Occurrence of Colletotrichum truncatum Causing Foliar Spot on Sesame (Sesamum indicum) in Mexico.

Sesame (Sesamum indicum L.) is an oilseed crop that present agronomic advantages and nutritional contributions in regions where water and soil fertility are limiting. In September 2020 and October 2022, anthracnose symptoms were observed on sesame fields in Mocorito (25°29'04"N;107°55'03"W) and Guasave (25°45'40"N;108°48'44"W), Sinaloa, Mexico. The disease incidence was estimated at up to 35 % (10 has) in five fields. Twenty samples were collected with symptoms on the leaves. On leaves, lesions were irregular and necrotic. Colletotrichum-like colonies were consistently isolated on PDA medium and five monoconidial isolates were obtained. One isolate was selected as a representative for morphological characterization, multilocus phylogenetic analysis, and pathogenicity tests. The isolate was deposited in the Culture Collection of Phytopathogenic Fungi of the Biotic Product Development Center at the National Polytechnic Institute under the accession number IPN 13.0101. On PDA, colonies were flat with an entire margin, initially white, then dark gray with black acervuli and setae. The growth rate was 9.3 mm/day. Conidia (n=100) on PDA were hyaloamerosporae, 17.5- 22.7 × 3.6-4.5 µm, smooth-walled, falcated and pointed at both ends, with granular content. Acervuli showed setae acicular (2-3 septate setae) tapered to the apex. The mycelial appressoria were brown, obclavate and irregular. Morphological features matched those of the Colletotrichum truncatum species complex (Damm et al. 2009). For molecular identification, total DNA was extracted, and the internal transcribed spacer (ITS) region (White et al. 1990), and partial sequences of actin (ACT), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified by PCR (Weir et al. 2012) and sequenced. The sequences were deposited in GenBank under accession nos. OQ214919 (ITS), OQ230773 (ACT), and OQ230774 (GAPDH). BLASTn searches in GenBank showed 100%, 100%, and 100% identity to MN842788 (ITS), MG198003 (ACT), and MF682518 (GAPDH) of C. truncatum, respectively. A phylogenetic tree based on the Maximum Likelihood method and Bayesian Inference including published ITS, ACT, and GAPDH sequence data for C. truncatum species complex was generated (Talhinhas and Baroncelli 2021). In the phylogenetic tree, the isolate IPN 13.0101 was placed in the same clade of C. truncatum. Pathogenicity of the isolate IPN 13.0101 was verified on 15 sesame seedlings leaves (Dormilon variety) (15-day-old) disinfected with sodium hypochlorite and sterile water. Each leave was inoculated with 200 µL of a conidial suspension (1 × 106 spores/mL). Five plants non inoculated served as controls. All plants were kept in a moist chamber for two days, and subsequently transferred to a shade house where the temperature ranged from 25 to 30°C. All inoculated leaves developed irregular and necrotic lesions ten days after inoculation, whereas no symptoms were observed on the control leaves. The fungus was consistently re-isolated from the diseased leaves, fulfilling Koch´s postulates. The experiment was conducted twice with similar results. Colletotrichum spp. has been previously reported (Farr and Rossman, 2023) to cause sesame anthracnose in Mexico (Alvarez, 1976), Thailand (Giatgong, 1980) and Cuba (Arnold, 1986), but this is the first report of C. truncatum causing sesame anthracnose in Mexico. This disease is a recurrent problem in sesame fields in Sinaloa, therefore further studies are required to understand its impact.

Synergism and Subadditivity of Verbascoside-Lignans and -Iridoids Binary Mixtures Isolated from Castilleja tenuiflora Benth. on NF-κB/AP-1 Inhibition Activity.

Pharmacodynamic interactions between plant isolated compounds are important to understand the mode of action of an herbal extract to formulate or create better standardized extracts, phytomedicines, or phytopharmaceuticals. In this work, we propose binary mixtures using a leader compound to found pharmacodynamic interactions in inhibition of the NF-κB/AP-1 pathway using RAW-Blue™ cells. Eight compounds were isolated from Castilleja tenuiflora, four were new furofuran-type lignans for the species magnolin, eudesmin, sesamin, and kobusin. Magnolin (60.97%) was the most effective lignan inhibiting the NF-κB/AP-1 pathway, followed by eudesmin (56.82%), tenuifloroside (52.91%), sesamin (52.63%), and kobusin (45.45%). Verbascoside, a major compound contained in wild C. tenuiflora showed an inhibitory effect on NF-κB/AP-1. This polyphenol was chosen as a leader compound for binary mixtures. Verbacoside-aucubin and verbascoside-kobusin produced synergism, while verbascoside-tenuifloroside had subadditivity in all concentrations. Verbascoside-kobusin is a promising mixture to use on NF-κB/AP-1 related diseases and anti-inflammatory C. tenuiflora-based phytomedicines.

Glucoindole alkaloid accumulation induced by yeast extract in Uncaria tomentosa root cultures is involved in defense response.

OBJECTIVE: To evaluate the induction of monoterpenoid indole alkaloids (MIA) and phenolic compound production by yeast extract (YE) and its relationship with defense responses in Uncaria tomentosa (Rubiaceae) root cultures. RESULTS: Root cultures were elicited by YE at three concentrations. The 0.5 mg YE ml-1 treatment did not affect cell viability but increased the hydrogen peroxide concentration by 5.7 times; guaiacol peroxidase activity by twofold; and the glucoindole alkaloid 3α-dihydrocadambine (DHC) content by 2.6 times (to 825.3 ± 27.3 µg g-1). This treatment did not affect the contents of monoterpenoid oxindole alkaloids or chlorogenic acids. In response to 0.5 mg YE ml-1 treatment, the transcript levels of MIA biosynthetic genes, TDC and LAMT, increased 5.4 and 1.9-fold, respectively, that of SGD decreased by 32%, and that of STR did not change. The transcript levels of genes related to phenolic compounds, PAL, CHS and HQT, increased by 1.7, 7.7, and 1.2-fold, respectively. Notably, the transcript levels of Prx1 and Prx encoding class III peroxidases increased by 1.4 and 2.5-fold. CONCLUSION: The YE elicitor induced an antioxidant defense response, increased the transcript levels of genes encoding enzymes related to strictosidine biosynthesis precursors and class III peroxidases, and decreased the transcript level of SGD. Thus, YE could stimulate antifungal DHC production in root cultures of U. tomentosa.

Anti-arthritic and anti-inflammatory effects of Baccharis conferta Kunth in a kaolin/carrageenan-induced monoarthritis model.

ETHNOPHARMACOLOGICAL RELEVANCE: Popularly known as "escoba" (broom) or "escobilla china" (Chinese brush), Baccharis conferta Kunth (Asteraceae), is a plant widely used in Mexican folk medicine for alleviating muscular and rheumatic pain. A recent study described that dichloromethane extract as well as fractions and isolated compounds, possess anti-inflammatory activity in TPA-induced acute edema. AIM OF THE STUDY: Based on the popular medicinal uses of B. conferta as well as previous studies on its anti-inflammatory activity, the aim of this research was to evaluate the anti-arthritic and anti-inflammatory effects of dichloromethane extract, fractions, and compounds from B. conferta in a monoarthritis model induced with kaolin/carrageenan (K/C). MATERIALS AND METHODS: Aerial parts of B. conferta were collected, dried, and macerated with dichloromethane. The dichloromethane extract (BcD) was separated by open column chromatography to obtain the BcD2 fraction where the diterpene kingidiol (KIN) was isolated and from the BcD3 fraction the flavonoid cirsimaritin (CIR), which are the most active compounds in the TPA model. In addition, the flavonoids acacetin, pectolinaringenin and 6-methoxykaempferide were identified and isolated from the BcD2 fraction. The content of the main compounds was estimated in BcD, BcD2 and BcD3. The anti-arthritic and anti-inflammatory effects of B. conferta were investigated by evaluating ankle joint inflammation, hyperalgesia using the hot plate test, and pro- and anti-inflammatory cytokine levels in the synovial capsule as well as histological changes in ankle joint tissue in a monoarthritis model induced with K/C in Balb/c mice. RESULTS: Oral administration of BcD2 fraction (25 mg/kg) and KIN (10 mg/kg) reduced the ankle thickness induced by K/C and decreased the levels of TNF-α, IL-1ß, IL-6 and IL-17, while BcD2 increased IL-10. In addition, BcD2 and KIN showed significant edema attenuation of the synovial membrane and decreased inflammatory infiltration and cartilage erosion compared to the VEH group. Finally, BcD (50 mg/kg), KIN (10 mg/kg) and CIR (5 mg/kg) decreased hyperalgesia. CONCLUSIONS: B. conferta constitutes a therapeutic or preventive candidate for osteoarthritis, because of decreased articular inflammation and pain accompanied with the modulation of cytokine concentrations, which confirms the anti-arthritic and anti-inflammatory activities of B. conferta and support its popular use.

Influence of spermine and nitrogen deficiency on growth and secondary metabolites accumulation in Castilleja tenuiflora Benth. cultured in a RITA® temporary immersion system.

The effect of exogenous spermine (SPM) on Castilleja tenuiflora shoots developing under nitrogen deficiency (ND) stress was evaluated. Shoots cultivated in a temporary immersion system were subjected to four experimental treatments: (1) control; (2) exogenous SPM; (3) ND; and (4) ND+SPM. Shoots were longer in the ND+SPM treatment (6.3 ± 0.5 cm) than in the ND treatment (4.2 ± 0.5 cm). The total chlorophyll content was similar in the control and SPM treatments (0.41 µg mg-1 FM) and the highest values of total phenolic content were detected at 21 days in the ND+SPM treatment (84.1 ± 0.05 GAE g-1 DM). In the ND+SPM treatment, the phenylalanine ammonia lyase activity increased earlier than in ND treatment, and reached its maximum at day 21 (3.9 ± 0.2 µmol E-CIN h-1 mg-1 protein). Compared with the control, the ND and ND+SPM treatments resulted in increased secondary metabolites contents in both root and aerial parts. The strongest effect was in the roots, where the SPM and ND+SPM treatments both resulted in increased quercetin content (4.3-fold that in the control). Our results showed that SPM partially counteract the damage caused by ND and results in increased contents of valuable bioactive compounds.

Beta vulgaris L. suspension cultures permeabilized with triton X-100 retain cell viability and betacyanines production ability: a digital image analysis study.

The influence of Triton X-100 on Beta vulgaris L. permeabilized cell culture viability, regrowth, and ability to produce betacyanines was evaluated in this study. A non-destructive method based on the analysis of images in the RGB (red, green, blue) system was developed to estimate betacyanines content. A treatment for 15 min with 0.7 mM Triton X-100 induced the release of 30% of betacyanines without loss of cell viability (>or=70%). After this permeabilization treatment, B. vulgaris cultures regrew normally, reaching a maximum biomass concentration of 48% higher than non-permeabilized cultures after 14 days of culture. Also, maximum betacyanines concentration was only 25% lower than that of non-permeabilized cultures.

Hydrodynamic stress induces monoterpenoid oxindole alkaloid accumulation by Uncaria tomentosa (Willd) D. C. cell suspension cultures via oxidative burst.

Uncaria tomentosa cell suspension cultures were grown in a 2-L stirred tank bioreactor operating at a shear rate gamma(.)(avg)=86 s(-1). The cultures showed an early monophasic oxidative burst measured as H2O2 production (2.15 micromol H2O2 g(-1) dw). This response was followed by a transient production of monoterpenoid oxindole alkaloids (178 +/- 40 microg L(-1) at 24 h). At the stationary phase (144 h), the increase of the shear rate gamma(.)(avg) up to 150 s(-1) and/or oxygen tension up to 85% generated H2O2, restoring oxindole alkaloid production. U. tomentosa cells cultured in Erlenmeyer flasks also exhibited the monophasic oxidative burst but the H2O2 production was 16-fold lower and the alkaloids were not detected. These cells exposed to H2O2 generated in situ produced oxindole alkaloids reaching a maximum of 234 +/- 40 microg L(-1). A positive correlation was observed between the oxindole alkaloid production and the endogenous H2O2 level. On the other hand, addition of 1 microM diphenyleneiodonium (NAD(P)H oxidase inhibitor) or 10 microM sodium azide (peroxidases inhibitor) reduced both H2O2 production and oxindole alkaloids build up, suggesting that these enzymes might play a role in the oxidative burst induced by the hydrodynamic stress.