Effect of Temperature on Conidial Germination ofBotryosphaeriaceaeSpecies Infecting Grapevines

Abstract

Germination of conidia of eight botryosphaeriaceous fungi infecting grapevines was evaluated after 2, 4, 6, 12, and 24 h incubation under eight different temperatures (5, 10, 15, 20, 25, 30, 35, and 40°C). The effect of temperature on conidial germination was also evaluated in different stages (hyaline versus pigmented conidia) of the species Lasiodiplodia theobromae. Conidial germination of Botryosphaeriaceae species infecting grapevines was significantly affected by temperature. Overall, conidial germination increased significantly with longer incubation times, especially from 2 to 12 h. In most cases, germination of conidia was not significantly different between 12 and 24 h incubation. Conidia of botryosphaeriaceous species did not germinate (with the exception of Botryosphaeria dothidea and Neofusicoccum parvum) at 5°C, and only B. dothidea, Diplodia seriata, and L. theobromae showed high levels of conidial germination at 40°C. Optimum conidial germination temperatures (defined as the temperature in which germination reached at least 50% in the shortest incubation time) were 25°C for B. dothidea and Dothiorella iberica, 25 to 30°C for Spencermartinsia viticola, 30°C for Diplodia corticola, D. mutila, D. seriata, N. parvum, and hyaline L. theobromae, and 40°C for pigmented L. theobromae conidia. Successful conidial germination of species of Botryosphaeriaceae infecting grapevines was always observed between 10 and 35°C with the exception of Dothiorella iberica and pigmented L. theobromae conidia, neither of which germinated at 35 and 10°C, respectively. Results of this study show conidia of botryosphaeriaceous species infecting grapevines to be capable of germination under a broad range of temperatures including those considered to be extreme, which may explain the success of these species as grapevine pathogens throughout most of the grape-growing areas in both Northern and Southern Hemispheres.

Phytotoxic metabolites from Neofusicoccum parvum, a pathogen of Botryosphaeria dieback of grapevine

“…Thus, their pathogenicity has been underestimated, and their epidemiology remains not fully investigated. To date, 30 botryosphaeriaceous species, including Neofusicoccum parvum, have been reported to be involved in dieback disease (Spagnolo et al, 2014a;Luque et al, 2009;Taylor et al, 2005;Úrbez-Torres, 2011). The wood symptoms of botryosphaeria dieback are associated with brown stripes located in the outer xylem.…”

Botryosphaeriaceae associated with the die-back of ornamental trees in the Western Balkans

“…''Botryosphaeria-like'' symptoms include leaf and shoot blights, gummosis, blue stain of the sapwood, tip die-back, cankers and in severe cases tree death Urbez-Torres 2011). Diseases caused by the Botryosphaeriaceae typically emerge after hosts have been subjected to stress caused by environmental factors such as drought, flooding or high temperatures Mehl et al 2013).…”

Declinación de la vid en Túnez asociada a hongos de las familias Diaporthaceae y Botryosphaeriaceae

“…Earlier studies on grapevine trunk disease have largely considered Botryosphaeriaceae species to be saprophytes, secondary colonizers or weak pathogens in grapevine wood (Phillips, 2002) until recent studies identified 21 different Botryosphaeriaceae species occurring in grapevines worldwide (Úrbez-Torres, 2011). In addition, canker symptoms caused by Botryosphaeriaceae in grapevines have probably been unnoticed due to the difficulty to differentiate them from those caused by other grapevine trunk disease pathogens, such as Eutypa lata (Leavitt, 1990), Phaeomoniella chlamydospora and Phaeoacremonium aleophilum (Phillips, 2002;Surico et al,2006).…”

“…In addition, canker symptoms caused by Botryosphaeriaceae in grapevines have probably been unnoticed due to the difficulty to differentiate them from those caused by other grapevine trunk disease pathogens, such as Eutypa lata (Leavitt, 1990), Phaeomoniella chlamydospora and Phaeoacremonium aleophilum (Phillips, 2002;Surico et al,2006). Moreover, grapevine trunk diseases, such as Eutypa dieback and Esca, have been the primary and, occasionally, sole focus of study for most researchers throughout the past century, which has not helped to clarify the role that Botryosphaeriaceae played in grapevine diseases (Úrbez-Torres, 2011). Moreover, fungal species from the genera Phomopsis and Diaporthe, belonging to the family Diaporthacea,e are known as grapevine pathogens and/or endophytes, from which the most commonly reported are Phomopsisviticola, Diaporthe neotheicola, D. ambigua and D. eres (Mostert et al, 2000;Schilder et al, 2005).…”