Role of Verticillium dahliae and V. tricorpus naturally infected tubers in causing Verticillium wilt disease, contribution of soil pathogen inoculum and subsequent progeny tuber infection

To investigate the relationship between stem colonizing ability of Verticillium and wilt disease development, the colonization capacities of Verticillium dahliae, race 1 or race 2, were compared in near-isolines of the cultivar Craigella, with (Ve+) and without (Ve−) Ve-gene resistance, and in the cultivar IRAT-L3, which also lacks the Ve-gene. Only the Ve+/V.d.1 interaction was resistant to disease. Lateral and vertical invasiveness of the pathogen were assessed cytologically and fungal biomass was monitored by PCR-based diagnostics. The pathogen was most aggressive in the Ve−/V.d.1 interaction; colonization capacity was reduced in the other five combinations, but most severely, and equivalently, in Ve+/V.d.1, IRAT/V.d.1, and IRAT/V.d.2. Further study of the development and role of the vascular coating response in IRAT-L3 indicated a pattern of expression similar to that observed in other susceptible plants, and it was concluded that the reduced colonization of this cultivar by V. dahliae resulted from another unknown defensive mechanism. Stem colonizing ability that is compatible with resistance in one cultivar and race combination may promote symptom expression and even death in another. Keywords: tomato, Verticillium dahliae, vascular coating, resistance.

Download Full-text

Verticillium Wilt of African Daisy (Osteospermum sp.) in Italy Caused by Verticillium dahliae

Plant Disease ◽

10.1094/pd-89-0688a ◽

2005 ◽

Vol 89 (6) ◽

pp. 688-688

Author(s):

A. Garibaldi ◽

A. Minuto ◽

M. L. Gullino

Keyword(s):

Verticillium Wilt ◽

Verticillium Dahliae ◽

Plant Disease ◽

Vascular Tissue ◽

Northern Italy ◽

Wilt Disease ◽

Pathogenicity Test ◽

Conidial Suspension ◽

Average Temperature ◽

Food Agric

During the winter of 2004, container-grown African daisy (Osteospermum sp.) plants, cv Seaside, showing symptoms of a wilt disease were observed in an open field in Albenga located in northern Italy. Symptoms were first observed on 120-day-old plants grown in a peat/composted bark/clay/pumice (50:20:10:20) substrate. The vascular tissues of affected plants appeared brown. These plants were stunted and developed yellow leaves with brown or black streaks in the vascular tissue. Verticillium dahliae was consistently and readily isolated from symptomatic vascular tissue when cultured on potato dextrose agar. Healthy rooted plants (40-day-old cv Seaside) were inoculated by root dip with a conidial suspension (5 × 107 CFU/ml) from one of three isolates of V. dahliae isolated from infected plants and transplanted into pots filled with steam-sterilized soil. Noninoculated plants served as control treatments. Plants (10 per treatment) were grown in a glasshouse at an average temperature of 25°C. First wilt symptoms and vascular discoloration in the roots, crown, and veins developed within 15 days on each inoculated plant and become very evident after 50 days. Noninoculated plants remained healthy. V. dahliae was consistently reisolated from inoculated plants. The pathogenicity test was conducted twice. To our knowledge, this is the first report of V. dahliae on Osteospermum sp. in Italy and in Europe. Verticillium wilt has been previously reported on O. fruticosum in California (1). Reference: (1) A. M. French. California Plant Disease Host Index. Calif. Dep. Food Agric. 1989.

Download Full-text

The Role of a New Compound Micronutrient Multifunctional Fertilizer against Verticillium dahliae on Cotton

Pathogens ◽

10.3390/pathogens10010081 ◽

2021 ◽

Vol 10 (1) ◽

pp. 81

Author(s):

Yalin Zhang ◽

Lihong Zhao ◽

Zili Feng ◽

Hongfu Guo ◽

Hongjie Feng ◽

...

Keyword(s):

Verticillium Wilt ◽

Verticillium Dahliae ◽

Hyphal Growth ◽

Phenylpropanoid Metabolism ◽

Nitric Oxide Signaling ◽

Hypocotyl Tissue ◽

Micronutrient Fertilizer

Verticillium dahliae Kleb., the causal pathogen of vascular wilt, can seriously reduce the yield and quality of many crops, including cotton (Gossypium hirsutum). To control the harm caused by V. dahliae, considering the environmental pollution of chemical fungicides and their residues, the strategy of plant nutrition regulation is becoming increasingly important as an eco-friendly method for disease control. A new compound micronutrient fertilizer (CMF) found in our previous study could reduce the damage of cotton Verticillium wilt and increase yield. However, there is little information about the mode of action of CMF to control this disease. In the present study, we evaluated the role of CMF against V. dahliae and its mechanism of action in vitro and in vivo. In the laboratory tests, we observed that CMF could inhibit hyphal growth, microsclerotia germination, and reduce sporulation of V. dahliae. Further studies revealed that the biomass of V. dahliae in the root and hypocotyl of cotton seedlings treated with CMF were significantly reduced compared with the control, and these results could explain the decline in the disease index of cotton Verticillium wilt. Furthermore, those key genes involved in the phenylpropanoid metabolism pathway, resistance-related genes defense, and nitric oxide signaling pathway were induced in cotton root and hypocotyl tissue when treated with CMF. These results suggest that CMF is a multifaceted micronutrient fertilizer with roles in inhibiting the growth, development, and pathogenicity of V. dahliae and promoting cotton growth.

Download Full-text

Role of Pectic Enzymes in the Verticillium Wilt Disease of Cotton

Nature ◽

10.1038/175264b0 ◽

1955 ◽

Vol 175 (4449) ◽

pp. 264-265 ◽

Cited By ~ 8

Author(s):

M. KAMAL ◽

R. K. S. WOOD

Keyword(s):

Verticillium Wilt ◽

Wilt Disease ◽

Pectic Enzymes

Download Full-text

Occurrence of Wilt Disease Caused by Verticillium dahliae on Ailanthus glandulosa in Greece

Plant Disease ◽

10.1094/pdis.1998.82.1.129b ◽

1998 ◽

Vol 82 (1) ◽

pp. 129-129 ◽

Cited By ~ 4

Author(s):

G. Skarmoutsos ◽

H. Skarmoutsou

Keyword(s):

Verticillium Wilt ◽

Cross Sections ◽

Verticillium Dahliae ◽

Tree Species ◽

Wilt Disease ◽

Vascular Wilt ◽

Northern Greece ◽

Globular Cells ◽

Short Time ◽

Different Parts

Ailanthus glandulosa is an introduced tree species in Greece used as ornamental and is considered resistant to both fungal and insect attacks. However, since 1992, a great number of A. glandulosa plants of different ages and in different parts of northern Greece have been dying. The phenomenon appeared either in single trees or in groups, and the number of affected plants increased from year to year. The symptoms were characteristic of a wilt disease. Dieback started on one or more branches and gradually spread, or whole trees were affected from the beginning. Death may occur during spring when trees do not resume their activity or later in the summer. Leaves wilt, turn yellow and fall in a short time. Trees may die in 1 to 3 years depending on their age. In cross sections of branches a continuous discoloured ring or arc was present in the outermost sapwood. Isolations made from dying trees from 25 different locations have yielded V. dahliae, a pathogen known to cause vascular wilt on many plant hosts, including Ailanthus (1). Isolations made from healthy trees did not yield the fungus. Abundant mycelium developed in the host vessels of infected trees; the hyphae were cylindrical, hyaline, and septate. On malt agar fungal cultures developed quickly and were initially a whitish to cream color that later turned black due to the formation of microsclerotia. In culture, microsclerotia started to form centrally and were dark brown to black, consisting of swollen globular cells that formed irregular masses variable in shape. The fungus also produced abundant verticillate conidiophores with phialides and conidia. This is a first report of Verticillium wilt on A. glandulosa in Greece. Reference: (1) G. Arnaud et al. Rev. Pathol. Veg. Entomol. Agric. Fr. 17:227, 1930.

Download Full-text

Verticillium dahliae inoculation and in vitro propagation modify the xylem microbiome and disease reaction to Verticillium wilt in a wild olive genotype

10.1101/2020.11.23.392977 ◽

2020 ◽

Author(s):

Manuel Anguita-Maeso ◽

José Luis Trapero ◽

Concepción Olivares-García ◽

David Ruano-Rosa ◽

Elena Palomo-Ríos ◽

...

Keyword(s):

Microbial Communities ◽

Verticillium Wilt ◽

Verticillium Dahliae ◽

Host Resistance ◽

Control Measure ◽

Infection Process ◽

Resistance Response ◽

Wild Olive

AbstractHost resistance is the most practical, long-term and economically efficient disease control measure for Verticillium wilt in olive caused by the xylem-invading fungus Verticillium dahliae (Vd), and it is at the core of the integrated disease management. Plant’s microbiome at the site of infection may have an influence on the host reaction to pathogens; however, the role of xylem microbial communities in the olive resistance to Vd has been overlooked and remain unexplored to date. This research was focused on elucidating whether in vitro olive propagation may alter the diversity and composition of the xylem-inhabiting microbiome and if those changes may modify the resistance response that a wild olive clone shows to the highly virulent defoliating (D) pathotype of Vd. Results indicated that although there were differences in microbial communities among the different propagation methodologies, most substantial changes occurred when plants were inoculated with Vd, regardless whether the infection process took place, with a significant increase in the diversity of bacterial communities when the pathogen was present in the soil. Furthermore, it was noticeable that olive plants multiplied under in vitro conditions developed a susceptible reaction to D Vd, characterized by severe wilting symptoms and 100% vascular infection. Moreover, those in vitro propagated plants showed an altered xylem microbiome with a decrease in total OTU numbers as compared to that of plants multiplied under non-aseptic conditions. Overall, 10 keystone bacterial genera were detected in olive xylem regardless infection by Vd and the propagation procedure of plants (in vitro vs nursery), with Cutibacterium (36.85%), Pseudomonas (20.93%), Anoxybacillus (6.28%), Staphylococcus (4.95%), Methylobacterium-Methylorubrum (3.91%), and Bradyrhizobium (3.54%) being the most abundant. Pseudomonas spp. appeared as the most predominant bacterial group in micropropagated plants and Anoxybacillus appeared as a keystone bacterium in Vd-inoculated plants irrespective of their propagation process. Our results are first to show a breakdown of resistance to Vd in a wild olive that potentially maybe related to a modification of its xylem microbiome, and will help to expand our knowledge of the role of indigenous xylem microbiome on host resistance which can be of use to fight against main vascular diseases of olive.

Download Full-text