthesis rate, and gas exchange indexes. Further, RNA-seq results revealed 33,497 and 36,740 differentially expressed genes in the S/Con and SMT/ConMT comparisons, respectively. The differences in the comparisons revealed that MT regulated heat shock transcription factors (HSFs) and heat shock proteins (HSPs), and the genes involved in Ca2+ signal transduction (CNGCs and CAM/CMLs), starch and sucrose metabolism (EDGL, BGLU, SuS, and SPS), hormone (PP2Cs, AUX/IAAs, EBFs, and MYC2), chlorophyll metabolism (HEMA and PORA), flavonoid biosynthesis (CHS, DFR, and FNS), and carotenoid biosynthesis (DXPS, GGDP, and PSY). MT effectively improved chrysanthemum seedling heat-resistance. Our study, thus, provides novel evidence of a gene network regulated by MT under heat stress.

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 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.

scholarly journals Comparative transcriptomic and metabolomic analyses of carotenoid biosynthesis reveal the basis of white petal color in Brassica napus

Planta ◽  
2021 ◽  
Vol 253 (1) ◽  
Author(s):  
Ledong Jia ◽  
Junsheng Wang ◽  
Rui Wang ◽  
Mouzheng Duan ◽  
Cailin Qiao ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Molecular Mechanisms ◽  
Flower Color ◽  
Carotenoid Biosynthesis ◽  
Differentially Expressed ◽  
Transcriptome Data ◽  
Oilseed Crops ◽  
Qrt Pcr ◽  
Carotenoid Metabolism ◽  
Rapeseed Cultivar

Abstract Main conclusion The molecular mechanism underlying white petal color in Brassica napus was revealed by transcriptomic and metabolomic analyses. Abstract Rapeseed (Brassica napus L.) is one of the most important oilseed crops worldwide, but the mechanisms underlying flower color in this crop are known less. Here, we performed metabolomic and transcriptomic analyses of the yellow-flowered rapeseed cultivar ‘Zhongshuang 11’ (ZS11) and the white-flowered inbred line ‘White Petal’ (WP). The total carotenoid contents were 1.778-fold and 1.969-fold higher in ZS11 vs. WP petals at stages S2 and S4, respectively. Our findings suggest that white petal color in WP flowers is primarily due to decreased lutein and zeaxanthin contents. Transcriptome analysis revealed 10,116 differentially expressed genes with a fourfold or greater change in expression (P-value less than 0.001) in WP vs. ZS11 petals, including 1,209 genes that were differentially expressed at four different stages and 20 genes in the carotenoid metabolism pathway. BnNCED4b, encoding a protein involved in carotenoid degradation, was expressed at abnormally high levels in WP petals, suggesting it might play a key role in white petal formation. The results of qRT-PCR were consistent with the transcriptome data. The results of this study provide important insights into the molecular mechanisms of the carotenoid metabolic pathway in rapeseed petals, and the candidate genes identified in this study provide a resource for the creation of new B. napus germplasms with different petal colors.

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