Search

Photoperiod is dominant environmental factor that controls plant growth and development. Even though research on plants response to photoperiod is significant in agriculture, molecular mechanisms of garlic in response to photoperiod remain largely unknown. In the current investigation, 3 months old garlic plants were treated with long day (LD) and short day (SD) for 10 and 20 days after treatment (DAT). Liquid chromatography-mass spectrometry (LC-MS) analysis of phytohormones exhibited that indole-3-acetic acid (IAA), zeatin riboside (ZR) and salicylic acid (SA) were observed maximum under LD at 10 DAT, whereas abscisic acid (ABA), gibberellic acid 3 (GA 3 ), zeatin (ZT) and jasmonic acid (JA) were observed maximum under LD at 20 DAT. Transcriptome sequencing analysis was done to evaluate the transcriptional response to LD and SD. Differentially expressed genes (DEGs) were detected to have pathway enrichment. i.e., DNA binding transcription factor activity, transcription regulator activity, transferase activity, transferring hexosyl groups, and sequence specific-DNA binding activity, plant hormone signal transduction, circadian rhythm-plant, biosynthesis of amino acids, phenylpropanoid biosynthesis, and starch and sucrose metabolism. Furthermore, 28 and 40 DEGs were identified related to photoperiod and hormone signaling, respectively and their interaction in response to LD and SD were discussed in detail. Outcomes of current investigation might be useful to provide novel resources for garlic bulb formation in response to photoperiod., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aqueous garlic extracts (AGE) and garlic allelochemical diallyl disulfide (DADS) have been recently reported to bear bioactive properties to stimulate plant growth and development and alter defense-related physiology. We, therefore, performed a bioassay to study these chemicals as possible biostimulants for defense against Verticillium dahliae in eggplant seedlings. AGE and DADS were applied as a foliar application to the eggplants and samples were collected before and after pathogen inoculation at various intervals to analyze the defense mechanism. The obtained data revealed that with the application of AGE and DADS, the seedlings showed responses including activation of antioxidant enzymes, an abundance of chlorophyll contents, alteration of photosynthesis system, and accumulation of plant hormones compared to the control plants. Furthermore, the microscopic analysis of the AGE or DADS treated plants showed high variability in pathogen density within the root crown at 28 days post-inoculation. The low abundance of reactive oxygen species was noticed in AGE or DADS treated plants, which indicates that the plants were able to successfully encounter pathogen attacks. The AGE and DADS treated plants exhibited a lower disease severity index (32.4% and 24.8% vs 87.1% in controls), indicating successful defense against Verticillium infection. Our results were therefore among the first to address the biostimulatory effects of AGE or DADS to induce resistance in eggplant seedlings against V. dahliae and may be used to establish preparation for garlic-derived bioactive compounds to improve growth and defense responses of eggplants under-protected horticultural situations such as glasshouse or plastic tunnels system., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Photoperiod and temperature are vital environmental factors that regulate plant developmental processes. However, the roles of these factors in garlic bulb enlargement are unclear. In this report, responses of garlic bulb morphology and physiology to combinations of photoperiod (light/dark: 10/14 h, 12/12 h, 14/10 h) and temperature (light/dark: 25/18 °C, 30/20 °C) were investigated. For garlic cultivar G103, bulb characteristics, phytohormones (IAA, ABA, ZT, tZR, JA), allicin and phenolic acids (p-coumaric and p-hydroxybenzoic) were highest under a photoperiod of 14 h at 30 °C. Maximum GA was observed under 14 h + 30 °C for cv. G2011-5. Maximum caffeic, ferulic and vanillic acids were detected for cv. G2011-5 at 14 h + 30 °C, 12 h + 25 °C and 14 h + 25 °C, respectively. Flavonoids (myricetin, quercetin, kaempferol and apigenin) were not detected in this trial. This is the first report describing the impact of long periods of light duration and higher temperatures on garlic morphology, phytohormones, phenolic acids and allicin content., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The incorporation of plant residues into soil can be considered a keystone sustainability factor in improving soil structure function. However, the effects of plant residue addition on the soil microbial communities involved in biochemical cycles and abiotic stress phenomena are poorly understood. In this study, experiments were conducted to evaluate the role of raw garlic stalk (RGS) amendment in avoiding monoculture-related production constraints by studying the changes in soil chemical properties and microbial community structures. RGS was applied in four different doses, namely the control (RGS0), 1% (RGS1), 3% (RGS2), and 5% (RGS3) per 100 g of soil. The RGS amendment significantly increased soil electrical conductivity (EC), N, P, K, and enzyme activity. The soil pH significantly decreased with RGS application. High-throughput Illumina MiSeq sequencing revealed significant alterations in bacterial community structures in response to RGS application. Among the 23 major taxa detected, Anaerolineaceae, Acidobacteria , and Cyanobacteria exhibited an increased abundance level. RGS2 increased some bacteria reported to be beneficial including Acidobacteria , Bacillus , and Planctomyces (by 42%, 64%, and 1% respectively). Furthermore, internal transcribed spacer (ITS) fungal regions revealed significant diversity among the different treatments, with taxa such as Chaetomium (56.2%), Acremonium (4.3%), Fusarium (4%), Aspergillus (3.4%), Sordariomycetes (3%), and Plectosphaerellaceae (2%) showing much abundance. Interestingly, Coprinellus (14%) was observed only in RGS-amended soil. RGS treatments effectively altered soil fungal community structures and reduced certain known pathogenic fungal genera, i.e., Fusarium and Acremonium . The results of the present study suggest that RGS amendment potentially affects the microbial community structures that probably affect the physiological and morphological attributes of eggplant under a plastic greenhouse vegetable cultivation system (PGVC) in monoculture.

Purpose: Verticillium wilt is a destructive vascular disease in eggplants. The complex defensive mechanisms of eggplant against this disease are very limited. Methods: Our work examined the bioactive properties of garlic allelochemical diallyl disulfide (DADS) as potential biostimulants for defense against V. dahliae in eggplant seedlings. We, therefore, foliar sprayed DADS on eggplants to study the defense response during the early biotrophic phase of V. dahliae (a hemibiotroph). Results: DADS application significantly increased root peroxidase (POD), phenylalanine-ammonia lyase (PAL) enzyme activity, and reduced H2O2 levels after 24 h of fungal inoculation. Salicylic acid (SA) in leaves and roots was significantly increased while, the jasmonic acid (JA), indole acetic acid (IAA), and abscisic acid (ABA) levels were decreased. The microscopic examinations of V. dahliae infection in roots displayed that the progression of infection was restricted in DADS-treated plants. Depositions of lignin and phenolic compounds such as ferulic acid, p-coumaric acid, and caffeic acid content were significantly higher in DADS-treated plants at 48 h post-inoculation. Similarly, the DADS application up-regulated pathogenesis-related (PR1, PR2, and PR5), mitogen-activated protein kinase (MPK1), and lipoxygenase (LOX) genes. Furthermore, DADS-treated plants exhibited a lower disease severity index (23.3% vs. 57.0% in controls), indicating successful defense against V. dahliae. Conclusions: Our findings concluded that the biological function of garlic allelochemical DADS has a prominent role in the higher defense resistance of eggplants during the early infection of V. dahliae. [ABSTRACT FROM AUTHOR]

Vegetable production under plastic sheds severely threatens regional eco-sustainability via anthropogenic activities (excessive use of agrochemicals, pesticides) and problems associated with replanting. Long-term successive cropping across growing seasons induces continuous cropping stress, whose effects manifest as diminished plant growth. Therefore, it is imperative that we develop environmentally sustainable approaches, such as replacing agrochemicals with vegetable waste like dry raw garlic stalk (DRGS) or use biofertilizers like arbuscular mycorrhizal fungi (AMF) (e.g., Diversispora epigaea). In this study, the influence of AMF on the growth, biochemical attributes, antioxidant defense system, phytohormones, accumulation of osmolytes, phenols, and mineral elements in eggplant grown on DRGS-amended soils under continuous monocropping (CMC) was studied. The results showed that inoculation with AMF or the DRGS amendment could improve the pigments' content, photosynthesis, and antioxidant defense system; augmented phytohormones synthesis (except for ABA), and increased the leaves' mineral nutrients. These parameters were enhanced most by the combined application of AMF and DRGS, which also increased the concentration of osmolytes, including proline, sugars, and free amino acids in eggplant when compared with the control. Furthermore, either AMF and DRGS alone, or in combination, ameliorated the induced stress from continuous cropping by reducing the incidence of Fusarium wilt and production of ROS (reactive oxygen species); lipid peroxidation underwent maximal reduction in plants grown under the combined treatments. The AMF, DRGS, and AMF + DRGS exhibited a lower disease severity index (33.46, 36.42, and 43.01%), respectively, over control. Hence, inoculation with AMF coupled with DRGS amendment alters the photosynthetic attributes in eggplant through the upregulation of its antioxidant system and greater accumulation of osmolytes, which led to the improved growth and yield of eggplant. [ABSTRACT FROM AUTHOR]

The current study was aimed to evaluate the seed priming potential of AGE (aqueous garlic extracts) to enhance seed germination and early seedling growth of eggplant. Different concentrations (100, 200, and 300 µg mL−1) of AGE were evaluated along with methyl jasmonate (MeJA) and salicylic acid (SA), plant growth regulators with reported seed priming potential whereas, water was taken as a control treatment. Eggplant seeds were primed for 4-, 8-, and 12-h and seed germination traits such germination rate index, germination percentage, mean germination time, and early seedling growth traits such as fresh and dry weights, root, and shoot lengths were observed. Moreover, plant antioxidant enzymes activities and lipid peroxidation levels, soluble protein contents and reactive oxygen species were monitored to establish the stimulatory/inhibitory effects of the treatments. Our results indicate priming potential of AGE, SA, and MeJA to enhance seed germination and early seedling growth in eggplant and the effects were obvious in various morphological and physiological traits. Seed priming significantly altered the antioxidant enzymes activities such as superoxide dismutase (SOD), and peroxidase (POD) with alteration in the reactive oxygen species (ROS). Interestingly, priming duration also affected the bioactivity of these chemicals because seed priming with 300 µg mL−1 AGE for 4 h had a positive influence, however, prolonged exposure to the same concentration inhibited the seed germination process and induced oxidative stress on the seedlings with elevated levels of malondialdehyde (MDA) content. We propose AGE seed priming as a bio-stimulant to enhance seed germination and early seedling growth in eggplant, and the results hence lay the foundation for the preparation of garlic-based compounds to improve vegetables production under plastic tunnels and greenhouse production units. [ABSTRACT FROM AUTHOR]

• Garlic responses to combinations of photoperiod (light/dark: 10/14 h, 12/12 h, 14/10 h) and temperature (light/dark: 25/18 °C, 30/20 °C) at different durations (10, 20 and 30 days after treatment) were studied for the first time. • Longer photoperiods and higher temperatures significantly enhanced garlic pseudostems phytohormones, phenolic acids, and allicin contents. • Our study provided new insights into improved bulb performance, hormonal balance, and contents of phenolics and the organosulfur compound allicin using light and temperature. Photoperiod and temperature are important environmental factors that regulate many developmental processes in plants. However, the roles of different durations of photoperiod and temperature in garlic bulbing and selected endogenous chemical factors are still unknown. This study is focused on morphological and selected endogenous chemical factors associated with garlic bulb formation in response to photoperiod and temperature. Endogenous phytohormones, phenolic acids and allicin level were analyzed in garlic when plants were subjected to different combinations of photoperiod (light/dark: 10/14 h, 12/12 h, 14/10 h) and temperature (light/dark: 25/18 °C, 30/20 °C) treatments at 10, 20 and 30 days after treatment (DAT). Garlic plant and bulb morphology was observed maximum under 14 h photoperiod and 30 °C at 30 DAT. 14 h photoperiod and 25 °C resulted in maximum ABA, ZT and ZR at 20, 30 and 10 DAT, respectively. Maximum GA and JA were observed under14 h photoperiod and 30 °C at 20 and 10 DAT, respectively. Whereas maximum IAA was detected under 12 h photoperiod and 30 °C at 30 DAT. Maximum ferulic and vanillic acids were detected under 14 h photoperiod and 25 °C at 20 and 30 DAT, respectively. Maximum caffeic, p -coumaric and p -hydroxybenzoic acids were detected under14 h photoperiod and 30 °C at 30 and 10 DAT, respectively. Maximum allicin content was observed under 14 h photoperiod and 25 °C at 30 DAT. Our results propose that endogenous phytohormones, phenolic acids and allicin in pseudostem might control bulbing in garlic. [ABSTRACT FROM AUTHOR]

Photoperiod (light) and temperature as abiotic factors having significant impact on the garlic bulb morphology and quality. In various bulb plants including garlic, bulbing is affected by photoperiod, temperature, sowing date and the plant age. In this backdrop experiments were performed to understand the effect of different photoperiods (10 h/14 h, 12 h/12 h and 14 h/10 h (light/dark)), temperatures (25 °C/18 °C and 30 °C/20 °C (light/dark)), sowing dates (D0801: 1st August, D0901: 1st September and D1001: 1st October) and plant ages (A80, A60 and A40: 80, 60 and 40 days after planting) on garlic cultivars viz; G103, G024 and G2011-5. Parameters including morphological (plant height, fresh weight and pseudostem diameter), bulb attributes (diameter, weight, height and bulbing index), growth period and bulb quality related traits (total soluble solid (TSS), contents of soluble protein, soluble sugar, total sugar, glucose, sucrose, fructose, starch, total phenol and total flavonoid) were assayed. Longer photoperiod (14 h), higher temperature (30 °C), early sowing (D0801) and maximum plant age (A80) had maximum morphological and bulb quality related traits for cv. G103. These results showed that early sowing, maximum plant age, longer photoperiod and higher temperature are important for garlic bulb formation and quality. Moreover, the regulation of garlic bulb morphology and quality is achievable over the switch of sowing date, plant age, light and growth temperature. [ABSTRACT FROM AUTHOR]

Growth and bulb development in garlic is affected considerably by variations in photoperiod and temperature thereby influencing its morphology, physiology, and nutritive quality. Varied combinations of photoperiods and temperatures may influence the bulb development and quality, and can determine the suitability of a cultivar for a particular region. Experiments were conducted to study the impact of different photoperiod and temperature combinations on the growth, morpho-physiology, and nutritive quality of garlic bulb. Three garlic cultivars viz; G103, G024, and G2011-5 were exposed to different combinations of photoperiod (8 h/16 h, 10 h/14 h, 12 h/12 h, 14 h/10 h, 16 h/8 h (light/dark)) and temperature (20 °C/15 °C, 25 °C/18 °C, and 30 °C/20 °C). Results revealed that longer photoperiod (14 h or 16 h) and higher temperature (25 °C or 30 °C) treatments significantly improved the garlic bulbing imparting maximum bulb diameter, height, bulbing index, and the shortest growth period. Whereas, 12-h photoperiod had maximum bulb weight. In addition, total soluble solid (TSS), content of soluble protein, soluble sugar, total sugar, glucose, sucrose, fructose, starch, total phenols, and total flavonoids increased significantly because of 14-h photoperiod and 30 °C temperature condition, however exhibited decline with 8 h photoperiod and lowest temperature (20 °C). These alterations were related to bulb characteristics and bulbing index. Maximum plant standing height and pseudostem diameter of the garlic plant were observed at 20 °C. Additionally, plants under the combination of 14 h–30 °C had maximum fresh weight, bulb diameter, shortest growth period, maximum physiological and nutritive quality traits of the bulb, while as 12 h–30 °C combinations resulted in maximum bulb weight and 16 h–30 °C had maximum bulb height. Among cultivars cv. G103 showed best response to tested photoperiod and temperature combinations in terms of morpho-physiological and biochemical attributes studied, except for bulbing index which was maximum in cv. G024. Present study concludes the influence of photoperiod and temperature combinations on garlic growth and bulbing characteristics through the modulations induced in soluble protein, sugars, and phenolic compounds. [ABSTRACT FROM AUTHOR]

Garlic (Allium Sativum L.) is a vegetable with known medicinal value. It is not only rich in nutrients, but also has the ability to combat different microbial infections. This is, however, the first study to investigate the effect of soil incorporation of the raw garlic stalk (RGS) on the growth and antioxidative defense system of eggplant. The experiments were conducted in pots using soil amendments of RGS in different ratios (RGS1 1:100; RGS2 3:100; RGS3 5:100 and control (CK) 0:100 of RGS: Soil w/w) and repeated in two consecutive years (2016 and 2017). A dose-dependent response of RGS amendment was observed in the growth and physiology of the eggplant. RGS1 and RGS2 significantly enhanced the plant height, root/shoot weight, stem diameter, leaf area, root length, root activity, pigment contents (chlorophyll a, chlorophyll b, and total chlorophyll), and photosynthetic parameters, but reduced intracellular CO2 (Ci) and enhanced fruit yield as compared with the respective controls. Consistently, RGS also enhanced activities of antioxidative enzymes of eggplant reported as a defense against stress indicators. RGS in its higher ratios (RGS3), however, caused a reduction in all of the growth and physiological parameters and increased stress indicators such as hydrogen peroxide (H2O2) and malondialdehyde (MDA). Overall, RGS2 was found to be the most efficient for regulation of plant defense systems, reducing H2O2 and MDA and enhancing superoxide dismutase (SOD), peroxidase (POD), and phenylalanine ammonia–lyase (PAL) activity. It can be concluded that the appropriate ratio of RGS could efficiently promote plant growth and regulate the reactive oxygen-based plant defense system. [ABSTRACT FROM AUTHOR]