Browsing by Person "Moradtalab, Narges"

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Effectiveness of bio-effectors on maize, wheat and tomato performance and phosphorus acquisition from greenhouse to field scales in Europe and Israel: a meta-analysis
(2024) Nkebiwe, Peteh Mehdi; Stevens Lekfeldt, Jonas D.; Symanczik, Sarah; Thonar, Cécile; Mäder, Paul; Bar-Tal, Asher; Halpern, Moshe; Biró, Borbala; Bradáčová, Klára; Caniullan, Pedro C.; Choudhary, Krishna K.; Cozzolino, Vincenza; Di Stasio, Emilio; Dobczinski, Stefan; Geistlinger, Joerg; Lüthi, Angelika; Gómez-Muñoz, Beatriz; Kandeler, Ellen; Kolberg, Flora; Kotroczó, Zsolt; Kulhanek, Martin; Mercl, Filip; Tamir, Guy; Moradtalab, Narges; Piccolo, Alessandro; Maggio, Albino; Nassal, Dinah; Szalai, Magdolna Zita; Juhos, Katalin; Fora, Ciprian G.; Florea, Andreea; Poşta, Gheorghe; Lauer, Karl Fritz; Toth, Brigitta; Tlustoš, Pavel; Mpanga, Isaac K.; Weber, Nino; Weinmann, Markus; Yermiyahu, Uri; Magid, Jakob; Müller, Torsten; Neumann, Günter; Ludewig, Uwe; de Neergaard, Andreas
Biostimulants (Bio-effectors, BEs) comprise plant growth-promoting microorganisms and active natural substances that promote plant nutrient-acquisition, stress resilience, growth, crop quality and yield. Unfortunately, the effectiveness of BEs, particularly under field conditions, appears highly variable and poorly quantified. Using random model meta-analyses tools, we summarize the effects of 107 BE treatments on the performance of major crops, mainly conducted within the EU-funded project BIOFECTOR with a focus on phosphorus (P) nutrition, over five years. Our analyses comprised 94 controlled pot and 47 field experiments under different geoclimatic conditions, with variable stress levels across European countries and Israel. The results show an average growth/yield increase by 9.3% (n=945), with substantial differences between crops (tomato > maize > wheat) and growth conditions (controlled nursery + field (Seed germination and nursery under controlled conditions and young plants transplanted to the field) > controlled > field). Average crop growth responses were independent of BE type, P fertilizer type, soil pH and plant-available soil P (water-P, Olsen-P or Calcium acetate lactate-P). BE effectiveness profited from manure and other organic fertilizers, increasing soil pH and presence of abiotic stresses (cold, drought/heat or salinity). Systematic meta-studies based on published literature commonly face the inherent problem of publication bias where the most suspected form is the selective publication of statistically significant results. In this meta-analysis, however, the results obtained from all experiments within the project are included. Therefore, it is free of publication bias. In contrast to reviews of published literature, our unique study design is based on a common standardized protocol which applies to all experiments conducted within the project to reduce sources of variability. Based on data of crop growth, yield and P acquisition, we conclude that application of BEs can save fertilizer resources in the future, but the efficiency of BE application depends on cropping systems and environments.
Loss of LaMATE impairs isoflavonoid release from cluster roots of phosphorus‐deficient white lupin
(2021) Zhou, Yaping; Olt, Philipp; Neuhäuser, Benjamin; Moradtalab, Narges; Bautista, William; Uhde‐Stone, Claudia; Neumann, Günter; Ludewig, Uwe
White lupin (Lupinus albus L.) forms brush‐like root structures called cluster roots under phosphorus‐deficient conditions. Clusters secrete citrate and other organic compounds to mobilize sparingly soluble soil phosphates. In the context of aluminum toxicity tolerance mechanisms in other species, citrate is released via a subgroup of MATE/DTX proteins (multidrug and toxic compound extrusion/detoxification). White lupin contains 56 MATE/DTX genes. Many of these are closely related to gene orthologs with known substrates in other species. LaMATE is a marker gene for functional, mature clusters and is, together with its close homolog LaMATE3, a candidate for the citrate release. Both were highest expressed in mature clusters and when expressed in oocytes, induced inward‐rectifying currents that were likely carried by endogenous channels. No citrate efflux was associated with LaMATE and LaMATE3 expression in oocytes. Furthermore, citrate secretion was largely unaffected in P‐deficient composite mutant plants with genome‐edited or RNAi‐silenced LaMATE in roots. Moderately lower concentrations of citrate and malate in the root tissue and consequently less organic acid anion secretion and lower malate in the xylem sap were identified. Interestingly, however, less genistein was consistently found in mutant exudates, opening the possibility that LaMATE is involved in isoflavonoid release.
Microbial consortia versus single-strain inoculants as drought stress protectants in potato affected by the form of N supply
(2024) Mamun, Abdullah Al; Neumann, Günter; Moradtalab, Narges; Ahmed, Aneesh; Dupuis, Brice; Darbon, Geoffrey; Nawaz, Fahim; Declerck, Stephane; Mai, Karin; Vogt, Wolfgang; Ludewig, Uwe; Weinmann, Markus
This study investigated the drought protection effects of six fungal and bacterial inoculants and ten consortia thereof on vegetative growth, nutritional status, and tuberization of potato under controlled and field conditions. It was hypothesized that microbial consortia offer improved drought protection as compared with single strains, due to complementary or synergistic effects, with differential impacts also of N fertilization management. Under NO3− fertilization, a 70% reduction in water supply over six weeks reduced shoot and tuber biomass of non-inoculated plants by 30% and 50%, respectively, and induced phosphate (P) limitation compared to the well-watered control. The P nutritional status was significantly increased above the deficiency threshold by three single-strain inoculants and eight consortia. This was associated with the presence of the arbuscular mycorrhizal fungus (AMF) inoculant Rhizophagus irregularis MUCL41833 (five cases) and stimulation of root growth (five cases). Additionally, Bacillus amyloliquefaciens FZB42 and AMF + Pseudomonas brassicacearum 3Re2-7 significantly reduced irreversible drought-induced leaf damage after recovery to well-watered conditions. However, the microbial inoculants did not mitigate drought-induced reductions in tuber biomass, neither in greenhouse nor in field experiments. By contrast, NH4+-dominated fertilization significantly increased tuber biomass under drought stress (534%), which was further increased by additional AMF inoculation (951%). This coincided with (i) improved enzymatic detoxification of drought-induced reactive oxygen species (ROS), (ii) improved osmotic adjustment in the shoot tissue (glycine betaine accumulation), (iii) increased shoot concentrations of ABA, jasmonic acid, and indole acetic acid, involved in drought stress signaling and tuberization, and (iv) reduced irreversible drought-induced leaf damage. Additional application of bacterial inoculants further improved ROS detoxification by increasing the production of antioxidants but stimulated biomass allocation towards shoot growth at the expense of tuber development. The results demonstrated that microbial consortia could increase the probability of drought protection effects influenced by the form of N supply. However, protective effects on vegetative growth do not necessarily translate into yield benefits, which can be achieved by adequate combination of inoculants and fertilizers.
Micronutrients, silicon and biostimulants as cold stress protectants in maize
(2020) Moradtalab, Narges; Streck, Thilo
Mitigation of abiotic stress in crops is a feature attributed to various so-called biostimulants based on plant growth-promoting microorganisms (PGPMs) plant-, compost- and seaweed extracts, protein hydrolylates, chitosan derivatives etc. but also to mineral nutrients with protective functions, such as zinc (Zn), manganese (Mn), boron (B), calcium (Ca) and silicon (Si), recommended as stress protectants in commercial formulations. This study focussed on the effects of selected biostimulants on cold stress mitigation during early growth in maize, as a major stress factor for cultivation of tropical and subtropical crops in temperate climates. Chilling stress and micronutrient supplementation Chilling stress, induced by moderately low soil temperatures (8-14°C) in a controlled root cooling system, was associated with inhibition of shoot growth, oxidative leaf damage (chlorosis, necrosis accumulation of stress anthocyanins) and a massive decline in root length (Chapter 4 and 5). Due to inhibition of root growth, nutrient acquisition in general was impaired. However, nutrient deficiencies were recorded particularly for the micronutrients zinc (Zn) and manganese (Mn). The impaired Zn and Mn status was obviously related with the observed limitations in plant performance, which were reverted by exogenous Zn and Mn supplementation (0.5 mg plant-1), finally leading to restored nutrient acquisition and improved plant recovery after termination of the cold stress period. Zinc and manganese deficiency was mainly related with impaired uptake of the micronutrients, since the cold stress-induced deficiency symptoms persisted even in hydroponic culture when all nutrients were freely available. Beneficial effects of Zn/Mn supplementation were only detectable when the micronutrients were supplied prior to the onset of the stress period via seed soaking, seed dressing or fertigation, when uptake and internal translocation was still possible. A transcriptome analysis of the shoot tissue (Chapter 5) revealed 1400 differentially expressed transcripts (DETs) after 7-days exposure of maize seedlings to chilling stress of 12°C, mostly associated with down-regulation of selected functional categories (BINs), related with photosynthesis, synthesis of amino acids, lipids and cell wall precursors, transport of mineral nutrients (N, P, K,), metal handling and synthesis of growth hormones (auxins, gibberellic acid) but also of jasmonic (JA) and salicylic acids (SA) involved in stress adaptations. In accordance with the impaired micronutrient status and oxidative leaf damage in response to the cold stress treatments, downregulation was also recorded for transcripts related with oxidative stress defence (superoxide dismutases SOD, catalase, peroxidases POD, synthesis of phenylpropanoids and lignification), particularly dependent on the supply of micronutrients as co-factors. Upregulation was recorded for BINs related with degradation of lipids, of cell wall precursors, synthesis of waxes and certain flavonoids and of stress hormones, such as abscisic acid (ABA) and ethylene but degradation of growth-promoting cytokinins (CK). Accordingly, supplementation of Zn and Mn increased the accumulation of anthocyanins and antioxidants, the activities of superoxide dismutase and peroxidases, associated with reduced ROS accumulation (H2O2), mitigation of oxidative leaf damage and improved plant recovery at the end of the cold stress period (Chapter 5 and 6). Effects of seaweed extracts Cold-protective properties similar to Zn/Mn supplementation, associated with an improved Zn/Mn-nutritional status and reduced oxidative damage, were recorded also after fertigation with seaweed extracts prior to the onset of the stress treatments (Chapter 4). However, this effect was detectable only with seaweed extract formulations rich in Zn/Mn (Algavyt+Zn/Mn; Algafect; 6-70 mg kg DM-1) but not with a more highly purified formulation (Superfifty) without detectable micronutrient contents. This finding suggests that the cold-protective effect by soil application of seaweed extracts is based on an improved micronutrient supply and not to an elicitor effect, frequently reported in the literature for stress-protective functions after foliar application of seaweed extracts. Silicon fertilization Similar to seaweed extracts, also silicon (Si), applied by seed soaking or fertigation with silicic acid, mimicked the cold-protective effects of Zn/Mn supplementation in maize seedlings (Chapter 5). The Zn/Mn status of the Si-treated plants was improved although, in this case no additional micronutrient supply was involved. However, Si application significantly reduced leaching losses of Zn/and Mn by 50-70%, as a consequence of cold stress-induced membrane damage in germinating maize seeds and favoured the root to shoot translocation of Zn. This was associated with a restoration of gene expression, similar to the profiles recorded for unstressed control plants. However, the expression of genes related with synthesis and signal transduction of ABA, as central regulator of adaptive cold stress responses in plants, was even more strongly upregulated than in the cold-stressed controls. Accordingly, expression of cold stress adaptations involved in oxidative stress defence (SOD, peroxidases, phenolics, antioxidants) and the reduction of oxidative leaf damage and improved plant recovery were similar to the plants with Zn/Mn supplementation. Plant growth promoting microorganisms Cold-protective functions were recorded also for selected microbial inoculants (Chapter 6). However, out of five tested inoculant formulations, based on strains of Pseudomonas sp., DSMZ13134, Bacillus amyloliquefaciens FZB42, Bacillus atrophaeus ABI05, Penicillium sp. PK112 (BFOD) and a consortium of Trichoderma harzianum OMG16 and five Bacillus strains (Combi-A), a significant protective effect was detectable only for Penicillium sp. and particularly for CombiA. The CombiA consortium significantly increased root length and reduced oxidative leaf damage of cold-stressed plants, associated with increased SOD and POD activities and accumulation of phenolics and antioxidants. Root growth stimulation was related with increased IAA (indole acetic acid) tissue contents and increased expression of genes involved in IAA biosynthesis (ZmTSA) transport (ZmPIN1A) and perception (ZmAFR12). The tissue concentrations of ABA were not affected by the microbial inoculants, but the shoot concentrations of JA and SA increased, suggesting an effect by induced systemic resistance (ISR). Moreover, root concentrations of cytokinins (CKs) as ABA antagonists and expression of IPT genes involved in CK biosynthesis declined, leading to an increased ABA/cytokinin ratio and accordingly to increased expression of ABA responsive genes (ZmABF2). These findings suggest that CombiA mainly acted via improvement of root growth and nutrient acquisition by activation of the plant auxin metabolism and activation of cold protective metabolic responses by induction of ISR via JA/SA signalling and ABA-mediated responses, due to inhibition of CK biosynthesis. Synergistic interactions While the different cold-stress protectants investigated in this study induced similar protective plant responses, synergistic effects were obtained by combined applications (Chapter 6). The combination of CombiA inoculation with Zn/Mn supplementation further increased the plant micronutrient status and the cold-protective effects of CombiA. For all treatments, generally the expression of cold-protective effects was further improved by use of DMPP-stabilized ammonium fertilizers instead of nitrate fertilization. Ammonium fertilization promoted micronutrient acquisition via root-induced rhizosphere acidification, increased the ABA shoot concentrations with a moderate activation of metabolic cold stress responses and stimulated root colonization of Trichoderma harzianum OMG16 (CombiA). Field performance A comparative evaluation of the various cold protectants under field conditions with stabilized ammonium starter fertilization, revealed a severely reduced seedling emergence at six weeks after sowing (44%) due to extremely cold and wet soil conditions by the end of April in 2016, associated with a low Zn-nutritional status (32 mg kg-1 shoot DM). Significant improvements were recorded particularly for starter treatments including Zn/Mn seed dressing (emergence 56%) or seed priming with K2SiO4 (emergence 72%) and also by inoculation with the fungal PGPM strain Penicillium sp. BFOD (emergence 49%) associated with a doubling of the Zn tissue concentrations. Even after re-sowing, a significant yield increase for silo maize was recorded exclusively for the K2SiO4 treatment (Chapter 5). Taken together, the findings suggest that exploitation of synergistic interactions by combined starter applications of protective nutrients with selected biostimulants, could offer a cost-effective option for cold-stress prophylaxis in sensitive crops.
Role of benzoic acid and lettucenin A in the defense response of lettuce against soil-borne pathogens
(2021) Windisch, Saskia; Walter, Anja; Moradtalab, Narges; Walker, Frank; Höglinger, Birgit; El-Hasan, Abbas; Ludewig, Uwe; Neumann, Günter; Grosch, Rita
Soil-borne pathogens can severely limit plant productivity. Induced defense responses are plant strategies to counteract pathogen-related damage and yield loss. In this study, we hypothesized that benzoic acid and lettucenin A are involved as defense compounds against Rhizoctonia solani and Olpidium virulentus in lettuce. To address this hypothesis, we conducted growth chamber experiments using hydroponics, peat culture substrate and soil culture in pots and minirhizotrons. Benzoic acid was identified as root exudate released from lettuce plants upon pathogen infection, with pre-accumulation of benzoic acid esters in the root tissue. The amounts were sufficient to inhibit hyphal growth of R. solani in vitro (30%), to mitigate growth retardation (51%) and damage of fine roots (130%) in lettuce plants caused by R. solani, but were not able to overcome plant growth suppression induced by Olpidium infection. Additionally, lettucenin A was identified as major phytoalexin, with local accumulation in affected plant tissues upon infection with pathogens or chemical elicitation (CuSO4) and detected in trace amounts in root exudates. The results suggest a two-stage defense mechanism with pathogen-induced benzoic acid exudation initially located in the rhizosphere followed by accumulation of lettucenin A locally restricted to affected root and leaf tissues.