Comparative analysis of infection process in Pima cotton differing in resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum race 4

Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) causes an early season cotton disease including seedling deaths. This study compared two Pima cottons (Gossypium barbadense) in the infection process of FOV4 using a confocal and a scanning electron microscope. Seedlings were grown in a hydroponic system and inoculated with a virulent local FOV4 isolate. As compared to the susceptible Pima S-7, the resistant Pima PHY 841 RF had significantly fewer conidia attached and germinated on the root surface. FOV4 penetration into the root epidermis of PHY 841 RF was delayed until 24 hours post-inoculation (hpi), as compared to 8 hpi in Pima S-7. In Pima S-7, hyphae progressed to the xylem through the cortex between 5 and 7 days post-inoculation. However, hyphae grew much slower in the cortex with no apparent hyphae observed in the xylem of PHY 841 RF. At plant maturity, no FOV4 was detected through fungal isolation and PCR in the stem of PHY 841 RF and its resistance donor parents PHY 800 and Pima S-6, as compared to Pima S-7 and DP 744 with positive results.

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Standardized bioassays: An improved method for studying Fusarium oxysporum f. sp. cubense race 4 (FocR4) pathogen stress response in Musa acuminata cv. ‘Berangan’

Asia Pacific Journal of Molecular Biology and Biotechnology ◽

10.35118/apjmbb.2019.027.3.10 ◽

2019 ◽

pp. 101-112

Author(s):

Yusmin Mohd-Yusuf ◽

Norzulaani Khalid ◽

Jameel R. Al-Obaidi ◽

Nadiya Akmal Baharum ◽

Kamilatulhusna Zaidi ◽

...

Keyword(s):

Fusarium Oxysporum ◽

Musa Acuminata ◽

Post Inoculation ◽

Molecular Approach ◽

Disease Response ◽

Pathogenesis Related ◽

Bioassay Experiment ◽

Infection Parameters ◽

Race 4 ◽

Leaf Symptoms

To date, there is no standardized Fusarium bioassay protocol established owing partly to the wide variety of Fusarium oxysporum f. sp. cubense (Foc) isolates and banana cultivars present. Thus, validation of the infection parameters is deemed essential prior to each bioassay experiment. In the current study, a simple standardized workflow was developed based on available assays for testing Fusarium wilt disease response in Musa acuminata using M. acuminata cv. ‘Berangan’ of tissue-culture origin as a model. The phenotypic assays were able to detect external disease symptoms less than one week post-inoculation, while the molecular approach using RT-qPCR identified differential expression of catalase (CAT), pathogenesis-related 10 (PR10), phenylalanine ammonia-lyase (PAL) and xylanase (XYL) genes as early as day 0. The transcript levels of PR10 and XYL fluctuated over 4 days of Foc Race 4 (FocR4 C1 HIR isolate) infection while the expression of CAT steadily increased over time. In contrast, PAL was highly upregulated at 2 days post-inoculation. These signature changes suggest that all genes tested might be involved in the early defense response of ‘Berangan’ plants against FocR4 infection. ‘Berangan’ cultivar was found to be highly susceptible to Foc Race 4 (C1 HIR isolate) with leaf symptoms index (LSI) and rhizome discoloration index (RDI) scores of 4.257 and 5.971, respectively. The procedure elaborated in this study can be used as a reference Foc bioassay for reproducible and comparable results possibly across cultivars and test isolates due to its simple steps aided by integration of phenotypic and molecular approach.

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Studies on Vascular Infection of Fusarium oxysporum f. sp. cubense Race 4 in Banana by Field Survey and Green Fluorescent Protein Reporter

International Journal of Phytopathology ◽

10.33687/phytopath.002.01.0064 ◽

2013 ◽

Vol 2 (1) ◽

pp. 44-51 ◽

Cited By ~ 1

Author(s):

Rong F. Xiao ◽

Yu-Jing Zhu ◽

Yan-Dan Li ◽

Bo Liu

Keyword(s):

Green Fluorescent Protein ◽

Fusarium Oxysporum ◽

Field Survey ◽

Fluorescent Protein ◽

Infection Process ◽

Gene Encoding ◽

Effective Prevention ◽

Green Fluorescent ◽

Banana Wilt ◽

Race 4

Fusarium wilt of banana (Musa spp.) caused by Fusarium oxysporum f. sp. cubense (Foc) is one of the most serious banana fungal diseases in the world. Understanding the infection process of Foc is important for development of effective ways in disease control. In order to follow infection and colonization of this pathogen from root to rhizome and pseudostem tissues of banana, a highly pathogenic strain FJAT-3076 of Foc race 4 (Foc4) was transformed with gene encoding green fluorescent protein (GFP) and the fungus carrying gfp (FJAT-3076-GFP) was used to inoculate banana plants (Cavendish cv. B.F.). After inoculation for 3 to 10 d, it was observed that the conidia and their germ-tubes had penetrated into epidermis of young roots. The hyphae were found inside the root xylem 10 d after inoculation in the rhizome and pseudostem xylem after inoculation for 17 d. All plants infected by Foc died in 24 d after inoculation. It was also observed that Foc had spread all over the xylem and part of hyphae reached the pseudostem surface. Hyphal population was found the highest in the pseudostem, lower in root and least in rhizome. Field survey confirmed that Foc4 were mostly present in the base of pseudostem and less in the rhizome. Thus, effective prevention of the Foc hyphae movement from the rhizome up to the pseudostem might delay or control banana wilt disease.

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Soil-free pathogenicity assay of Fusarium oxysporum f.sp. vasinfectum race 4 on Pima cotton (Gossypium barbadense) seedlings

10.1101/2021.04.01.438137 ◽

2021 ◽

Author(s):

Won Bo Shim ◽

Lia D Murty

Keyword(s):

Fusarium Oxysporum ◽

Fusarium Wilt ◽

Gossypium Barbadense ◽

Small Scale ◽

Post Inoculation ◽

Common Symptom ◽

Symptom Development ◽

Pima Cotton ◽

Recent Emergence ◽

Race 4

One of the key early season diseases of cotton is Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum (Fov). Recent emergence of highly virulent Fov race 4 (Fov4) and its aggressiveness toward Gossypium barbadense (pima) cultivars are raising significant concerns for the US cotton industry. One of the key challenges in studying Fov4 virulence and cotton Fusarium wilt pathogenesis is establishing a disease assay strategy that can help researcher overcome several technical challenges, including efficient infection and highly reproducible and consistent symptom development. Here, we have developed a small-scale, soil-free Fusarium wilt disease assay that can complement conventional assays with faster symptom development and high reproducibility in infected pima cotton seedlings. Our data showed statistically significant differences (p<0.0001) between Fov4-infected and non-infected pima cotton at 4 and 6 days post inoculation (dpi) when compared to control experiments. At 6 dpi, longitudinal observations under magnification showed Fov4 colonization in primary xylem of infected plants, which is a common symptom observed in Fov4 triggered Fusarium wilt in pima cotton. While this is an artificial assay system, this soil-free disease testing strategy can offer another strategy to supplement current assays when studying pathogen-host interaction in soil-borne diseases.

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Detection and characterization of Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) race 4 causing Fusarium wilt of cotton seedlings in New Mexico, USA

Plant Disease ◽

10.1094/pdis-10-20-2174-re ◽

2021 ◽

Author(s):

Yi Zhu ◽

Abdelraheem Abdelraheem ◽

Phillip A. Lujan ◽

John Idowu ◽

Patrick Sullivan ◽

...

Keyword(s):

New Mexico ◽

Fusarium Oxysporum ◽

Fusarium Wilt ◽

Post Inoculation ◽

Cotton Production ◽

Fusarium Spp ◽

Progress Curve ◽

Cotton Fields ◽

Cotton Belt ◽

Race 4

Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. vasinfectum (Atk.) W.C. Snyder & H.N. Hans (FOV), is one of the most destructive diseases in cotton (Gossypium spp.) worldwide. FOV race 4 (FOV4) is a highly virulent nominal race of this pathogen and is a significant threat to cotton production in the western and southwestern US and potentially the entire Cotton Belt. A field survey in three southern counties of New Mexico was conducted in 619 cotton fields in 2018-2020 to identify FOV4. From 132 samples of cotton plants that exhibited wilt symptoms, Fusarium spp. were the most frequently isolated group of fungal species with an isolation frequency of 57.4%. Eighty-four Fusarium spp. isolates were subsequently characterized by a DNA sequence analysis of three genes, EF-1α, PHO and BT encoding for translation elongation factor, phosphate permease and β-tubulin, respectively. Forty-two isolates were identified to be FOV4 from 10 cotton fields and confirmed with a positive 500 bp fragment that is diagnostic for FOV4. Twenty-six (62%) of the 42 FOV4 isolates were T type and the remainder (38%) were Null type with and without a Tfo1 insertion in PHO, respectively; and each FOV4-infested field contained the same FOV4 genotype. Ten representative FOV4 isolates with one each from the 10 FOV4-infested fields were evaluated for their pathogenicity on resistant Pima PHY 841 RF and susceptible Upland PHY 725 RF at 7, 14, 21, and 28 days post inoculation under temperature-controlled conditions at 21-22°C. Based on disease severity rating (DSR), mortality rate (MR) and the area under the disease progress curve (AUDPC) value, all the 10 isolates were pathogenic to both cotton cultivars and differed in virulence in that four isolates of the T genotype as a whole were more virulent than the six isolates of the N genotype. PHY 841 RF had significantly higher levels of resistance than PHY 725 RF to all FOV4 isolates. The results provide the first comprehensive account of the occurrence, distribution and virulence of FOV4 in cotton production in New Mexico and will be useful in developing an effective strategy to manage FW in both the state of New Mexico and entire southwestern Cotton Belt.

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Effects of Fusarium oxysporum f. sp. cubense race 4 on microorganisms and enzyme activities in the rhizosphere soil of banana

JOURNAL OF HUNAN AGRICULTURAL UNIVERSITY ◽

10.3724/sp.j.1238.2012.00173 ◽

2013 ◽

Vol 38 (2) ◽

pp. 173-176 ◽

Cited By ~ 1

Author(s):

Yong-hong HUANG ◽

Shun LÜ ◽

Chun-yu LI ◽

Yue-rong WEI ◽

Gan-jun YI

Keyword(s):

Fusarium Oxysporum ◽

Enzyme Activities ◽

Rhizosphere Soil ◽

Race 4

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Cytological and histochemical characteristics of the axenic root surface of Alnus glutinosa

Canadian Journal of Botany ◽

10.1139/b86-296 ◽

1986 ◽

Vol 64 (10) ◽

pp. 2216-2226 ◽

Cited By ~ 9

Author(s):

Yves Prin ◽

Mireille Rougier

Keyword(s):

Cell Wall ◽

Root Hair ◽

Root Hairs ◽

Root Apex ◽

Alnus Glutinosa ◽

Root Surface ◽

Infection Process ◽

Root Cap ◽

A Cell ◽

Histochemical Tests

The aim of the present study was to investigate the Alnus root surface using seedlings grown axenically. This study has focused on root zones where infection by the symbiotic actinomycete Frankia takes place. The zones examined extend from the root cap to the emerging root hair zone. The root cap ensheaths the Alnus root apex and extends over the root surface as a layer of highly flattened cells closely appressed to the root epidermal cell wall. These cells contain phenolic compounds as demonstrated by various histochemical tests. They are externally bordered by a thin cell wall coated by a thin mucilage layer. The root cap is ruptured when underlying epidermal cells elongate, and cell remnants are still found in the emerging root hair zone. Young emerging root hairs are bordered externally by a cell wall covered by a thin mucilage layer which reacts positively to the tests used for the detection of polysaccharides, glycoproteins, and anionic sites. The characteristics of the Alnus root surface and the biological function of mucilage and phenols present at the root surface are discussed in relation to the infection process.

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First Report of Fusarium Wilt on Cavendish Bananas, Caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (VCG 01213/16), in Vietnam

Plant Disease ◽

10.1094/pdis-08-17-1140-pdn ◽

2018 ◽

Vol 102 (2) ◽

pp. 448-448 ◽

Cited By ~ 9

Author(s):

T. N. Hung ◽

N. Q. Hung ◽

D. Mostert ◽

A. Viljoen ◽

C. P Chao ◽

...

Keyword(s):

Fusarium Oxysporum ◽

Fusarium Wilt ◽

First Report ◽

Race 4

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The Distribution of Fusarium Wilt of Blackeyed Cowpeas within California Caused by Fusarium oxysporum f. sp. tracheiphilum Race 4

Plant Disease ◽

10.1094/pdis.1999.83.7.694c ◽

1999 ◽

Vol 83 (7) ◽

pp. 694-694 ◽

Cited By ~ 6

Author(s):

S. N. Smith ◽

D. M. Helms ◽

S. R. Temple ◽

C. Frate

Keyword(s):

Fusarium Oxysporum ◽

Fusarium Wilt ◽

San Joaquin Valley ◽

University Of California ◽

Crop Damage ◽

Breeding Lines ◽

1960S And 1970S ◽

Single Field ◽

The 1960S ◽

Race 4

Fusarium wilt of blackeyed cowpeas has been known in California since the 1930s, and breeding for resistance to this disease pathogen has been a continuous effort. During the 1960s and 1970s, California Blackeye 5 (CB 5) cowpea (Vigna unguiculata L. Walp.), a widely grown cultivar of the time, became increasingly diseased by Fusarium oxysporum f. sp. tracheiphilum (Fot) Race 3 (2) throughout the growing regions of California. University of California cultivars CB 46 and CB 88 (1) were developed for resistance to Fot Races 1, 2, and 3. CB 46 is currently the principal blackeye cultivar grown on the majority of the acreage in the San Joaquin Valley. In 1989, a new race we designate “Fot Race 4” was isolated from wilted plants at a single field site in Stanislaus County. In years prior to identification, Fot Race 4 had caused severe wilt of CB 46 and CB 88 in this field. Even though the new Fot Race 4 remained confined to a small area for a number of years, sources of host plant resistance to Fot Race 4 were identified, hybridized, and screened, resulting in new progeny with desirable commercial agronomic characteristics. As observed in Stanislaus County, F. oxysporum f. sp. tracheiphilum Race 4 has the potential to cause serious crop damage, depending on virulence and soil inoculum levels, which may vary from year to year. In 1997 and 1998, an entirely different area in the southern San Joaquin Valley, about 140 miles from the original site in Stanislaus County, was found to have plants infected with Fot Race 4. Diseased plants were collected from patches in three separate CB 46 or CB 88 field sites in Tulare County. About 30 cultures were isolated from the diseased plants, which showed stunting, yellowing, and vascular discoloration. In greenhouse fusarium dip tests CB 46, CB 88, CB 5, and several Fot Race 4 resistant breeding lines were inoculated with all the collected isolates and evaluated. CB 46, CB 88, and CB 5 proved to be susceptible to these isolates, showing typical Fot Race 4 symptoms. The Fot Race 4 pathogen was then reisolated from greenhouse-grown, diseased stem tissue of CB 46, CB 88, and CB 5. These findings emphasize the importance of vigilance and necessity of continual disease surveys. They serve as an early alert for the University of California breeding program, and validate local cooperation with University of California Extension Farm Advisors. As a result of this effort new cultivar candidates with resistance to Fot Race 4 are in the final phases of multi-year commercial testing. References: (1) D. M. Helms et al. Crop Sci. 31:1703, 1991. (2) K. S. Rigert and K. W. Foster. Crop Sci. 27:220, 1987.

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