New Analytical Approach to Quinolizidine Alkaloids and Their Assumed Biosynthesis Pathways in Lupin Seeds.

Alkaloids play an essential role in protecting plants against herbivores. Humans can also benefit from the pharmacological effects of these compounds. Plants produce an immense variety of structurally different alkaloids, including quinolizidine alkaloids, a group of bi-, tri-, and tetracyclic compounds produced by Lupinus species. Various lupin species produce different alkaloid profiles. To study the composition of quinolizidine alkaloids in lupin seeds, we collected 31 populations of two wild species native to Israel, L. pilosus and L. palaestinus, and analyzed their quinolizidine alkaloid contents. Our goal was to study the alkaloid profiles of these two wild species to better understand the challenges and prospective uses of wild lupins. We compared their profiles with those of other commercial and wild lupin species. To this end, a straightforward method for extracting alkaloids from seeds and determining the quinolizidine alkaloid profile by LC-MS/MS was developed and validated in-house. For the quantification of quinolizidine alkaloids, 15 analytical reference standards were used. We used GC-MS to verify and cross-reference the identity of certain alkaloids for which no analytical standards were available. The results enabled further exploration of quinolizidine alkaloid biosynthesis. We reviewed and re-analyzed the suggested quinolizidine alkaloid biosynthesis pathway, including the relationship between the amino acid precursor l-lysine and the different quinolizidine alkaloids occurring in seeds of lupin species. Revealing alkaloid compositions and highlighting some aspects of their formation pathway are important steps in evaluating the use of wild lupins as a novel legume crop.

Valorization of Local Legumes and Nuts as Key Components of the Mediterranean Diet.

Legumes and nuts are components of high importance in the diet of many countries, mainly those in the Mediterranean region. They are also very versatile and culturally diverse foods found all over the world, acting as a basic protein source in certain countries. Their genetic diversity is needed to sustain the food supply and security for humans and livestock, especially because of the current loss of habitats, species, and genetic diversity worldwide, but also because of the ever present need to feed the increasing human population. Even though both legumes and nuts are considered as high-protein food and environmentally friendly crops, developed countries have lower consumption rates when compared to Asia or Africa. With a view to increasing the consumption of legumes and nuts, the objective of this review is to present the advantages on the use of autochthonous varieties from different countries around the world, thus providing a boost to the local market in the area. The consumption of these varieties could be helped by their use in ready-to-eat foods (RTE), which are now on the rise thanks to today's fast-paced lifestyles and the search for more nutritious and sustainable foods. The versatility of legumes and nuts covers a wide range of possibilities through their use in plant-based dairy analogues, providing alternative-protein and maximal amounts of nutrients and bioactive compounds, potential plant-based flours for bakery and pasta, and added-value traditional RTE meals. For this reason, information about legume and nut nutrition could possibly increase its acceptance with consumers.

Caterpillars on a phytochemical landscape: The case of alfalfa and the Melissa blue butterfly.

Modern metabolomic approaches that generate more comprehensive phytochemical profiles than were previously available are providing new opportunities for understanding plant-animal interactions. Specifically, we can characterize the phytochemical landscape by asking how a larger number of individual compounds affect herbivores and how compounds covary among plants. Here we use the recent colonization of alfalfa (Medicago sativa) by the Melissa blue butterfly (Lycaeides melissa) to investigate the effects of indivdiual compounds and suites of covarying phytochemicals on caterpillar performance. We find that survival, development time, and adult weight are all associated with variation in nutrition and toxicity, including biomolecules associated with plant cell function as well as putative anti-herbivore action. The plant-insect interface is complex, with clusters of covarying compounds in many cases encompassing divergent effects on different aspects of caterpillar performance. Individual compounds with the strongest associations are largely specialized metabolites, including alkaloids, phenolic glycosides, and saponins. The saponins are represented in our data by more than 25 individual compounds with beneficial and detrimental effects on L. melissa caterpillars, which highlights the value of metabolomic data as opposed to approaches that rely on total concentrations within broad defensive classes.

Thermal Benefits From White Variegation of Silybum marianum Leaves.

Leaves of the spiny winter annual Silybum marianum express white patches (variegation) that can cover significant surface areas, the outcome of air spaces formed between the epidermis and the green chlorenchyma. We asked: (1) what characterizes the white patches in S. marianum and what differs them from green patches? (2) Do white patches differ from green patches in photosynthetic efficiency under lower temperatures? We predicted that the air spaces in white patches have physiological benefits, elevating photosynthetic rates under low temperatures. To test our hypotheses we used both a variegated wild type and entirely green mutants. We grew the plants under moderate temperatures (20°C/10°C d/n) and compared them to plants grown under lower temperatures (15°C/5°C d/n). The developed plants were exposed to different temperatures for 1 h and their photosynthetic activity was measured. In addition, we compared in green vs. white patches, the reflectance spectra, patch structure, chlorophyll and dehydrin content, stomatal structure, plant growth, and leaf temperature. White patches were not significantly different from green patches in their biochemistry and photosynthesis. However, under lower temperatures, variegated wild-type leaves were significantly warmer than all-green mutants - possible explanations for that are discussed These findings support our hypothesis, that white variegation of S. marianum leaves has a physiological role, elevating leaf temperature during cold winter days.

Tripartite symbiosis of plant-weevil-bacteria is a widespread phenomenon in the Negev Desert.

The weevil Conorhynchus palumbus develops in a mud chamber affixed to the roots of the summer annual plant Salsola inermis in the Negev Desert of Israel. The weevil carries nitrogen fixing bacteria, and evidence suggests that plants with weevils utilize the fixed nitrogen. To characterize the distribution, abundance and significance of this unique interaction, we surveyed Salsola plants in 16 sites throughout the Negev Desert. We excavated ~100 plants from each site, recorded the presence of weevils in their roots, and characterized the soil properties in each site. Weevil mud chambers were present in all of the sampled sites and their abundance was positively correlated with soil nitrogen content and with plant size, and negatively correlated with soil grain-size. Intriguingly, we found two additional weevil species-Menecleonus virgatus and Maximus mimosae-residing in mud chambers on Salsola roots, and found one additional Salsola species-S. incanescens-accommodating weevils. Nitrogen fixing bacteria were found in weevil larvae of the two additional species and at multiple sites. Overall, our findings suggest that potentially beneficial associations between weevils and plants may be more common than previously acknowledged, and may play an important role in this desert ecosystem.

The Value of Native Plants and Local Production in an Era of Global Agriculture.

For addressing potential food shortages, a fundamental tradeoff exists between investing more resources to increasing productivity of existing crops, as opposed to increasing crop diversity by incorporating more species. We explore ways to use local plants as food resources and the potential to promote food diversity and agricultural resilience. We discuss how use of local plants and the practice of local agriculture can contribute to ongoing adaptability in times of global change. Most food crops are now produced, transported, and consumed long distances from their homelands of origin. At the same time, research and practices are directed primarily at improving the productivity of a small number of existing crops that form the cornerstone of a global food economy, rather than to increasing crop diversity. The result is a loss of agro-biodiversity, leading to a food industry that is more susceptible to abiotic and biotic stressors, and more at risk of catastrophic losses. Humans cultivate only about 150 of an estimated 30,000 edible plant species worldwide, with only 30 plant species comprising the vast majority of our diets. To some extent, these practices explain the food disparity among human populations, where nearly 1 billion people suffer insufficient nutrition and 2 billion people are obese or overweight. Commercial uses of new crops and wild plants of local origin have the potential to diversify global food production and better enable local adaptation to the diverse environments humans inhabit. We discuss the advantages, obstacles, and risks of using local plants. We also describe a case study-the missed opportunity to produce pine nuts commercially in the Western United States. We discuss the potential consequences of using local pine nuts rather than importing them overseas. Finally, we provide a list of edible native plants, and synthesize the state of research concerning the potential and challenges in using them for food production. The goal of our synthesis is to support more local food production using native plants in an ecologically sustainable manner.

Insights into root structure and function of Bassia indica: water redistribution and element dispersion.

In the last few decades, research has increasingly been aimed at clarifying how root system architecture, physiology and function are related to environmental drivers. 'Negative halotropism' has been defined as the alteration of root growth direction to avoid salinity. We suggested that 'positive halotropism' may be found in halophytes relying on salinity for optimal growth. Investigating root structure of the halophyte Bassia indica (Wight) A. J. Scott, we have shown that positive halotropism can explain the growth of horizontal roots towards optimal salt concentrations along a soil salinity gradient. Here we tested three hypotheses. First, that development of B. indica roots depends on a trade-off between optimal nutrient supply and saline concentrations: results of split-root-experiment showed a preference for sand enriched with nutrients and poor in salts. Second, that shallow horizontal roots enable B. indica to forage for nutrient-rich patches. Results demonstrated that bulk elemental analysis was not consistent with tissue-specific elemental analysis, and this can be explained by substantial variability of element composition of particular root segments. Third, we hypothesised that B. indica redistributes water horizontally through shallow horizontal roots. Results showed that back flow of water from the tap root towards tip root was possible in horizontal roots in saline microenvironment.

The role of dew in Negev Desert plants.

We investigated the possible use of dew as a water source for three desert plant species native to the Negev Desert: an annual Salsola inermis, and two perennials Artemisia sieberi and Haloxylon scoparium, with different rooting depths of 15, 30 and 90 cm, respectively. We quantified dew-water inputs and used stable isotope analyses to determine the proportion of dew as compared to the proportion of soil water each species utilized. Dew was isotopically enriched (δD values ranged from -25 to 5 ‰), relative to rainfall with δD values that ranged from -40 to -20 ‰ and relative to soil water with δD values that ranged from -65 to -35 ‰. Using a two-source isotope mixing model, we found that S. inermis, A. sieberi and H. scoparium used, on average, 56, 63 and 46 % of their water from dewfall, respectively. Our results suggest that dew-water utilization by Negev Desert plants is highly significant ecologically and thus may be more common than previously thought. In light of future predicted climate change, it may be increasingly important for plants of the Negev Desert to make use of dew as a water resource as it may play an important role in their ability to cope with the associated hydrological constraints predicted for the Negev region.

Tri-party underground symbiosis between a weevil, bacteria and a desert plant.

Inhabitants of arid ecosystems face severe nitrogen and water limitations. Inventive adaptations by organisms occupying such habitats are essential for survival. This study describes a tri-party symbiotic interaction between a plant (Salsola inermis), a beetle (Conorhynchus pistor), and a bacterium (Klebsiella pneumonia). The weevil survives by living within a mud structure affixed to the plant roots, thus benefiting from increased carbon and water, and refuge from predators and parasites. Active nitrogen-fixing bacteria harbored within the weevil's gut mediate this interaction, by supplying nitrogen to the system, which eventually promotes seed development. We studied the correlation between the weevil's existence and (i) root carbon and nitrogen content, (ii) soil water content and (iii) seed weight. Roots hosting weevils contained more nitrogen, heavier seeds and less carbon. In addition, water content was higher around the roots than in open spaces a short distance from the plant stem. Bacterial studies and nitrogen-fixation analyses, including molecular and chemical assays, indicated atmospheric nitrogen fixation in the larval stage and identified the bacterium. The coexistence of weevil and bacterial behavior coinciding with the plant's life cycle was revealed here by a long period of field observations. Out of over 60,000 known weevils, this is the only report of a weevil living most of its life underground without harming plants. The unique tri-party interaction described herein shows the important ecological role of desert plant roots and provides an example of a sustainable consortium of living organisms coping with the challenging desert environment.

Increased root oxygen uptake in pea plants responding to non-self neighbors.

Recent studies have demonstrated that plants alter root growth and decrease competition with roots of the same individual (self); however, the physiological traits accompanying this response are still widely unknown. In this study, we investigated the effect of root identity on gas exchange in the model species pea (Pisum sativum L.). Split-root plants were planted so that each pot contained either two roots of the same plant (self) or of two different plants (non-self), and the responses of biomass, photosynthesis, and respiration were measured. The photosynthetic rate was not affected by the identity of the root neighbor. We found a reduction of leaf dark respiration by half, accompanied by an increase in nocturnal root respiration by 29 % in plants neighboring with non-self. The activity of the alternative oxidase (AOX) pathway increased when plants responded to non-self neighbors. The increased activity of AOX in plants responding to non-self indicates carbon imbalances in roots, possibly as a consequence of increased root exudation and communication between individuals. If such an effect occurs more widely, it may change the assumptions made for the quantity of respiration as used in carbon budget models.

The use of Bassia indica for salt phytoremediation in constructed wetlands.

The treatment and reuse of wastewater in constructed wetlands offers a low-cost, environmentally-friendly alternative for common engineered systems. Salinity in treated wastewater is often increased, especially in arid and semi-arid areas, and may harm crops irrigated from wetlands. We have strong evidence that halophyte plants are able to reduce the salinity of wastewater by accumulating salts in their tissues. Bassia indica is an annual halophyte with unique adaptations for salt tolerance. We performed three experiments to evaluate the capability of B. indica for salt phytoremediation as follows: a hydroponic system with mixed salt solutions, a recirculated vertical flow constructed wetland (RVFCW) with domestic wastewater, and a vertical flow constructed wetland (VFCW) for treating goat farm effluents. B. Indica plants developed successfully in all three systems and reduced the effluent salinity by 20-60% in comparison with unplanted systems or systems planted with other wetland plants. Salinity reduction was attributed to the accumulation of salts, mainly Na and K, in the leaves. Our experiments were carried out on an operative scale, suggesting a novel treatment for green desalination in constructed wetlands by salt phytoremediation in desert regions and other ecosystems.

Physiological parameters of plants as indicators of water quality in a constructed wetland.

INTRODUCTION: Increasing demand for water has stimulated efforts to treat wastewater for reuse in agriculture. Decentralized facilities for wastewater treatment became popular as a solution to remote and small communities. These systems mimic natural wetlands, cleaning wastewater as they flow through a complex of filter media, microbial fauna, and vegetation. The function of plants in constructed wetlands (CWs) has not been fully elucidated yet. DISCUSSION: In the research reported here, we provide evidence for a new use of plant physiological parameters in CWs as bioindicators of water quality along the system. We measured improved plant performance downstream of the CW by means of photochemical efficiency, CO(2) assimilation rate, and cell membrane stability. In addition, we found evidence for temporal improvement of plant performance, which was correlated to the establishment phase of plants in a newly operating CW. It is suggested that improved monitoring and management of CWs should take into planning consideration the promising potential of phyto-indicators.

Establishment of a constructed wetland in extreme dryland.

BACKGROUND, AIM, AND SCOPE: The project was set to construct an extensive wetland in the southernmost region of Israel at Kibbutz Neot Smadar (30 degree 02'45" N and 35 degree 01'19" E). The results of the first period of monitoring, summary, and perspectives are presented. The constructed wetland (CW) was built and the subsequent monitoring performed in the framework of the Southern Arava Sustainable Waste Management Plan, funded by the EU LIFE Fund. The specific aims were: (1) To end current sewage disposal and pollution of the ground, the aquifer, and the dry river bed (wadi) paths by biologically treating the sewage as part of the creation of a sustainable wetland ecosystem. (2) Serve as an example of CW in the Negev highlands and the Arava Valley climates for neighboring communities and as a test ground for plants and building methods appropriate to hyper arid climate. (3) Serve as an educational resource and tourist attraction for groups to learn about water reuse, recycling, local wildlife and migrating birds, including serving the heart of a planned Ecological-Educational Bird Park. This report is intended to allow others who are planning similar systems in hyper arid climates to learn from our experience. MATERIALS AND METHODS: The project is located in an extreme arid desert with less than 40 mm of rain annually and temperature ranges of -5 degree C to +42 degree C. The site receives 165-185 m3 of municipal and agricultural wastes daily, including cowshed and goat wastes and winery outflow. RESULTS: The CW establishment at Neot Smadar was completed in October 2006. For 8 months, clean water flowed through the system while the plants were taking root. In June 2007, the wetland was connected to the oxidation pond and full operation began. Because of seepage and evaporation, during the first several months, the water level was not high enough to allow free flow from one bed to the next. To bed A, the water was pumped periodically from the oxidation pond (Fig. 1) and from there flowed by gravitation through the rest of the system. The initial results of the monitoring are promising. In nearly all measurements, the system succeeded as expected to reduce levels of contaminants at least to the level acceptable for irrigating fruit trees and often to the level of unlimited irrigation. The introduction of the plants in the system and their physiological performance were evaluated and were found to correlate well to the quality of water in the various beds. DISCUSSION: It should be said at the outset that evaluation of the performance of a CW system is a long-term process. Thus, the main aim of this report is to present the problems, difficulties, preliminary results, and concepts concerned with the first stage of establishment of CW in an extremely dry region. CONCLUSIONS: The CW system was designed to dispose of municipal and agricultural wastes in a way that not merely reduces pollution, but adds to environmental quality by creating accessible parkland for local residents and tourists. Several factors affected the performance of the system at the initial stages of operation: ecological balance between microbes and plants, big seasonal variations, seepage and evaporation reduced the flow in the initial operation of the system. Despite the initial difficulties, the quality of water coming out the system is acceptable for irrigation. RECOMMENDATIONS AND PERSPECTIVES: The CW can function well under extreme dryland conditions. The oxidation pond was the major source of evaporation and bad odors. Therefore, alternatives to the oxidation pond are needed. Cost effectiveness of the system still has to be evaluated systematically.