Abstract Introduction The kinin-kallikrein system has been implicated in muscle performance: bradykinin promotes glucose uptake and blood flow in muscle through bradykinin receptor 2 (BDKRB2). BDKRB2 variants include rs1799722 and rs5810761, where the T and -9 alleles respectively have associated with increased transcriptional rates and were overrepresented in endurance athletes. However, these variants have rarely been studied among older people or those with sarcopenia. Methods The Leucine and ACE inhibitor (ACE) trial enrolled 145 participants aged ≥70 years with low grip strength and low gait speed. Participants’ blood samples had DNA extracted and were genotyped for rs179972 using TaqMan and rs5810761 by amplification through Hotstar Taq (and visualised through 4% agarose gel electrophoresis). The differences in genotypes for each variant against physical performance measures (e.g. six-minute walk distance [6MWD]) was calculated using t-tests or Mann-Whitney tests where appropriate. Genotypes were also tested for Hardy-Weinberg equilibrium (HWE) using Chi-squared test. Results Data from 136 individuals were included in the analysis. For rs1799722, the genotype frequency (TT: 17, CC: 48, CT: 71) remained in HWE (p=0.248). No difference between TT and CC/CT group was seen for 6MWD, grip strength or SPPB. Among men, the TT genotype had greater 6MWD compared to CC/CT (400m vs 312m, p=0.007), and also greater leg muscle mass (17.6kg vs 15.3kg, p =0.005), but no difference was noted in women. For rs5810761, the genotype frequency (-9-9: 31, +9+9: 43, -9+9: 60) also remained in HWE (p=0.269). No difference between -9-9 and +9+9/+9-9 was seen for 6MWD, grip strength or SPPB. In men, but not women, -9-9 genotype had reduced arm fat baseline (1.85kg vs 2.72kg; p=0.005). Conclusion Among men, the TT genotype was associated with longer 6MW distance and higher leg muscle mass. The -9-9 genotype was associated with lower regional fat mass in men.

Introduction Understanding genetic contributors to sarcopenia (age-related loss of muscle strength and mass) is key to finding effective therapies. Variants of the bradykinin receptor 2 (BDKRB2) have been linked to athletic and muscle performance. The rs1799722–9 and rs5810761 T alleles have been shown to be overrepresented in endurance athletes, possibly due to increased transcriptional rates of the receptor. These variants have been rarely studied in older people or people with sarcopenia. Methods We performed a post hoc sub-study of the Leucine and ACE (LACE) inhibitor trial, which enrolled 145 participants aged ≥70 years with low grip strength and low gait speed. Participants’ blood samples were genotyped for rs179972 using TaqMan and rs5810761 by amplification through Hotstar Taq. Genotypes were compared with outcomes of physical performance and body composition measures. Results Data from 136 individuals were included in the analysis. For rs1799722 the genotype frequency (TT: 17, CC: 48, CT: 71) remained in Hardy-Weinberg Equilibrium (HWE p = 0.248). There was no difference between the genotypes for six-Minute Walk Distance (6MWD) or Short Physical Performance Battery (SPPB). Men with the TT genotype had a significantly greater 6MWD than other genotypes (TT 400m vs CT 310m vs CC 314m, p = 0.027), and greater leg muscle mass (TT 17.59kg vs CT 15.04kg vs CC 15.65kg, p = 0.007). For rs5810761, the genotype frequency (-9-9: 31, +9+9: 43, -9+9: 60) remained in HWE (p = 0.269). The +9+9 genotype was associated with a significant change in SPPB score at 12 months (-9-9 0 vs -9+9 0 vs +9+9–1, p<0.001), suggesting an improvement. In men, the -9-9 genotype was associated with lower arm fat (-9-9 2.39kg vs -9+9 2.72kg vs +9+9 2.76kg, p = 0.019). Conclusion In men, the rs1799722 TT genotype was associated with longer 6MWD and greater leg muscle mass, while the rs5810761 -9-9 genotype was associated with lower arm fat mass.

BACKGROUND:Ageing is associated with changes in body composition including an overall reduction in muscle mass and a proportionate increase in fat mass. Sarcopenia is characterised by losses in both muscle mass and strength. Body composition and muscle strength are at least in part genetically determined, consequently polymorphisms in pathways important in muscle biology (e.g., the activin/myostatin signalling pathway) are hypothesised to contribute to the development of sarcopenia.METHODS:We compared regional body composition measured by DXA with genotypes for two polymorphisms (rs10783486, minor allele frequency (MAF) = 0.26 and rs2854464, MAF = 0.26) in the activin 1B receptor (ACVR1B) determined by PCR in a cross-sectional analysis of DNA from 110 older individuals with sarcopenia from the LACE trial.RESULTS:Neither muscle mass nor strength showed any significant associations with either genotype in this cohort. Initial analysis of rs10783486 showed that males with the AA/AG genotype were taller than GG males (174±7cm vs 170±5cm, p = 0.023) and had higher arm fat mass, (median higher by 15%, p = 0.008), and leg fat mass (median higher by 14%, p = 0.042). After correcting for height, arm fat mass remained significantly higher (median higher by 4% padj = 0.024). No associations (adjusted or unadjusted) were seen in females. Similar analysis of the rs2854464 allele showed a similar pattern with the presence of the minor allele (GG/AG) being associated with greater height (GG/AG = 174±7 cm vs AA = 170 ±5cm, p = 0.017) and greater arm fat mass (median higher by 16%, p = 0.023). Again, the difference in arm fat remained after correction for height. No similar associations were seen in females analysed alone.CONCLUSION:These data suggest that polymorphic variation in the ACVR1B locus could be associated with body composition in older males. The activin/myostatin pathway might offer a novel potential target to prevent fat accumulation in older individuals.

BACKGROUND:Angiotensin II (AII), has been suggested to promote muscle loss. Reducing AII synthesis, by inhibiting angiotensin converting enzyme (ACE) activity has been proposed as a method to inhibit muscle loss. The LACE clinical trial was designed to determine whether ACE inhibition would reduce further muscle loss in individuals with sarcopenia but suffered from low recruitment and returned a negative result. Polymorphic variation in the ACE promoter (I/D alleles) has been associated with differences in ACE activity and muscle physiology in a range of clinical conditions. This aim of this analysis was to determine whether I/D polymorphic variation is associated with muscle mass, strength, in sarcopenia or contributed to the lack of response to treatment in the LACE study.METHODS:Sarcopenic individuals were recruited into a 2x2 factorial multicentre double-blind study of the effects of perindopril and/or leucine versus placebo on physical performance and muscle mass. DNA extracted from blood samples (n = 130 72 women and 58 men) was genotyped by PCR for the ACE I/D polymorphism. Genotypes were then compared with body composition measured by DXA, hand grip and quadriceps strength before and after 12 months' treatment with leucine and/or perindopril in a cross-sectional analysis of the influence of genotype on these variables.RESULTS:Allele frequencies for the normal UK population were extracted from 13 previous studies (I = 0.473, D = 0.527). In the LACE cohort the D allele was over-represented (I = 0.412, D = 0.588, p = 0.046). This over-representation was present in men (I = 0.353, D = 0.647, p = 0.010) but not women (I = 0.458, D = 0.532, p = 0.708). In men but not women, individuals with the I allele had greater leg strength (II/ID = 18.00 kg (14.50, 21.60) vs DD = 13.20 kg (10.50, 15.90), p = 0.028). Over the 12 months individuals with the DD genotype increased in quadriceps strength but those with the II or ID genotype did not. Perindopril did not increase muscle strength or mass in any polymorphism group relative to placebo.CONCLUSION:Our results suggest that although ACE genotype was not associated with response to ACE inhibitor therapy in the LACE trial population, sarcopenic men with the ACE DD genotype may be weaker than those with the ACE I/D or II genotype.

Nitrogen is an essential micronutrient for both plant and animal life and naturally exists in both reactive and inert chemical forms. Modern agriculture is heavily reliant on nitrogen that has been “fixed” into a reactive form via the energetically expensive Haber-Bosch process, with significant environmental consequences.

Background: Angiotensin-converting enzyme inhibitors and leucine are promising potential treatments for sarcopenia. Neither has yet been tested in adequately powered randomised trials in patients with sarcopenia. Objectives: To determine the efficacy of leucine and perindopril in improving physical function in older people with sarcopenia, to evaluate the effect of leucine and perindopril on muscle mass and to evaluate the predictive biomarkers of sarcopenia. Design: A placebo-controlled, parallel group, double-blind, randomised 2 × 2 factorial trial. Setting: Primary care and geriatric medicine secondary care departments in 14 UK centres. Participants: Adults aged ≥ 70 years with low muscle strength and mass, without contraindications to angiotensin-converting enzyme inhibitors and without known diagnosis-specific skeletal myopathy. Interventions: Eligible participants were randomised 1 : 1 to receive 4 mg of oral perindopril or a matching placebo and, separately, were randomised 1 : 1 to receive 2.5 g of oral leucine powder or a matching placebo powder taken thrice daily with meals. Randomisation was performed using an interactive web-based randomisation system run independently of the research team to preserve allocation concealment. Main outcome measures: The primary outcome was the between-group difference in the Short Physical Performance Battery (SPPB) score over the 12-month follow-up period. Other outcome measures included appendicular muscle mass, EQ-5D (EuroQol-5 Dimensions) quality-of-life score, grip strength, quadriceps strength, 6-minute walk distance, activities of daily living, hip bone mineral density and insulin resistance. All adverse events and falls were recorded. Protein-, DNA (deoxyribonucleic acid)- and RNA (ribonucleic acid)-based biomarkers were collected at baseline and at 3 and 12 months. Results: We screened 320 people and randomised 145 participants. Participants had a mean age of 79 (standard deviation 6) years, 78 (54%) were women and the mean SPPB was 7.0 (standard deviation 2.4). The median adherence was lower for perindopril than for placebo (76% vs. 96%; p < 0.001). Perindopril did not improve the primary outcome (adjusted treatment effect –0.1 points, 95% confidence interval –1.2 to 1.0 points). Quality of life was worse in the perindopril group (treatment effect –12 points, 95% confidence interval –21 to –3 points) and more adverse events occurred in the perindopril group (n = 218 vs. n = 165). Falls rates between the groups were similar and other secondary outcomes showed no significant treatment effect. For leucine compared with placebo, median adherence was the same in both groups (76% vs. 76%; p = 0.99). Leucine did not improve the primary outcome (adjusted treatment effect 0.1 point, 95% confidence interval –1.0 to 1.1 points). No significant treatment effect was found for any secondary outcome. There were similar numbers of adverse events and falls in both groups. Limitations: The trial did not reach its original recruitment target; this trial alone cannot confidently exclude clinically important effects of either perindopril or leucine. Future work: Further exploration of biomarkers predicting response to sarcopenia interventions is warranted. Conclusions: Neither perindopril nor leucine improved physical performance or muscle mass in this trial; meta-analysis confirmed the lack of efficacy of both treatments in improving physical performance. Study registration: This trial is registered as ISRCTN90094835 and EudraCT 2014-003455-61. The systematic review is registered as PROSPERO CRD42014013398. Funding: This project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a MRC and National Institute for Health and Care Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 9, No. 8. See the NIHR Journals Library website for further project information.

Abstract Background This trial aimed to determine the efficacy of leucine and/or perindopril in improving physical function in older people with sarcopenia. Methods Placebo‐controlled, parallel group, double‐blind, randomized two‐by‐two factorial trial. We recruited adults aged ≥ 70 years with sarcopenia, defined as low gait speed (<0.8 m/s on 4 m walk) and/or low handgrip strength (women < 20 kg, men < 30 kg) plus low muscle mass (using sex and body mass index category‐specific thresholds derived from normative UK BioBank data) from 14 UK centres. Eligible participants were randomized to perindopril 4 mg or placebo, and to oral leucine powder 2.5 g or placebo thrice daily. The primary outcome was the between‐group difference in the short physical performance battery (SPPB) score over 12‐month follow‐up by repeated‐measures mixed models. Results were combined with existing systematic reviews using random‐effects meta‐analysis to derive summary estimates of treatment efficacy. Results We screened 320 people and randomized 145 participants compared with an original target of 440 participants. For perindopril [n = 73, mean age 79 (SD 6), female sex 39 (53%), mean SPPB 7.1 (SD 2.3)] versus no perindopril [n = 72, mean age 79 (SD 6), female sex 39 (54%), mean SPPB 6.9 (SD 2.4)], median adherence to perindopril was lower (76% vs. 96%; P < 0.001). Perindopril did not improve the primary outcome [adjusted treatment effect −0.1 points (95%CI −1.2 to 1.0), P = 0.89]. No significant treatment benefit was seen for any secondary outcome including muscle mass [adjusted treatment effect −0.4 kg (95%CI −1.1 to 0.3), P = 0.27]. More adverse events occurred in the perindopril group (218 vs. 165), but falls rates were similar. For leucine [n = 72, mean age 78 (SD 6), female sex 38 (53%), mean SPPB 7.0 (SD 2.1)] versus no leucine [n = 72, mean age 79 (SD 6), female sex 40 (55%), mean SPPB 7.0 (SD 2.5)], median adherence was the same in both groups (76% vs. 76%; P = 0.99). Leucine did not improve the primary outcome [adjusted treatment effect 0.1 point (95%CI −1.0 to 1.1), P = 0.90]. No significant treatment benefit was seen for any secondary outcome including muscle mass [adjusted treatment effect −0.3 kg (95%CI −1.0 to 0.4), P = 0.47]. Meta‐analysis of angiotensin converting enzyme inhibitor/angiotensin receptor blocker trials showed no clinically important treatment effect for the SPPB [between‐group difference −0.1 points (95%CI −0.4 to 0.2)]. Conclusions Neither perindopril nor leucine improved physical performance or muscle mass in this trial; meta‐analysis did not find evidence of efficacy of either ACE inhibitors or leucine as treatments to improve physical performance.

AbstractPhenotypic heterogeneity in clonal bacterial batch cultures is an important adaptive strategy to changing environments, including in diazotrophs with the unique capacity to convert di-nitrogen into bio-available ammonium. In diazotrophicKlebsiella oxytocawe simultaneously measured mRNA levels of key regulatory (glnK-amtB, nifLA) and structural (nifHDK) operons required for establishing nitrogen fixation, using dual molecule, single cell RNA-FISH. Through stochastic transcription models and mutual information analysis we revealed likely molecular origins for heterogeneity in nitrogenase expression. In wildtype and regulatory variant strains we inferred contributions from intrinsic and extrinsic noise, finding thatnifHDKtranscription is inherently bursty, but that noise propagation through signalling is also significant. The regulatory geneglnKhad the highest discernible effect onnifHDKvariance, while noise from factors outside of the regulatory pathway were negligible. Results provide evidence that heterogeneity is a fundamental property of this regulatory system, indicating potential constraints for engineering homogeneous nitrogenase expression.

Phenotypic heterogeneity in clonal bacterial batch cultures is an important adaptive strategy to changing environments, including in diazotrophs with the unique capacity to convert di-nitrogen into bio-available ammonium. In diazotrophic we simultaneously measured mRNA levels of key regulatory () and structural () operons required for establishing nitrogen fixation, using dual molecule, single cell RNA-FISH. Through stochastic transcription models and mutual information analysis we revealed likely molecular origins for heterogeneity in nitrogenase expression. In wildtype and regulatory variant strains we inferred contributions from intrinsic and extrinsic noise, finding that transcription is inherently bursty, but that noise propagation through signalling is also significant. The regulatory gene had the highest discernible effect on variance, while noise from factors outside of the regulatory pathway were negligible. Results provide evidence that heterogeneity is a fundamental property of this regulatory system, indicating potential constraints for engineering homogeneous nitrogenase expression.

Extensive growth of cancer in humans is a major cause of death. Numerous studies are being conducted to improve the early diagnosis, prevention, and treatment of cancer. Recent technological advancements in medical science and research indicate molecular target therapy holds much promise in cancer treatment. In the past, therapeutic and diagnostic targeting of non-glycolytic and glycolytic enzymes in cancer have been successful, and discoveries of biomarker enzymes in cancer hold promise for therapeutic treatments. In this review, we discuss the roles of several cancer-associated enzymes that could potentially act as therapeutic targets, and place special focus on non-glycolytic and glycolytic enzymes. This review indicates that the targeting of metabolic signaling offers a promising means of developing novel anti-cancer therapies.

Sound vibration (SV) treatment can trigger various molecular and physiological changes in plants. Previously, we showed that pre-exposure of Arabidopsis plants to SV boosts its defense response against Botrytis cinerea fungus. The present study was aimed to investigate the changes in the proteome states in the SV-treated Arabidopsis during disease progression. Proteomics analysis identified several upregulated proteins in the SV-infected plants (i.e., SV-treated plants carrying Botrytis infection). These upregulated proteins are involved in a plethora of biological functions, e.g., primary metabolism (i.e., glycolysis, tricarboxylic acid cycle, ATP synthesis, cysteine metabolism, and photosynthesis), redox homeostasis, and defense response. Additionally, our enzyme assays confirmed the enhanced activity of antioxidant enzymes in the SV-infected plants compared to control plants. Broadly, our results suggest that SV pre-treatment evokes a more efficient defense response in the SV-infected plants by modulating the primary metabolism and reactive oxygen species scavenging activity.

Phytohormone auxin plays an indispensable role in the plethora of plant developmental process starting from the cell division, and cell elongation to morphogenesis. Auxins are transported to different parts of the plant by different sophisticated transporter molecules known as ‘auxin transporters’.There are four auxin transporter families that have been reported so far in the plant kingdom which includes AUX/LAX (AUXIN-RESISTANT1–LIKES), PIN (PIN-FORMED, auxin efflux carriers), ABCB ((ATP-binding cassette-B (ABCB)/P-glycoprotein (PGP)) and PILS (PIN-Likes). Auxin influx and efflux carriers are distributed in a polar fashion in the plasma membrane whereas ABCB and PILS are present in a non-polar fashion. Other than AUX/LAX, other auxin transporters harbor N-and C-terminal conserved domains along with a variable hydrophilic loop in the transmembrane domain. The AUX/LAX, ABCB and PIN transporters mediate long distance auxin transport whereas PILS and PIN5 protein involved in intracellular auxin homeostasis.

Upon exposure to abiotic stresses, plants activate early stress-signaling mechanisms within a few seconds to a few hours to counter the stress responses and bring tolerance. The most versatile signaling molecules involved during the early events of abiotic stress signaling are Ca2+ (calcium ion) and reactive oxygen species (ROS), 1O2, O2−, and H2O2. Initially, apoplastic Ca2+ activates plasma membrane-bound NADPH oxidase and generates H2O2, which acts as a second messenger and further leads to the activation of downstream signaling processes. Subsequently, H2O2 activates calcium-dependent protein kinase (CDPK) and mitogen activated protein kinase (MAPK) pathways, leading to stress tolerance through downstream signaling cascades. In addition, fast influx of Ca2+ from the apoplast to the cytosol further activates cytosolic CDPKs and respiratory burst oxidase D and regulates Ca2+ and ROS signaling. Sub-cellular organelles further produce ROS and Ca2+ to bring stress tolerance. Excessive ROS produced during these processes are quenched by ROS scavenging enzymes, whereas excessive Ca2+ is neutralized by the action of the calcium binding proteins CDPKs, CaMs, CMLs, and CBLs. The phytohormone ABA further regulates the production of H2O2, thus maintaining the positive feedback system for ROS production and stress tolerance. Additionally, CBL proteins modulate H2O2 production in the presence of NADPH oxidase via interaction with CIPK, thus maintaining a positive feedback mechanism in stress tolerance. Similarly, CaM proteins bind with MAPK and regulate stress tolerance by activating the MAPK cascade.

Hybridization has been routinely practiced in agriculture to enhance the crop yield. Principally, it can cause hybrid vigor where hybrid plants display increased size, biomass, fertility, and resistance to diseases, when compared to their parents. During hybridization, hybrid offspring receive a genomic shock due to mixing of distant parental genomes, which triggers a myriad of genomic rearrangements, e.g., transpositions, genome size changes, chromosomal rearrangements, and other effects on the chromatin. Recently, it has been reported that, besides genomic rearrangements, hybridization can also alter the somatic mutation rates in plants. In this review, we provide in-depth insights about hybridization triggered genomic rearrangements and somatic mutations in plants.

Plant abiotic stresses are the major constraint on plant growth and development, causing enormous crop losses across the world. Plants have unique features to defend themselves against these challenging adverse stress conditions. They modulate their phenotypes upon changes in physiological, biochemical, molecular and genetic information, thus making them tolerant against abiotic stresses. It is of paramount importance to determine the stress-tolerant traits of a diverse range of genotypes of plant species and integrate those traits for crop improvement. Stress-tolerant traits can be identified by conducting genome-wide analysis of stress-tolerant genotypes through the highly advanced structural and functional genomics approach. Specifically, whole-genome sequencing, development of molecular markers, genome-wide association studies and comparative analysis of interaction networks between tolerant and susceptible crop varieties grown under stress conditions can greatly facilitate discovery of novel agronomic traits that protect plants against abiotic stresses.

Nature's silicon marvel, the diatoms have lately astounded the scientific community with its intricate designs and lasting durability. Diatoms are a major group of phytoplanktons involved in the biogeochemical cycling of silica and are virtually inherent in every environment ranging from water to ice to soil. The usage of diatoms has proved prudently cost effective and its handling neither requires costly materials nor sophisticated instruments. Diatoms can easily be acquired from the environment, their culture requires ambient condition and does not involve any costly media or expensive instruments, besides, they can be transported in small quantities and proliferated to a desirable confluence from that scratch, thus are excellent cost effective industrial raw material. Naturally occurring diatom frustules are a source of nanomaterials. Their silica bio-shells have raised curiosity among nanotechnologists who hope that diatoms will facilitate tailoring minuscule structures which are beyond the capabilities of material scientists. Additionally, there is a colossal diversity in the dimensions of diatoms as the frustule shape differs from species to species; this provides a scope for the choice of a particular species of diatom to be tailored to an exacting requisite, thus paving the way to create desired three dimensional nanocomposites. The present article explores the use of diatoms in various arenas of science, may it be in nanotechnology, biotechnology, environmental science, biophysics or biochemistry and summarizes facets of diatom biology under one umbrella. Special emphasis has been given to biosilicification, biomineralization and use of diatoms as nanomaterials', drug delivery vehicles, optical and immune-biosensors, filters, immunodiagnostics, aquaculture feeds, lab-on-a-chip, metabolites, and biofuels.

Little is known on the effect of parental reproductive age on the somatic mutation rates in flowering plants. With a set of Arabidopsis mutation detector lines, we examined the effect of parental reproductive age on the spectrum of mutations induced and their rates in the subsequent progeny. We scored rates of point and frameshift mutations, as well as homologous recombination (HR) and transposition events based on functional GUS reversion of a mutated or truncated uid A gene. We observed that T-C transition rates increased with the parental reproductive age in the offspring. Similarly, frameshift mutation (G10) and transposition rates rose in the progeny as a consequence of increased parental age with a pronounced effect of maternal age. However, the HR frequency decreased with the age of parents. Our study shows that parental reproductive age alters the somatic mutation rates in progeny of Arabidopsis plants.

Plant secondary metabolites (PSMs) provide taste, color, odor, and resistance to plants, and they are also used to treat cancer and cardiovascular diseases. Synthesis of PSMs in plants is stimulated in response to different forms of external stress. Use of ultrasonication (US) to clean or decontaminate fruits and vegetables leads to physical stress that finally results in the accumulation of PSMs. US can stimulate accumulation of taxol, ginsenoside saponins, shikonin, and resveratrol, e.g., up to 319-fold increase of resveratrol synthesis has been observed in grape due to US. US also increases carotenoids, total phenolics, and isoflavonoids accumulation. Furthermore, US shows synergistic effects in PSMs synthesis-when combined with ultraviolet (UV) irradiation, jasmonic acid (JA) or salicylic acid (SA). It has been observed that US stimulates the production of reactive oxygen species (ROS) which then upregulates expression of phenylalanine ammonia lyase (PAL), resulting in the synthesis of PSMs. In this review, we summarize the effects of US, as a physical stress, to maximize the accumulation of PSMs in crop produce and in cell cultures.

Light-emitting diodes (LEDs) are characterized by their narrow-spectrum, non-thermal photon emission, greater longevity, and energy-saving characteristics, which are better than traditional light sources. LEDs thus hold the potential to revolutionize horticulture lighting technology for crop production, protection, and preservation. Exposure to different LED wavelengths can induce the synthesis of bioactive compounds and antioxidants, which in turn can improve the nutritional quality of horticultural crops. Similarly, LEDs increase the nutrient contents, reduce microbial contamination, and alter the ripening of postharvest fruits and vegetables. LED-treated agronomic products can be beneficial for human health due to their good nutrient value and high antioxidant properties. Besides that, the non-thermal properties of LEDs make them easy to use in closed-canopy or within-canopy lighting systems. Such configurations minimize electricity consumption by maintaining optimal incident photon fluxes. Interestingly, red, blue, and green LEDs can induce systemic acquired resistance in various plant species against fungal pathogens. Hence, when seasonal clouds restrict sunlight, LEDs can provide a controllable, alternative source of selected single or mixed wavelength photon source in greenhouse conditions.