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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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    VvERF17 mediates chlorophyll degradation by transcriptional activation of chlorophyll catabolic genes in grape berry skin

    Lu, SuwenZhang, MengweiZhuge, YaxianFu, Weihong...
    10页
    查看更多>>摘要：Chlorophylls in the skin contribute to grape (Vitis vinifera) berry color and quality. Degradation of chlorophyll occurs during berry development in grape, but less is known about the molecular mechanisms of this process. Here, we characterized an ethylene response factor, VvERF17, as a putative regulator of chlorophyll degradation in grape berry. VvERF17 expression was strongly correlates with development-induced and ETH-triggered chlorophyll degradation. Transient overexpression of VvERF17 in tobacco leaves, tomato fruits, and grape leaves led to color break and chlorophyll degradation, which were resulted from the upregulated expression of chlorophyll catabolic genes (CCGs), including Chlorophyll-b-reductase (NOL), pheophytinase (PPH), pheophorbide a oxygenase (PAO), and red Chlorophyll catabolite reductase (RCCR). Inversely, silencing of VvERF17 in grape leaves partially suppressed the expression of CCGs' expression. Major CCGs' expression was closely related to chlorophyll degradation and VvERF17 expression. It was further demonstrated that VvERF17 could activate the expression of major CCGs by directly binding to the ERF binding sites in their promoters. We conclude that VvERF17 mediates chlorophyll degradation by transcriptional activation of NOL, PPH, PAO, and RCCR. These findings elucidate the regulation mechanisms of chlorophyll degradation in grape and enrich our understanding of grape berry color formation.
      原文链接:
    • NSTL
    • Elsevier

    Arbuscular mycorrhizal fungi and nitrilotriacetic acid regulated Suaeda salsa growth in Cd-contaminated saline soil by driving rhizosphere bacterial assemblages

    Li, XueZhang, ZhechaoLuo, JunqingCui, Xi...
    11页
    查看更多>>摘要：Phytoremediation is an environmentally friendly method to remediate heavy metal contaminated saline soil. Arbuscular mycorrhizal fungi (AMF) and biodegradable chelators have potential roles in enhancing the phytoremediation efficiency, while their combined effects are largely unexplored. This study was objected to evaluate the effects of AMF and nitrilotriacetic acid (NTA) on phytoremediation using Suaeda salsa. A pot experiment consisting of four treatments (CK, AMF, NTA and AMF + NTA) was conducted for this purpose. The results showed that the shoot and root biomass of Suaeda salsa ranged from 1.84 to 5.86 mg kg(-1) and 0.09 to 0.48 mg kg(-1) respectively, and were the highest in the AMF + NTA treatment. The AMF + NTA treatment enhanced the Na accumulation by 116 % and 490 %, and enhanced Cd accumulation by 61 % and 33 %, respectively, in plant shoots and roots compared with the CK. The AMF treatment significantly promoted the dominance of Actinobacteria (mainly including Arenimonas, Gaiella, Nocardioides and Marmoricola), whereas the AMF + NTA treatment enhanced that of Proteobacteria (mainly including Aminobacter, Candidatus_Paracaedibacter, Longimicrobium and Flavitalea) in rhizosphere bacterial communities. Network analysis revealed that the bacteria related to Cd were independent from that related to Na in the AMF treatment, but they were consistent in the AMF + NTA treatment. Structural equation modeling further confirmed that single application of AMF or NTA affected plant growth both directly and indirectly, and their combined application could further promote phytoremediation efficiency by enhancing the interactions among bacteria, soil and plants. This study not only proved the benefit of the combined application of AMF and NTA to the improvement of phytoremediation efficiency, but also provided insights into the mechanisms for the improvement from the perspective of rhizosphere microbial community changes.
      原文链接:
    • NSTL
    • Elsevier

    Zinc-induced anti-oxidative defense and osmotic adjustments to enhance drought stress tolerance in sunflower (Helianthus annuus L.)

    Jan, Amin UllahHadi, FazalDitta, AllahSuleman, Muhammad...
    9页
    查看更多>>摘要：Zinc (Zn) is an essential micronutrient for plant growth and development and plays a vital role in drought stress tolerance. To explore the physiological mechanisms of drought stress tolerance improved by exogenous application of Zn in sunflower, a hydroponic experiment was conducted. The present study comprised of two factors i. e. PEG-6000 induced drought stress for 0, 7, and 14 days and Zn treatments (0, 1, and 3 mu M ZnSO4), arranged in a completely randomized factorial design. Exogenous application of Zn significantly boosted the photosynthetic pigments i.e. chlorophyll a (31.2 %), chlorophyll b (35.9 %), photosynthetic rate (41.7 %), and shoot (44.0 %) and root dry matter (38.7 %) of sunflower under PEG-6000 induced drought stress compared to the control without any Zn treatment. In comparison to control, antioxidant enzymes activities, i.e. ascorbate peroxidase, superoxide dismutase and catalase and non-enzymatic antioxidant i.e. ascorbic acid were significantly enhanced by 57.1, 26.6, 62.3, and 38.3 %, respectively while the malondialdehyde (MDA) contents reduced by 83.5 % with exogenous application 3 mu M ZnSO4 under PEG-6000 induced drought stress. The same treatment enhanced osmoregulatory substances such as soluble proteins (79.5 %) and free proline contents (70.5 %) under PEG-6000 induced drought stress as compared to control. Relative water contents showed highly significant positive correlation with free proline (R-2 = 0.95), soluble proteins (R-2 = 0.98), superoxide dismutase (R-2 = 0.91) and negative correlation with MDA contents (R-2 = 0.91). It is concluded that exogenous application Zn enhanced anti-oxidative defense and osmotic adjustment and ultimately drought stress tolerance in sunflower (Helianthus annuus L.).
      原文链接:
    • NSTL
    • Elsevier

    Interaction of gravitropism and phototropism in roots of Brassica oleracea

    Romano, Leone ErmesMuthert, Lucius Wilhelminus FranciscusIovane, MaurizioCapozzi, Fiore...
    10页
    查看更多>>摘要：Gravitropism and phototropism play a primary role in orienting root growth. Tropistic responses of roots mediated by gravity and light have been extensively investigated, and a complex mutual interaction occurs between these two tropisms. To date, most studies have been conducted in 1 g, microgravity, or simulated microgravity, whereas no studies investigated root phototropism in hypergravity. Therefore, we studied the effects of several gravity treatments with those of different light wavelengths on root growth orientation. Here, we report growth and curvature of Brassica oleracea roots under different g levels, from simulated microgravity up to 20 g, and unilateral illumination with different spectral treatments provided by light emitting diodes. Microgravity was simulated with a random positioning machine whereas hypergravity conditions were obtained using the Large Diameter Centrifuge at the laboratories of the European Space Agency in the Netherlands. Four light treatments (white light, blue light, red light, and dark) were used in this study. Overall, roots of seedlings grown in the dark were longer than those developed under unilateral light treatments, regardless of the gravity level. Unilateral blue light or white light stimulated a negative phototropism of roots under all g levels, and root curvature was not affected by either hypergravity or simulated microgravity compared to 1 g. Results also confirmed previous findings on the effect of light intensity on root curvature and highlighted the relevance of blue-light photon flux density in root phototropism. Roots illuminated with red light showed a weak curvature in simulated microgravity but not in hypergravity. Moreover, root curvature under red light was similar to darkgrown roots in all g levels, suggesting a possible involvement of surface-dependent phenomena in root skewing under either red light or dark conditions. Further studies can confirm phototropic responses of B. oleracea in the weightless environment of orbiting spacecraft. Nevertheless, according to our findings, directional lighting represents an effective stimulus to guide root growth in a wide range of gravity conditions.
      原文链接:
    • NSTL
    • Elsevier

    Proline accumulation, ion homeostasis and antioxidant defence system alleviate salt stress and protect carbon assimilation in bread wheat genotypes of Omani origin

    Al Hinai, Marwa SulaimanUllah, AmanAl-Rajhi, Rashid SaidFarooq, Muhammad...
    9页
    查看更多>>摘要：In this study, the responses of bread wheat genotypes of Omani origin to salt stress (40, 80, and 120 mM NaCl) were evaluated to elucidate the salt tolerance mechanism. The tested bread wheat genotypes varied significantly for their responses to different levels of salt stress. A significant decrease in plant growth and carbon assimilation was noted under salt stress and this reduction increased with an increase in salinity levels. However, salinity caused a significant increase in the tissue sodium and chloride, malondialdehyde contents, leaf proline, and activities of antioxidant enzymes. The genotype SIS-12 was least affected for growth and carbon assimilation under all levels of salt stress. This genotype also had the lowest tissue sodium and leaf malondialdehyde contents, and the highest proline and catalase activity under all levels of salt stress. This was followed by genotypes Sayreea and Messani Black whereas the genotypes Bahree, Messani White, Waleedi and Cooley were sensitive to salt stress. The microsatellite loci showed a high value of polymorphism information content (PIC) ranging from 0.73 to 0.87, with an average of 0.81 PIC. The genotypes with higher proline, activities of catalase and superoxide dismutase, and lower tissue sodium and chloride levels were better able to sustain growth under salt stress. These traits and a moderate level of genetic diversity in Omani wheat genotypes can be used in future breeding programs to develop salt-tolerant wheat genotypes.
      原文链接:
    • NSTL
    • Elsevier

    From the effective herbicide to the environmental contaminant: A review of recent studies on quinclorac

    Song, DeanJiang, XiaohuaWang, DabinFang, Song...
    9页
    查看更多>>摘要：Quinclorac is a specific auxin herbicide with chloro-quinolinecarboxylic acid structure and has been widely recognized as the preferred option for controlling both broadleaf weed and barnyard grass. However, the extensive application of quinclorac has resulted in the evolution of resistant plants, the frequent detection in the environment, and the hazard to non-target organisms. Consequently, the aim of this review is to comprehensively summarize the recent investigations on quinclorac, so as to help promoting the further study for reasonably employing quinclorac and effectively controlling the related risks. In this review, the action mechanism of quinclorac was discussed based on the structure and property, suggesting the involvements of ethylene, phytohormone and even cyanide in sensitive plants. The evolved resistance might be related to auxin production, gene expression, translocation and metabolism. By establishing the reliable methods in previous studies, the quinclorac residue was widely detected and could cause the obvious toxicity such as physiological changes and oxidative stress. Nevertheless, there is still a lack of the remediation technique, which can be efficiently applied in practical engineering.
      原文链接:
    • NSTL
    • Elsevier

    SlMAPK3 enhances tolerance to salt stress in tomato plants by scavenging ROS accumulation and up-regulating the expression of ethylene signaling related genes

    Li, YujingLi, ZiyeSheng, JipingShen, Lin...
    10页
    查看更多>>摘要：Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction stimulus decoder that can translate extracellular signals into intracellular responses and play a crucial role in plant biotic and abiotic stress responses. However, no direct evidence of SlMAPK3 in response to salt stress of tomato plants had been obtained until now. Here, SlMAPK3 over-expression line (OE.MAPK3-5) and SlMAPK3 knock-out line (slmapk3-8) were used to investigate the role of SlMAPK3 in regulating tomato plants response to salt stress. The results showed that OE.MAPK3-5 plants showed higher fresh weight and seedlings height as well as seminal root length than wild type (WT) plants and slmapk3-8 plants under salt stress, which indicated that SlMAPK3 improved tomato tolerance to salt stress. In addition, knockout of SlMAPK3 increased salt sensitivity as revealed by the accumulation of H2O2 and MDA, reduction of soluble sugar and soluble protein contents, and suppression of antioxidant enzymes activities (POD, SOD, CAT and APX). High salinity induced cell death and chlorophyll degradation were more severe in slmapk3-8 plants but slighter in OE.MAPK3-5 plants compared with WT. Moreover, OE.MAPK3-5 plants exhibited increased expression of salt overly sensitive (SOS) pathway genes (SlSOS1, SlSOS2, SlSOS3) and ethylene signaling pathways genes (SlACS2, SlEIN2, SlERF2) compared with WT and slmapk3-8 plants under salt stress. These results unveil an expected function for SlMAPK3 in tomato plants positively response to salt stress by scavenging ROS accumulation and up-regulating the expression of ethylene signaling related genes.
      原文链接:
    • NSTL
    • Elsevier

    The response of photosystem I to fluctuating light is influenced by leaf nitrogen content in tomato

    Sun, HuZhang, Shi-BaoHuang, WeiShi, Qi...
    9页
    查看更多>>摘要：Fluctuating light and nitrogen (N) deficiency can occur synchronously under natural growth conditions. How-ever, little is known about the photosynthetic regulation under fluctuating light in plants grown with N deficiency. In the present study, we examined the effect of N supply on the response of photosystem I (PSI) to fluctuating light in tomato. Plants grown under high N concentration (HN-plants) had higher leaf N content, chlorophyll content and saturating CO2 assimilation rate than plants grown under middle and low N concentrations (MN- and LN-plants). After an abrupt increase in illumination for 10 s, all plants could not generate a sufficient proton gradient (Delta pH). Meanwhile, PSI was over-reduced in HN-and MN-plants but was highly oxidized in LN-plants. In LN-plants, the smallest PSII electron flow avoided an over-reduction of PSI under fluctuating light. After transition from low to high light, CEF gradually increased to the peak in 30 s in HN-plants but rapidly increased to the peak in 10 s in MN-plants. Such delayed activation of CEF in HN-plants accelerated the over-reduction of PSI. After fluctuating light treatment, HN-plants displayed the greatest PSI photoinhibition, followed by MN-and LN-plants. These results indicated that leaf N content significantly affected the response of PSI to fluctuating light in tomato.
      原文链接:
    • NSTL
    • Elsevier

    The behavior of heavy metals in relation to their influence on the common bean (Phaseolus vulgaris) symbiosis

    Parsa, MehdiHammami, HosseinBayat, HassanAminifard, Mohammad Hossein...
    11页
    查看更多>>摘要：Heavy metals (HMs) concentration is continuously increasing in agricultural soils, mainly through anthropogenic activities. Among HMs, cadmium (Cd), lead (Pb), and nickel (Ni) have shown more hazardous effects on living organs by bioaccumulation throughout the food chain. A pot experiment was arranged as a completely randomized factorial design with four replications to investigate the effects of Cd, Pb, and Ni on biological, physiological, and biochemical responses of common bean (Phaseolus vulgaris). The present study results revealed that Cd, Pb, and Ni effects on biological, physiological, and biochemical characteristics of common bean include root and shoot dry weight, shoot to root ratio, pod number, root and shoot nitrogen content, nodule number, nodule dry weight, photosynthesis pigments, leaf greenness (SPAD), DPPH scavenging, the activity of guaiacol peroxidase (POD), superoxide dismutase (SOD), ascorbate (APX), and Catalase (CAT). HMs toxicity caused a significant decrease in root and shoot dry weight, shoot to root ratio, pod number, root and shoot nitrogen content, nodule number, nodule dry weight, and intensively decreased by increasing HMs concentration in soil. HMs toxicity also decreased photosynthesis pigments and leaf greenness (SPAD). Moreover, biochemical characteristics include DPPH scavenging, POD, SOD, APX, and CAT activities improved by increasing HMs concentration. The findings also revealed that the highest adverse effects on common bean's biological, physiological, and biochemical characteristics were observed at Cd treatments compared to Pb and Ni. BCF, BAC, TF, and TE% for Cd and Ni showed a negative relationship with their concentration in soil. However, TF and TE% were improved by increasing Pb concentration in soil. Therefore, a common bean restricts the absorption and translocation of Cd, Pb, and Ni in highly polluted soil to avoid the toxic effects of Cd and Ni.
      原文链接:
    • NSTL
    • Elsevier

    The metallochaperone OsHIPP56 gene is required for cadmium detoxification in rice crops

    Yang, Zhi MinZhao, Ya NingWang, Mong QiLi, Chao...
    10页
    查看更多>>摘要：Rice (Oryza sativa), a paddy crop, is the major target of Cd contamination in farmland. Limiting Cd accumulation in rice crop and environment is a great challenge for managing cleaner production and food security. This report describes an uncharacterized metallochaperone family gene OsHIPP56 in mediating Cd detoxification and accumulation in the plant. OsHIPP56 resides in the nucleus and plasma membrane, and sufficiently expresses in roots by Cd exposure. Mutation of OsHIPP56 by CRISPR/Cas9 approach leads to compromised growth responses, while transgenic rice overexpressing OsHIPP56 displays phenotypes comparable to the wild-type control. In hydroponic studies with Cd exposure, the knockout mutants had a significantly higher level of Cd in rice tissues, whereas the less Cd was accumulated in the transgenic lines. When the varieties were exposed to 0.5 mu M Cd for 30 days, the Cd concentrations in the mutant lines were increased by 16.9-21.3 % in shoots and 22.6-55.6 % in roots; in contrast, those in the overexpression lines were reduced by 28.1-34.8 % in shoots and 13.5-231 % roots compared to the wild-type. The contrasting Cd accumulation in the two genotypes was well confirmed by the study with rice growing in the soil (0.21 mg/kg Cd) under natural condition. Mutation caused by CRISPR/Cas9 accumulated similarly more Cd in rice straws, seeds and brown rice, whereas the Cd concentrations in the overexpression lines were relatively lower. These results signify that the metal chaperone gene OsHIPP56 is able to repress the cadmium toxicity by reducing Cd accumulation in the crops. Overall, our work contributes to the understanding the functional role of OsHIPP56 in rice detoxification of Cd, which would be potentially applicable for the clean-up of Cd-contaminated wetland and generating cleaner crops with minimal Cd accumulation.
      原文链接:
    • NSTL
    • Elsevier