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Summary: Significant progress has been recently made in our understanding of the evolution of jasmonates biosynthesis and signaling. The bioactive jasmonate activating COI1-JAZ co-receptor differs in bryophytes and vascular plants. Dinor-iso-12-oxo-phytodienoic acid (dn-iso-OPDA) is the bioactive hormone in bryophytes and lycophytes. However, further studies showed that the full activation of hormone signaling in Marchantia polymorpha requires additional unidentified hormones. Δ4-dn-OPDAs were previously identified as novel bioactive jasmonates in M. polymorpha. In this paper, we describe the major bioactive isomer of Δ4-dn-OPDAs as Δ4-dn-iso-OPDA through chemical synthesis, receptor binding assay, and biological activity in M. polymorpha. In addition, we disclosed that Δ4-dn-cis-OPDA is a biosynthetic precursor of Δ4-dn-iso-OPDA. We demonstrated that in planta cis-to-iso conversion of Δ4-dn-cis-OPDA occurs in the biosynthesis of Δ4-dn-iso-OPDA, defining a key biosynthetic step in the chemical evolution of hormone structure. We predict that these findings will facilitate further understanding of the molecular evolution of plant hormone signaling.

Chimaphila umbellata has been studied for almost two centuries now, with the first paper exploring the phytochemistry of the plant published in 1860. Almost all contemporary studies focus on the biotechnological advances of C. umbellata including its utilization as a natural alternative in the cosmetic, food, biofuel, and healthcare industry, with a special focus on its therapeutic uses. This literature review critically investigates the significance and applications of secondary metabolites extracted from the plant and presses on the biotechnological approaches to improve its utilization. C. umbellata is home to many industrially and medicinally important phytochemicals, the majority of which belong to phenolics, sterols, and triterpenoids. Other important compounds include 5-hydroxymethylfurfural, isohomoarbutin, and methyl salicylate (the only essential oil of the plant). Chimaphilin is the characteristic phytochemical of the plant. This review focuses on the phytochemistry of C. umbellata and digs into their chemical structures and attributes. It further discusses the challenges of working with C. umbellata including its alarming conservation status, problems with in-vitro cultivation, and research and development issues. This review concludes with recommendations based on biotechnology, bioinformatics, and their crucial interface. [ABSTRACT FROM AUTHOR]

Summary: Interactions between algae and bacteria are ubiquitous and play fundamental roles in nutrient cycling and biomass production. Recent studies have shown that the plant auxin indole acetic acid (IAA) can mediate chemical crosstalk between algae and bacteria, resembling its role in plant-bacterial associations. Here, we report a mechanism for algal extracellular IAA production from L-tryptophan mediated by the enzyme L-amino acid oxidase (LAO1) in the model Chlamydomonas reinhardtii. High levels of IAA inhibit algal cell multiplication and chlorophyll degradation, and these inhibitory effects can be relieved by the presence of the plant-growth-promoting bacterium (PGPB) Methylobacterium aquaticum, whose growth is mutualistically enhanced by the presence of the alga. These findings reveal a complex interplay of microbial auxin production and degradation by algal-bacterial consortia and draws attention to potential ecophysiological roles of terrestrial microalgae and PGPB in association with land plants.

SUMMARY: Floral scent plays a crucial role in the reproductive process of many plants. Humans have been fascinated by floral scents throughout history, and have transported and traded floral scent products for which they have found multiple uses, such as in food additives, hygiene and perfume products, and medicines. Yet the scientific study of how plants synthesize floral scent compounds began later than studies on most other major plant metabolites, and the first report of the characterization of an enzyme responsible for the synthesis of a floral scent compound, namely linalool in Clarkia breweri, a California annual, appeared in 1994. In the almost 30 years since, enzymes and genes involved in the synthesis of hundreds of scent compounds from multiple plant species have been described. This review recapitulates this history and describes the major findings relating to the various aspects of floral scent biosynthesis and emission, including genes and enzymes and their evolution, storage and emission of scent volatiles, and the regulation of the biochemical processes. Significance Statement: This reviews describes our existing knowledge of how flowers produce and emit volatile compounds, and discusses the reasons for why research in this area lagged behind other topics in plant biochemistry. [ABSTRACT FROM AUTHOR]

Summary: The transcription factor LEAFY (LFY) plays crucial roles in flower development by activating floral homeotic genes. Activation of LFY targets requires the combined action of LFY and the E3 ubiquitin ligase UFO, although the precise underlying mechanism remains unclear. Here, we show that LFY accumulates in biomolecular condensates within the cytoplasm, while recombinant LFY forms condensates with similar properties in vitro. UFO interacts with LFY within these condensates and marks it for degradation. LFY levels in the nucleus are buffered against changes in total LFY levels induced by proteasome inhibition, UFO overexpression, or mutation of lysine residues in a disordered region of LFY. Perturbation of cytoplasmic LFY condensates by 1,6-hexanediol treatment induces the relocalization of LFY to the nucleus and the subsequent activation of the LFY target AP3 in flowers. Our data suggest that nucleocytoplasmic partitioning, condensation, and ubiquitin-dependent degradation regulate LFY levels in the nucleus to control its activity.

Summary: To improve the treatment of pigmentation disorders, looking for natural and safe inhibitors of melanin synthesis has become an area of research interest. The quinoa husk peptides reportedly elicit various biological activities (e.g., anti-cancer, antioxidant, anti-hypertensive, and so forth), but its effects on melanin inhibition remain unknown. In the current study, we purified quinoa husk peptides with 30 and 80% ethanol using a macroporous adsorption resin (DA201-C). Component screening revealed that the 80%-ethanol fraction (i.e., QHP fraction) contained numerous short peptides (84.41%) and hydrophobic amino acids (45.60%), while eliciting a superior tyrosinase [TYR]-inhibition rate, 2,2-diphenyl-1-picryhydrazil-scavenging rate, reducing activity, and chelating capacity compared to the 30% fraction and was thus applied in subsequent analyses. Differentially expressed genes in the QHP fraction were primarily enriched in the Akt-signaling pathways based on transcriptomics. Thus, we assessed the expression of related proteins and genes in A375 cells and rat skin cells following treatment with QHP.

The tree of heaven, Ailanthus altissima (MILL.) SWINGLE, is a globally invasive plant known to secrete allelopathic metabolites called quassinoids. Quassinoids are highly modified triterpenoids. So far, nothing has been known about the biochemical basis of quassinoid biosynthesis. Here, based on transcriptome and metabolome data of Ailanthus altissima, we present the first three steps of quassinoid biosynthesis, which are catalysed by an oxidosqualene cyclase and two cytochrome P450 monooxygenases, resulting in the formation of the protolimonoid melianol. Strikingly, these steps are identical to the first steps of the biosynthesis of limonoids, structurally different triterpenoids from sister plant families within the same order Sapindales. Our results are therefore not only important to fully understand the biosynthesis of complex triterpenoids in plants, but also confirm the long-standing hypothesis that quassinoids and limonoids share an evolutionary origin. In addition, our transcriptome data for Ailanthus altissima will be beneficial to other researchers investigating the physiology and ecology of this invasive tree. [ABSTRACT FROM AUTHOR]

To cope with relentless environmental pressures, plants produce an arsenal of structurally diverse chemicals, often called specialized metabolites. These lineage-specific compounds are derived from the simple building blocks made by ubiquitous core metabolic pathways. Although the structures of many specialized metabolites are known, the underlying metabolic pathways and the evolutionary events that have shaped the plant chemical diversity landscape are only beginning to be understood. However, with the advent of multi-omics data sets and the relative ease of studying pathways in previously intractable non-model species, plant specialized metabolic pathways are now being systematically identified. These large datasets also provide a foundation for comparative, phylogeny-guided studies of plant metabolism. Comparisons of metabolic traits and features like chemical abundances, enzyme activities, or gene sequences from phylogenetically diverse plants provide insights into how metabolic pathways evolved. This review highlights the power of studying evolution through the lens of comparative biochemistry, particularly how placing metabolism into a phylogenetic context can help a researcher identify the metabolic innovations enabling the evolution of structurally diverse plant metabolites. [ABSTRACT FROM AUTHOR]

Hormonal balance is important for plant metabolism and, consequently, berry development of grapevines (Vitis vinifera L.). Exogenous application of plant growth regulators (PGRs) combined with mineral elements, in satisfactory dosages, can promotes physiologic efficiency. We investigated the effect of foliar application of PGRs alone or combined with mineral elements on 'Crimson Seedless' grapevines. The metabolism and development of the plants were examined. The treatments were applied via foliar spraying consisting in a PGRs mixture [cytokinin (kinetin—Kt), auxin [4-Indole-3-butyric acid (IBA)], and gibberellin (gibberellic acid—GA3)] and a cobalt (Co) and molybdenum (Mo) mixture were studied. The PGRs and nutrients combined acted as protectors against stress, presenting increases in antioxidant enzyme activities but with a low level of lipid peroxidation. We concluded that the mixture of PGR applied alone or combined with mineral elements favoured content of photosynthetic pigments in the grapevines leaves, antioxidant enzyme activity, translocation and accumulation of reserves. [ABSTRACT FROM AUTHOR]

The rose aphid, Macrosiphum rosae (L.) (Hemiptera: Aphididae), is one of the most important pests on Rosa species, which cause serious damage to plants. Salicylic acid (SA) and Potassium sulfate (PS) have the potential to affect the population of pests on plants. In this study, different concentrations of SA (0.7 and 1.4 mM), PS (11 and 28 mM) and SA (1.4 mM) + PS (28 mM) were used as foliar applications on rose plants to evaluate the life table parameters of M. rosae. The chemical constituents of rose leaves were also assessed using Gas Chromatography--Mass Spectrometry (GC/MS). Results showed that the life table parameters of M. rosae were significantly affected by various treatments. The longevity of the aphid was longest on control and shortest on SA (1.4 mM). M. rosae had the least fecundity on SA (1.4 mM) treatment. The intrinsic rate of natural increase (rm) of M. rosae ranged from 0.202 to 0.298 day-1 on different treatments, which was lowest on SA (1.4 mM) and highest on control. GC/MS analysis showed that Squalene, 2-(1,3-benzothiazol-2-ylsulfanyl)-1-(3,5- dimethylpyrazol-1-yl) ethanone, and 9,12,15-octadecatrienoic acid, as secondary metabolite, were the major compounds in SA (1.4 mM) treatment. The results of this study demonstrated that application of SA (1.4 mM) on rose plants has a good potential for reducing the population of M. rosae and can be used in integrated pest management programs. [ABSTRACT FROM AUTHOR]

SUMMARY: Rhomboid‐like proteins are intramembrane proteases with a variety of regulatory roles in cells. Though many rhomboid‐like proteins are predicted in plants, their detailed molecular mechanisms or cellular functions are not yet known. Of the 13 predicted rhomboids in Arabidopsis thaliana, one, RBL10, affects lipid metabolism in the chloroplast, because in the respective rbl10 mutant the transfer of phosphatidic acid through the inner envelope membrane is disrupted. Here we show that RBL10 is part of a high‐molecular‐weight complex of 250 kDa or greater in size. Nine likely components of this complex are identified by two independent methods and include Acyl Carrier Protein 4 (ACP4) and Carboxyltransferase Interactor1 (CTI1), which have known roles in chloroplast lipid metabolism. The acp4 mutant has decreased C16:3 fatty acid content of monogalactosyldiacylglycerol, similar to the rbl10 mutant, prompting us to offer a mechanistic model of how an interaction between ACP4 and RBL10 might affect chloroplast lipid assembly. We also demonstrate the presence of a seventh transmembrane domain in RBL10, refining the currently accepted topology of this protein. Taken together, the identity of possible RBL10 complex components as well as insights into RBL10 topology and distribution in the membrane provide a stepping‐stone towards a deeper understanding of RBL10 function in Arabidopsis lipid metabolism. Significance Statement: Little is known about the function of plant rhomboid proteases such as RBL10, which is a chloroplast‐located rhomboid protease previously shown to affect the lipid composition of photosynthetic membranes. Here we provide evidence for an RBL10‐containing complex in the chloroplast and identify several protein interactors, including ACP4 and CTI1, which have roles in lipid metabolism. [ABSTRACT FROM AUTHOR]

The Green Revolution left millions of the world's smallholder farmers behind. Increasing the role of farmers in agricultural innovation can help them catch up--and will lead to better science in [...]

Haricot bean is primarily grown in Ethiopia for human consumption and export earnings. A market demand for haricot bean, both in the domestic and export market, has triggered the production of haricot bean in selected areas of Ethiopia though its production is constrained by several factors such as poor soil fertility and erratic rainfall. This study was carried out to investigate the combined effect of phosphorus and sulfur fertilizers on yield, yield related traits and protein content of haricot bean (Phaseolus vulgaris) varieties at the research field of Mekoni Agricultural Research Center during 2016/17 cropping season. The experiment was laid out in split plot design where varieties were assigned to the main plots and fertilizer rates to the sub plots in three replications. Three phosphorus (P) rates (10, 20 and 30 kg ha (-1)) were combined with four sulfur (S) rates (15, 30, 45 and 60 kg ha (-1)) and applied in combination to Melka Awash-98 and Nasir varieties. Data on phenological, agronomic and quality traits were collected and determined. Partial budget analysis was carried out to assess the profitability of the applications. P-S fertilizer treatments were significantly affected by varieties. Treatments were significantly affected by varieties and the imposed P and S rates. The interaction effect due to variety by fertilizer the two factors significantly affect days to flowering, plant height, hundred seed weight and protein content. Tallest plants, fewer days to flowering and maturity, many pods/plant, heavier seeds, higher grain yield ha (-1) and better protein content were recorded where the fertilizer application rate was 20 kg ha (-1)P and 30 kg ha (-1) S for both varieties. Grain yield ranged from 1520 to 3000 kg ha (-1) depending on P-S fertilizer rates and varieties. Nasir variety seems to be superior over Melka Awash-98 for most traits except protein content. However, production of Melka Awash-98 under 20 kg ha (-1)P and 15 kg ha (-1) S fertilization tend to be more economical as it resulted in highest net benefit return. Although not profitable, planting Melka Awash-98 using an application rate of 20 kg ha (-1)P and 30 kg ha (-1) S could be suggested for use in the area to ensure earliness and high grain yield. Key words: Haricot bean, fertilizer, phosphorus, sulfur, irrigation, yield, protein, net benefit, INTRODUCTION Ethiopia is known as the homeland for several domesticated crop plants. It is among the top pulse producing countries in the world. Out of total Ethiopian grain production, pulses [...]

Competence in the processing of soybean is constrained by many factors which directly influence the consumption pattern in Nigeria. Youth involvement in soybean processing is a strategy to successfully incorporate soybean utilization in households across South-west Nigeria. The study identified factors that influence competence in soybean processing among secondary school students in Ibadan metropolis of Oyo state. The study is an offshoot of a training activity embarked by Institute of Agricultural Research and Training, (IAR&T) Ibadan to improve the knowledge of soybean processing among secondary students. Thus, study purposively selected three secondary schools adopted by the Institute and all the senior secondary students formed the study population. However, 30% of the senior students were randomly sampled which gave a total of 203 respondents. Independent variables such as personal characteristics of students, knowledge of benefit of soybean and competence in the processing of soybean were collected using validated questionnaire. Competence was measured in a four-point scale of high competence, average competence, low competence and no competence. Data were described using percentage and mean, and were analyzed using Analysis of Variance (ANOVA), Chi square, Pearson Product Moment Correlation (PPMC), and multiple regression analysis. Findings revealed that the mean age of respondents was 15.9 years and majority (57.6%) was female. Highest education attained by mothers (57.1%) was secondary education and majority (62.6%) of mothers was involved in trading. The knowledge of benefit of soybean was high among majority (64.1%) but majority (62.0%) also had low competence in soybean processing. Data analysis revealed a significant relationship (p Key words: Competence, Knowledge, Soybean processing, nutrition, secondary schools students, adopted schools, INTRODUCTION Soybean contains major vitamins and minerals lacking in other legumes and some cereals. It contains 40% high quality protein, 20% edible vegetable oil and a good balance of amino-acid [...]

Biotic and abiotic stresses cause substantial changes in plant biochemistry. These changes are typically revealed by high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS). This information can be used to determine underlying molecular mechanisms of biotic and abiotic stresses in plants. A growing body of evidence suggests that changes in plant biochemistry can be probed by Raman spectroscopy, an emerging analytical technique that is based on inelastic light scattering. Non-invasive and non-destructive detection and identification of these changes allow for the use of Raman spectroscopy for confirmatory diagnostics of plant biotic and abiotic stresses. In this study, we couple HPLC and HPLC-MS findings on biochemical changes caused by Candidatus Liberibacter spp. (Ca. L. asiaticus) in citrus trees to the spectroscopic signatures of plant leaves derived by Raman spectroscopy. Our results show that Ca. L. asiaticus cause an increase in hydroxycinnamates, the precursors of lignins, and flavones, as well as a decrease in the concentration of lutein that are detected by Raman spectroscopy. These findings suggest that Ca. L. asiaticus induce a strong plant defense response that aims to exterminate bacteria present in the plant phloem. This work also suggests that Raman spectroscopy can be used to resolve stress-induced changes in plant biochemistry on the molecular level. [ABSTRACT FROM AUTHOR]

Pesticides may manipulate plant physiology as non-target organisms. In this study, we examined biochemical responses of pistachio plants (Pistacia vera L.) to imidacloprid and phosalone as common pesticides used to control pistachio psyllids. Enzymatic characterization in treated plants with pesticides showed greater specific activities of superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, phenylalanine ammonia-lyase, glutathione reductase, and glutathione S-transferase compared with untreated plants during 14 days after treatment. Further experiments displayed elevated levels of total phenols and total proteins coupled with significant increases in proline and total soluble carbohydrate contents in treated plants in comparison to untreated plants. Moreover, pesticide treatment leads to a significant decrease in polyphenol oxidase activity. Nevertheless, no significant changes in contents of hydrogen peroxide, malondialdehyde, total chlorophyll, and electrolyte leakage index were obtained in treated plants. Pesticides' impacts on host plant physiology resulted in similar responses between two pesticides with differences in peak days. Overall, the findings of this study provide an insight into the side effects of phosalone and imidacloprid, chemicals with no specific target site in plants, on the physiology and biochemistry of pistachio plants at recommended rates. [ABSTRACT FROM AUTHOR]

Biotic and abiotic stresses cause substantial changes in plant biochemistry. These changes are typically revealed by high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS). This information can be used to determine underlying molecular mechanisms of biotic and abiotic stresses in plants. A growing body of evidence suggests that changes in plant biochemistry can be probed by Raman spectroscopy, an emerging analytical technique that is based on inelastic light scattering. Non-invasive and non-destructive detection and identification of these changes allow for the use of Raman spectroscopy for confirmatory diagnostics of plant biotic and abiotic stresses. In this study, we couple HPLC and HPLC-MS findings on biochemical changes caused by Candidatus Liberibacter spp. (Ca. L. asiaticus) in citrus trees to the spectroscopic signatures of plant leaves derived by Raman spectroscopy. Our results show that Ca. L. asiaticus cause an increase in hydroxycinnamates, the precursors of lignins, and flavones, as well as a decrease in the concentration of lutein that are detected by Raman spectroscopy. These findings suggest that Ca. L. asiaticus induce a strong plant defense response that aims to exterminate bacteria present in the plant phloem. This work also suggests that Raman spectroscopy can be used to resolve stress-induced changes in plant biochemistry on the molecular level.

CBL1 is an EF hand Ca2+ binding protein from A. thaliana that is involved in the detection of cellular Ca2+ signals and the downstream signal transmission by interaction with the protein kinase CIPK23. So far, the structure and calcium ion binding affinities of CBL1 remain elusive. In this study it was observed that CBL1 tends to form higher oligomeric states due to an intrinsic hydrophobicity and the presence of the detergent BriJ35 was required for the purification of monomeric and functional protein. Functional insights into the in vitro Ca2+ binding capabilities of CBL1 were obtained by isothermal titration calorimetry (ITC) of the wildtype protein as well as single site EF hand mutants. Based on our results, a binding model of CBL1 for Ca2+ in vivo is proposed. Additionally, upon both, ITC measurements and the analysis of an AlphaFold2 model of CBL1, we could gain first insights into the formation of the dimer interface. We could identify an area around EF hand 4 to be relevant for the structural and functional integrity of monomeric CBL1 and likely EF hand 1 to be involved in the dimer interface. • Thermodynamic analysis of Ca2+, Mg2+, and Mn2+ binding to CBL1. • Mutational studies of individual EF hands in CBL1 allows a proposal of stepwise Ca2+ binding. • First insights in the structural basis for CBL1 dimerization. • Model to relate stepwise Ca2+ binding to the molecular function of CBL1. [ABSTRACT FROM AUTHOR]

In order to study the false positive problem during detecting heme binding protein with horseradish peroxidase (HRP) as secondary antibody, spinach cytochrome b6f complex (Cyt b6f ) and ferredoxin-NADP+ oxidoreductase (FNR) are used as the test material (the former contains the heme binding protein Cyt f, and the latter does not contain heme group). A comparative experiment is designed through the use of the primary antibody of spinach FNR and secondary antibodies labeled with HRP and alkaline phosphatase (ALP). The results indicate that in the HRP-labeled secondary antibody system, Cyt f could be colored even without the incubation by the primary antibody and the secondary antibody, which is a significant false positive. In the ALP-labeled secondary antibody system, the Cyt f doesn't show color, and only the FNR is colored. In western blot experiments, if the protein to be detected is a heme-binding protein or contains a small amount of heme-binding protein, HRP-labeled secondary antibodies should be avoided and ALP-labeled secondary antibodies or other secondary antibodies should be recommended. It is speculated that the heme-binding protein has an HRP-like oxidoreductase activity, namely it can react with the color developing solution, thereby generating a false positive and interfering with the judgment of the experimental results.

SUMMARY: The high rates of photosynthesis and the carbon‐concentrating mechanism (CCM) in C4 plants are initiated by the enzyme phosphoenolpyruvate (PEP) carboxylase (PEPC). The flow of inorganic carbon into the CCM of C4 plants is driven by PEPC's affinity for bicarbonate (KHCO3), which can be rate limiting when atmospheric CO2 availability is restricted due to low stomatal conductance. We hypothesize that natural variation in KHCO3 across C4 plants is driven by specific amino acid substitutions to impact rates of C4 photosynthesis under environments such as drought that restrict stomatal conductance. To test this hypothesis, we measured KHCO3 from 20 C4 grasses to compare kinetic properties with specific amino acid substitutions. There was nearly a twofold range in KHCO3 across these C4 grasses (24.3 ± 1.5 to 46.3 ± 2.4 μm), which significantly impacts modeled rates of C4 photosynthesis. Additionally, molecular engineering of a low‐HCO3− affinity PEPC identified key domains that confer variation in KHCO3. This study advances our understanding of PEPC kinetics and builds the foundation for engineering increased‐HCO3− affinity and C4 photosynthetic efficiency in important C4 crops. Significance Statement: Phosphoenolpyruvate carboxylase (PEPC) is an essential enzyme involved in C4 photosynthesis and our research determined significant variability in the binding affinity for bicarbonate (KHCO3) among 20 PEPC isozymes from C4 grasses. Additionally, we identified the region of the PEPC enzyme that is responsible for this variability in KHCO3, which builds the foundation for engineering a kinetically enhanced PEPC to increase photosynthesis and production in C4 crops to meet the demands of the growing population. [ABSTRACT FROM AUTHOR]

Late embryogenesis abundant (LEA) proteins are produced during seed embryogenesis and in vegetative tissue in response to various abiotic stressors. A correlation has been established between LEA expression and stress tolerance, yet their precise biochemical mechanism remains elusive. LEA proteins are very rich in hydrophilic amino acids, and they have been found to be intrinsically disordered proteins (IDPs) in vitro. Here, we perform biochemical and structural analyses of the four LEA3 proteins from Arabidopsis thaliana (AtLEA3). We show that the LEA3 proteins are disordered in solution but have regions with propensity for order. All LEA3 proteins were effective cryoprotectants of LDH in the freeze/thaw assays, while only one member, AtLEA3‐4, was shown to bind Cu2+ and Fe3+ ions with micromolar affinity. As well, only AtLEA3‐4 showed binding and a gain in α‐helicity in the presence of the membrane mimic dodecylphosphocholine (DPC). We explored this interaction in greater detail using 15N‐heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance, and demonstrate that two sets of conserved motifs present in AtLEA3‐4 are involved in the interaction with the DPC micelles, which themselves gain α‐helical structure. [ABSTRACT FROM AUTHOR]

Our climate is changing due to anthropogenic emissions of greenhouse gases from the production and use of fossil fuels. Present atmospheric levels of CO2 were last seen 3 million years ago, when planetary temperature sustained high Arctic camels. As scientists and educators, we should feel a professional responsibility to discuss major scientific issues like climate change, and its profound consequences for humanity, with students who look up to us for knowledge and leadership, and who will be most affected in the future. We offer simple to complex backgrounds and examples to enable and encourage biochemistry educators to routinely incorporate this most important topic into their classrooms. [ABSTRACT FROM AUTHOR]

Journal of International Affairs (JIA): What do soil regeneration and carbon farming have to do with climate change? Eric Toensmeier (ET): Regenerating soil involves increasing the carbon stored in the [...]

Virtually all marine life depends on the productivity of phytoplankton--microscopic organisms that work tirelessly at the ocean's surface to absorb the carbon dioxide that gets dissolved into the upper ocean [...]

African Agricultural Technology Foundation (AATF) promotes DroughtTEGO[R] drought-tolerant maize hybrids developed by Water Efficient Maize for Africa (WEMA) project in partnership with CIMMYT, Monsanto and five National Agricultural Research Systems for Kenya, Uganda, Tanzania, Mozambique, and South Africa to address the impact of drought occasioned by climate change. To determine the level of adoption and use of DroughtTEGO[R] maize hybrids in Kenya, a survey was conducted involving 642 farming households from six counties. The results indicated a high rate of awareness of at least one of the DroughtTEGO[R] varieties (61%). The adoption rate stood at 26% with WE1101 maize hybrid being the most widely known and adopted due to its availability and high yields. Expected adoption was calculated at 89% with about 65% new farmers adopting the DroughtTEGO[R] hybrids. Lack of full information on the productivity, non-availability of the seed when required and the varieties being expensive compared to other locally available varieties were found to be key barriers to its adoption. The econometric results reveal statistical differences between the variables that influence awareness and adoption of DroughtTEGO[R] hybrid seed. Variables that determined adoption included age of the household head, fellow farmers and demonstration sites as the primary main source of seed information. Other variables were record-keeping, women's control of household resources, perception of food security, price, and location. Well-thought-out strategies that target these variables can be effective in attracting new adopters. Thus, the study recommends, promotional messages and extension approaches appropriate to both the young and the aged, better seed pricing strategies, women's control of household resources to be encouraged, and specific locations with low probability of adoption should be given priority. Steps could include the promotion of the varieties through on-farm demonstrations with wider coverage, strengthening of the extension service and allocation of resources for extension activities in Kenya. Other broad recommendations that emanated from the study included timely availability and delivery of quality DroughtTEGO[R] seed and availability of credit facilities. It is important to investigate the case of adopters who discontinued using these varieties. Key words: Technology adoption, climate-smart, maize hybrid, food security, DroughtTEGO[R], INTRODUCTION In Kenya, maize (Zea mays L.) is considered an essential food crop and accounts for about 65% of total staple food caloric intake and 36% of total food caloric [...]

Somalia is among the poorest countries on the planet. Since the fall of Siad Barre's regime in 1991, the country has been in a near-constant state of food insecurity and suffered two officially declared famines. In order to address the issue of food insecurity in Somalia, a greater understanding of each of the components that contribute to the Somali food supply is merited. Cereal crops make up a third to half of the Somali diet by calories and are among the most important food crops produced by the country. This study investigated the historic trends in domestic cereal production, cereal imports, and food aid (reported in cereal equivalents) in Somalia by exploring secondary data publicly available from the Food and Agriculture Organization (FAO) of the United Nations, and the World Food Programme. These data were related to World Bank population data in Microsoft Excel and average per capita production, import, and aid figures were calculated. Median changes over time and their associated interquartile ranges were reported. The data demonstrated that Somali cereal production levels have not improved since the 1960's, and since that time, they have been characterized by an extreme amount of year-to-year volatility. Moreover, maize and sorghum are the only meaningful fractions of Somalia's domestic cereal production, and recent total production of each crop is well below the levels observed in the 1980's. When combined, per capita production of maize and sorghum has decreased precipitously over time (falling from a high of 91 kg per capita in 1972 to just 30 kg per capita in 2012). This is likely due to a combination of stagnant production and rapidly increasing Somali population (up over 350% since 1961). This has increased the importance of cereal imports and aid to Somalia and has made the country vulnerable to disruptions in international cereal markets and foreign government policies. Improving domestic cereal production in Somalia should be part of any future food security strategy for the country. Recent agricultural research in Somalia suggests that the implementation of simple agricultural best management practices can increase cereal production in the country. Key words: Somalia, Population Growth, Cereal Production, Cereal Imports, Food Aid, INTRODUCTION Political and civil unrest have hindered Somalia's economic development since the fall of the Siad Barre regime in 1991 [1]. This instability has resulted in high mortality rates, a [...]

Retention of trees after logging is a method of preserving epiphytic lichens; however, epiphytes' responses to logging disturbance are insufficiently known. We aimed to characterize four viability measures--effective PSII yield ([[PHI].sub.PSII]; a proxy for photosynthesis), maximal photosystem II efficiency ([F.sub.V]/[F.sub.M]; a proxy for photoinhibition), chlorophyll a content, and chlorophyll a/b ratio--and the functional parameter specific thallus mass (STM; a proxy for water storage) in sympatric populations of two old-growth lichens (Lobaria retigera (Bory) Trevisan and Lobaria oregana (Tuck.) Mull. Arg.) and the less old-growth dependent Lobaria pulmonaria (L.) Hoffm. along recently logged forest edge gradients within retained forest patches. All species experienced substantially reduced chlorophyll contents near edges, whereas [[PHI].sub.PSII] was lower in the two old-growth lichens than in L. pulmonaria. STM, and thus lichen water storage, did not respond to logging, probably because chlorophyll degradation reduced the carbon gain required for necessary acclimation. Reported edge effects on lichen viability were so strong that most of the epiphytic lichens in the retained forest patches were affected. Measured viability variables improved linearly with distances up to [approximately equal to]120 m from the edge. To avoid logging-induced adverse impacts on the threatened epiphytic lichens of these old-growth rainforests, there is a need to retain forest patches wider than 240 m. Key words: canopy retention, edge effect, epiphytic lichens, logging disturbance, temperate rainforest. La retention d'arbres apres une coupe est une methode de preservation des lichens epiphytes. Cependant, la reaction des epiphytes aux perturbations causees par l'exploitation forestiere n'est pas suffisamment connue. Nous avons caracterise quatre mesures de viabilite : le rendement effectif du photosysteme II ([[PHI].sub.PSII], un indicateur de la photosynthese), l'efficacite maximum du PSII ([F.sub.V]/[F.sub.M], un indicateur de la photo-inhibition), la teneur en chlorophylle a, le rapport de la chlorophylle a/b, ainsi que le parametre fonctionnel de la masse specifique du thalle (MST), un indicateur du stockage de l'eau. L'etude a ete realisee dans les populations sympatriques de deux lichens de vieilles forets (Lobaria retigera (Bory) Trevisan, Lobaria oregana (Tuck.) Mull. Arg.) et de Lobaria pulmonaria (L.) Hoffm.), qui est moins dependant des vieilles forets, le long de transects allant de la bordure de la foret recemment coupee et traversant des ilots de foret preserves. Toutes les especes ont connu une reduction substantielle de la teneur en chlorophylle pres des bordures, tandis que le [[PHI].sub.PSII] etait moins eleve chez les deux lichens de vieilles forets que chez L. pulmonaria. La MST, et par consequent le stockage de l'eau chez les lichens, n'a pas reagi a l'exploitation forestiere, probablement parce que la degradation de la chlorophylle II a reduit le gain en carbone requis pour l'acclimatation rendue necessaire. Les effets de bordures qui ont ete rapportes etaient si importants que la viabilite dans la plupart des lichens epiphytes des ilots de foret preserves a ete affectee. Les variables de viabilite qui ont ete mesurees s'amelioraient de facon lineaire en fonction de la distance jusqu'a environ 120 m vers l'interieur a partir de la bordure des ilots. Pour eviter les impacts nefastes de l'exploitation forestiere sur les lichens epiphytes menaces dans ces vieilles forets pluviales, on doit conserver des ilots de foret avec un diametre superieur a 240 m. [Traduit par la Redaction] Mots-cles: retention du couvert forestier, effet de bordure, lichens epiphytes, perturbation due a l'exploitation forestiere, foret pluviale temperee., Introduction Forest canopy lichens often show reduced survival along edges after logging (Dettki and Esseen 2003), because they rapidly become damaged when exposed to sudden increases in light levels (Gauslaa [...]

Methylation of cytosine to 5-methylcytosine (5mC) is a prevalent DNA modification found in many organisms. Sequential oxidation of 5mC by ten-eleven translocation (TET) dioxygenases results in a cascade of additional epigenetic marks and promotes demethylation of DNA in mammals.sup.1,2. However, the enzymatic activity and function of TET homologues in other eukaryotes remains largely unexplored. Here we show that the green alga Chlamydomonas reinhardtii contains a 5mC-modifying enzyme (CMD1) that is a TET homologue and catalyses the conjugation of a glyceryl moiety to the methyl group of 5mC through a carbon-carbon bond, resulting in two stereoisomeric nucleobase products. The catalytic activity of CMD1 requires Fe(ii) and the integrity of its binding motif His-X-Asp, which is conserved in Fe-dependent dioxygenases.sup.3. However, unlike previously described TET enzymes, which use 2-oxoglutarate as a co-substrate.sup.4, CMD1 uses l-ascorbic acid (vitamin C) as an essential co-substrate. Vitamin C donates the glyceryl moiety to 5mC with concurrent formation of glyoxylic acid and CO.sub.2. The vitamin-C-derived DNA modification is present in the genome of wild-type C. reinhardtii but at a substantially lower level in a CMD1 mutant strain. The fitness of CMD1 mutant cells during exposure to high light levels is reduced. LHCSR3, a gene that is critical for the protection of C. reinhardtii from photo-oxidative damage under high light conditions, is hypermethylated and downregulated in CMD1 mutant cells compared to wild-type cells, causing a reduced capacity for photoprotective non-photochemical quenching. Our study thus identifies a eukaryotic DNA base modification that is catalysed by a divergent TET homologue and unexpectedly derived from vitamin C, and describes its role as a potential epigenetic mark that may counteract DNA methylation in the regulation of photosynthesis. An algal TET dioxygenase homologue, CMD1, uses vitamin C as a glycerol donor to modify 5-methylcytosine and helps to regulate gene transcription in response to high light levels., Author(s): Jian-Huang Xue [sup.1] , Guo-Dong Chen [sup.1] , Fuhua Hao [sup.2] , Hui Chen [sup.1] [sup.3] , Zhaoyuan Fang [sup.1] , Fang-Fang Chen [sup.4] , Bo Pang [sup.5] , [...]

Sacoglossan sea slugs feed by suctorially consuming siphonaceous green algae. Most sacoglossan species are feeding specialists, but the Caribbean coral reef-dwelling Elysia crispata is polyphagous and sequesters chloroplasts from multiple algal species into cells lining its digestive diverticulum for use in photosynthesis. We have used sequences of the chloroplast-encoded rbcL gene to compare the chloroplast donor algae in five populations of E. crispata from various Caribbean locations. We found that E. crispata utilizes more algal species than was previously known, including some algae previously not reported as present in the region. In addition, slugs from each location had unique chloroplast arrays with little overlap, except that all locations had slugs feeding on algae within the genus Bryopsis. This variation in diet between locations suggests that the slugs may be exhibiting local adaptation in their dietary choices, and it highlights ecological differences between the Caribbean-wide reef-dwelling ecotypes and the mangrove lagoon ecotypes found in the Florida Keys., Introduction Most species of herbivorous sacoglossan sea slugs feed on siphonaceous green algae by puncturing the algal filament with a radular tooth and then suctorially removing the cytoplasmic contents (Jensen, [...]

Summary: The plant cell wall, a form of the extracellular matrix, is a complex and dynamic network of polymers mediating a plethora of physiological functions. How polysaccharides assemble into a coherent and heterogeneous matrix remains mostly undefined. Further progress requires improved molecular-level visualization methods that would gain a deeper understanding of the cell wall nanoarchitecture. dSTORM, a type of super-resolution microscopy, permits quantitative nanoimaging of the cell wall. However, due to the lack of single-cell model systems and the requirement of tissue-level imaging, its use in plant science is almost absent. Here we overcome these limitations; we compare two methods to achieve three-dimensional dSTORM and identify optimal photoswitching dyes for tissue-level multicolor nanoscopy. Combining dSTORM with spatial statistics, we reveal and characterize the ultrastructure of three major polysaccharides, callose, mannan, and cellulose, in the plant cell wall precursor and provide evidence for cellulose structural re-organization related to callose content.

Electron transfer plays a crucial part in many chemical reactions.sup.1,2, including photosynthesis, combustion and corrosion. But even though redox-state transitions change the electronic structure of the molecules involved, mapping these changes at the single-molecule level is challenging. Scanning tunnelling microscopy provides insights into the orbital structure.sup.3 of single molecules and their interactions.sup.4,5, but requires the use of a conductive substrate that keeps molecules in a given charge state and thereby suppresses redox-state transitions. Atomic force microscopy can be used on insulating substrates to obtain structural.sup.6 and electrostatic.sup.7,8 information but does not generally access electronic states. Here we show that when synchronizing voltage pulses that steer electron tunnelling between a conductive atomic force microscope tip and a substrate with the oscillation of the tip, we can perform tunnelling experiments on non-conductive substrates and thereby map the orbital structure of isolated molecules as a function of their redox state. This allows us to resolve previously inaccessible electronic transitions in space and energy and to visualize the effects of electron transfer and polaron formation on individual molecular orbitals. We anticipate that our approach will prove useful for the investigation of complex redox reactions and charging-related phenomena with sub-ångström resolution.Driving single-electron tunnelling in synchronization with the oscillations of the conductive tip of an atomic force microscope allows mapping of the electronic structure of individual molecules in different charge states., Author(s): Laerte L. Patera [sup.1] , Fabian Queck [sup.1] , Philipp Scheuerer [sup.1] , Jascha Repp [sup.1] Author Affiliations:(1) Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, GermanyMain [...]

Reduction in the proportion of undernourished people worldwide has been achieved despite global population increase. However, the achievement of reducing undernourishment globally was uneven; sub-Saharan Africa (SSA) in particular has the least progress. In SSA, agriculture is only slowly changing with actual well below potential yields. Failures in agricultural policies, weak institutions, and poor governance are the root of growth stagnation. Agriculture contributes a significant share to the SSA economy and a majority of the population derives their livelihood from this sector. It is justifiable to assume that for sustainable growth of the African economy, significant investment and creative innovation in agriculture are needed. However, several factors such as growth of the farming population, loss of soil fertility, climate change, water scarcity, post-harvest losses, and limited market access could challenge such expectation. On the other hand, new policy reforms and initiatives, and appropriate investment that directly or indirectly support agricultural innovation and growth are emerging. This chapter discusses the challenges and opportunities to advance agricultural growth and food systems in Africa and makes recommendations for solutions. Key words: Africa, food systems, agriculture, agricultural research, agricultural investment, Introduction Significant progress in the effort to reduce the proportion of undernourished people worldwide has been achieved. Despite the addition of 1.9 billion people to the global population between 1990 [...]

In order to meet the future challenges of African agriculture, scientists and policy makers will need to move away from prescriptive measures, to more adaptive ways of understanding and addressing problems based on local capabilities and resources. Ethnographic frameworks and methods are one adaptive tool that researchers can use in parsing out complex situations within the context of local practice and culture. This paper highlights the use of an ethnographic framework called the Livelihoods as Intimate Government (LIG) approach and its application in Ghana and Malawi. The authors demonstrate how without preconceived ideas about what challenges exist, the LIG approach is able to illuminate some of the most pressing needs that affect the livelihoods of rural smallholder farmers. Preconceived notions tend to lead to poor diagnosis of problems, which then results in misplaced solutions and misapplication of funds to implement recommended strategies. Use of LIG sets parameters that are specific to the local context, which promotes development of appropriate policies, and sustainability of food security programs, ensuring that limited funds are used appropriately. Key words: Ethnography, field methods, Ghana, Malawi, Background There exists a growing consensus that in order to meet the challenges of African agriculture (Fischer et al., 2009) such as climate change (Schlenker and Lobell, 2010; Thorton et [...]

Although the terrestrial biosphere absorbs about 25 per cent of anthropogenic carbon dioxide (CO.sub.2) emissions, the rate of land carbon uptake remains highly uncertain, leading to uncertainties in climate projections.sup.1,2. Understanding the factors that limit or drive land carbon storage is therefore important for improving climate predictions. One potential limiting factor for land carbon uptake is soil moisture, which can reduce gross primary production through ecosystem water stress.sup.3,4, cause vegetation mortality.sup.5 and further exacerbate climate extremes due to land-atmosphere feedbacks.sup.6. Previous work has explored the impact of soil-moisture availability on past carbon-flux variability.sup.3,7,8. However, the influence of soil-moisture variability and trends on the long-term carbon sink and the mechanisms responsible for associated carbon losses remain uncertain. Here we use the data output from four Earth system models.sup.9 from a series of experiments to analyse the responses of terrestrial net biome productivity to soil-moisture changes, and find that soil-moisture variability and trends induce large CO.sub.2 fluxes (about two to three gigatons of carbon per year; comparable with the land carbon sink itself.sup.1) throughout the twenty-first century. Subseasonal and interannual soil-moisture variability generate CO.sub.2 as a result of the nonlinear response of photosynthesis and net ecosystem exchange to soil-water availability and of the increased temperature and vapour pressure deficit caused by land-atmosphere interactions. Soil-moisture variability reduces the present land carbon sink, and its increase and drying trends in several regions are expected to reduce it further. Our results emphasize that the capacity of continents to act as a future carbon sink critically depends on the nonlinear response of carbon fluxes to soil moisture and on land-atmosphere interactions. This suggests that the increasing trend in carbon uptake rate may not be sustained past the middle of the century and could result in accelerated atmospheric CO.sub.2 growth.Earth system models suggest that soil-moisture variability and trends will induce large carbon releases throughout the twenty-first century., Author(s): Julia K. Green [sup.1] , Sonia I. Seneviratne [sup.2] , Alexis M. Berg [sup.3] , Kirsten L. Findell [sup.4] , Stefan Hagemann [sup.5] , David M. Lawrence [sup.6] , [...]

Climate warming will influence photosynthesis via thermal effects and by altering soil moisture.sup.1-11. Both effects may be important for the vast areas of global forests that fluctuate between periods when cool temperatures limit photosynthesis and periods when soil moisture may be limiting to carbon gain.sup.4-6,9-11. Here we show that the effects of climate warming flip from positive to negative as southern boreal forests transition from rainy to modestly dry periods during the growing season. In a three-year open-air warming experiment with juveniles of 11 temperate and boreal tree species, an increase of 3.4 °C in temperature increased light-saturated net photosynthesis and leaf diffusive conductance on average on the one-third of days with the wettest soils. In all 11 species, leaf diffusive conductance and, as a result, light-saturated net photosynthesis decreased during dry spells, and did so more sharply in warmed plants than in plants at ambient temperatures. Consequently, across the 11 species, warming reduced light-saturated net photosynthesis on the two-thirds of days with driest soils. Thus, low soil moisture may reduce, or even reverse, the potential benefits of climate warming on photosynthesis in mesic, seasonally cold environments, both during drought and in regularly occurring, modestly dry periods during the growing season.Low soil moisture may reduce, or even reverse, the potential benefits of climate warming on photosynthesis in mesic, seasonally cold environments, both during drought and in regularly occurring, modestly dry periods during the growing season., Author(s): Peter B. Reich [sup.1] [sup.2] , Kerrie M. Sendall [sup.1] [sup.3] , Artur Stefanski [sup.1] , Roy L. Rich [sup.1] [sup.4] , Sarah E. Hobbie [sup.5] , Rebecca A. [...]