Ethylene production and toxigenicity of methionine and its derivatives with riboflavin in cultures of Verticillium, Fusarium and Colletotrichum species exposed to light

Abstract

1984. Ethylene production and toxigenicity of methionine and its derivatives with riboflavin in cultures of VerticUUum, Fusarium and Colletotrichum species exposed to light. Ethylene was produced by VerticUUum dahliae Kleb. grown in liquid Czapek's medium. The rate of ethylene production was enhanced by light but was not affected by shaking or the growth rate of the cuitures. L-, D-and OL-methionine, DL-ethionine and a-keto-y-methylthiobutyric acid (KMBA) were good substrates for ethyiene production. KMBA may be an intermediate in ethylene production and it appears to be degraded to ethylene either enzymatically by peroxidase or photochemically in the presence of riboflavin. Addition of riboflavin or briefly heating the cuitures to 10()°C enhanced ethylene production greatly, whiie the addition of sodium azide, potassium cyanide and cataiase were very inhibitory. The SS4 (non-defoiiating) pathotype of V. dahliae produced significantly more ethylene (up to 108.4 nl ethylene h' from 20 ml-10-day-old cultures) than did the T9 (dei'oliating) pathotype with all substrates tested. The results suggest that the in vitro rate of ethylene production is not related to the relative virulence of pathotypes of V. dahliae on cotton. A number of VerticUUum species, Fusarium oxysporum f. sp. vasinfectum and Colletotrichum dematium var. truncatum were able to produce ethylene in liquid Czapek"s medium containing 1 mM I,-methionine under continuous light. Riboflavin, although highly stimuiatory to ethylene production, caused a fungicidal reaction to all the fungi tested in Czapek's medium containing L-methionine under continuous light. The fungicidal effect of the riboflavin-methionine-light combination occurred at concentrations of riboflavin and methionine less than 1.33 \xM and 0.5 mM, respectively. No fungicidal activity was detected when the cultures were grown in total darkness or when either methionine or riboflavin was omitted from the culture medium.Additional key words -KMBA, Photodynamic effect.

Roles of the catalytic subunit of cAMP-dependent protein kinase A in virulence and development of the soilborne plant pathogen Verticillium dahliae

“…However, previous studies showed that the amount of in vitro ethylene production is not always directly related to virulence of V. dahliae (DeVay, 1989;Wiese and DeVay, 1970;Tzeng and DeVay, 1985;Chagué et al, 2006). For example, a highly virulent V. dahliae cotton defoliating strain produced less ethylene than a less virulent non-defoliating strain in culture (Tzeng and DeVay, 1984). As plants also produce considerable higher amounts of ethylene, it is unclear whether ethylene synthesized during infection was derived from the host, the pathogen, or both.…”

Ethylene perception via ETR1 is required in Arabidopsis infection by Verticillium dahliae

“…These transcriptional changes led to reduced fungal growth in vascular tissues and symptom development in etr1‐1 plants. It is an open question whether V. dahliae employs ET perception via ETR1 to escape the activation of the plant defence mechanisms, as it is known that V. dahliae produces ET in vitro (Tzeng and DeVay, 1984). Verticillium dahliae constitutes a serious threat for a number of crops, as there is no chemical treatment; in the present study, we have attempted to elucidate and show the key role of the ETR1 gene in a plant defence mechanism against this vascular wilt pathogen as a step towards the understanding and uncoupling of a plant–pathogen interaction that threats and reduces the agricultural capita in a world that demands additional safer plant products.…”

Ethylene biosynthesis in Botrytis cinerea

“…In higher organisms, the KMBA pathway has been described in the yeast Saccharomyces cerevisiae and in the filamentous fungus P. digitatum [14]. In addition, it has been suggested as a pathway of ethylene biosynthesis in the fungi F. oxysporum , Colletotrichum dematium , in several species of Verticillium [15] and in Laccaria laccata [16].…”