scholarly journals First Report of Powdery Mildew Caused by Podosphaera xanthii on Sigesbeckia orientalis in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Irum Mukhtar ◽  
Ruanni Chen ◽  
Yunying Cheng ◽  
IBATSAM KHOKHAR ◽  
Chen Liang ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Lateral Position ◽  
Production Quality ◽  
Podosphaera Xanthii ◽  
Ageratum Conyzoides ◽  
First Report ◽  
Eclipta Prostrata ◽  
Wide Range ◽  
Young Leaves ◽  
Natural Herb

Sigesbeckia orientalis L., (St Paul’s wort) is an annually grown natural herb of Asteraceae with a long therapeutic history for a wide range of inflammation-related diseases in China (Zhong et al. 2019). In June 2020, typical symptoms of powdery mildew were observed on 30% of wild S. orientalis plants grown along the roadsides and gardens in Minjiang University, Fuzhou, China. Circular to irregular white powdery fungal colonies were observed on both surfaces of the leaves and young stems, causing necrosis and premature senescence. Fungal hyphae were epigenous, flexuous to straight, branched, and septate. Appressoria on the hyphae were nipple-shaped or nearly absent. Conidiophores were straight, 30 to 210× 8 to 12 μm, and produced 3 to 7 immature conidia in chains with a crenate outline. Foot-cells were cylindrical, 45 to 75 ×10 to 12 μm, followed by 1 to 2 shorter cells. Conidia were hyaline, ellipsoid-ovoid to barrel-shaped, 25 to 38 × 18 to 23 μm with distinct fibrosin bodies. Germ tubes were produced from a lateral position on the conidia. Chasmothecia were not observed on the infected leaves. Based on anamorph characteristics, fungus was identified as Podosphaera xanthii (Castagne) U. Braun & N. Shishkoff (Braun and Cook 2012). For molecular identification, total genomic DNA was extracted (Mukhtar et al. 2018) from fungal colonies on infected leaves of five collections separately. For each DNA sample, the part of LSU and ITS regions were amplified using primers LSU1/LSU2 and ITS1/ITS4 (Scholin et al. 1994; White et al. 1990), respectively. A BLAST search revealed 100 % sequences similarity with P. xanthii sequences reported on Ageratum conyzoides (KY274485), Eclipta prostrata (MT260063), Euphorbia hirta (KY388505), Sonchus asper (MN134013), and Verbena bonariensis (AB462804). Representative sequences (ITS: MZ613309; LSU: MZ614707) of an isolate were deposited in GenBank. The phylogenetic analysis also grouped the obtain sequences into P. xanthii clade. Pathogenicity was confirmed by gently pressing the infected leaves onto young leaves of five healthy one-month-old S. orientalis plants, while three non-inoculated plants were used as controls. All plants were maintained in a greenhouse at 25 ± 2°C. After, seven days, white powdery colonies were observed on inoculated plants, whereas controls remained mildew-free. On inoculated leaves, the fungus was morphologically and molecularly identical to the fungus on the original specimens. P. xanthii has been reported as a significant damaging pathogen on a wide range of plants in China (Farr and Rossman 2021). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on S. orientalis in China as well as worldwide. S. orientalis is one of the most important commercial Chinese medicinal herbs and the occurrence of powdery mildew is a threat to its production, quality, and marketability. References: Braun, U., and Cook, R. T. A. 2012. The Taxonomic Manual of the Erysiphales (Powdery Mildews). CBS Biodiversity Series 11: CBS. Utrecht, The Netherlands. Farr, D. F., and Rossman, A. Y. 2021. Fungal Databases. Syst. Mycol. Microbiol. Lab., USDA ARS, 9 October 2021. Mukhtar, I., et al. 2018. Sydowia.70:155. Scholin, C. A., et al. 1994. J. Phycol. 30:999. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Zhong, Z., et al., 2019. Chin. Med. (U. K.) 14, 1–12. 10.1186/s13020-019-0260-y

scholarly journals First Report of Powdery Mildew of Eclipta prostrata Caused by Podosphaera xanthii in China

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3263
Author(s):  
D.-D. Xu ◽  
F. Qiao ◽  
J.-H. Xu ◽  
L.-Y. Shi ◽  
L.-Q. Jiang
Keyword(s):  
Powdery Mildew ◽  
Podosphaera Xanthii ◽  
First Report ◽  
Eclipta Prostrata

scholarly journals First Report of Powdery Mildew caused by Podosphaera xanthii on Euphorbia tithymaloides in Malaysia

Plant Disease ◽  
2020 ◽  
Author(s):  
Siti Izera Ismail ◽  
Aziera Roslen
Keyword(s):  
Powdery Mildew ◽  
Sequence Data ◽  
Morphological Characteristics ◽  
Pathogenicity Test ◽  
Podosphaera Xanthii ◽  
Sequence Alignments ◽  
Voucher Specimen ◽  
First Report ◽  
Initial Symptoms ◽  
Young Leaves

Euphorbia tithymaloides L. (zig-zag plant) is a succulent, perennial shrub belonging to the Euphorbiaceae family and is widely cultivated in Malaysia for ornamental purposes and commercial values. In June 2019, typical symptoms of powdery mildew were observed on over 50% of the leaves of E. tithymaloides in a garden at Universiti Putra Malaysia, Serdang city of Selangor province, Malaysia. Initial symptoms included circular to irregular white powdery fungal colonies on both leaf surfaces and later covered the entire leaf surface. Severely infected leaves became necrotic, distorted and senesced. A voucher specimen Ma (PM001-Ma) was deposited in the Mycology laboratory, Faculty of Agriculture, UPM. Microscopic observation showed hyphae hyaline, branched, thin-walled, smooth, 3 to 6 µm wide with nipple-shaped appressoria. Conidiophores were straight, measured 30 to 90 μm long × 8 to 12 μm wide and composed of a cylindrical foot cell, 50 to 75 μm long. Conidia formed in chains were hyaline, ellipsoid to oval with fibrosin bodies, measured 25 to 36 × 16 to 20.1 μm in size and chasmothecia were not observed on the infected leaves. Genomic DNA was directly isolated from mycelia and conidia of isolate Ma using DNeasy Plant Mini Kit (Qiagen, USA). The universal primer pair ITS4/ITS5 of rDNA (White et al. 1990) was used for amplification and the resulting 569-bp sequence was deposited in GenBank (Accession no. MT704550). A BLAST nucleotide search revealed 100% similarity with that of Podosphaera xanthii on Momordica charantia wild from Taiwan (Accession no. KM505135) (Kirschner and Liu 2015). Both the morphological characteristics of the anamorph and ITS sequence data support the identification of this powdery mildew on E. tithymaloides as Podosphaera xanthii (Castagne) U. Braun & Shishkoff (Braun and Cook 2012). A pathogenicity test was conducted by gently pressing the infected leaves onto young leaves of five healthy potted plants. Five noninoculated plants were used as controls. The inoculated plants were maintained in a greenhouse at 25 ± 2°C and the test was repeated. Seven days after inoculation, white powdery symptoms were observed similar to those on the naturally infected leaves, while control plants remained asymptomatic. The fungus on the inoculated leaves was morphologically and molecularly identical to the fungus on the original specimens. Sequence alignments were made using MAFFT v.7.0 (Katoh et al. 2019) and a maximum likelihood phylogram was generated by MEGA v.7.0 (Kumar et al. 2016). Isolate Ma grouped in a strongly supported clade (100% bootstrap value) with the related species of P. xanthii available in GenBank based on the ITS region. Powdery mildew caused by P. xanthii has been reported as a damaging disease that can infect a broad range of plants worldwide (Farr and Rossman 2020). It also has been recently reported on Sonchus asper in China (Shi et al. 2020). According to our knowledge, this is the first report of powdery mildew caused by P. xanthii on E. tithymaloides worldwide. The occurrence of powdery mildew on E. tithymaloides could pose a serious threat to the health of this plant, resulting in death and premature senescence of young leaves.

scholarly journals First Confirmed Report of Powdery Mildew Caused by Podosphaera xanthii on Farfugium japonicum in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (5) ◽  
pp. 691-691 ◽  
Author(s):  
S. E. Cho ◽  
M. J. Park ◽  
C. H. Shin ◽  
H. D. Shin
Keyword(s):  
Powdery Mildew ◽  
Signs And Symptoms ◽  
Its Region ◽  
Lateral Position ◽  
Width Ratio ◽  
Podosphaera Xanthii ◽  
Potted Plants ◽  
Ampelomyces Quisqualis ◽  
Young Leaves ◽  
Farfugium Japonicum

Farfugium japonicum (L.) Kitam., known as Japanese silver leaf, is native to Japan, Korea, and Taiwan. It is grown as an ornamental plant for garden plantings and containers not only in East Asia but more recently also in Europe and North America. Since 2003, powdery mildew infections of F. japonicum ‘Gigantea’ have been consistently found in the southern part of Korea, including the districts of Jeju, Seogwipo, Busan, Wando, and Ulleungdo. Specimens have been deposited in the Korea University Herbarium (KUS). Signs of powdery mildew first appeared as circular to irregular white patches on both sides of the leaves. The infections were usually severe on young leaves and caused malformation and browning. Appressoria on the mycelium were nipple-shaped or nearly absent. Conidiophores, measuring 160 to 280 × 10 to 12.5 μm, were simple and produced 2 to 12 immature conidia in chains, followed by 2 to 3 cells. Foot-cells in conidiophores were relatively short, 50 to 95 μm long, and constricted at the base. Conidia were hyaline, ellipsoid to ovate, 32 to 48 × 17.5 to 25 μm (length/width ratio = 1.4 to 2.3), had distinct fibrosin bodies, and produced germ tubes on the lateral position. No chasmothecia were observed. The morphology and dimentions of reproductive structures were compatible with those of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (1). To confirm the identity of the causal fungus, the complete ITS region of rDNA from isolate KUS-F26469 was amplified with primers ITS5 and P3 (4) and directly sequenced. The resulting sequence of 475 bp was deposited in GenBank (Accession No. KC155426). A GenBank BLAST search of this sequence revealed 100% identity (475/475 bp) with those of many P. fusca isolates on plants in the Aster family plants including Calendula officinalis, Euryops pectinatus, Syneilesis palmata, and F. japonicum from Japan (e.g., AB040346). The P. fusca isolates listed above are now placed in P. xanthii (1). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of three healthy potted plants of the same cultivar. Three non-inoculated plants served as controls. Plants were maintained in a greenhouse at 25 ± 2°C. Inoculated plants developed typical signs and symptoms of powdery mildew after 8 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that originally observed on diseased plants. Powdery mildew infections of F. japonicum caused by P. fusca (syn. P. fuliginea) have been reported previously in both Japan and Korea (2). In Korea, it was listed simply as a host fungus of Ampelomyces quisqualis, which is hyperparasitic to powdery midlews, without any data on its identity (3). To our knowledge, this is the first confirmed report of powdery mildew caused by P. xanthii on F. japonicum in Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 14, 2012. (3) M. J. Park et al. Fungal Biol. 114:235, 2010. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

scholarly journals First report of powdery mildew caused by Podosphaera xanthii on Cucurbita maxima in Korea

2019 ◽  
Vol 102 (2) ◽  
pp. 599-599 ◽  
Author(s):  
In-Young Choi ◽  
Young-Joon Choi ◽  
Hyeon-Dong Shin
Keyword(s):  
Powdery Mildew ◽  
Podosphaera Xanthii ◽  
Cucurbita Maxima ◽  
First Report

scholarly journals First Report of Powdery Mildew Caused by Podosphaera xanthii on Cucumis dipsaceus in China

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 985-985
Author(s):  
Xuewen Xu ◽  
Xueli Liu ◽  
Ming Tan ◽  
Xiaohua Qi ◽  
Qiang Xu ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Podosphaera Xanthii ◽  
First Report

scholarly journals First report of Podosphaera xanthii causing powdery mildew on Xanthium strumarium in India

2018 ◽  
Vol 100 (1) ◽  
pp. 129-129
Author(s):  
Sachin Vasantrao Thite ◽  
Basavaraj A. Kore ◽  
Moisés Camacho-Tapia ◽  
Juan Manuel Tovar-Pedraza
Keyword(s):  
Powdery Mildew ◽  
Xanthium Strumarium ◽  
Podosphaera Xanthii ◽  
First Report

scholarly journals First Report of Powdery Mildew Caused by Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii on Papaya in Taiwan

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1188-1188 ◽  
Author(s):  
J.-G. Tsay ◽  
R.-S. Chen ◽  
H.-L. Wang ◽  
W.-L. Wang ◽  
B.-C. Weng
Keyword(s):  
Powdery Mildew ◽  
Morphological Characteristics ◽  
Its Region ◽  
Podosphaera Xanthii ◽  
Oidium Neolycopersici ◽  
First Report ◽  
Plastic Bags ◽  
The World ◽  
Golovinomyces Cichoracearum ◽  
Powdery Mildew Fungi

Powdery mildew can be found in most papaya (Carica papaya L.) fields during the winter and spring seasons in Taiwan. It usually causes severe yellowing of the leaf lamina and petiole and serious defoliation. Three types of powdery mildew fungi were isolated from papaya leaves in Chiayi City (23.28°N, 120.28°E) at the beginning of 2008. Conidia of the first one were single, globose, hyaline, and 24 to 36 × 14 to 18 μm (average 30.2 × 15.6 μm) without fibrosin bodies and with straight or occasionally flexuous conidiophores at the base. The second one had short pseudo-chains of two to four conidia which were ellipsoidal to ovoid, hyaline, and 24 to 40 × 12 to 16 μm (average 29.7 × 13.4 μm) without fibrosin bodies. The third type had chains of ellipsoidal conidia that were hyaline, 24 to 28 × 12 to 16 μm (average 26.3 × 14.4 μm) and contained fibrosin bodies. To confirm the identity of the three fungi, the internal transcribed spacer (ITS) region of rDNA was amplified using the primer pairs G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/Ed2 (5′-CGC GTA GAG CCC ACG TCG GA-3′), G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/On2 (5′-TGT GAT CCA TGT GAC TGG AA-3′), and S1 (5′-GGA TCA TTA CTG AGC GCG AGG CCC CG-3′)/S2 (5′-CGC CGC CCT GGC GCG AGA TAC A-3′). The alignment of obtained sequences (GenBank Accession Nos. GU358452, 507 bp; GU358451, 580 bp; and GU358450, 455 bp) showed a sequence identity of 100, 99, and 99% with the ITS sequences of Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii (GenBank Accession Nos. FJ378880, EU909694, and GQ927254), respectively. On the basis of morphological characteristics and ITS sequence similarities, these fungi were identified as E. diffusa (Cooke & Peck) U. Braun & S. Takam., O. neolycopersici L. Kiss, and P. xanthii (Castagne) U. Braun & S. Takam., respectively (1,3). Single colonies on papaya leaves infected with powdery mildew were identified in the laboratory and maintained on papaya leaves as inoculum. Pathogenicity was confirmed through inoculations by gently pressing a single colony of each fungus onto leaves of healthy papaya seedlings (cv. Horng-Fe). Five seedlings were inoculated for each fungus and then covered with plastic bags for 2 days. Five noninoculated seedlings served as control. After inoculation, treated plants were maintained separately from the control in different rooms of a greenhouse at 25°C under natural daylight conditions. Seven days after inoculation, typical symptoms of powdery mildew were observed on inoculated plants, but not on noninoculated plants. The same species from diseased lesions following artificial inoculation with each fungus were identified with light microscopy. Papaya was previously described as a host to O. caricae Noack in many tropical and subtropical areas of the world including Taiwan (2). However E. cruciferarum, Golovinomyces cichoracearum, Oidiopsis sicula, O. caricae, O. caricae-papayae, O. caricicola, O. indicum, O. papayae, Ovulariopsis papayae, P. caricae-papayae, P. macularis, P. xanthii, and Streptopodium caricae were reported to infect papaya (4). To our knowledge, this is the first report of papaya powdery mildew caused by E. diffusa and O. neolycopersici in the world and the first report of the three fungi found on papaya in Taiwan. References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (2) H. S. Chien and H. L. Wang. J. Agric. Res. China 33:320, 1984. (3) L. Kiss et al. Mycol. Res. 105:684, 2001. (4) J. R. Liberato et al. Mycol. Res. 108:1185, 2004.

scholarly journals First report of the powdery mildew Podosphaera xanthii on Gynura bicolor

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuan-Min Shen ◽  
Tung-Chin Huang ◽  
Hsing-Lung Liu ◽  
Chia-Hung Chao
Keyword(s):  
Powdery Mildew ◽  
Podosphaera Xanthii ◽  
First Report ◽  
Gynura Bicolor
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