scholarly journals Antifungal Activity against Fusarium culmorum of Stevioside, Silybum marianum Seed Extracts, and Their Conjugate Complexes

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 440 ◽  
Author(s):  
Laura Buzón-Durán ◽  
Jesús Martín-Gil ◽  
María del Carmen Ramos-Sánchez ◽  
Eduardo Pérez-Lebeña ◽  
José Luis Marcos-Robles ◽  
...  

Fusarium head blight (FHB) is a disease that poses a major challenge in cereal production that has important food and feed safety implications due to trichothecene contamination. In this study, the effect of stevioside—a glycoside found in the leaves of candyleaf (Stevia rebaudiana Bertoni)—was evaluated in vitro against Fusarium culmorum (W.G. Smith) Sacc., alone and in combination (in a 1:1 molar ratio) with polyphenols obtained from milk thistle seeds (Silybum marianum (L.) Gaertn). Different concentrations, ranging from 32 to 512 µg·mL−1, were assayed, finding EC50 and EC90 inhibitory concentrations of 156 and 221 µg·mL−1, respectively, for the treatment based only on stevioside, and EC50 and EC90 values of 123 and 160 µg·mL−1, respectively, for the treatment based on the stevioside–polyphenol conjugate complexes. Colony formation inhibition results were consistent, reaching full inhibition at 256 µg·mL−1. Given that synergistic behavior was observed for this latter formulation (SF = 1.43, according to Wadley’s method), it was further assessed for grain protection at storage, mostly directed against mycotoxin contamination caused by the aforementioned phytopathogen, confirming that it could inhibit fungal growth and avoid trichothecene contamination. Moreover, seed tests showed that the treatment did not affect the percentage of germination, and it resulted in a lower incidence of root rot caused by the pathogen in Kamut and winter wheat seedlings. Hence, the application of these stevioside–S. marianum seed extract conjugate complexes may be put forward as a promising and environmentally friendly treatment for the protection of cereal crops and stored grain against FHB.

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 820
Author(s):  
Clara Azzam ◽  
Sudad Al-Taweel ◽  
Ranya Abdel-Aziz ◽  
Karim Rabea ◽  
Alaa Abou-Sreea ◽  
...  

Stevia rebaudiana Bertoni is a little bush, which is cultivated on a large scale in many countries for medicinal purposes and used as a natural sweetener in food products. The present work aims to conduct a protocol for stevia propagation in vitro to produce and introduce Stevia rebaudiana plants as a new sweetener crop to Egyptian agriculture. To efficiently maximize its propagation, it is important to study the influence of stress factors on the growth and development of Stevia rebaudiana grown in vitro. Two stevia varieties were investigated (Sugar High A3 and Spanti) against salt stress. Leaves were used as the source of explants for callus initiation, regeneration, multiplication and rooting. Some stress-related traits, i.e., photosynthetic pigments, proline contents, and enzyme activity for peroxidase (POD), polyphenol oxidase (PPO), and malate dehydrogenase (MDH) were studied. Murashig and Skoog (MS) medium was supplemented with four NaCl concentrations: 500, 1000, 2000, and 3000 mgL−1, while a salt-free medium was used as the control. The data revealed that salinity negatively affected all studied characters: the number of surviving calli, regeneration%, shoot length, the number of multiple shoots, number of leaf plantlets−1, number of root plantlets−1, and root length. The data also revealed that Sugar High A3 is more tolerant than Spanti. The total chlorophyll content decreased gradually with increasing NaCl concentration. However, the opposite was true for proline content. Isozyme’s fractionation exhibited high levels of variability among the two varieties. Various biochemical parameters associated with salt tolerance were detected in POD. Namely, POD4, POD6, POD 9 at an Rf of 0.34, 0.57, and 0.91 in the Sugar High A3 variety under high salt concentration conditions, as well as POD 10 at an Rf of 0.98 in both varieties under high salt concentrations. In addition, the overexpression of POD 5 and POD 10 at Rf 0.52 and 0.83 was found in both varieties at high NaCl concentrations. Biochemical parameters associated with salt tolerance were detected in PPO (PPO1, PPO2 and PPO4 at an Rf of 0.38, 0.42 and 0.62 in the Sugar High A3 variety under high salt concentrations) and MDH (MDH 3 at an Rf of 0.40 in both varieties at high salt concentrations). Therefore, these could be considered as important biochemical markers associated with salt tolerance and could be applied in stevia breeding programs (marker-assisted selection). This investigation recommends stevia variety Sugar High A3 to be cultivated under salt conditions.


Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 195
Author(s):  
Alla A. Shulgina ◽  
Elena A. Kalashnikova ◽  
Ivan G. Tarakanov ◽  
Rima N. Kirakosyan ◽  
Mikhail Yu. Cherednichenko ◽  
...  

We investigated the influence of different conditions (light composition and plant growth regulators (PGRs) in culture media) on the morphophysiological parameters of Stevia rebaudiana Bertoni in vitro and in vivo. Both PGRs and the light spectra applied were found to significantly affect plant morphogenesis. During the micropropagation stage of S. rebaudiana, optimal growth, with a multiplication coefficient of 15, was obtained in an MS culture medium containing 2,4-epibrassinolide (Epin) and indole-3-acetic acid (IAA) at concentrations of 0.1 and 0.5 mg L−1, respectively. During the rooting stage, we found that the addition of 0.5 mg L−1 hydroxycinnamic acid (Zircon) to the MS medium led to an optimal root formation frequency of 85% and resulted in the formation of strong plants with well-developed leaf blades. Cultivation on media containing 0.1 mg L−1 Epin and 0.5 mg L−1 IAA and receiving coherent light irradiation on a weekly basis resulted in a 100% increase in the multiplication coefficient, better adventitious shoot growth, and a 33% increase in the number of leaves. S. rebaudiana microshoots, cultured on MS media containing 1.0 mg L−1 6-benzylaminopurine (BAP) and 0.5 mg L−1 IAA with red monochrome light treatments, increased the multiplication coefficient by 30% compared with controls (white light, media without PGRs).


2014 ◽  
Vol 57 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Ummi Nur Ain Abdul Razak ◽  
Chong Boon Ong ◽  
Tiew Sing Yu ◽  
Li Kiaw Lau

2016 ◽  
Vol 58 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Żaneta Michalec-Warzecha ◽  
Laura Pistelli ◽  
Francesca D’Angiolillo ◽  
Marta Libik-Konieczny

Abstract Leaves and internodes from Stevia rebaudiana Bertoni plants growing in different conditions were used for transformation with two strains of Agrobacterium rhizogenes: ATCC 15384 and LBA 9402. Hairy roots formation was observed and the percentage of the transformed explants depended on the type of explant, time of inoculation and inoculum concentration. Inoculation of explants from ex vitro and in vitro plants with LBA 9402 strain led to higher efficiency of transformation than inoculation with ATCC 15384 strain. Growth rate of hairy roots in liquid culture was assessed under light and dark conditions. It was found that the growth of hairy roots decreased significantly under light conditions. Transformation of hairy roots growing in different culture conditions was confirmed at the molecular level using PCR method with primers constructed against rolB and rolC genes from A. rhizogenes.


2017 ◽  
Vol 50 (3) ◽  
pp. 95-105 ◽  
Author(s):  
V. Rameeh ◽  
M. Gerami ◽  
V. Ghasemi Omran ◽  
S. Ghavampour

Abstract Stevia (Stevia rebaudiana Bertoni), with great potential as a natural sweeteners source, has a high content of sweeteners, which are up to 150 times sweeter than sugar, but virtually with no calories. Stevia also suitable to be cultivated in semiarid climates and coastal areas, which are characterized by the low quality of the irrigation water. Soil salinity occupies a prominent place among the soil problems that threaten the sustainability of agriculture over a vast area in the world. Glycine betaine is an osmoprotectant, that plays an important role and accumulates rapidly in many plants during salinity or drought stress. In order to evaluation of glycine betaine amending effects on salinity stress in stevia under in vitro condition, a factorial experiment was conducted in 2015. Four NaCl levels, including 0, 50, 75 and 100 mM, along with 0, 1, 12.5, 25 and 50 mM of glycine betaine concentrations were used in Murashige and Skoog (MS) medium. The results showed that salinity levels had significant reduction effects on plant height, root length, shoot fresh weight, number of leaf, total chlorophyll, rebaudioside A and stevioside of the stevia genotype. Due to increasing of glycine betaine, levels all the traits were increased. Owing to amending effect of glycine betaine, its high concentrations made less hazarding effects of salinity on the researched traits. The highest mean value of rebaudioside A (10.62rt) and stevioside (23.38rt) determined at 50 mM of glycine betaine with 0 mM of NaCl concentration.


Plant Disease ◽  
2021 ◽  
Author(s):  
Brian Mueller ◽  
Carol Groves ◽  
Damon L. Smith

Fusarium graminearum commonly causes Fusarium head blight (FHB) on wheat, barley, rice, and oats. Fusarium graminearum produces nivalenol and deoxynivalenol (DON) and forms derivatives of DON based on its acetylation sites. The fungus is profiled into chemotypes based on DON derivative chemotypes (3 acetyldeoxynivalenol (3ADON) chemotype; 15 acetyldeoxynivalenol (15ADON) chemotype) and/or the nivalenol (NIV) chemotype. The current study assessed the Fusarium population found on wheat and the chemotype profile of the isolates collected from 2016 and 2017 in Wisconsin. Fusarium graminearum was isolated from all locations sampled in both 2016 and 2017. Fusarium culmorum was isolated only from Door County in 2016. Over both growing seasons, 91% of isolates were identified as the 15ADON chemotype while 9% of isolates were identified as the 3ADON chemotype. Aggressiveness was quantified by area under disease progress curve (AUDPC). The isolates with the highest AUDPC values were from the highest wheat producing cropping districts in the state. Deoxynivalenol production in grain and sporulation and growth rate in vitro were compared to aggressiveness in the greenhouse. Our results showed that 3ADON isolates in Wisconsin were among the highest in sporulation capacity, growth rate, and DON production in grain. However, there were no significant differences in aggressiveness between the 3ADON and 15ADON isolates. The results of this research detail the baseline frequency and distribution of 3ADON and 15ADON chemotypes observed in Wisconsin. Chemotype distributions within populations of F. graminearum in Wisconsin should continue to be monitored in the future.


Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 560
Author(s):  
Elena Maria Colombo ◽  
Andrea Kunova ◽  
Claudio Gardana ◽  
Cristina Pizzatti ◽  
Paolo Simonetti ◽  
...  

Streptomyces spp. can be exploited as biocontrol agents (BCAs) against plant pathogens such as Fusarium graminearum, the main causal agent of Fusarium head blight (FHB) and against the contamination of grains with deoxynivalenol (DON). In the present research, four Streptomyces strains active against F. graminearum in dual plate assays were characterized for their ability to colonize detached wheat grains in the presence of F. graminearum and to limit DON production. The pathogen and BCA abundance were assessed by a quantitative real-time PCR, while DON production was assessed by HPLC quantification and compared to ergosterol to correlate the toxin production to the amount of fungal mycelium. Fungal growth and mycotoxin production were assessed with both co-inoculation and late inoculation of the BCAs in vitro (three days post-Fusarium inoculation) to test the interaction between the fungus and the bacteria. The level of inhibition of the pathogen and the toxin production were strain-specific. Overall, a higher level of DON inhibition (up to 99%) and a strong reduction in fungal biomass (up to 71%) were achieved when streptomycetes were co-inoculated with the fungus. This research enabled studying the antifungal efficacy of the four Streptomyces strains and monitoring their development in DON-inducing conditions.


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