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Environmental and experimental botany
Pergamon Press,
Environmental and experimental botany

Pergamon Press,

0098-8472

Environmental and experimental botany/Journal Environmental and experimental botanySCIISTP
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    Heavy metal tolerance strategies in metallicolous and non-metallicolous populations of mosses: Insights of gamma plus beta-tocopherol regulatory role

    Cogoni, AnnalenaCortis, PierluigiVacca, AndreaBecerril, Jose Maria...
    14页
    查看更多>>摘要：As bryophytes present the capacity to colonize a wide range of habitats, including extreme environments (e.g., mine areas), we first checked the global response of bryophytes to heavy metals (HM) by a systematic review. This analysis found i) the lack of studies in a polluted environment and ii) resulted in a global trend of photochemical efficiency decrease when bryophytes faced heavy metals. Secondly, we characterized the photoprotective responses of four metallicolous populations of mosses (Lewinskya rupestris, Polytrichum commune, Ptychostomum compactum and Rhynchostegium confertum) naturally growing in an abandoned mine area by an experimental field approach. As a result, we found markedly species-specific tolerance patterns: i) less tolerant species, presenting high pollutants content accompanied by marked dissipative and antioxidative strategies. This strategy was depicted by the species R. confertum that result to be a good sentinel species due to the high pollutant content and high physiological sensitivity.; ii) intermediate tolerant species presenting a medium content of pollutants and less marked photoprotective mechanisms, and iii) most tolerant species minimizing pollutants content and consequently presenting no changes in their physiological performance. This evidence support that species' bryological attributes have a key role in determining species' tolerance towards environmental heavy metals, and should be taken into consideration in future studies. The findings of this study also pointed out that the higher levels of gamma + beta-tocopherol in metallicolous populations could play a regulatory role in metal stress tolerance in mosses and it could be a suitable functional responsive trait for environmental response prediction to heavy metals in polluted environments.
      原文链接:
    • NSTL
    • Elsevier

    Low nitrogen level improves low-light tolerance in tall fescue by regulating carbon and nitrogen metabolism

    Wen, SuyunLiu, BowenLong, SiGao, Shuanghong...
    13页
    查看更多>>摘要：Low-light (LL) stress is a primary factor contributing to turf deterioration. Previous studies have recommended the use of reduced nitrogen (N) fertility for maintaining turf grasses and improving their LL tolerance. However, the mechanism for turf grass susceptibility to LL-induced stress is still unclear. The present study investigated the role of low N in improving tall fescue photosynthesis under LL stress by regulating carbon and N metabolism. The LL stress significantly reduced tiller numbers, biomass, chlorophyll content, net photosynthetic rate (Pn), the maximum quantum yield of photosystem photochemistry (Fv/Fm), actual photochemical efficiency of photosystem II (Phi(PSII)), and the carbon and N contents in roots and leaves. The stress also reduced the sugars contents but increased the C/N ratio in the roots and leaves. However, low N alleviated the effects of LL stress by significantly increasing the tiller numbers, root length, root-to-shoot ratio, and sugars contents in roots. Under low light and low nitrogen (40 mu mol m(-2) s(-1) PPFD + 1.0 mM N, LN-) conditions, the tiller number, Pn, soluble sugar content and protein content in the roots increased by 24.72%, 19.43%, 71.91%, and 16.05%, respectively, compared to the low light and normal nitrogen (40 mu mol m(-2) s(-1) PPFD + 6.0 mM N, LN) conditions. Additionally, the activities of sucrose synthase (SS), glutamate dehydrogenase (GDH), and total amylase (AMY) in leaves and the activity of glutamate synthase (GOGAT) in roots were also remarkably enhanced by the low N level. Subsequently, a total of 514 metabolites were detected by non-targeted metabolomics analysis. There were 83 and 173 differential metabolites in the LL stress and control leaves and roots, respectively. Meanwhile, 54 and 67 differential metabolites were also detected in the leaves and roots under LN treatment and LN-treatment, respectively. The KEGG analysis showed that the LN-treatment significantly affected carbon and amino acid metabolism in tall fescue. Conversely, organic acids, amino acids, nucleic acids, and their respective derivatives were reduced in response to LL-induced stress. Furthermore, the LN-treatment enhanced the citrate cycle and increased the glucose and sucrose contents compared to the LN treatment. In addition, the asparagine level was significantly reduced in the leaves but significantly increased in the roots under LN-treatment. Thus, these results indicated that low N level increases photosynthesis by regulating the balance between carbon and N metabolism in the roots and leaves, thereby improving tolerance to LL-induced stress.
      原文链接:
    • NSTL
    • Elsevier

    An integrated analysis of transcriptome and metabolome provides insights into the responses of maize (Zea mays L.) roots to different straw and fertilizer conditions

    Zhang, YulanXiao, JiahuiLiu, PeiyongZhang, Ying...
    19页
    查看更多>>摘要：Returning straw back to the field with an appropriate amount of fertilizer has been proven to be beneficial in the promotion of soil fertility, crop yield, and the sustainability of an agricultural system. However, little is known regarding the molecular and metabolic understandings of enhanced crop growth in a straw return system. By performing an integrated transcriptomic and metabolomics analysis, we investigated the effects of straw removal and straw return with two chemical fertilizer rates on root morphology in a mesh bag field experiment on maize in northwest China. Our results showed that straw return played a role in root thickening (bigger root diameter), while fertilization enhanced root branching (more root number). Different from straw return alone, straw return with fertilizer significantly decreased the root/shoot ratio (p < 0.01) and increased the total root number (p < 0.01), and root total nitrogen concentration (p < 0.001). Root morphological responses were tightly associated with transcriptional regulation (e.g., root dry weight, Mantel's r = 0.6468, p < 0.001) and metabolism modulation (e.g., root/shoot ratio, Mantel's r = 0.7229, p < 0.001), mainly including the activation of genes related to phenylpropanoid and flavonoid metabolic pathways (e.g., BGLU, PAL and POD), the fine regulation of genes associated with auxin synthesis, homeostasis, flow and signaling (e.g., YUC, AUX1 and SAUR), and cell wall remodeling (e.g., CESA and EXPA), and the regulation of transcription factors and genes that function in the development of roots (primary, seminal, and lateral), root hairs, root tips, and root caps (e.g., BBM, LRP1 and RTCS), and the accumulation of different metabolites (e.g., indole, esculin, and sucrose) under straw return with fertilization. We revealed important insights into the growth-promoting and morphology-modifying effects of straw return, as well as its highly novel effects on the transcriptional regulation and metabolism reprogram of maize root, which may help to elucidate how maize roots respond under straw return conditions to optimize soil resource acquisition and then guide the suitable utilization of crop residue resources in the agricultural system.
      原文链接:
    • NSTL
    • Elsevier

    A novel sweetpotato GATA transcription factor, IbGATA24, interacting with IbCOP9-5a positively regulates drought and salt tolerance

    Zhu, HongHe, ShaozhenZhang, HuanGao, Shaopei...
    13页
    查看更多>>摘要：The GATA family is a group of zinc finger transcription factors that plays important roles in regulating developmental processes. However, the functions of GATA family members in the response of plants to drought and salt stress remain poorly studied. Here, we isolated a novel GATA gene (IbGATA24) from sweetpotato. The expression of IbGATA24 was strongly induced by PEG6000, NaCl, and abscisic acid (ABA) treatments. IbGATA24 was located in the nucleus and exhibited no transactivation activity. IbGATA24-overexpressing plants showed significantly enhanced tolerance to drought and salt stress. The leaf water loss rate and the leaf stomatal aperture of overexpression plants were significantly decreased. Genes involved in abscisic acid and jasmonic acid signaling pathways, and reactive oxygen species scavenging were up-regulated in transgenic plants under drought and salt treatments. The ABA, JA, and proline content and the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly higher, and the accumulation of malondialdehyde (MDA) and H2O2 was lower, in transgenic plants than in wild-type plants under stress conditions. IbGATA24 could interact with constitutive photomorphogenesis 9-5a (COP9-5a). Overexpression of IbCOP9-5a enhanced drought and salt stress resistance through regulating ABA and reactive oxygen species (ROS) accumulating. These results suggest that IbGATA24 interacting with IbCOP9-5a plays a positive regulatory role in abiotic stress tolerance. Our study identified a novel GATA transcription factor that could be used to improve the tolerance of sweetpotato and other plants to abiotic stress.
      原文链接:
    • NSTL
    • Elsevier

    Genotype-dependent and temperature-induced modulation of secondary metabolites, antioxidative defense and gene expression profile in Solanum viarum Dunal

    Patel, PreetiPrasad, ArchanaSrivastava, DipaliNiranjan, Abhishek...
    14页
    查看更多>>摘要：The medicinal plant, Solanum viarum Dunal includes a number of compounds with important pharmacological effects. The effect of temperature (heat and cold) stress on growth, secondary metabolite levels and defense mechanism in two genotypes (prickled and prickleless) of S. viarum was evaluated. The two thermal regimes (4 degrees C for cold and 35 degrees C for heat stress) were found to be the most optimum for the accumulation of metabolites (steroidal alkaloids and glycoalkaloids, phenolic acids as well as flavonoids). Prickleless genotype showed 4.08 and 1.51 fold higher total alkaloids/glycoalkaloid content at 35 degrees C and 4 degrees C temperatures respectively, in comparison with prickled plants. Prickleless plants also registered 2.03 and 2.28 higher fresh and dry biomass accumulation respectively, under cold stress over the control plants. The accretion of phenolic and flavonoid compounds under heat and cold stress is mainly contributed by gallic and ferulic acid in both the genotypes. The quantitative real-time PCR expression analysis showed the abundance of gene transcript involve in the biosynthesis of alkaloids/glycoalkaloid and phenolics/flavonoids that corroborates with the accumulation of their respective metabolites in prickleless plants under temperature stress. Results revealed that the prickleless plants inhibiting the reactive oxygen species (ROS) mediated oxidative damage by activating the enzymatic (superoxide dismutase, peroxidase, catalase and ascorbate peroxidase) and non-enzymatic (alkaloids, phenols, flavonoids, carotenoids and proline) antioxidants mechanism that confirms its efficiency to tolerate thermal stress under both the thermal regimes. The overall result showed that the prickleless genotype served as a better accumulator of biomass, secondary metabolites with an improved antioxidative mechanism in comparison to prickled genotype. Our findings suggest that thermal stress responses differ significantly between genotypes, emphasizing the necessity of maintaining genotypic diversity in adaptive evolution as in the context of global warming and climate change. The present study also opens the possibility of exploiting improved prickleless genotype of S. viarum as a potential system that can be cultivated under different temperature stress conditions to attain the phytopharmaceutical benefits.
      原文链接:
    • NSTL
    • Elsevier

    Genome-wide association mapping of genotype-environment interactions affecting yield-related traits of spring wheat grown in three watering regimes

    Said, Alaa A.MacQueen, Alice H.Shawky, HaithamReynolds, Matthew...
    9页
    查看更多>>摘要：Genotype-environment interaction (GxE) has a great impact on wheat physiology, morphology and grain yield (GY). We evaluated an association mapping panel of spring wheat advanced lines for chlorophyll content, canopy temperature (CT), and yield-related traits under three different watering regimes in two consecutive growing seasons. Genome-wide association mapping identified 457 SNPs, with significant effects that varied with the watering regimes and growing seasons, of which 199 and 69 SNPs showed pleiotropic and conditionally neutral effects, respectively, on the measured traits. We mapped 61 SNPs with effects higher than 10% on all traits, showing antagonistic pleiotropic effects on CT, corresponding to 46 genes; some of these genes represent good candidates to control wheat response to water availability. Surprisingly, no significant SNPs were mapped in the semi-dwarfing genes, Rht-B1b or Rht-D1b. However, haplotype analysis of the SNPs located at the positions of both genes revealed significant interactions of GY with the watering regimes for Rht-B1b and with the growing season for Rht-D1b. We selected genotypes that outperformed two local check cultivars; some of them overlapped across the three watering regimes and could be used to create a multi-parent population to further unravel the genetic factors underlying yield component traits across drought stress. Our results demonstrate the importance of incorporating GxE in mapping models to better understand wheat response to different watering regimes and to select stable markers for selection.
      原文链接:
    • NSTL
    • Elsevier

    Insights into salt tolerance of mustard (Brassica juncea L. Czern & Coss): A metabolomics perspective

    Singh, JogendraSingh, VijayataWalia, NishaKumawat, Gayatri...
    14页
    查看更多>>摘要：Salt stress is one of the key abiotic factor which leads to reduced global agricultural productions through negatively impacting the growth and development of crops. Indian mustard (Brassica juncea), the most important cruciferous crop with significant nutritional and medicinal values, is majorly affected by salt stress. In this study, we explored the global metabolomic response of two Indian mustard genotypes, CS 60 and CS 245-2-80-7 grown under salt stress for different time periods to unleash the role of differentially accumulated metabolites and relevant metabolic pathways involved in the salt tolerance mechanism. A total of 608 known compounds were detected from 4119 metabolites using DionexUltiMate (R) 3000 Ultra High-Performance Liquid Chromatographic System combined with "Q ExactiveTM Plus OrbitrapTM Mass Spectrometer (UHPLC-MS/MS) analysis, from which 111 significantly altered metabolites in both genotypes were selected based on t-test and VIP score values. Using MetPa from MetaboAnalyst 5.0 platform, metabolic pathways with significant impact values were considered to be involved in the salt tolerance mechanism. Increased accumulation of metabolites and detected relevant pathways majorly regulating the anti-oxidant defense system gives CS 60, a high yielding variety, an edge against the genotype CS 245-2-80-7, which might be the chief tolerance mechanism to withstand salt stress.
      原文链接:
    • NSTL
    • Elsevier

    Low-level cadmium exposure influences rice resistance to herbivores by priming jasmonate signaling

    Chen, YumengHuang, JiangnanWei, JiqianLiu, Xiaoli...
    10页
    查看更多>>摘要：The heavy metal, cadmium (Cd), has become a new threat to rice production in paddy fields. Cd is absorbed by rice roots and translocated to shoots, where it accumulates in different tissues. Rice is also commonly attacked by insect herbivores, but the effects of low-level Cd exposure on the performance of rice pests and the underlying mechanisms remain unexplored. We investigated brown planthopper (BPH) performance on Cd-exposed rice in the laboratory and field. Low-level Cd exposure did not significantly affect rice growth but decreased hatching rate and extended hatching duration of BPH eggs. No direct toxic effect of low Cd exposure on BPH eggs were found in in vitro developmental rate assays. By transcriptome analysis, a total of 747 rice genes were differentially expressed in Cd-exposed plants under BPH attack. Interestingly, BPH-elicited jasmonate (JA) and phenylpropanoid pathway genes were up-regulated by Cd exposure. Consistently, the levels of JAs and JA-mediated phenylpropanoid derivatives were also increased. Furthermore, Cd exposure did not affect BPH performance on mutant plants impaired in JA biosynthesis (aoc-2) and signaling (myc2-5), suggesting that JA is required to influence BPH performance under Cd exposure. In the field, herbivore populations were reduced on Cd-treated plants compared with control plants. This study revealed that low-level Cd exposure primes JA-mediated defense responses in rice and thereby affects herbivore performance.
      原文链接:
    • NSTL
    • Elsevier

    How far can chlorophyll a fluorescence detect phosphorus status in wheat leaves (Triticum durum L.)

    El-Mejjaouy, YousraLahrir, MeryemeNaciri, RachidaZeroual, Youssef...
    9页
    查看更多>>摘要：Phosphorus (P) is an essential macronutrient for crop growth and food production since it is involved in many biochemical processes in plants. Its deficiency causes physiological, biochemical, and morphological changes. These visual changes occur when the photosynthetic apparatus system is already damaged, and they are often irreversible. Consequently, it is necessary to develop novel methods for determining nutritional plant status early in the season for rapid intervention in crop production. This challenge can be tackled using emerging techniques for crop monitoring and rapid detection of stresses. Chlorophyll a fluorescence has proved its potential to detect early abiotic stresses effects on photosynthetic efficiency. Here, we evaluate the potential of this technique to assess phosphorus status in wheat leaves (Triticum durum L.), grown in different concentrations of phosphorus insured by different fertilizer forms (two orthophosphates and one polyphosphate). Results have shown a significant effect of the applied P concentration and fertilizer form on P leaves uptake at an early development stage and improved chlorophyll content index. Phosphorus level and fertilizer form were found to affect also the kinetics of the Chlorophyll a fluorescent transient (OJIP-transient) and related fluorescence parameters. Three predictive models were generated and compared. The results from partial least squares regression (PLSR) performed on fluorescence parameters with cross-validation (CV) were: the root mean square error and the determination coefficient of cross-validation (RMSECV = 0.095 and R2 = 0.67, respectively). The obtained model predicted phosphorus leaf content with RMSE of prediction (RMSEP) of 0.079 g 0.100 g-1 and R2 of 0.56. Results showed that the generated PLS predictive model using chlorophyll a fluorescence parameters has some potential to detect phosphorus status in wheat fresh leaves and can be highly informative about the photosynthetic apparatus state under P deficiency.
      原文链接:
    • NSTL
    • Elsevier

    Tamarix hispida ThEIL1 improves salt tolerance by adjusting osmotic potential and increasing reactive oxygen species scavenging capability

    Shi, XinxinHe, YutingWang, ZhiboLiu, Zhujun...
    15页
    查看更多>>摘要：The ETHYLENE INSENSITIVE 3-LIKE (EIL) transcription factor (TF) family plays a key role in the ethylene signal transduction pathway. However, it is still unknown how EIL proteins mediate salt tolerance in Tamarix hispida. Here, we cloned and functionally characterized the TF ThEIL1 from T. hispida. ThEIL1 is a nuclear protein possessing transcriptional activation activity. In addition to binding to the PERE motif (GGATTCAA), a novel EIL protein-DNA interaction was identified, in which ThEIL1 binds to GCC-box (AGCCGCC). Gain- and loss-offunction analysis in T. hispida showed that ThEIL1 regulates the expression of trehalose-6-phosphate synthase (TPS), pyrroline-5-carboxylate synthetase (P5CS), and trehalose-6-phosphate phosphatase (TPP) to mediate the biosynthesis of proline and trehalose, respectively, thereby elevating osmotic potential. Additionally, ThEIL1 controls the activities of peroxidase (POD) and superoxide dismutase (SOD) by regulating the expression of genes encoding SODs and PODs, leading to increased reactive oxygen species scavenging capability. Moreover, overexpression of ThEIL1 in Arabidopsis significantly increased root length and fresh weight under salt treatment conditions. Furthermore, the physiological traits of T. hispida were consistent with those of Arabidopsis stably overexpressing ThEIL1. Thus, ThEIL1 serves as a TF that mediates salt tolerance by elevating osmotic potential and improving ROS scavenging capability.
      原文链接:
    • NSTL
    • Elsevier