Lactuca Indica Research Articles

Chemical profile and quantitative comparison of constituents in different medicinal parts of Lactuca indica during varied harvest periods using UPLC-MS/MS method

Lactuca indica L. cv. Mengzao (LIM), acknowledged as a pivotal “One Root of Medicine and Food”, boasts dual applications in both culinary and medicinal domains. This research delves into the influence of various harvest periods (vegetative, budding, blossom, and fruiting) on distinct medicinal parts (roots, stems, leaves, flowers, and seeds) of LIM, employing plant metabolomics to assess its chemical constituents. A total of 66 chemical constituents were identified in LIM, with 11 chemical components emerging as potential markers for distinguish medicinal parts. Notably, nutritional organs exhibited elevated levels of cichoric acid, rutin and chlorogenic acid. Specifically, leaves during the budding stage displayed the highest chicoric acid content at 11.70 mg·g−1. Conversely, reproductive organs showed heightened concentrations of cichoric acid, rutin and chlorogenic acid, with seeds exhibiting the peak cichoric acid content at 4.53 mg g−1. This study enriches our understanding of LIM by offering novel insights into quality assessment and the comprehensive utilization of its diverse parts.

Metabolic profiling provides insights into the accumulation patterns of flavonoids and phenolic acids in different parts of Lactuca indica L.

Lactuca indica L. contains high amounts of flavonoids and phenolic acids. However, there is limited information on the composition of these compounds in different parts of the plant. The present study analyzed the secondary metabolite profiles of the stem, leaf, flower, and seed of Lactuca indicaL.cv. Mengzao (LIM) using a widely targeted metabolomic approach. A total of 576 secondary metabolites were identified, including 218, 267, 232, 286, 302, and 308 differentially accumulated metabolites (DAMs) in the stem_vs_leaf, stem_vs_flower, stem_vs_seed, leaf_vs_flower, leaf_vs_seed, and flower_vs_seed comparisons. In particular, considerable differences were detected in the flavonoids and phenolic acids, five flavonoids, five phenolic acids, one triterpenoid and one alkaloid being differentially accumulated in the four parts. Compared to the stem and flower, the leaf and seed had higher total flavonoid content and total phenolic content. Thses findings provide comprehensive insights into utilizing different parts of LIM in developing functional food products.

Anti-inflammatory and anti-oxidant activity-guided investigation of phytoconstituents from Lactuca indica L.

Vietnamese dandelion(Lactuca indica L.)presents various remedies to cure pustules and several derma-inflammatory diseases in terms of traditional medicine. In this study, the anti-inflammatory and antioxidant effects of several fractions from L. indica were screened by assessing the inhibitory capacity of nitric oxide production in RAW 264.7 cells and the DPPH scavenging activity. Through screening steps, the chloroform extract exhibited extraordinary inhibition on NO synthesis, whereas the ethyl acetate singly showed a remarkable capacity to neutralise the DPPH radical. Bioactivity-guided isolation led to the identification of six compounds from the chloroform and ethyl acetate extracts, including pentadecanoic acid (1), lupeol (2), vanillin (3), 5-hydroxy-3ʹ,4ʹ,7-trimethoxyflavone (4), luteolin-7-O-β-D-glucoside (5), acacetin-7-O-β-D-rutinoside (6). Only compound (5) exhibited notable interruption in NO synthesis (IC50=13.86±1.10 μM) and simultaneously neutralised DPPH radical (IC50=26.93±0.10 μM). This study suggests that compound (5) as well as the chloroform and ethyl acetate extracts could be potential in preventing inflammatory diseases mediated by excessive production of NO. Additionally, (5) and the ethyl acetate extract could potentially be natural anti-oxidants.

First report of leaf blight caused by Alternaria alternata on Lactuca indicain China.

Lactuca indica, an annual or biennial herbaceous plant, is widespread in valleys, shrubland, ditches, hillside meadows or fields (Wang et al. 2003). In China, it is widely used as medicine and high protein feed for herbivorous animal husbandry. In July 2022, leaf blight on L. indica was observed at Zhejiang Normal University (29°8'4″N, 119°37'54″E) in Jinhua City, Zhejiang Province, China. 70% of the 87 plants investigated were infected.Small brown spots with a yellow halos first appeared on the leaves, then became irregular necrotic spots until the entire leaf wilted and fell off. To identify the pathogen, four symptomatic leaves were collected and disinfected according to Wang et al. 2023. Then they were transferred onto potato dextrose agar (PDA), and incubated at 28°C for 7 days. To obtain the pure culture, the marginal mycelium was transferred to a new PDA plate. The colony of the isolated LPB-1 was light gray and regularly round at the early stage, and then changed to dark gray and villous. The back of the culture plate appeared sooty black. The conidia of the isolated fungi (n=50) were in chains, brown, obclavate, ovoid or ellipsoid, with an average size of 29.09 µm long and 6.41 µm wide, with 0 to 3 longitudinal and 1 to 7 transverse septa. These cultural and morphological characteristics were consistent with those of Alternaria alternata (Simmons 2007). To identify the strain, internal transcribed spacer (ITS) region, RNA polymerase Ⅱ second largest subunit (RPB2), and translation elongation factor 1-alpha (TEF1-α) genes were amplified with the primers ITS1/ITS4 (White et al. 1990), RPB2-5F/RPB2-7cR (Liu et al. 1999) and EF1-728F/EF1-986R (Carbone & Kohn 1999). The RPB2 (OP909715), TEF-1α (OP909714), and ITS (OP776880) were 99 to 100% identical to those of A. alternata (GenBank accession nos. MZ170963.1, MK605900.1, and MK605895.1 for RPB2 sequences; ON951981.1, KJ008702.1, and MK672900.1 for TEF-1α sequences; OP850817.1, OP811328.1, and OP740510.1 for ITS sequences). In addition, the phylogenetic analysis also showed that the stain LPB-1 was A. alternata. To complete Koch's postulates, the conidial suspension (1×108 conidia/mL) were spray-inoculated on healthy leaves of three mature L. indica plants with sterile water as a control. All plants were incubated at 28 ℃ in a greenhouse with 12-h-light/12-h-dark photoperiod and approximately 70% humidity (Li et al. 2019). Fourteen days after incubation, the inoculated leaves showed symptoms similar to those of naturally infected leaves, while the controls remained asymptomatic. The pathogen reisolated from the inoculated leaves had the same morphological characteristics and molecular identification results as the original isolate. All the results shown above indicated that A. alternata was responsible for the leaf blight of L. indica. As far as we know, this is the first report of leaf blight caused by Alternaria alternata on Lactuca indicain China. The identification of the pathogen could provide relevant information for the establishment of methods to control the disease.

Optimization of ultrasonic-assisted extraction of flavonoids from Lactuca indica L. cv. Mengzao and their antioxidant properties.

In this study, the ultrasound-assisted extraction (UAE) conditions of flavonoids from Lactuca indica L.cv. Mengzao (LIM) leaves was optimized, and the flavonoids content and their antioxidant potential in different parts were analyzed. The optimal extraction parameters to obtain the highest total flavonoids content (TFC) were a a ratio of liquid to solid of 24.76 mL/g, ultrasonic power of 411.43 W, ethanol concentration of 58.86% and an extraction time of 30 min, the average TFC of LIM leaves could reach 48.01 mg/g. For the yield of flavonoids, the UAE method had the best extraction capacity compared with solvent extraction and microwave-assisted extraction (MAE). In general, the TFC in different parts of LIM followed the order flower > leaf > stem > root, the flowering period is the most suitable harvesting period. From ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) quantification, the flower samples showed significantly higher six flavonoids and had the highest radical scavenging capacities compared to other samples. A high positive correlation was observed between the antioxidant activity and TFC, luteolin-7-O-glucoside and rutin were significantly (p < 0.05) correlated with all antioxidant evaluations. This study provides valuable information for the development and utilization of flavonoids in Lactuca indica as ingredients in food, feed and nutritional health products.

Identity and Diversity of Invasive Plant Affecting the Growth of Native Lactuca indica.

Despite the significant number of studies that have recently focused on plant invasion and invasive plants' success, many uncertainties still exist on the effects of invasive plant identity and diversity on the native plant response under different levels of diversity. A mixed planting experiment was conducted using the native Lactuca indica (L. indica) and four invasive plants. The treatments consisted of 1, 2, 3, and 4 levels of invasive plants richness in different combinations in competition with the native L. indica. Here, the results showed that native plant response depends on the invasive plant identity and invasive plant diversity, which increases the native plant total biomass under 2-3 levels of invasive plant richness and decreases under high invasive plant density. This plant diversity effect was more significant in the native plant relative interaction index, which shows negative values except under a single invasion with Solidago canadensis and Pilosa bidens. The native plant leaf nitrogen level increased under four levels of invasive plant richness, which means more affected by invasive plant identity than invasive plant diversity. Finally, this study demonstrated that native plant response under invasion depends on the identity and diversity of invasive plants.

Optimization of Extraction Process and Dynamic Changes in Triterpenoids of Lactuca indica from Different Medicinal Parts and Growth Periods.

In this study, the triterpenoids in the leaves of Lactuca indica L.cv. Mengzao (LIM) were extracted via microwave-assisted ethanol extraction, and the optimum extraction conditions for triterpenoids were determined through single-factor experiments and the Box-Behnken method. The effects of three factors (solid-liquid ratio, microwave power and extraction time) on the total triterpenoids content (TTC) were evaluated. The TTC of different parts (roots, stems, leaves and flowers) of LIM in different growth stages was studied, and the scavenging effects of the highest TTC parts on DPPH, ABTS and hydroxyl free radicals were investigated. The results showed that the optimum extraction conditions for microwave-assisted extraction of total triterpenoids from LIM leaves were as follows: solid-liquid ratio of 1:20 g/mL; microwave power of 400 W; and extraction time of 60 min. Under these conditions, the TTC was 29.17 mg/g. Compared with the fresh raw materials, the TTC of the materials increased after freeze drying. The leaves of LIM had the highest TTC, and the flowering stage was the best time. The triterpenoids from the leaves had a strong ability to eliminate DPPH and ABTS free radicals, and the elimination effect of dried leaves was better than that of fresh leaves, while the elimination effect of hydroxyl free radicals was not obvious. The tested method was used to extract total triterpenoids from LIM using a simple process at low cost, which provides a reference for developing intensive processing methods for L. indica.

Synergistic effects of soil nutrient level and native species identity and diversity on biotic resistance to Sicyos angulatus, an invasive species.

Sicyos angulatus is a serious threat to riverine ecosystem functions and services worldwide. Here, we studied the effect of species identity and diversity on biotic resistance to S. angulatus under two different soil nutrient levels (unfertilized vs. fertilized). Soil nutrient levels showed no significant effect on invasion by S. angulatus in the control treatment, where intervention by native plants was absent. Species identity of native plants and its interaction with soil nutrient levels had a significant effect on biotic resistance to S. angulatus. For instance, Pennisetum alopecuroides and Lespedeza cuneata best resisted invasion in fertilized soil, whereas Lespedeza bicolor and Lactuca indica best resisted invasion in unfertilized soil. In addition, a mixture of four plant species resisted invasion equally as well as the monoculture of a species in unfertilized soil, whereas the mixed treatment resisted invasion much better in fertilized soil compared with unfertilized soil. Structural equation modeling revealed that species identity and diversity as well as fertilizer application significantly influenced biotic resistance to S. angulatus invasion, while soil nutrients did not influence invasion success directly. Based on these results, we strongly suggest sowing seed mixtures of various species after eradicating S. angulatus plants to prevent re-invasion. Overall, these results demonstrate how native plants rely on resource availability to resist colonization by an invasive plant, such as S. angulatus. This information can be used for the development of improved guidelines for plant restoration and invasive species control.

Anti-Hyperlipidemia Effects of Sijukkot Leaf Extract Ethanol (Lactuca Indica)

Lactuca indica from Indonesia (Humbang Hasundutan) is a plant used to treat as antihyperlipidemia :Cholesterol, Trigliserida (TG), High Density Lippoprotein (HDL), Low Density Lippoprotein (LDL),on 28 male rats of the wistar strain (Rattus norvegicus) that have been given high-fat diets were given to3 control groups, namely rats given standard feed, groups of rats given standard and high-fat diets, andgroups of rats given simvastatin with treatment for 21 days. The groups with different doses were 100mg/kg bw, 200 mg/kg bw, 300 mg/kg bw and 400 mg/kg bw. Giving the ethanol extract of the leaves ofthe sijukkot plant has an effect on reducing total cholesterol levels. With the analysis obtained that theShapiro-Wilk Normality Test with a sig value &gt; 0.05, the data is normally distributed. The results of theanalysis in the Test of Homogeneity of Variances table obtained a Sig value of 0.510. Cholesterol SigValue 0.510 &gt; 0.05; TG 0.102&gt;0.05; HDL 0.01 &lt;0.05 and LDL 0.257&gt; 0.05. Thus, the ethanolic extractof sijukkot leaves gave a positive effect on cholesterol levels in the serum lipid profile of High DensityLippoprotein (HDL and Low Density Lippoprotein (LDL).

High Genetic Diversity of 16 Indian lettuce (Lactuca indica L.) Accessions from Vietnam.

&lt;b&gt;Background and Objective:&lt;/b&gt; Plant genetic resources provide the raw material for crop improvement and plant breeding program largely depends on it. Therefore, the evaluation of plant genetic resources plays a critical role in crop improvement and also in conserving valuable genetic resources for the future. In this study, the genetic diversity of 16 &lt;i&gt;Lactuca indica&lt;/i&gt; L. accessions collected in Vietnam was investigated by using ISSR and RAPD markers. &lt;b&gt;Materials and Methods:&lt;/b&gt; Genetic diversity of 16 &lt;i&gt;Lactuca sativa&lt;/i&gt; L. genotypes collected in Vietnam were evaluated using Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeat (ISSR) molecular markers. &lt;b&gt;Results:&lt;/b&gt; In this study, 42 RAPD and ISSR primers were initially used, of which 12 and 9 primers, respectively were finally selected as they produced scorable patterns. RAPD markers produced a total of 113 loci, out of which 52 loci (45.96%) were polymorphic. The average percentage of the polymorphic band for RAPD primer is 45.96% and the genetic similarity based on simple matching coefficient ranged from 69.0-94.7%. ISSR analysis detected a total of 60 loci, out of which 22 loci (36.32%) were polymorphic and the genetic similarity ranged from 56.7-95.0%. In general, ISSR markers amplified fewer loci and showed lower variation in the percentage of polymorphism compares to the RAPD assay. &lt;b&gt;Conclusion:&lt;/b&gt; These results indicate that the 16 collected Indian lettuce genotypes are genetically diverse. Because of these genetic diversities, the collected genotypes could be used for preserving or crossing programs to improve this precious medicinal plant in Vietnam.

Screening of Endophytic Bacteria Isolated from Weed Plant to Biocontrol Stem Rot Disease on Pitaya (Hylocereus undatus)

HIGHLIGHTS First report of endophytic bacteria isolated from weed (Lactuca indica) Endophytic bacteria, L115 strain, inhibit significantly the development of Alternaria alternata. L115 strain promotes the growth parameters of multiple plants compared to the control.

Comparative Analysis of Major Flavonoids among Parts of Lactuca indica during Different Growth Periods.

L. indica L. cv. Mengzao, a medicinal plant of the Ixeris genus, is rich in flavonoids. In order to thoroughly analyze the the distribution and dynamic change of major flavonoids in its various parts from different growth periods, the flavonoids extracted from L. indica L. cv. Mengzao were identified and quantitatively analyzed by ultra-high-performance liquid chromatography mass spectrometer (LC-MS/MS). Results indicated that 15 flavonoids were identified from L. indica L. cv. Mengzao, and rutin, luteolin, luteolin-7-O-glucoside, kaempferol, quercetin, and apigenin are the major flavonoids in L. indica L. cv. Mengzao. In general, the total flavonoids’ content in different parts of L. indica L. cv. Mengzao followed the order flowers > leaves > stems > roots. Flowers and leaves are the main harvesting parts of L. indica L. cv. Mengzao, and the flowering period is the most suitable harvesting period. This study provides valuable information for the development and utilization of L. indica L. cv. Mengzao and determined the best part to harvest and the optimal time for harvesting.

Analysis of genetic variability and agronomic performance of Indian lettuce (Lactuca indica L.)

Lactuca indica L. is an undomesticated medicinal crop in the Asteraceae family. The study was carried out to identify elite genotypes for lettuce cultivation and breeding improvement. Data was recorded for 19 morphological and developmental traits across 38 accessions (Acc). The genotypic mean square variance was significant for all characters. The higher extent of genotypic and phenotypic coefficient of variation were obtained for basal branch, leaf blade width, and node number. The broad-sense heritability (H2B) ranged from 45.85% (seed length) to 98.59% (node number), whereas genetic advance as a percentage of the mean (GAM%) ranged from 9.33 to 191. Vegetative characters such as node number, plant height, basal branches were conjugated with high H2B and high GAM% indicating additive gene effect and selection of these traits based on phenotypic observation is effective for better gain. Reproductive traits, including bolting duration, flowering duration, and seed weight were linked with high H2B, and moderate GAM% revealing that these traits are amenable to genetic improvement, these traits also showed a significant and high positive correlation. Acc 55 and 8 showed the best performance for the majority of the attributes could be good material for further research and breeding. In the Wards’ phylogenetic tree of morphological traits, accessions were clustered based on their phenotypic characters rather than the geographic origin.

In vitro propagation, lactucin quantification, and antibacterial activity of Indian lettuce (Lactuca indica L.)

Lactuca indica L. (Asteraceae), a wild lettuce, is used as a vegetable and in traditional medicine. This study aims to establish in vitro propagation protocol and evaluate lactucin and antibacterial property from in vitro and natural plant tissues. Leaf blades and petioles were cultured in vitro on Murashige and Skoog (MS) medium supplemented with various concentrations of 6-benzylaminopurine (BAP) and 1.2 mg L–1 indoleacetic acid (IAA). Leaf petioles and a lower BAP concentration (0.5 mg L–1) were optimal for direct shoot induction, while the leaf blade and a higher BAP (4 mg L–1) concentration performed best for callus induction. When the callus was subcultured, 98.7% of samples regenerated plants on MS medium supplemented with 1.5 mg L–1 BAP and 0.5 mg L–1 IAA. MS medium containing 1 mg L–1 IAA was best for in vitro rooting. A high-performance liquid chromatography analysis of the in vitro samples revealed a higher amount of lactucin (sesquiterpene lactones) in the root than the callus and the leaf, whereas in naturally grown plants, higher lactucin amounts were obtained from the juvenile root followed by the root of the flowering plant and juvenile leaf as the lowest concentration. All tissue extracts showed antibacterial activity against Pseudomonas fuscovaginae (a rice pathogen) and Escherichia coli, which was directly proportional to amount of lactucin produced. This in vitro regeneration and phytochemical investigation will facilitate the further exploitation of this useful wild plant.

ẢNH HƯỞNG CỦA ĐIỀU KIỆN THIẾU NƯỚC ĐẾN MỘT SỐ CHỈ TIÊU SINH LÍ CỦA CÂY BỒ CÔNG ANH ẤN ĐỘ (Lactuca indica L.)

Indian Lettuce (Lactuca indica L.) is a valuable medicinal herb but there are still no many researches about this plant. In this work, the physiological responses of Indian lettuce plants under water deficit conditions (5, 8, and 11 days of water stress) were investigated. The Indian lettuce wilted after 5 days of water stress (66.66%), the wilting rate increased after 8 (93.33%) and 11 days (100%) of water stress. The longer duration of water deficit stress caused the slower recovery of plants after rewatering. The water deficit stress caused a decrease in chlorophyll fluorescence, non-associated water content as well as flower formation of Indian lettuce. But the water deficit stress increases the associated water content and the flowering time of this plant.

Phythochemical and Toxicity of Ethanol extract Sijukkot Leaves (Lactuca IndicaL)

Phytochemical screening on Sijukkot which determined as Lactuca indica L, the plants from an area in the village of Parsaora Sibisa Ajibata, Toba Samosir, North Sumatera has been done. Test was carried out to determine the composition of secondary metabolites contained in these plants. It was started by extracting plant leaves using 96% ethanol. Phytochemical test was used to identify compounds from the ethanol extract of sijukkot leaves. The identification results obtained compounds as Flavonoids, tannins, saponins, steroids and triterpenoids. Furthermore, the toxicity test was carried out using the BSLT method and the results showed LC50: 11.644 ppm, thus the ethanol extract of the leaves had a strong toxicity.

PHYTOCHEMICAL SCREENING OF SIJUKKOT EKSTRACT (Lactuca Indica L.)

Have been carried out Phytochemical screening on Sijukkot which determited as Lactuca indica L, the plant from Gibeon hill forrest area in the village of Parsaora Sibisa Ajibata, Toba Samosir, North Sumatera. Test carried out to determine the composition of secondary metabolites contained in these plants. It was started by extracting plant leaves using 96% ethanol solvent which was carried out by maceration method and concentrated using a rotary evaporator. The concentrated extract obtained was sponsored by phytochemical tests. Phytochemical test results on ethanol extracts from the leaves of the Sijukkot plant were obtained compositions namely Flavonoids, tannins, saponins, steroids and triterpenoids.

ANTIOXIDANT ACTIVITY TEST of SIJUKKOT (Lactuca indica L.) LEAVES EXTRACT LEAF

Has been investigated the antioxidant activity of sijukkot ( Lactuca indica L.) The antioxidant activity was tested by capturing 2,2’-diphenyl-picrylhydrazyl (DPPH) free radical method and Vitamin C as a standard of comparison, to absorption using UV-Vis spectrophotometry at a wavelength of 517nm. The data obtained were analyzed using the SPSS for windows, resulting in a value of y = 0.2036x + 30.35 for sijukkot extract and y = 29.625x - 73.664 for vitamin C. It was found the leaves have an antioxidant site with 96,51 ppm through IC50 test 4,17 ppm which used Vitamin C as a control.

Changes in Growth Characteristics and Functional Components of Lactuca indica L. ‘Sunhyang’ Baby Leaf Vegetable by Light Intensity and Cultivation Period

Changes in Growth Characteristics and Functional Components of Lactuca indica L. ‘Sunhyang’ Baby Leaf Vegetable by Light Intensity and Cultivation Period

Powdery Mildew of Pterocypsela indica Caused by Podosphaera xanthii in China

Pterocypsela indica L. Shih (synonym Lactuca indica L.) is an annual or biennial herbaceous plant in the Asteraceae that has a worldwide distribution. In China, it is often used as a component for traditional Chinese medicine or as a leafy edible foraged from the wild. In September 2018 in Qianxi county (27.24 N, 106.01 E) of China, where a 2-ha field of P. indica was being planted, severe powdery mildew was observed on the leaves of P. indica. Approximately 35% of leaves on a plant were symptomatic, and about 40% of the plants were infected. Colonies were circular or irregular. White patches on the adaxial surface of the leaves appeared from June to September, and necrotic symptoms were observed in the autumn. To identify the pathogen, a voucher specimen (isolate CG) was examined for morphological characters using a microscope under 40× magnification. Each unbranched conidiophore was composed of a cylindrical foot cell followed by one to three short cells, ranging in size from 90 to 270 × 8 to 14 μm (n = 40). Conidia of the pathogen were ellipsoid-ovoid to barrel-shaped and measured 25 to 34 × 17 to 22 μm (n = 40). Fibrosin bodies were absent. Fungal hyphae were septate, branched, flexuous to straight, and up to 7 μm wide. These structures were identical with those of the anamorph of Podosphaera xanthii U. Braun & N. Shishkoff (Braun and Cook 2012), previously known as Podosphaera fusca (Cho et al. 2013). The pathogen was identified as P. xanthii on the basis of morphology and the sequence of ITS1-5.8s-ITS2 region of rDNA amplified by polymerase chain reaction with universal primers ITS-1 (5′-TCCGTAGGTGAACCTGCGGaaawf-3′) and ITS-4 (5′-TCCTCCGCTTATTGATATGC-3′) (White et al. 1990). The sequence submitted on December 6, 2017 (GenBank accession MG647826.1) of the ITS region exactly matched the sequences of P. xanthii accessions (e.g., GenBank accession nos. KX369541.1 and MG754404.1). Pathogenicity of the fungus was confirmed by performing Koch’s postulate as follows. Six healthy P. indica plants at the eight-leaf stage were selected for the test in the greenhouse. They were inoculated with conidia from an infected plant. Another six plants not inoculated were regarded as controls. After the inoculation, all plants were incubated in the greenhouse for symptom development. They were kept at room temperature, >70% relative humidity, 80 Lux, and 8 h light/day. The experiments were conducted twice. Fourteen days after incubation, powdery mildew symptoms appeared on the leaves of inoculated plants, and the pathogen morphology was similar to that of the original voucher, whereas control plants were still asymptomatic. Powdery mildew caused by P. xanthii has been reported on cucurbits, composites, and solanaceous crops in China (Fan et al. 2019) and on papaya in Korea (Joa et al. 2013). However, to the best of our knowledge, this is the first report of P. xanthii causing powdery mildew on P. indica in China. Owing to abundant dissemination of conidia of P. xanthii, the disease could be a threat to P. indica in Qianxi county of China, and this geography is right for P. xanthii to possibly spread to Lactuca sativa.