Water relations and ethylene production as related to symptom expression in cocoa seedlings infected with defoliating and non-defoliating isolates of Verticillium dahliae

1996 ◽  
Vol 45 (5) ◽  
pp. 964-972 ◽  
Author(s):  
M. L. V. RESENDE ◽  
R. MEPSTED ◽  
J. FLOOD ◽  
R. M. COOPER
Keyword(s):  
Water Relations ◽  
Verticillium Dahliae ◽  
Ethylene Production ◽  
Symptom Expression ◽  
Cocoa Seedlings

scholarly journals Effects of methyl jasmonate and gums formed in stone fruit trees on in vitro ethylene production by mycelium of verticillium dahliae and alternaria alternata

2013 ◽  
Vol 21 (2) ◽  
pp. 87-93
Author(s):  
Elżbieta Węgrzynowicz-Lesiak ◽  
Anna Jarecka Boncela ◽  
Justyna Góraj ◽  
Marian Saniewski
Keyword(s):  
Methyl Jasmonate ◽  
Verticillium Dahliae ◽  
Ethylene Production ◽  
Alternaria Alternata ◽  
Pathogenic Fungi ◽  
Fruit Trees ◽  
Stone Fruit ◽  
Mycelium Growth

ABSTRACT The knowledge about the role of jasmonates in ethylene production by pathogenic fungi is ambiguous. In this study, we describe the effect of methyl jasmonate (JA-Me) and gums formed in stone fruit trees on the growth and in vitro ethylene production by mycelium of Verticillium dahliae and Alternaria alternata. Methyl jasmonate at concentrations of 100, 250 and 500 μg·cm-3 inhibited the mycelium growth of V. dahliae and A. alternata, proportionally to the concentrations used. After 8 days of incubation, JA-Me at concentration of 500 μg·cm-3 limited the area of mycelium of these pathogens by 7-8 times but did not entirely inhibited the pathogen growth. Addition of gums produced by trees of cherry and peach to a medium containing 40 μg·cm-3 JA-Me did not influence the mycelium growth of V. dahliae, but gums of plum and apricot trees stimulated mycelium growth, in comparison to JA-Me only. Methyl jasmonate at concentrations of 2 and 40 μg·cm-3 stimulated the ethylene production by mycelium of V. dahliae and A. alternata. It is possible that methyl jasmonate stimulated ethylene production in mycelium of these pathogens through interaction with some fractions of galactans formed during hydrolysis of agar. The lack of interaction of JA-Me with polysaccharides of stone fruit trees gums concerning ethylene production was documented and it needs further explanation.

scholarly journals Salt stress effect on epinasty in relation to ethylene production and water relations in tomato

Agronomie ◽  
2000 ◽  
Vol 20 (4) ◽  
pp. 399-406 ◽  
Author(s):  
Youssef El-Iklil ◽  
Mohammed Karrou ◽  
Mohamed Benichou
Keyword(s):  
Salt Stress ◽  
Water Relations ◽  
Ethylene Production ◽  
Stress Effect

Colonization of tomatoes by Verticillium dahliae: determinative phase II

1996 ◽  
Vol 74 (8) ◽  
pp. 1279-1288 ◽  
Author(s):  
Julie Gold ◽  
Barbara Lee ◽  
J. Robb
Keyword(s):  
Verticillium Dahliae ◽  
Wilt Disease ◽  
Symptom Expression ◽  
Race 1 ◽  
Race 2 ◽  
The Relationship ◽  
Ve Gene ◽  
Defensive Mechanism ◽  
Colonizing Ability

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.

scholarly journals Cellulase Activity in Isolates of Verticillium dahliae Differing in Aggressiveness

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 155-160 ◽  
Author(s):  
M. Novo ◽  
F. Pomar ◽  
C. Gayoso ◽  
F. Merino
Keyword(s):  
Verticillium Dahliae ◽  
Carbon Sources ◽  
Cellulase Activity ◽  
Cellulase Production ◽  
High Variability ◽  
Crystalline Cellulose ◽  
Symptom Expression ◽  
Determining Factor

Ten Verticillium dahliae isolates from different Galician locations were classified by degree of aggressiveness. High variability exists independent of locality of origin. Two isolates differing in aggressiveness were evaluated for cellulase production on several carbon sources. V. dahliae is able to degrade crystalline cellulose (Avicel) and, therefore, has the three enzymes necessary for its hydrolysis. The two isolates behaved similarly in the presence of soluble cellulose, but the most aggressive isolate had greater β-1,4-glucosidase (EC. 3.2.1.21) and endo-β-1,4-glucanase (EC. 3.2.1.4) activity. The less aggressive isolate needed more time to degrade crystalline cellulose. Cellulases may not be the determining factor for aggressiveness and symptom expression; however, they may play a role in penetration.

Ultrastructure of wilt syndrome caused by Verticillium dahliae. III. Chronological symptom development in sunflower leaves

1977 ◽  
Vol 55 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Jane Robb ◽  
Lloyd Busch ◽  
Jean D. Brisson ◽  
B. C. Lu
Keyword(s):  
Phenolic Compounds ◽  
Verticillium Dahliae ◽  
Temporal Order ◽  
Band 3 ◽  
Xylem Vessel ◽  
Ultrastructural Changes ◽  
Symptom Expression ◽  
Symptom Development ◽  
Mesophyll Tissue ◽  
Foliar Symptom

When sunflowers are infected by the vascular pathogen Verticillium dahliae, the first visible foliar symptom is the appearance of tiny chlorotic flecks. An attempt was made to determine the temporal order in which early ultrastructural changes leading to symptom expression occur. The evidence indicates that ultrastructural changes occur in the following order: (1) degradation of xylem vessel walls, (2) initiation of the necrotic band, (3) degeneration of the mesophyll tissue remote from the vein, and (4) degeneration of the phloem. The possible importance of xylem vessel plugs and of phenolic compounds to the initiation of symptom development is also discussed.

Ethylene, Water Relations and Tolerance to Waterlogging of Three Eucalyptus Species

1981 ◽  
Vol 8 (6) ◽  
pp. 497 ◽  
Author(s):  
TJ Blake ◽  
DM Reid
Keyword(s):  
Water Relations ◽  
Ethylene Production ◽  
Stomatal Closure ◽  
Initial Increase ◽  
Flood Tolerance ◽  
Eucalyptus Species ◽  
Aerenchyma Formation ◽  
Subsequent Increase ◽  
Exogenous Ethylene ◽  
Lower Stem

Effects of flooding of the roots on ethylene levels and water relations of flood-tolerant and flood-susceptible eucalypts were studied in an attempt to shed light on mechanisms of adaptation to waterlogging. The order of most flood tolerant to least tolerant were Eucalyptus camaldulensis Dehnh., E. globulus Labill., and E. obliqua L'Hérit. Tolerance of flooding in E. camaldulensis was associated with an initial increase in ethylene production by the roots, a subsequent increase in ethylene evolution by the lower stem, and basal stem thickening and aerenchyma formation in response to flooding. In addition, exogenous ethylene gas (500 �ll-1) increased stem thickening in E. camaldulensis seedlings compared with untreated controls. Although treatment of the flood-susceptible E. obliqua with ethylene gas resulted in stem hypertrophy, flooding did not induce either the stem thickening response nor did it stimulate ethylene production. Eucalyptus globulus was intermediate as regards flood tolerance and basal stem thickening; ethylene production by the roots increased but it did not show marked hypertrophy of the unflooded lower stem and was unresponsive to exogenous ethylene gas. Water stress was not associated with flooding damage in eucalypts. Early stomatal closure as shown by high leaf stomatal resistances occurred in both the flood-tolerant and the flood-susceptible species and leaf water potential did not decrease in any of the three species in response to flooding. The results suggest that the high degree of flood-tolerance in E. camaldulensis may be due to (1) increased ethylene production which results in (2) tissue hypertrophy and basal stem thickening. Such tissue hypertrophy would permit the plant to eliminate the build-up of the potentially toxic gas ethylene and could also enhance the transport of oxygen to the roots. The other species lacked one or other of these adaptive mechanisms and exhibited a lesser degree of flood tolerance.

Sign in / Sign up

Export Citation Format

Share Document