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Prickly lettuce (Lactuca serriola), an invasive annual plant, poses a significant threat to the agricultural systems of many countries, including Korea. In 2020, leaf blight symptoms were observed in the prickly lettuce populations of various farms across Korea. Detailed morphological and molecular sequence analyses revealed that the disease was caused by the fungus, Curvularia intermedia. A pathogenicity test confirmed that the fungus can cause the same symptoms in healthy prickly lettuce, thereby fulfilling Koch’s postulates. To the best of our knowledge, this is the first report of C. intermedia causing leaf blight on L. serriola in Korea, suggesting its potential as a biocontrol agent for this weed. However, further investigations are necessary to determine its ecological impact to prevent any nontarget effects.

Invasive alien plants can severely threaten biodiversity and cause economic losses in the agricultural industry; therefore, identifying the critical environmental factors related to the distribution of alien plants plays a crucial role in ecosystem management. In this study, we applied partial least squares regression (PLSR) and geographically weighted regression (GWR) to estimate the important environmental factors affecting the spread of two invasive and expansive plants, Lactuca scariola L. and Aster pilosus Willd., across South Korea. GWR provides more accurate predictions than ordinary least squares regression, and the local coefficients of GWR allow for the determination of the spatial relationships between alien plant distributions and environmental variables. Based on the model’s results, the distributions of these alien species were significantly associated with anthropogenic effects, such as human population density, residential area, and road density. Furthermore, the two alien species can establish themselves in habitats where native plants cannot thrive, owing to their broad tolerance to temperature and drought conditions. This study suggests that urban development and expansion can facilitate the invasion of these species in metropolitan cities.

The experiment was conducted to evaluate the efficacy of Withania (W.) somnifera (commonly known as Ashwagandha) and Lactuca (L.) scariola (commonly known as Kahu) on serum health markers of hyperlipidemic rabbits. Rabbits were randomly divided into five groups attributed as negative control, positive control, simvastatin treated group, W. somnifera treated group and L. scariola treated group. Except negative control group, all other groups were fed with atherogenic diet for first 90 days to induce experimental hyperlipidemia, followed by therapeutic regime after which the treatment (comprised of different plants extracts along with regular feed) was started to each group. Blood sampling was done thrice at days 30, 60 and 90 post treatment. The serum was separated to determine the total antioxidant capacity (TAC), total oxidant status (TOS), paraoxonase activity, arylesterase activity, ceruloplasmin activity and homocysteine concentration. Study revealed that both plants has significant efficacy (P<0.05) in reducing overall oxidative stress and improving health biomarkers of the body affected by the hypercholesterolemia however, L. scariola showed more promising results in comparison to W. somnifera. It is therefore recommended that L. scariola along with other plant formulations would be a good therapy in evading the drastic effects of obesity/hyperlipidemia with the minimal side effects as compared to the synthetic drugs. [ABSTRACT FROM AUTHOR]

Abstract: A new antibacterial triterpenoid saponin, 3β-O-[α-l-rhamnopyranosyl]-30-norolean-12,19-diene-28-oic acid 28-O-[β-d-glucopyranosyl-(1→4)-O-β-d-galactopyranosyl]-ester (1); has been isolated from the stems of Lactuca scariola. Its structure was determined by chemical degradations and spectral analysis. [Copyright &y& Elsevier]

A new triterpenoid saponin, 3-O-[β-D-galactopyranosyl-(1 → 3)-O-β-D-xylopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl]-oleanolic acid; has been isolated from the seeds of Lactuca scariola. Its structure was determined by various spectral analysis and chemical degradations. This compound shows antimicrobial activity against various bacteria and fungi. [ABSTRACT FROM AUTHOR]

The antioxidant activity of Lactuca scariola (Compositae) was investigated by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical. The methanolic extract of the aerial parts of Lactuca scariola showed strong radical scavenging activity. The EtOAc soluble fraction exhibited a stronger activity than the others, and was purified by silica gel and Sephadex LH-20 column chromatography. Quercetin-3- O-P-D-glucopyranoside, luteolin-7- O-β-D-glucopyranoside, luteolin, quercetin and kaempferol, together with 11β,13-dihydrolactucin were isolated from the EtOAc soluble fraction as active ingredients. [ABSTRACT FROM AUTHOR]

Invasive alien plants can severely threaten biodiversity and cause economic losses in the agricultural industry; therefore, identifying the critical environmental factors related to the distribution of alien plants plays a crucial role in ecosystem management. In this study, we applied partial least squares regression (PLSR) and geographically weighted regression (GWR) to estimate the important environmental factors affecting the spread of two invasive and expansive plants, Lactuca scariola L. and Aster pilosus Willd., across South Korea. GWR provides more accurate predictions than ordinary least squares regression, and the local coefficients of GWR allow for the determination of the spatial relationships between alien plant distributions and environmental variables. Based on the model's results, the distributions of these alien species were significantly associated with anthropogenic effects, such as human population density, residential area, and road density. Furthermore, the two alien species can establish themselves in habitats where native plants cannot thrive, owing to their broad tolerance to temperature and drought conditions. This study suggests that urban development and expansion can facilitate the invasion of these species in metropolitan cities. [ABSTRACT FROM AUTHOR]

• Fe is the most effective catalyst for light bio-oil and heavy bio-oil yields. • Fe catalyst is active in monoaromatic compound formation. • Zn catalyst is active in polyaromatic and aliphatic formation. • Zn + Fe catalyst system was found effective in the formation of oxygen compounds. In this study, lignocellulosic biomass was converted into liquid products by catalytic hydrothermal liquefaction. Zn, Fe, and Zn + Fe were used to obtaining products with high energy value as heterogeneous catalyst systems in this study. The different experimental parameters were used to examine temperature (220, 240, 260, 280, 300 °C), reaction time (0, 5, 10, 15, 20, 30 min.), and the synergistic effect of catalysts (Zn + Fe) on conversion rate. The products obtained were examined by GC–MS, Elemental, FT-IR, 1H NMR, SEM-EDX, and XRD analysis methods. According to the results of the experiment, it has been determined that Fe is the most effective catalyst for light bio-oil and heavy bio-oil yields and Zn + Fe is the most effective catalyst system for the gas + aqueous phase products. Fe catalyst in monoaromatics formation, Zn catalyst in polyaromatic and aliphatics compound formation, Zn + Fe catalyst system in oxygen compounds formation are effective. [ABSTRACT FROM AUTHOR]

Lactuca serriola L. (syn. L. scariola L.) is an annual Asteraceae plant, native to Europe, and accidentally introduced to Korea in the late 1970s (Yim and Jeon, 1981). The Korean Ministry of Environment designated this weed as a harmful plant, which may disturb the balance of ecosystems (Kim et al., 2013). In July 2019, wilting symptoms of prickly lettuce were found among a roadside in Sangju (36°26'15'' N, 128°07'35'' E), Korea, with a disease incidence of 60%. Initial symptoms appeared pale to dark brown lesions on the basal stem and leaves of the plant, and over time the lesions expanded to the upper parts of the plant, resulting in extensive rot. Ultimately, the plants wilted and died. Symptomatic vascular tissues (5 x 5 mm2) of two diseased plants were surface sterilized in 2% NaClO solution for 1 min, followed by 70% ethanol for 1min, and rinsed two times in sterile distilled water. The pieces were placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for a week. Each single spore isolate was obtained from the hypha tip growing on PDA and examined for morphological and molecular analysis. A representative isolate has been deposited at the Korean Agricultural Culture Collection (KACC49588). Macroconidia were slender, straight, and measured 20.4 to 59.6 × 2.5 to 3.9 μm (n=50), with three to five septa. Microconidia were clavate and measured 6.1 to 13 × 2.5 to 3.3 μm (n=50). Chlamydospores were absent. The colonies developed white aerial mycelium and turned pale purple after a week on PDA. Both morphological and cultural characteristics of the Korean isolate were close to Fusarium fujikuroi (Leslie and Summerell, 2006). Also, DNA sequence-based identification was carried out using primer sets of ITS1-F/ITS4 for the internal transcribed spacer (ITS) rDNA region, Btu-F-F01/Btu-F-R01 for β-tubulin (TUB) gene (Watanabe et al., 2011), and EF-1/EF-2 for translation elongation factor 1-alpha (TEF) gene. The resulting sequences were deposited in GenBank with accession numbers MT102938 for ITS, MT182734 for TUB, and MT625962 for TEF. On a BLASTn search, the Korean isolate revealed 100% sequence identity with the verified sequences of F. fujikuroi MF984413.1 for ITS, 99.79% (1 out of 368 bp is different) with U34415.1 for TUB, and 99.85% (1 out of 675 bp) with MN193860.1 for TEF. Pathogenicity was tested by dipping the roots of five healthy prickly lettuce seedlings in the spore suspension (1 × 106 conidia/ml) for 1 hour. Inoculated plants were transplanted into pots and maintained in a growth chamber at 90% relative humidity and 20°C. Five non-inoculated plants served as controls. After four weeks, wilt symptoms accompanied by expanding brown spots were observed on the basal stem and leaves of all inoculated seedlings, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical to one of the original infections, fulfilling Koch's postulates. Based on the morphological characteristics, sequencing data, and pathogenicity test, the pathogen was identified as F. fujikuroi. Bakanae (foolish seedling) disease caused by F. fujikuroi is one of the most serious rice diseases in Asia, but also this pathogen has been recorded on Lactuca sativa in Thailand (Farr and Rossman 2020). To our knowledge, this is the first report of F. fujikuroi causing Fusarium wilt on L. serriola in Korea.