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The Robert H. Smith Institute of
Plant Sciences and Genetics
in Agriculture
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Neomi Maimon 
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Prof. Naomi Ori
Tel: 972-8-948-9605
E-mail: naomi.ori@mail.huji.ac.il

 

Publications

2021
Goldwasser, Y. ; Rabinovitz, O. ; Gerstl, Z. ; Nasser, A. ; Paporisch, A. ; Kuzikaro, H. ; Sibony, M. ; Rubin, B. . Imazapic Herbigation For Egyptian Broomrape (Phelipanche Aegyptiaca) Control In Processing Tomatoes-Laboratory And Greenhouse Studies. PLANTS-BASEL 2021, 10.Abstract
Parasitic plants belonging to the Orobanchaceae family include species that cause heavy damage to crops in Mediterranean climate regions. Phelipanche aegyptiaca is the most common of the Orobanchaceae species in Israel inflicting heavy damage to a wide range of broadleaf crops, including processing tomatoes. P. aegyptiaca is extremely difficult to control due to its minute and vast number of seeds and its underground association with host plant roots. The highly efficient attachment of the parasite haustoria into the host phloem and xylem enables the diversion of water, assimilates and minerals from the host into the parasite. Drip irrigation is the most common method of irrigation in processing tomatoes in Israel, but the delivery of herbicides via drip irrigation systems (herbigation) has not been thoroughly studied. The aim of these studies was to test, under laboratory and greenhouse conditions, the factors involved in the behavior of soil-herbigated imazapic, and the consequential influence of imazapic on P. aegyptiaca and tomato plants. Dose-response Petri dish studies showed that imazapic does not impede P. aegyptiaca seed germination and non-attached seedlings, even at the high rate of 5000 ppb. Imazapic applied to tomato roots inoculated with P. aegyptiaca seeds in a PE bag system revealed that the parasite is killed only after its attachment to the tomato roots, at concentrations as low as 2.5 ppb. Imazapic sorption curves and calculated Kd and Koc values indicated that the herbicide Kd is similar in all soils excluding a two-fold higher coefficient in the Gadash farm soil, while the Koc was similar in all soils except the Eden farm soil, in which it was more than twofold lower. In greenhouse studies, control of P. aegyptiaca was achieved at >2.5 ppb imazapic, but adequate control requires repeated applications due to the 7-day half-life (t(1/2)) of the herbicide in the soil. Tracking of imazapic in soil and tomato roots revealed that the herbicide accumulates in the tomato host plant roots, but its movement to newly formed roots is limited. The data obtained in the laboratory and greenhouse studies provide invaluable knowledge for devising field imazapic application strategies via drip irrigation systems for efficient and selective broomrape control.
Matzrafi, M. ; Peleg, Z. ; Lati, R. . Herbicide Resistance In Weed Management. Agronomy 2021, 11. Publisher's VersionAbstract
Herbicides are the most efficient and cost-effective means of weed management [...]
Uni, D. ; Groner, E. ; Soloway, E. ; Hjazin, A. ; Johnswick, S. ; Winters, G. ; Sheffer, E. ; Rog, I. ; Wagner, Y. ; Klein, T. . Unexpectedly Low Delta C-13 In Leaves, Branches, Stems And Roots Of Three Acacia Species Growing In Hyper-Arid Environments. JOURNAL OF PLANT ECOLOGY 2021, 14, 117-131.Abstract
Aims In plant eco-physiology, less negative (enriched) carbon 13 (C-13) in the leaves indicates conditions of reducing leaf gas exchange through stomata, e.g. under drought. In addition, C-13 is expected to be less negative in non-photosynthetic tissues as compared with leaves. However, these relationships in delta C-13 from leaves (photosynthetic organs) to branches, stems and roots (non-photosynthetic organs) are rarely tested across multiple closely related tree species, multiple compartments, or in trees growing under extreme heat and drought. Methods We measured leaf-to-root C-13 in three closely related desert acacia species (Acacia tortilis, A. raddiana and A. pachyceras). We measured delta C-13 in leaf tissues from mature trees in southern Israel. In parallel, a 7-year irrigation experiment with 0.5, 1.0 or 4.0 L day(-1) was conducted in an experimental orchard. At the end of the experiment, growth parameters and delta C-13 were measured in leaves, branches, stems and roots. Important Findings The delta C-13 in leaf tissues sampled from mature trees was ca. -27 parts per thousand, far more depleted than expected from a desert tree growing in one of the Earth's driest and hottest environments. Across acacia species and compartments, delta C-13 was not enriched at all irrigation levels (-28 parts per thousand to ca. -27 parts per thousand), confirming our measurements in the mature trees. Among compartments, leaf delta C-13 was unexpectedly similar to branch and root delta C-13, and surprisingly, even less negative than stem delta C-13. The highly depleted leaf delta C-13 suggests that these trees have high stomatal gas exchange, despite growing in extremely dry habitats. The lack of delta C-13 enrichment in non-photosynthetic tissues might be related to the seasonal coupling of growth of leaves and heterotrophic tissues.
Allelign Ashagre, H. ; Zaltzman, D. ; Idan-Molakandov, A. ; Romano, H. ; Tzfadia, O. ; Harpaz-Saad, S. . Fasciclin-Like 18 Is A New Player Regulating Root Elongation In Arabidopsis Thaliana. FRONTIERS IN PLANT SCIENCE 2021, 12.Abstract
The plasticity of root development represents a key trait that enables plants to adapt to diverse environmental cues. The pattern of cell wall deposition, alongside other parameters, affects the extent, and direction of root growth. In this study, we report that FASCICLIN-LIKE ARABINOGALACTAN PROTEIN 18 (FLA18) plays a role during root elongation in Arabidopsis thaliana. Using root-specific co-expression analysis, we identified FLA18 to be co-expressed with a sub-set of genes required for root elongation. FLA18 encodes for a putative extra-cellular arabinogalactan protein from the FLA-gene family. Two independent T-DNA insertion lines, named fla18-1 and fla18-2, display short and swollen lateral roots (LRs) when grown on sensitizing condition of high-sucrose containing medium. Unlike fla4/salt overly sensitive 5 (sos5), previously shown to display short and swollen primary root (PR) and LRs under these conditions, the PR of the fla18 mutants is slightly longer compared to the wild-type. Overexpression of the FLA18 CDS complemented the fla18 root phenotype. Genetic interaction between either of the fla18 alleles and sos5 reveals a more severe perturbation of anisotropic growth in both PR and LRs, as compared to the single mutants and the wild-type under restrictive conditions of high sucrose or high-salt containing medium. Additionally, under salt-stress conditions, fla18sos5 had a small, chlorotic shoot phenotype, that was not observed in any of the single mutants or the wild type. As previously shown for sos5, the fla18-1 and fla18-1sos5 root-elongation phenotype is suppressed by abscisic acid (ABA) and display hypersensitivity to the ABA synthesis inhibitor, Fluridon. Last, similar to other cell wall mutants, fla18 root elongation is hypersensitive to the cellulose synthase inhibitor, Isoxaben. Altogether, the presented data assign a new role for FLA18 in the regulation of root elongation. Future studies of the unique vs. redundant roles of FLA proteins during root elongation is anticipated to shed a new light on the regulation of root architecture during plant adaptation to different growth conditions.
Ben-Ari, G. ; Biton, I. ; Many, Y. ; Namdar, D. ; Samach, A. . Elevated Temperatures Negatively Affect Olive Productive Cycle And Oil Quality. AGRONOMY-BASEL 2021, 11.Abstract
Climate change, with elevated temperatures throughout the year, affects many stages of the reproductive growth and development of olives as well as oil quality at harvest. Although olive (Olea europaea L.) is well adapted to the environmental conditions of the Mediterranean Basin, agricultural techniques and breeding through selection programs will have to adapt to these climate change, threatening to worsen in the near future. Defining the pathways controlling high fruit productivity and oil quantity and quality, despite elevated temperatures and sub-optimal growing conditions, is important for coping with current and predicted climate changes. As breeding programs aiming to address these crucial changes may take several decades, an urgent need to designate specific olive cultivars that are more resistant to high temperatures emerges.
Wang, H. ; Cahaner, A. ; Lou, L. ; Zhang, L. ; Ge, Y. ; Li, Q. ; Zhang, X. . Genetics And Breeding Of A Black-Bone And Blue Eggshell Chicken Line. 1. Body Weight, Skin Color, And Their Combined Selection. POULTRY SCIENCE 2021, 100.Abstract
{{An experimental population of chickens was developed from the cross between 2 indigenous Chinese breeds, Dongxiang blue eggshell and Jiangshan black-bone. This breeding was aimed at eventually combining dark heavy black-bone body and blue eggshell, into a single dual-purpose breed. BW was recorded and skin L*, a*, and b* color parameters were measured by a Chroma Meter at several ages (56, 105, 150, 200, 250, and 300 d). At 250 d, 3 independent observers classified skin darkness using a 3-level visual scale (1 = light
Biru, F. N. ; Islam, T. ; Cibils-Stewart, X. ; Cazzonelli, C. I. ; Elbaum, R. ; Johnson, S. N. . Anti-Herbivore Silicon Defences In A Model Grass Are Greatest Under Miocene Levels Of Atmospheric Co2. GLOBAL CHANGE BIOLOGY 2021, 27, 2959-2969.Abstract
Silicon (Si) has an important role in mitigating diverse biotic and abiotic stresses in plants, mainly via the silicification of plant tissues. Environmental changes such as atmospheric CO2 concentrations may affect grass Si concentrations which, in turn, can alter herbivore performance. We recently demonstrated that pre-industrial atmospheric CO2 increased Si accumulation in Brachypodium distachyon grass, yet the patterns of Si deposition in leaves and whether this affects insect herbivore performance remains unknown. Moreover, it is unclear whether CO2-driven changes in Si accumulation are linked to changes in gas exchange (e.g. transpiration rates). We therefore investigated how pre-industrial (reduced; rCO(2), 200 ppm), ambient (aCO(2), 410 ppm) and elevated (eCO(2), 640 ppm) CO2 concentrations, in combination with Si-treatment (Si+ or Si-), affected Si accumulation in B. distachyon and its subsequent effect on the performance of the global insect pest, Helicoverpa armigera. rCO(2) increased Si concentrations by 29% and 36% compared to aCO(2) and eCO(2) respectively. These changes were not related to observed changes in gas exchange under different CO2 regimes, however. The increased Si accumulation under rCO(2) decreased herbivore relative growth rate (RGR) by 120% relative to eCO(2,) whereas rCO(2) caused herbivore RGR to decrease by 26% compared to eCO(2). Si supplementation also increased the density of macrohairs, silica and prickle cells, which was associated with reduced herbivore performance. There was a negative correlation among macrohair density, silica cell density, prickle cell density and herbivore RGR under rCO(2) suggesting that these changes in leaf surface morphology were linked to reduced performance under this CO2 regime. To our knowledge, this is the first study to demonstrate that increased Si accumulation under pre-industrial CO2 reduces insect herbivore performance. Contrastingly, we found reduced Si accumulation under higher CO2, which suggests that some grasses may become more susceptible to insect herbivores under projected climate change scenarios.
Paporisch, A. ; Laor, Y. ; Rubin, B. ; Eizenberg, H. . Simulating Sulfosulfuron Fate In Soil Under Different Weather Scenarios To Support Weed Management Decisions. PEST MANAGEMENT SCIENCE 2021, 77, 253-263.Abstract
BACKGROUND Residual herbicides are an important component in many weed control strategies. Their herbicidal activity depends on their fate in soil, with respect to the required concentration for weed control in space and time. In this study, the effect of weather conditions on sulfosulfuron fate in soil, following pre-planting incorporation, and the predicted control efficacy of Egyptian broomrape in tomato, were analyzed for two sites using simulations in Hydrus-1D modeling software. Simulated concentration was compared to measured data from field experiments. RESULTS Model evaluation against measured data from two fields, with weakly alkaline clay soils, showed high correlations between simulated and measured sulfosulfuron concentrations (r= 0.98 and 0.89). The ratio of measured to simulated concentration was relatively low (1.03) at the top 10-cm layer, in which the mean measured concentration was high (29.6 ng g(-1)). This ratio was higher (12.5) at the 30-60 cm depth, in which the mean measured concentration was lower (0.3 ng g(-1)). Simulations of sulfosulfuron fate in each site, using weather data from the years 2009 to 2019, revealed substantial variations in transport patterns. Thirty days after treatment, 16 out of the 22 years simulated for the two sites (11 at each site) resulted in concentrations lower than the critical value for Egyptian broomrape control throughout the soil profile. The data indicates that variation in sulfosulfuron fate is mainly due to differences in the cumulative precipitation. According to simulation results, cumulative precipitation above 20 or 10 mm during the first 10 or 20 days after treatment, respectively, is expected to reduce the efficiency of broomrape control. CONCLUSION Considering weather effects when planning herbicide application could optimize herbicide use efficiency. A decision-support tool is presented, whose factors are the time gap and precipitation amount between sulfosulfuron application and tomato planting.
Bacher, H. ; Zhu, F. ; Gao, T. ; Liu, K. ; Dhatt, B. K. ; Awada, T. ; Zhang, C. ; Distelfeld, A. ; Yu, H. ; Peleg, Z. ; et al. Wild Emmer Introgression Alters Root-To-Shoot Growth Dynamics In Durum Wheat In Response To Water Stress. PLANT PHYSIOLOGY 2021, 187, 1149-1162.Abstract
Water deficit during the early vegetative growth stages of wheat (Triticum) can limit shoot growth and ultimately impact grain productivity. Introducing diversity in wheat cultivars to enhance the range of phenotypic responses to water limitations during vegetative growth can provide potential avenues for mitigating subsequent yield losses. We tested this hypothesis in an elite durum wheat background by introducing a series of introgressions from a wild emmer (Triticum turgidum ssp. dicoccoides) wheat. Wild emmer populations harbor rich phenotypic diversity for drought-adaptive traits. To determine the effect of these introgressions on vegetative growth under water-limited conditions, we used image-based phenotyping to catalog divergent growth responses to water stress ranging from high plasticity to high stability. One of the introgression lines exhibited a significant shift in root-to-shoot ratio in response to water stress. We characterized this shift by combining genetic analysis and root transcriptome profiling to identify candidate genes (including a root-specific kinase) that may be linked to the root-to-shoot carbon reallocation under water stress. Our results highlight the potential of introducing functional diversity into elite durum wheat for enhancing the range of water stress adaptation. Wild emmer introgressions in wheat introduce divergent water stress responses associated with a shift in root-to-shoot growth dynamics for enhanced stress adaptation.
Weksler, S. ; Rozenstein, O. ; Haish, N. ; Moshelion, M. ; Wallach, R. ; Ben-Dor, E. . Pepper Plants Leaf Spectral Reflectance Changes As A Result Of Root Rot Damage. REMOTE SENSING 2021, 13.Abstract
Symptoms of root stress are hard to detect using non-invasive tools. This study reveals proof of concept for vegetation indices' ability, usually used to sense canopy status, to detect root stress, and performance status. Pepper plants were grown under controlled greenhouse conditions under different potassium and salinity treatments. The plants' spectral reflectance was measured on the last day of the experiment when more than half of the plants were already naturally infected by root disease. Vegetation indices were calculated for testing the capability to distinguish between healthy and root-damaged plants using spectral measurements. While no visible symptoms were observed in the leaves, the vegetation indices and red-edge position showed clear differences between the healthy and the root-infected plants. These results were achieved after a growth period of 32 days, indicating the ability to monitor root damage at an early growing stage using leaf spectral reflectance.
Curzon, A. Y. ; Kottakota, C. ; Nashef, K. ; Abbo, S. ; Bonfil, D. J. ; Reifen, R. ; Bar-El, S. ; Rabinovich, O. ; Avneri, A. ; Ben-David, R. . Assessing Adaptive Requirements And Breeding Potential Of Spelt Under Mediterranean Environment. SCIENTIFIC REPORTS 2021, 11.Abstract
The rising demand for spelt wheat (Triticum aestivum ssp. spelta) as a high-value grain crop has raised interest in its introduction into non-traditional spelt growing areas. This study aimed to assess adaptive constrains of spelt under short Mediterranean season. At first screening of a wide spelt collection for phenology and allelic distribution at the photoperiod (PPD) and vernalization (VRN) loci was done. In addition an in-depth phenotypic evaluation of a selected panel (n=20) was performed, including agronomically important traits and concentration of grain mineral (GMC) and grain protein (GPC) content. Results from both wide screening and in-depth in panel (group of 18 spelt lines and two bread wheat lines) evaluation shows that the major adaptive constraint for spelt under Mediterranean conditions is late heading, caused by day length sensitivity, as evident from phenology and allelic profile (PPD and VRN). All lines carrying the photoperiod-sensitive allele (PPD-D1b) were late flowering (>120DH). Based on the panel field evaluations those consequently suffer from low grain yield and poor agronomic performances. As for minerals, GMC for all but Zn, significantly correlated with GPC. In general, GMC negatively correlated with yield which complicated the assessment of GMC per-se and challenge the claim for higher mineral content in spelt grains. The exceptions were, Fe and Zn, which did not correlate with yield. Spelt lines showing high Fe and Zn concentration in a high-yield background illustrate their potential for spelt wheat breeding. Improving spelt adaptation to Mediterranean environments could be mediated by introducing the insensitive-PPD-D1a allele to spelt wheat background. Following this breeding path spelt could better compete with bread wheat under short season with limited and fluctuating rain fall.
Mandelmilch, M. ; Dadon, A. ; Ben-Dor, E. ; Sheffer, E. . Pca-Based Classification Using Airborne Hyperspectral Radiance Data, A Case Study: Mount Horshan Mediterranean Forest. GEOCARTO INTERNATIONAL 2021.Abstract
Atmospheric correction (ATC) of radiance image data is a preliminary and necessary procedure to reach a coherent unsupervised classification. Though ATC results in removal of noise artefacts related to path radiance, loss of some data is inherent by the process. The unsupervised principal component analysis-based classification (PCABC) was harnessed in this paper using radiance data that bypass the ATC protocol. Being primarily based on the variability of the input hyperspectral remote sensing (HRS) image regardless of its physical attributes, it was assumed that PCABC can be applied to radiance HRS image just as already shown on reflectance domain. To test this assumption, PCABC was tested on a radiance HRS image of Specim's AisaFENIX taken over the Mediterranean forest of Mount Horshan, Israel. With no application of ATC or noise reduction, while tested unsupervised classification methods were insufficient, PCABC was able to classify four different plant species with an overall accuracy of 68%.
Dovrat, G. ; Sheffer, E. ; Landau, S. Y. ; Deutch, T. ; Gorelik, H. ; Henkin, Z. . Can Grazing Moderate Climatic Effects On Herbage Nutritional Quality?. AGRONOMY-BASEL 2021, 11.Abstract
In Mediterranean grasslands, the composition of vegetation and its nutritional quality for animals are strongly affected by the climatic conditions prevailing during winter and spring. Therefore, these seasonal ecosystems provide an opportunity to examine how variability in climatic conditions affects the regeneration and quality of pasture vegetation. The intensity of grazing in this seasonal system can moderate, or alternatively exacerbate, climatic effects on the nutritional quality of the vegetation. Herein, we analyzed the interactive effects of climate variables, grazing intensity, and grazing exclusion on herbage quality parameters using long-term vegetation and climate data collected during 2005-2018 from an extensive experiment in Galilee, Israel. We evaluated the contribution of different climate variables to the prediction of herbage quality parameters. Our results showed that climate variables have a dramatic effect on herbage quality and that this effect interacts with grazing intensity. Herbage quality improved in temperate rainy years compared to warm and dry years. High grazing intensity improved herbage quality under temperate climate conditions, but this effect was moderated or completely disappeared as winter conditions become warmer and drier. The results of the study foresee negative effects of warming and drying on the carrying capacity of natural pastures.
Wang, R. ; Lenka, S. K. ; Kumar, V. ; Gashu, K. ; Sikron-Persi, N. ; Dynkin, I. ; Weiss, D. ; Perl, A. ; Fait, A. ; Oren-Shamir, M. . Metabolic Engineering Strategy Enables A Hundred-Fold Increase In Viniferin Levels In Vitis Vinifera Cv. Gamay Red Cell Culture. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021, 69, 3124-3133.Abstract
Stilbenes are phytoalexins with health-promoting benefits for humans. Here, we boost stilbenes' production, and in particular the resveratrol dehydrodimer viniferin, with significant pharmacological properties, by overexpressing stilbene synthase (STS) under unlimited phenylalanine (Phe) supply. Vitis vinifera cell cultures were co-transformed with a feedback-insensitive E. coli DAHP synthase (AroG*) and STS genes, under constitutive promoters. All transgenic lines had increased levels of Phe and stilbenes (74-fold higher viniferin reaching 0.74 mg/g DW). External Phe feeding of AroG* + STS lines caused a synergistic effect on resveratrol and viniferin accumulation, achieving a 26-fold (1.33 mg/g DW) increase in resveratrol and a 620-fold increase (6.2 mg/g DW) in viniferin, which to date is the highest viniferin accumulation reported in plant cultures. We suggest that this strategy of combining higher Phe availability and STS expression generates grape cell cultures as potential factories for sustainable production of stilbenes with a minor effect on the levels of flavonoids.
Drori, R. ; Ziv, B. ; Saaroni, H. ; Etkin, A. ; Sheffer, E. . Recent Changes In The Rain Regime Over The Mediterranean Climate Region Of Israel. CLIMATIC CHANGE 2021, 167.Abstract
Previous observational analyses have shown a declining rainfall trend over Israel, mostly statistically insignificant. The current study, for the period 1975-2020, undermines these findings, and the alarming future projections, and elaborates other ingredients of the rain regime. No trend is found for the annual rainfall, reflecting a balance between a negative trend in the number of rainy days and a positive trend in the daily rainfall intensity, both on the order of 2.0%/decade. In the mid-winter, the rainfall and the daily intensity increased, while both declined in the autumn and spring, implying a contraction of the rainy season. The time span between accumulation of 10% and 90% of the annual rainfall, being 112 days on the average, shortened by 7 days during the study period. This is also expressed by an increase of the Seasonality Index, indicating that the regional climate is shifting from ``markedly seasonal with a long dry season'' to ``most rain in <= 3 months.'' The intra-seasonal course of the rainfall trend corresponds to that of the occurrence and intensity of the Cyprus Lows and the Mediterranean Oscillation. The contraction of the rainy season and the increase in the daily intensity have far-reaching environmental impacts in this vulnerable region.
Shulner, I. ; Asaf, E. ; Ben-Simhon, Z. ; Cohen-Zinder, M. ; Shabtay, A. ; Peleg, Z. ; Lati, R. N. . Optimizing Weed Management For The New Super-Forage Moringa Oleifera. AGRONOMY-BASEL 2021, 11.Abstract
Moringa oleifera Lam. (moringa hereafter) is cultivated as a new summer super-forage field crop in Israel, yet no weed control protocol has been developed for it. The objective of the study was to develop an integrated weed management (IWM) practice for the moringa agro-system in arid and semi-arid regions like the Mediterranean basin. We tested various herbicides applied pre (PRE) and post (POST) crop emergence and cultivation methods for weed control, with an emphasis on crop safety. The PRE herbicides were the most effective and safe control mean. Their application resulted in minor (<5%) crop fresh weight reductions and weed cover area, compared with the control. The POST herbicides were also effective, yet their crop safety level was lower and non-consistent in some treatments. Generally, the finger weeder was less effective than the herbicide treatments and caused higher fresh weight reduction. However, this means was more effective when applied at earlier stages. Management and environmental conditions had a high impact on the moringa growth; hence, these aspects should be considered. Our results show the potential use of different herbicides and non-chemical tools and set the basis for a future IWM protocol for moringa. The wide range of options offered here can ensure economic and environmentally viable solutions for this new crop.
Elbaz, S. ; Sheffer, E. ; Lensky, I. M. ; Levin, N. . The Impacts Of Spatial Resolution, Viewing Angle, And Spectral Vegetation Indices On The Quantification Of Woody Mediterranean Species Seasonality Using Remote Sensing. REMOTE SENSING 2021, 13.Abstract
Discriminating between woody plant species using a single image is not straightforward due to similarity in their spectral signatures, and limitations in the spatial resolution of many sensors. Seasonal changes in vegetation indices can potentially improve vegetation mapping; however, for mapping at the individual species level, very high spatial resolution is needed. In this study we examined the ability of the Israel/French satellite of VEN mu S and other sensors with higher spatial resolutions, for identifying woody Mediterranean species, based on the seasonal patterns of vegetation indices (VIs). For the study area, we chose a site with natural and highly heterogeneous vegetation in the Judean Mountains (Israel), which well represents the Mediterranean maquis vegetation of the region. We used three sensors from which the indices were derived: a consumer-grade ground-based camera (weekly images at VIS-NIR; six VIs; 547 individual plants), UAV imagery (11 images, five bands, seven VIs) resampled to 14, 30, 125, and 500 cm to simulate the spatial resolutions available from some satellites, and VEN mu S Level 1 product (with a nominal spatial resolution of 5.3 m at nadir; seven VIs; 1551 individual plants). The various sensors described seasonal changes in the species' VIs at different levels of success. Strong correlations between the near-surface sensors for a given VI and species mostly persisted for all spatial resolutions <= 125 cm. The UAV ExG index presented high correlations with the ground camera data in most species (pixel size <= 125 cm; 9 of 12 species with R >= 0.85; p < 0.001), and high classification accuracies (pixel size <= 30 cm; 8 species with >70%), demonstrating the possibility for detailed species mapping from space. The seasonal dynamics of the species obtained from VEN mu S demonstrated the dominant role of ephemeral herbaceous vegetation on the signal recorded by the sensor. The low variance between the species as observed from VEN mu S may be explained by its coarse spatial resolution (effective ground spatial resolution of 7.5) and its non-nadir viewing angle (29.7 degrees) over the study area. However, considering the challenging characteristics of the research site, it may be that using a VEN mu S type sensor (with a spatial resolution of similar to 1 m) from a nadir point of view and in more homogeneous and dense areas would allow for detailed mapping of Mediterranean species based on their seasonality.
Firsov, A. ; Pushin, A. ; Motyleva, S. ; Pigoleva, S. ; Shaloiko, L. ; Vainstein, A. ; Dolgov, S. . Heterologous Biosynthesis Of Artemisinin In Chrysanthemum Morifolium Ramat. SEPARATIONS 2021, 8.Abstract
Artemisinin-based drugs are the most effective medicine against multidrug-resistant Plasmodium spp., the parasite that causes malaria. To this day, wormwood A. annua L. is the sole commercial source of artemisinin, where it is produced in minor amounts. The artemisinin yield depends on numerous poorly regulated agricultural factors and the genetic variability of this non-domesticated plant. This has aroused significant interest in the development of heterologous expression platforms for artemisinin production. Previously, we obtained lines of Chrysanthemum morifolium Ramat. (C. morifolium Ramat.), cvs. White Snowdon and Egyptianka, transformed with artemisinin biosynthesis genes. Here, we report the results of an analysis of artemisinin production in transgenic chrysanthemums. Transcription of heterologous amorpha-4,11-diene monooxygenase and cytochrome P450 reductase genes in transgenic lines was confirmed using high-resolution melting analysis. Artemisinin accumulation was detected using GC-MS in White Snowdon plants, but not in Egyptianka ones, thereby demonstrating the possibility of transplanting active artemisinin biosynthetic pathway into chrysanthemum. Ways of increasing its content in producer plants are discussed.
Graff van Creveld, S. ; Ben-Dor, S. ; Mizrachi, A. ; Alcolombri, U. ; Hopes, A. ; Mock, T. ; Rosenwasser, S. ; Vardi, A. . Biochemical Characterization Of A Novel Redox-Regulated Metacaspase In A Marine Diatom. FRONTIERS IN MICROBIOLOGY 2021, 12.Abstract
Programmed cell death (PCD) in marine microalgae was suggested to be one of the mechanisms that facilitates bloom demise, yet its molecular components in phytoplankton are unknown. Phytoplankton are completely lacking any of the canonical components of PCD, such as caspases, but possess metacaspases. Metacaspases were shown to regulate PCD in plants and some protists, but their roles in algae and other organisms are still elusive. Here, we identified and biochemically characterized a type III metacaspase from the model diatom Phaeodactylum tricornutum, termed PtMCA-IIIc. Through expression of recombinant PtMCA-IIIc in E. coli, we revealed that PtMCA-IIIc exhibits a calcium-dependent protease activity, including auto-processing and cleavage after arginine. Similar metacaspase activity was detected in P. tricornutum cell extracts. PtMCA-IIIc overexpressing cells exhibited higher metacaspase activity, while CRISPR/Cas9-mediated knockout cells had decreased metacaspase activity compared to WT cells. Site-directed mutagenesis of cysteines that were predicted to form a disulfide bond decreased recombinant PtMCA-IIIc activity, suggesting its enhancement under oxidizing conditions. One of those cysteines was oxidized, detected in redox proteomics, specifically in response to lethal concentrations of hydrogen peroxide and a diatom derived aldehyde. Phylogenetic analysis revealed that this cysteine-pair is unique and widespread among diatom type III metacaspases. The characterization of a cell death associated protein in diatoms provides insights into the evolutionary origins of PCD and its ecological significance in algal bloom dynamics.
Wagner, Y. ; Pozner, E. ; Bar-On, P. ; Ramon, U. ; Raveh, E. ; Neuhaus, E. ; Cohen, S. ; Grünzweig, J. ; Klein, T. . Rapid Stomatal Response In Lemon Saves Trees And Their Fruit Yields Under Summer Desiccation, But Fails Under Recurring Droughts. AGRICULTURAL AND FOREST METEOROLOGY 2021, 307.Abstract
Lemon (Citrus limon) is a fruit tree with major agricultural importance around the Mediterranean basin and is considered to be highly drought resistant. In this study, we tested the effect of two months summer-desiccation on physiological and yield parameters of mature lemon trees growing under Mediterranean climate during three consecutive years. We also examined the efficiency of current irrigation regime, which is based on reference evapo-transpiration. We measured leaf gas exchange and water potential (Psi(l)), monitored sap flow and soil moisture and followed flowering, fruit set and fruit size. Lemon trees showed an isohydric stomatal regulation, as stomata maintained leaf water potential >-2 MPa. Summer desiccation caused a gradual decrease in diurnal tree water use, starting immediately after cessation of irrigation, with leaf gas exchange practically halted at the end of the drought period. Tree function recovered following re-irrigation, and fruit yields were not reduced, but even mildly increased during the first year. In contrast, summer desiccation during two consecutive years caused long-term effects of tree activity decrease, significantly lower yield, main branch collapse and even tree mortality. Irrigation amounts matched closely tree water-use amounts; soil moisture was maintained around 26% (v/v); and irrigation responded dynamically to meteorological changes, indicating that current irrigation regime represents highly efficient water management. The lemon desiccation protocol relied on the physiological capacity of this species to avoid short-term drought effects through stomatal closure. Still, this protocol must be managed carefully, to reduce risk to trees and save yields.