Mechanistic insights into strigolactone biosynthesis, signaling and regulation during plant growth and development

Strigolactones (SLs) constitute a group of carotenoid-derived phytohormones with butenolide moieties. These hormones are involved in various functions, including regulation of secondary growth, shoot branching and hypocotyl elongation, and stimulation of seed germination. SLs also control hyphal branching of arbuscular mycorrhizal (AM) fungi, and mediate responses to both abiotic and biotic cues. Most of these functions stem from the interplay of SLs with other hormones, enabling plants to appropriately respond to changing environmental conditions. This dynamic interplay provides opportunities for phytohormones to modulate and augment one another. In this article, we review our current mechanistic understanding of SL biosynthesis, receptors and signaling. We also highlight recent advances regarding the interaction of SLs with other hormones during developmental processes and stress conditions

Regulatory Mechanisms for the Conservation of Endangered Plant Species, <i>Chlorophytum tuberosum</i>—Potential Medicinal Plant Species

The present review paper is an attempt to examine and provide an overview of the various conservation strategies and regulatory framework to protect endangered plants, including Chlorophytum tuberosum, popularly known as Safed Musli in the local language. C. tuberosum belongs to the family Liliaceae and is being used in the indigenous systems of medicine as a galactagogue, aphrodisiac, antitumor, immunomodulatory, antidiabetic, analgesic, anti-inflammatory, hypolipidemic, anti-ageing, antimicrobial, etc. This plant has great medicinal and commercial value and is part of the Biological Diversity Act, but due to a lack of effective conservation, it is on the verge of extinction because of natural and manmade reasons, such as loss of habitat, climate change, pollution, excessive harvesting, etc. The most valuable medicinal plants have great importance; hence, many conservation techniques are being employed to protect them. In furtherance to the conservation of such plant species, strategic efforts, in the form of laws and policies, are laid; however, existing legislative mechanisms and policy parameters are not sufficient to overcome the challenges of conservation of such plant species, including Safed Musli, hence, this plant has been considered as a critically endangered plant in India. It is pertinent to note that we do not have specific legislation enacted for the protection of plant species; however, efforts are being made to conserve it under various laws, such as the Forest Conservation Act, Biological Diversity Act 2002, and many other allied legislations. This basic legislation of the Biological Diversity Act also lacks focal attention on the conservation of endangered plant species. Moreover, decentralization of power and actual community participation in conservation practices are also missing. A cumulative effect of both scientific measures and legal mechanisms supported by community participation may produce better results in the conservation of plant species, including Safed Musli. The protection of rich sources and biological diversity is not being taken as seriously as it ought to be, hence, it is necessary to improve awareness and public participation in conservation techniques with effective legislation for the conservation of highly endangered plant species

Synergistic effects of plant defense elicitors and Trichoderma harzianum on enhanced induction of antioxidant defense system in tomato against Fusarium wilt disease

Abstract Plant defense against their pathogens can be induced by a complex network of different inducers. The present study investigates the synergistic effect of Trichoderma harzianum, exogenous salicylic acid (SA) and methyl jasmonate (MeJA) over the response and regulation of the antioxidant defense mechanisms and lipid peroxidation in tomato plants against Fusarium wilt disease. In the present work, tomato plants were infected by Fusarium oxysporum f. sp. lycopersici 3 days after inoculated with T. harzianum and/or sprayed daily for 3 days with chemical inducers (SA and MeJA). Plants were analysed at 0, 24, 48, 72 and 96 h after inoculation with Fusarium oxysporum f. sp. lycopersici. Infection of tomato plants by pathogen led to strong reduction in the dry weight of roots and shoots with the enhanced concentration of H2O2 and varying degree of lipid peroxidation. Concurrently, exogenous SA, when applied with pathogen greatly enhanced H2O2 content as well as activities of antioxidant enzymes except catalase (CAT) and ascorbate peroxidase (APx). The pathogen challenged plants pretreated with T. harzianum and MeJA together exhibited less lipid peroxidation and as well as the elevated level of ascorbic acid and enhanced activities of antioxidant enzymes. All applied treatments protected tomato seedlings against Fusarium wilt disease but the percentage of protection was found higher in plants pretreated with the combination of T. harzianum and chemical inducers

Alternaria Toxins: Potential Virulence Factors and Genes Related to Pathogenesis

Alternaria is an important fungus to study due to their different life style from saprophytes to endophytes and a very successful fungal pathogen that causes diseases to a number of economically important crops. Alternaria species have been well-characterized for the production of different host-specific toxins (HSTs) and non-host specific toxins (nHSTs) which depend upon their physiological and morphological stages. The pathogenicity of Alternaria species depends on host susceptibility or resistance as well as quantitative production of HSTs and nHSTs. These toxins are chemically low molecular weight secondary metabolites (SMs). The effects of toxins are mainly on different parts of cells like mitochondria, chloroplast, plasma membrane, Golgi complex, nucleus, etc. Alternaria species produce several nHSTs such as brefeldin A, tenuazonic acid, tentoxin, and zinniol. HSTs that act in very low concentrations affect only certain plant varieties or genotype and play a role in determining the host range of specificity of plant pathogens. The commonly known HSTs are AAL-, AK-, AM-, AF-, ACR-, and ACT-toxins which are named by their host specificity and these toxins are classified into different family groups. The HSTs are differentiated on the basis of bio-statistical and other molecular analyses. All these toxins have different mode of action, biochemical reactions and signaling mechanisms to cause diseases. Different species of Alternaria produced toxins which reveal its biochemical and genetic effects on itself as well as on its host cells tissues. The genes responsible for the production of HSTs are found on the conditionally dispensable chromosomes (CDCs) which have been well characterized. Different bio-statistical methods like basic local alignment search tool (BLAST) data analysis used for the annotation of gene prediction, pathogenicity-related genes may provide surprising knowledge in present and future

Comparative evaluation of biochemical changes in tomato (lycopersicon esculentum mill.) infected by alternaria alternata and its toxic metabolites (tea, aoh, and ame)

In the present study, we have evaluated the comparative biochemical defense response generated against Alternaria alternate and its purified toxins viz. alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA). The necrotic lesions developed due to treatment with toxins were almost similar as those produced by the pathogen, indicating the crucial role of these toxins in plant pathogenesis. An oxidative burst reaction characterized by the rapid and transient production of a large amount of reactive oxygen species (ROS) occurs following the pathogen infection/toxin exposure. The maximum concentration of hydrogen peroxide (H2O2) produced was reported in the pathogen infected samples (22.2-fold) at 24 h post inoculation followed by TeA (18.2-fold), AOH (15.9-fold), and AME (14.1-fold) in treated tissues. 3,3\u27-Diaminobenzidine staining predicted the possible sites of H2O2 accumulation while the extent of cell death was measured by Evans blue dye. The extent of lipid peroxidation and malondialdehyde (MDA) content was higher (15.8-fold) at 48 h in the sample of inoculated leaves of the pathogen when compared to control. The cellular damages were observed as increased MDA content and reduced chlorophyll. The activities of antioxidative defense enzymes increased in both the pathogen infected as well as toxin treated samples. Superoxide dismutase (SOD) activity was 5.9-fold higher at 24 h post inoculation in leaves followed by TeA (5.0-fold), AOH (4.1-fold) and AME (2.3-fold) treated leaves than control. Catalase (CAT) activity was found to be increased upto 48 h post inoculation and maximum in the pathogen challenged samples followed by other toxins. The native PAGE results showed the variations in the intensities of isozyme (SOD and CAT) bands in the pathogen infected and toxin treated samples. Ascorbate peroxidase (APx) and glutathione reductase (GR) activities followed the similar trend to scavenge the excess H2O2. The reduction in CAT activities after 48 h post inoculation demonstrate that the biochemical defense programming shown by the host against the pathogen is not well efficient resulting in the compatible host pathogen interaction. The elicitor (toxins) induced biochemical changes depends on the potential toxi

Comparative evaluation of biochemical changes in tomato (lycopersicon esculentum mill.) infected by alternaria alternata and its toxic metabolites (tea, aoh, and ame)

In the present study, we have evaluated the comparative biochemical defense response generated against Alternaria alternate and its purified toxins viz. alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA). The necrotic lesions developed due to treatment with toxins were almost similar as those produced by the pathogen, indicating the crucial role of these toxins in plant pathogenesis. An oxidative burst reaction characterized by the rapid and transient production of a large amount of reactive oxygen species (ROS) occurs following the pathogen infection/toxin exposure. The maximum concentration of hydrogen peroxide (H2O2) produced was reported in the pathogen infected samples (22.2-fold) at 24 h post inoculation followed by TeA (18.2-fold), AOH (15.9-fold), and AME (14.1-fold) in treated tissues. 3,3'-Diaminobenzidine staining predicted the possible sites of H2O2 accumulation while the extent of cell death was measured by Evans blue dye. The extent of lipid peroxidation and malondialdehyde (MDA) content was higher (15.8-fold) at 48 h in the sample of inoculated leaves of the pathogen when compared to control. The cellular damages were observed as increased MDA content and reduced chlorophyll. The activities of antioxidative defense enzymes increased in both the pathogen infected as well as toxin treated samples. Superoxide dismutase (SOD) activity was 5.9-fold higher at 24 h post inoculation in leaves followed by TeA (5.0-fold), AOH (4.1-fold) and AME (2.3-fold) treated leaves than control. Catalase (CAT) activity was found to be increased upto 48 h post inoculation and maximum in the pathogen challenged samples followed by other toxins. The native PAGE results showed the variations in the intensities of isozyme (SOD and CAT) bands in the pathogen infected and toxin treated samples. Ascorbate peroxidase (APx) and glutathione reductase (GR) activities followed the similar trend to scavenge the excess H2O2. The reduction in CAT activities after 48 h post inoculation demonstrate that the biochemical defense programming shown by the host against the pathogen is not well efficient resulting in the compatible host pathogen interaction. The elicitor (toxins) induced biochemical changes depends on the potential toxi

Comparative evaluation of biochemical changes in tomato (lycopersicon esculentum mill.) infected by alternaria alternata and its toxic metabolites (tea, aoh, and ame)

In the present study, we have evaluated the comparative biochemical defense response generated against Alternaria alternate and its purified toxins viz. alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA). The necrotic lesions developed due to treatment with toxins were almost similar as those produced by the pathogen, indicating the crucial role of these toxins in plant pathogenesis. An oxidative burst reaction characterized by the rapid and transient production of a large amount of reactive oxygen species (ROS) occurs following the pathogen infection/toxin exposure. The maximum concentration of hydrogen peroxide (H2O2) produced was reported in the pathogen infected samples (22.2-fold) at 24 h post inoculation followed by TeA (18.2-fold), AOH (15.9-fold), and AME (14.1-fold) in treated tissues. 3,3'-Diaminobenzidine staining predicted the possible sites of H2O2 accumulation while the extent of cell death was measured by Evans blue dye. The extent of lipid peroxidation and malondialdehyde (MDA) content was higher (15.8-fold) at 48 h in the sample of inoculated leaves of the pathogen when compared to control. The cellular damages were observed as increased MDA content and reduced chlorophyll. The activities of antioxidative defense enzymes increased in both the pathogen infected as well as toxin treated samples. Superoxide dismutase (SOD) activity was 5.9-fold higher at 24 h post inoculation in leaves followed by TeA (5.0-fold), AOH (4.1-fold) and AME (2.3-fold) treated leaves than control. Catalase (CAT) activity was found to be increased upto 48 h post inoculation and maximum in the pathogen challenged samples followed by other toxins. The native PAGE results showed the variations in the intensities of isozyme (SOD and CAT) bands in the pathogen infected and toxin treated samples. Ascorbate peroxidase (APx) and glutathione reductase (GR) activities followed the similar trend to scavenge the excess H2O2. The reduction in CAT activities after 48 h post inoculation demonstrate that the biochemical defense programming shown by the host against the pathogen is not well efficient resulting in the compatible host pathogen interaction. The elicitor (toxins) induced biochemical changes depends on the potential toxi

Enhanced protection of tomato against Fusarium wilt through biopriming with Trichoderma harzianum

Objective: Microbial priming represents an adaptive strategy to enhance the plant defense against subsequent challenges incited by pathogenic microbes. The aim of the study was to investigate the effect of priming with Trichoderma harzianum (Th) on the induced resistance potential of tomato after challenged with Fusarium oxysporum f. sp. lycopersici (Fol) pathogen. Methods: This work demonstrated antioxidative and defense related enzyme activities and qRT-PCR to study the resistance mechanisms of tomato plants bioprimed with T. harzianum against Fol pathogen. Result: Microbial biopriming with T. harzianum resulted into enhanced expression of tomato defense-related genes and was accompanied by increased antioxidative enzymic activities. The study reported that the T. harzianum primed plants showed 2.71-fold higher SOD than control and 1.34-fold (Fol + Th) higher SOD activity compared to Fol challenged plants. In contrast, Fol + Th treated showed 5.87-fold and 1.34-fold higher CAT enzyme activity as compared to control and pathogen exposed plants. T. harzianum bioprimed plants noted 1.47- and 11.47-fold enhanced PPO activity as compared to Fol challenged and controls, respectively. PAL and PO activities were also found higher in T. harzianum primed plants. The qRT-PCR revealed that expression of defense related gene showed higher up-regulation in T. harzianum primed plants as compared to pathogen challenged plants. As compared to control, Fol + Th treated plants also showed higher up-regulation of all the studied genes. Conclusion: The study concluded T. harzianum priming aggravates the plant defense system against the Fol challenged condition and accompanied by higher expression of defense related genes and increased antioxidative activities against subsequent Fol attack

Improvement Strategies, Cost Effective Production, and Potential Applications of Fungal Glucose Oxidase (GOD): Current Updates

Fungal glucose oxidase (GOD) is widely employed in the different sectors of food industries for use in baking products, dry egg powder, beverages, and gluconic acid production. GOD also has several other novel applications in chemical, pharmaceutical, textile, and other biotechnological industries. The electrochemical suitability of GOD catalyzed reactions has enabled its successful use in bioelectronic devices, particularly biofuel cells, and biosensors. Other crucial aspects of GOD such as improved feeding efficiency in response to GOD supplemental diet, roles in antimicrobial activities, and enhancing pathogen defense response, thereby providing induced resistance in plants have also been reported. Moreover, the medical science, another emerging branch where GOD was recently reported to induce several apoptosis characteristics as well as cellular senescence by downregulating Klotho gene expression. These widespread applications of GOD have led to increased demand for more extensive research to improve its production, characterization, and enhanced stability to enable long term usages. Currently, GOD is mainly produced and purified from Aspergillus niger and Penicillium species, but the yield is relatively low and the purification process is troublesome. It is practical to build an excellent GOD-producing strain. Therefore, the present review describes innovative methods of enhancing fungal GOD production by using genetic and non-genetic approaches in-depth along with purification techniques. The review also highlights current research progress in the cost effective production of GOD, including key advances, potential applications and limitations. Therefore, there is an extensive need to commercialize these processes by developing and optimizing novel strategies for cost effective GOD production

Analisi del comfort globale in aule universitarie: aspetti normativi, indagine statistico-sperimentale, casi di studio

Scopo del presente lavoro è la valutazione della qualità dell’ambiente interno (IEQ) in aule universitarie facenti parte del complesso della Scuola di Ingegneria dell’Università di Pisa. Lo studio mira inoltre a sviluppare una metodologia di confronto basata sull’analisi tra i parametri quantitativamente misurati e gli aspetti qualitativi del benessere, determinati dalla risposta da parte dei singoli occupanti ad un questionario specificatamente elaborato. Nel caso specifico, l’attenzione viene posta sulla percezione di alcuni aspetti di comfort acustico e visivo all’interno degli ambienti in esame. La metodologia di analisi utilizzata si sviluppa in quattro fasi: 1. Sondaggio effettuato attraverso dei questionari per la valutazione soggettiva della qualità ambientale interna da parte degli occupanti e analisi statistica dei risultati; 2. Osservazioni e registrazioni delle condizioni ambientali esterne; 3. Misurazione dei parametri ambientali interni (tempo di riverberazione, indice di chiarezza, indice di trasmissione del parlato, illuminamento medio, uniformità di illuminamento, fattore medio di luce diurna) al fine di determinare gli indicatori ambientali di benessere acustico e visivo in maniera oggettiva; 4. Confronto tra parametri soggettivi e parametri oggettivi rilevati. Complessivamente, l’indagine soggettiva non ha mostrato particolare insoddisfazione degli utenti all’interno delle aule oggetto di studio. L’analisi statistica ha dimostrato la diversa incidenza dei singoli aspetti di comfort globale nella valutazione complessiva del benessere e messo in evidenza le effettive problematiche di ciascuna aula. Nel presente studio sono state inoltre riscontrate criticità connesse al questionario proposto e al confronto tra parametri oggettivi e soggettivi rilevati. Sono stati perciò proposti interventi migliorativi del metodo adottato per possibili sviluppi futuri. Analysis of global comfort in university classrooms: regulatory aspects, statistical and experimental investigation, case studies The aim of this study is to evaluate of indoor environmental quality (IEQ) in university classroom within the School of Engineering of Pisa. The study also aims to develop a methodology of comparison based on the analysis between quantitatively measured parameters and qualitative aspects of well-being, which are determined by the response of individual occupants to a specifically elaborated questionnaire. In this case, the focus is on the perception of some aspects of acoustic and visual comfort within the environments in question. The analysis methodology used is developed in four phases: 1. Survey conducted through questionnaires for subjective assessment of occupational environmental quality by occupants and statistical analysis of results; 2. Observations and recordings of external environmental conditions; 3. Measurement of indoor environmental parameters (reverberation time, clarity index, speech transmission index, mean illumination, uniformity of illumination, mean daylight factor) in order to objectively determine the environmental indicators of acoustic and visual comfort; 4. Comparison of subjective parameters and objective parameters detected. Overall, the subjective survey did not show particular dissatisfaction among users within the classrooms studied. The statistical analysis demonstrated the different incidence of the various aspects of global comfort in the general evaluation of well-being and it highlighted the actual problems of each classroom. In the present study, there were also critical points related to the questionnaire proposed and the comparison of objective and subjective parameters detected. They were, therefore, proposed improvement measures of the method used for possible future developments