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Song W, Yin Z, Lu X, Shen D, Dou D. Plant secondary metabolite citral interferes with Phytophthora capsici virulence by manipulating the expression of effector genes. Mol Plant Pathol 2023; 24:932-946. [PMID: 37092279 PMCID: PMC10346372 DOI: 10.1111/mpp.13340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/14/2023] [Accepted: 04/02/2023] [Indexed: 05/03/2023]
Abstract
Phytophthora capsici is a notorious pathogen that infects various economically important plants and causes serious threats to agriculture worldwide. Plants deploy a variety of plant secondary metabolites to fend off pathogen attacks, but the molecular mechanisms are largely unknown. In this study, we screened 11 plant secondary metabolites to evaluate their biofumigation effects against P. capsici, and found that citral, carvacrol, and trans-2-decenal exhibited strong antimicrobial effects. Intriguingly, a low concentration of citral was effective in restricting P. capsici infection in Nicotiana benthamiana, but it was unable to inhibit the mycelial growth. A high concentration of citral affected the mycelial growth and morphology, zoospore germination, and cell membrane permeability of P. capsici. Further investigations showed that citral did not induce expression of tested plant immunity-related genes and reactive oxygen species (ROS) production, suggesting that a low concentration of citral could not trigger plant immunity. Moreover, RNA-Seq analysis showed that citral treatment regulated the expression of some P. capsici effector genes such as RxLR genes and P. cactorum-fragaria (PCF)/small cysteine-rich (SCR)74-like genes during the infection process, which was also verified by reverse transcription-quantitative PCR assay. Five candidate effector genes suppressed by citral significantly facilitated P. capsici infection in N. benthamiana or inhibited ROS triggered by flg22, suggesting that they were virulence factors of P. capsici. Together, our results revealed that plant-derived citral exhibited excellent inhibitory efficacy against P. capsici by suppressing vegetative growth and manipulating expression of effector genes, which provides a promising application of citral for controlling Phytophthora blight.
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Affiliation(s)
- Wen Song
- Department of Plant PathologyNanjing Agricultural UniversityNanjingChina
| | - Zhiyuan Yin
- Department of Plant PathologyNanjing Agricultural UniversityNanjingChina
| | - Xinyu Lu
- Institute of BotanyJiangsu Province and Chinese Academy of SciencesNanjingChina
| | - Danyu Shen
- Department of Plant PathologyNanjing Agricultural UniversityNanjingChina
| | - Daolong Dou
- Department of Plant PathologyNanjing Agricultural UniversityNanjingChina
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Sanogo S, Lamour K, Kousik CS, Lozada DN, Parada-Rojas CH, Quesada-Ocampo LM, Wyenandt CA, Babadoost M, Hausbeck MK, Hansen Z, Ali E, McGrath MT, Hu J, Crosby K, Miller SA. Phytophthora capsici, 100 Years Later: Research Mile Markers from 1922 to 2022. Phytopathology 2023; 113:921-930. [PMID: 36401843 DOI: 10.1094/phyto-08-22-0297-rvw] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In 1922, Phytophthora capsici was described by Leon Hatching Leonian as a new pathogen infecting pepper (Capsicum annuum), with disease symptoms of root rot, stem and fruit blight, seed rot, and plant wilting and death. Extensive research has been conducted on P. capsici over the last 100 years. This review succinctly describes the salient mile markers of research on P. capsici with current perspectives on the pathogen's distribution, economic importance, epidemiology, genetics and genomics, fungicide resistance, host susceptibility, pathogenicity mechanisms, and management.
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Affiliation(s)
- Soum Sanogo
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
| | - Kurt Lamour
- Department of Entomology and Plant Pathology, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996
| | - Chandrasekar S Kousik
- U.S. Vegetable Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Charleston, SC 29414
| | - Dennis N Lozada
- Department of Plant and Environmental Sciences and Chile Pepper Institute, New Mexico State University, Las Cruces, NM 88003
| | - Camilo H Parada-Rojas
- Department of Entomology and Plant Pathology, NC Plant Sciences Initiative, North Carolina State University, Raleigh, NC 27695
| | - Lina M Quesada-Ocampo
- Department of Entomology and Plant Pathology, NC Plant Sciences Initiative, North Carolina State University, Raleigh, NC 27695
| | - Christian A Wyenandt
- Department of Plant Biology, Rutgers University, Rutgers Agricultural Research and Extension Center, Bridgeton, NJ 08302
| | | | - Mary K Hausbeck
- Department of Soil, Plant, and Microbial Sciences, Michigan State University, East Lansing, MI 48824
| | - Zachariah Hansen
- Department of Entomology and Plant Pathology, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996
| | - Emran Ali
- Department of Agriculture, Nutrition, and Food Systems, University of New Hampshire, Durham, NH 03824
| | - Margaret T McGrath
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Long Island Horticultural Research and Extension Center, Riverhead, NY 11901
| | - Jiahuai Hu
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721
| | - Kevin Crosby
- Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843
| | - Sally A Miller
- Department of Plant Pathology, The Ohio State University, Wooster, OH 44691
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Ro N, Haile M, Hur O, Geum B, Rhee J, Hwang A, Kim B, Lee J, Hahn BS, Lee J, Kang BC. Genome-Wide Association Study of Resistance to Phytophthora capsici in the Pepper ( Capsicum spp.) Collection. Front Plant Sci 2022; 13:902464. [PMID: 35668797 PMCID: PMC9164128 DOI: 10.3389/fpls.2022.902464] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
One of the most serious pepper diseases is Phytophthora blight, which is caused by Phytophthora capsici. It is crucial to assess the resistance of pepper genetic resources to Phytophthora blight, understand the genetic resistances, and develop markers for selecting resistant pepper materials in breeding programs. In this study, the resistance of 342 pepper accessions to P. capsici was evaluated. The disease severity score method was used to evaluate the phenotypic responses of pepper accessions inoculated with the KCP7 isolate. A genome-wide association study (GWAS) was performed to identify single nucleotide polymorphisms (SNPs) linked to P. capsici (isolate KCP7) resistance. The pepper population was genotyped using the genotype-by-sequencing (GBS) method, and 45,481 SNPs were obtained. A GWAS analysis was performed using resistance evaluation data and SNP markers. Significantly associated SNPs for P. capsici resistance at 4 weeks after inoculation of the GWAS pepper population were selected. These SNPs for Phytophthora blight resistance were found on all chromosomes except Chr.05, Chr.09, and Chr.11. One of the SNPs found on Chr.02 was converted into a high-resolution melting (HRM) marker, and another marker (QTL5-1) from the previous study was applied to pepper accessions and breeding lines for validation and comparison. This SNP marker was selected because the resistance phenotype and the HRM marker genotype matched well. The selected SNP was named Chr02-1126 and was located at 112 Mb on Chr.02. The Chr02-1126 marker predicted P. capsici resistance with 78.5% accuracy, while the QTL5-1 marker predicted resistance with 80.2% accuracy. Along with the marker for major quantitative traits loci (QTLs) on Chr.05, this Chr02-1126 marker could be used to accurately predict Phytophthora blight resistance in pepper genetic resources. Therefore, this study will assist in the selection of resistant pepper plants in order to breed new phytophthora blight-resistant varieties.
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Affiliation(s)
- Nayoung Ro
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
- Department of Plant Science and Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
| | - Mesfin Haile
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Onsook Hur
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Bora Geum
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Juhee Rhee
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Aejin Hwang
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Bitsam Kim
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Jeaeun Lee
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Bum-Soo Hahn
- National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea
| | - Jundae Lee
- Department of Horticulture, Chonbuk National University, Jeonju, South Korea
| | - Byoung-Cheorl Kang
- Department of Plant Science and Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
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Asekova S, Oh E, Kulkarni KP, Siddique MI, Lee MH, Kim JI, Lee JD, Kim M, Oh KW, Ha TJ, Kim SU, Cho KS. An Integrated Approach of QTL Mapping and Genome-Wide Association Analysis Identifies Candidate Genes for Phytophthora Blight Resistance in Sesame ( Sesamum indicum L.). Front Plant Sci 2021; 12:604709. [PMID: 33664756 PMCID: PMC7920980 DOI: 10.3389/fpls.2021.604709] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/11/2021] [Indexed: 05/05/2023]
Abstract
Phytophthora blight (PB) caused by Phytophthora nicotianae is a highly destructive disease in sesame (Sesamum indicum L.). In this study, we used linkage mapping and genome-wide association study (GWAS) to identify quantitative trait loci (QTL) and candidate genes associated with PB resistance. The QTL mapping in 90 RILs of the Goenbaek × Osan cross using genotyping-by-sequencing detected significant QTLs for PB resistance on chromosome 10, explaining 12.79%-13.34% of phenotypic variation. Association of this locus to PB resistance was also revealed through bulked segregant analysis in second RIL population (Goenbaek × Milsung cross) comprising 188 RILs. The GWAS of 87 sesame accessions evaluated against three P. nicotianae isolates identified 29 SNPs on chromosome 10 significantly associated with PB resistance. These SNPs were located within a 0.79 Mb region, which co-located with the QTL intervals identified in RIL populations, and hence scanned for identifying candidate genes. This region contained several defense-related candidate R genes, five of which were selected for quantitative expression analysis. One of these genes, SIN_1019016 was found to show significantly higher expression in the resistant parent compared to that in the susceptible parents and selected RILs. Paired-end sequencing of the gene SIN_1019016 in parental cultivars revealed two synonymous SNPs between Goenbaek and Osan in exon 2 of coding DNA sequence. These results suggested SIN_1019016 as one of the candidate gene conferring PB resistance in sesame. The findings from this study will be useful in the marker-assisted selection as well as the functional analysis of PB resistance candidate gene(s) in sesame.
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Affiliation(s)
- Sovetgul Asekova
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | - Eunyoung Oh
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | | | - Muhammad Irfan Siddique
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Myoung Hee Lee
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | - Jung In Kim
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | - Jeong-Dong Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Minsu Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Ki-Won Oh
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | - Tae-Joung Ha
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | - Sung-Up Kim
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
| | - Kwang-Soo Cho
- Department of Southern Area Crop Science, National Institute of Crop Science, RDA, Miryang-si, South Korea
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Jeong JJ, Sang MK, Lee DW, Choi IG, Kim KD. Chryseobacterium phosphatilyticum sp. nov., a phosphate-solubilizing endophyte isolated from cucumber (Cucumis sativus L.) root. Int J Syst Evol Microbiol 2018; 69:610-615. [PMID: 30372407 DOI: 10.1099/ijsem.0.003091] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A bacterial strain, designated as ISE14T, with Gram-stain-negative and non-motile rod-shaped cells, was isolated from the root of a cucumber plant collected in a field in Iksan, Republic of Korea and was characterized using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ISE14T represented a member of the genus Chryseobacterium and was closely related to Chryseobacterium viscerum 687B-08T (16S rRNA gene sequence similarity of 98.50 %), Chryseobacterium lactis NCTC 11390T (98.49 %), Chryseobacterium ureilyticum F-Fue-04IIIaaaaT (98.49 %) and Chryseobacterium oncorhynchi 701B-08T (98.04 %). Average nucleotide identity values between genome sequences of strain ISE14T and the closely related species ranged from 81.44 to 83.15 %, which were lower than the threshold of 95 % (corresponding to a DNA-DNA hybridization value of 70 %). The DNA G+C content of strain ISE14T was 36.3 mol%. The dominant fatty acids were iso-C15 : 0, summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl), summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, three unidentified aminolipids and eight unidentified lipids; the predominant respiratory quinone was MK-6. On the basis of the evidence presented in this study, strain ISE14T can be distinguished from closely related species belonging to the genus Chryseobacterium. Thus, strain ISE14T is a novel species of the genus Chryseobacterium, for which the name Chryseobacteriumphosphatilyticum sp. nov. is proposed. The type strain is ISE14T (=KACC 19820T=JCM 32876T).
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Affiliation(s)
- Jin-Ju Jeong
- 1Department of Biosystems and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Mee Kyung Sang
- 1Department of Biosystems and Biotechnology, Korea University, Seoul, Republic of Korea.,2Division of Agricultural Microbiology, National Academy of Agricultural Science, Rural Development Administration, Wanju, Republic of Korea
| | - Dong Wan Lee
- 1Department of Biosystems and Biotechnology, Korea University, Seoul, Republic of Korea
| | - In-Geol Choi
- 3Department of Biotechnology, Korea University, Seoul, Republic of Korea
| | - Ki Deok Kim
- 1Department of Biosystems and Biotechnology, Korea University, Seoul, Republic of Korea
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Balaraju K, Kim CJ, Park DJ, Nam KW, Zhang K, Sang MK, Park K. Paromomycin Derived from Streptomyces sp. AG-P 1441 Induces Resistance against Two Major Pathogens of Chili Pepper. J Microbiol Biotechnol 2016; 26:1542-50. [PMID: 27291677 DOI: 10.4014/jmb.1603.03019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
This is the first report that paromomycin, an antibiotic derived from Streptomyces sp. AG-P 1441 (AG-P 1441), controlled Phytophthora blight and soft rot diseases caused by Phytophthora capsici and Pectobacterium carotovorum, respectively, in chili pepper (Capsicum annum L.). Chili pepper plants treated with paromomycin by foliar spray or soil drenching 7 days prior to inoculation with P. capsici zoospores showed significant (p < 0.05) reduction in disease severity (%) when compared with untreated control plants. The disease severity of Phytophthora blight was recorded as 8% and 50% for foliar spray and soil drench, respectively, at 1.0 ppm of paromomycin, compared with untreated control, where disease severity was 83% and 100% by foliar spray and soil drench, respectively. A greater reduction of soft rot lesion areas per leaf disk was observed in treated plants using paromomycin (1.0 μg/ml) by infiltration or soil drench in comparison with untreated control plants. Paromomycin treatment did not negatively affect the growth of chili pepper. Furthermore, the treatment slightly promoted growth; this growth was supported by increased chlorophyll content in paromomycin-treated chili pepper plants. Additionally, paromomycin likely induced resistance as confirmed by the expression of pathogenesis-related (PR) genes: PR-1, β-1,3-glucanase, chitinase, PR-4, peroxidase, and PR-10, which enhanced plant defense against P. capsici in chili pepper. This finding indicates that AG-P 1441 plays a role in pathogen resistance upon the activation of defense genes, by secretion of the plant resistance elicitor, paromomycin.
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Affiliation(s)
- Kotnala Balaraju
- Microbial Plant Activation Laboratory, Agricultural Microbiology Division, National Academy of Agricultural Science (NAAS), RDA, Jeonju 55365, Republic of Korea
| | - Chang-Jin Kim
- Korean Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Dong-Jin Park
- Korean Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Ki-Woong Nam
- Department of Horticulture, Hankyung National University, Ansung 17579, Republic of Korea
| | - Kecheng Zhang
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, P.R. China
| | - Mee Kyung Sang
- Microbial Plant Activation Laboratory, Agricultural Microbiology Division, National Academy of Agricultural Science (NAAS), RDA, Jeonju 55365, Republic of Korea
| | - Kyungseok Park
- Microbial Plant Activation Laboratory, Agricultural Microbiology Division, National Academy of Agricultural Science (NAAS), RDA, Jeonju 55365, Republic of Korea
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Jiang L, Wang H, Xu H, Qiao K, Xia X, Wang K. Transportation behaviour of fluopicolide and its control effect against Phytophthora capsici in greenhouse tomatoes after soil application. Pest Manag Sci 2015; 71:1008-1014. [PMID: 25132333 DOI: 10.1002/ps.3879] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 07/14/2014] [Accepted: 08/07/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Fluopicolide, a novel benzamide fungicide, was registered for control of oomycete pathogens, including Phytophthora capsici. In this study, fluopicolide (5% SC) was applied in soil at rates of 1.5, 3 and 6 L ha(-1) [the normal (ND), double (DD) and quadruple dosages (QD) respectively] to investigate its transportation behaviour and control efficiency on tomato blight as a soil treatment agent. RESULTS The results showed that fluopicolide applied to soil could be absorbed by tomato roots and then transplanted to stems and leaves. It could exist in tomato roots for more than 30 days, and in leaves and stems until day 20 after application. The decline in fluopicolide in soil was in accordance with a first-order dynamics equation, with half-lives of 5.33, 4.75 and 5.42 days for the ND, DD and QD treatments respectively. The control efficiencies of fluopicolide were better with soil application than with spraying application, and the inhibition ratios were 93.02, 97.67 and 100 on day 21 for the ND, DD and QD treatments respectively. CONCLUSION Soil application of fluopicolide could control P. capsici in greenhouse tomatoes with high efficiency and long persistence.
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Affiliation(s)
- Lili Jiang
- Department of Plant Protection, Shandong Agricultural University, Tai'an, Shandong, China
| | - Hongyan Wang
- Cotton Research Centre, Shandong Academy of Agricultural Sciences, Ji'nan, Shandong, China
| | - Hui Xu
- Shandong United Pesticide Industry Co. Ltd, Ji'nan, Shandong, China
| | - Kang Qiao
- Department of Plant Protection, Shandong Agricultural University, Tai'an, Shandong, China
| | - Xiaoming Xia
- Department of Plant Protection, Shandong Agricultural University, Tai'an, Shandong, China
| | - Kaiyun Wang
- Department of Plant Protection, Shandong Agricultural University, Tai'an, Shandong, China
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Pavón CF, Babadoost M, Lambert KN. Quantification of Phytophthora capsici Oospores in Soil by Sieving-Centrifugation and Real-Time Polymerase Chain Reaction. Plant Dis 2008; 92:143-149. [PMID: 30786362 DOI: 10.1094/pdis-92-1-0143] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A procedure was developed to quantify Phytophthora capsici oospores in soil by combining a sieving-centrifugation method and a real-time quantitative polymerase chain reaction (QPCR) assay. Five soil samples representing three different soil textures were infested with oospores of P. capsici to produce 101, 102, 103, 104, or 105 spores per 10 g of air-dried soil. Each 10-g sample of infested soil was suspended in 400 ml of water and then passed through 106-, 63-, and 38-μm metal sieves. The filtrate was then passed through a 20-μm mesh filter. Materials caught on the filter were washed with water into two 50-ml centrifuge tubes and spun for 4 min (900 × g). The pellet was suspended in 30 ml of 1.6 M sucrose solution and centrifuged for 45 s (190 × g). The supernatant was passed through the 20-μm mesh filter. The sucrose extraction process of oospores was repeated five times to maximize oospore extraction. Materials caught on the 20-μm mesh filter were washed with water into a 50-ml tube and spun for 4 min (900 × g). The pellet was suspended in 1 ml of water, and the number of oospores was determined with a haemocytometer. The relationship between number of oospores recovered from the soil and number of oospores incorporated into the soil was Ŷ = -0.95 + 1.31X - 0.03X2 (R2 = 0.98), in which Ŷ = log10 of number of oospores recovered from the soil and X = log10 of number of oospores incorporated into the soil. The oospores were germinated after treatment with 0.1% KMnO4 solution for 10 min to induce germination. On the basis of the detection of ribosomal DNA, a QPCR method for P. capsici oospores was developed. PCR inhibitors were eliminated by extracting oospores from the soil by sieving-centrifugation. DNA was extracted and quantified from P. capsici oospores with suspensions of 101, 101.5, 102, 102.5, 103, 103.5, 104, 104.5, and 105 oospores per ml of water. The relationship between the DNA quantities and number of P. capsici oospores was Ŷ = -3.57 - 0.54X + 0.30X2 (R2 = 0.93), in which Ŷ = log10 (nanogram of P. capsici DNA) and X = log10 (number of oospores). The relationship between the quantity of DNA of P. capsici oospores recovered from the soil and the number of oospores incorporated into the soil was determined by Ŷ = -3.53 - 0.73X + 0.32X2 (R2 = 0.955, P < 0.05), in which Ŷ = log10 (DNA quantity of P. capsici oospores recovered from the soil) and X = log10 (number of P. capsici oospores incorporated into the soil). Utilizing the sieving-centrifugation and QPCR methods, oospores of P. capsici were quantified in soil samples collected from commercial fields.
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Affiliation(s)
- C F Pavón
- Department of Crop Sciences, University of Illinois, Urbana, 61801
| | - M Babadoost
- Department of Crop Sciences, University of Illinois, Urbana, 61801
| | - K N Lambert
- Department of Crop Sciences, University of Illinois, Urbana, 61801
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French-Monar RD, Jones JB, Roberts PD. Characterization of Phytophthora capsici Associated with Roots of Weeds on Florida Vegetable Farms. Plant Dis 2006; 90:345-350. [PMID: 30786560 DOI: 10.1094/pd-90-0345] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Weeds were sampled in commercial vegetable fields in Palm Beach County, FL in August 2001, December 2001, and March 2002 for the presence of Phytophthora capsici. Fields sampled had a recent history of this plant pathogen. P. capsici was successfully isolated from the roots of six of 42 Carolina geranium (Geranium carolinianum) plants, four of 28 American black nightshade (Solanum americanum) plants, and two of 130 common purslane (Portulaca oleracea) plants. All but one of the 12 isolates were of the A1 mating type. All 12 isolates were resistant to mefenoxam, although at different levels. All but one isolate were strongly pathogenic on pepper seedlings. When two or three isolates recovered from each weed were inoculated onto the roots of their weed host of origin, P. capsici was recovered from the roots. Isolates of P. capsici were tested on four other solanaceous weeds of importance or potential importance to agricultural fields in Florida: Solanum nigrum, S. ptycanthum, S. carolinense, and S. capsicoides. Recovery of P. capsici from roots varied with weed species and isolate tested. P. capsici caused disease mortality on S. nigrum, and no reisolation of P. capsici was possible with S. capsicoides. This is the first report of S. americanum and G. carolinianum being alternative hosts for P. capsici under field conditions. This study also validated P. oleracea as an alternative host. In Florida, and perhaps elsewhere, weeds may contribute to pathogen survival in the absence of a host crop or when propagules may not readily survive in soil or plant debris.
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Affiliation(s)
- Ronald D French-Monar
- University of Florida-IFAS, Plant Pathology Department, Southwest Florida Research & Education Center, 2686 State Road 29 North, Immokalee 34142-9515
| | - Jeffrey B Jones
- University of Florida-IFAS, Plant Pathology Department, Gainesville 32611-0680
| | - Pamela D Roberts
- University of Florida-IFAS, Plant Pathology Department, Southwest Florida Research & Education Center, 2686 State Road 29 North, Immokalee 34142-9515
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Islam SZ, Babadoost M, Lambert KN, Ndeme A, Fouly HM. Characterization of Phytophthora capsici Isolates from Processing Pumpkin in Illinois. Plant Dis 2005; 89:191-197. [PMID: 30795223 DOI: 10.1094/pd-89-0191] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This study was conducted to investigate pathogenic, morphologic, and genetic variations among Phytophthora capsici isolates from processing pumpkin (Cucurbita moschata) fields in Illinois. Random amplified polymorphic DNA (RAPD) markers were employed to assess genetic variation among 24 isolates of P. capsici from 10 individual fields at six locations. Unweighted mean pair group analysis clustered isolates into six groups. The genetic distances ranged from 0.03 to 0.45. Inoculation of pumpkin seedlings in the greenhouse revealed that the isolates belonged to six distinct genetic groups differing significantly (P = 0.05) in virulence. Isolates tested exhibited four growth patterns in culture: cottony, rosaceous, petaloid, and stellate. P. capsici isolates, including an ATCC isolate (ATCC-15427), with cottony growth pattern did not grow at 36°C. The mean oospore diameter of A1 mating type isolates was greater than that of A2 mating type isolates. Nine of 24 isolates tested produced chlamydospores in V8-CaCO3 liquid medium.
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Affiliation(s)
- S Z Islam
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - M Babadoost
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - K N Lambert
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - A Ndeme
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - H M Fouly
- Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana 61801
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Abstract
This study was conducted to determine the host range of Phytophthora capsici isolates from pumpkin and virulence of the isolates on pumpkin cultivars. The pathogenicity of P. capsici isolates from pumpkin was evaluated on 45 species of herbaceous plants, including 36 species of crops grown in rotation sequences with pumpkin and nine species of weeds that commonly grow in pumpkin fields in Illinois. Plants were grown in the greenhouse, and 4-week-old seedlings were inoculated by adding 5 ml of a zoospore suspension (2 × 105 spores per ml of water) onto the soil surface around the stem of each plant in the pot. Twenty-two crop species and two weed species became infected with P. capsici and developed symptoms. P. capsici was reisolated from all of the symptomatic plants by culturing tissues onto a semiselective medium (PARP). Also, P. capsici was detected in 87.5% of symptomatic plants by a polymerase chain reaction (PCR) method using PCAP and IT5 primers. Cucurbits and pepper were the most susceptible hosts of P. capsici. Five crop species or varieties, beet (Beta vulgaris), Swiss-chard (Beta vulgaris var. cicla), lima beans (Phaseolus lunatus), turnip (Brassica rapa), and spinach (Spinacia oleracea), and one weed species, velvet-leaf (Abutilon theophrasti), were found to be hosts of P. capsici for the first time. Six isolates of P. capsici were inoculated onto six pumpkin cultivars (three processing and three jack-o-lantern pumpkins) in the greenhouse and resulted in significant interactions between pathogen isolates and pumpkin types. P. capsici isolates were more virulent on jack-o-lantern pumpkins than on processing pumpkins.
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Affiliation(s)
- D Tian
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - M Babadoost
- Department of Crop Sciences, University of Illinois, Urbana 61801
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