Physiological response of grapevines to vascular pathogens a review

Abstract

The successful infection of a grapevine vascular system by a plant pathogen and expression of disease symptoms occur only when the pathogen has overcome the wound response and other defences of the vine Even when pathogens do successfully infect the vascular system of grapevines symptom expression is not often observed in the first season Symptoms may be observed in one year but the same vine can have reduced or no symptoms the following season Information is presented on physiological stress in association with trunk diseases as one factor that may contribute to symptom expression in vines A hypothesis of grapevine wound response is proposed as part of the discussion of vine physiological response Information on individual trunk diseases and physiological interactions is also provided

Visual symptoms of trunk diseases do not predict vine death

“…Therefore, management decisions for a vineyard block should not be based on a single time-point observation of visual symptoms. While the cause(s) of death for the vines in the study block reported in this paper were not determined, it has been hypothesised that stress conditions in the grapevine, such as drought or low carbohydrate reserves, may increase the rate of vine mortality from trunk diseases (Mundy & Manning 2011). Therefore, pre-season climatic conditions may influence both foliar symptoms and vine mortality in any given season.…”

“…To make better predictions of vine deaths due to trunk disease, direct non-destructive sampling of vines and then observation over time will be required, linked with detailed records of weather data and vineyard management practices. Information of this type would be required to test the hypothesis that conditions for symptom expression are different from those for infection and colonisation (Mundy & Manning 2011). However in the meantime, repeated visual assessments of vineyards over time may give an indication of which blocks are most likely to require replanting, based on relative symptom expression.…”

“…Eutypa dieback has the distinctive symptom of stunted, chlorotic shoots in late spring as a result of toxin production (Sosnowski et al 2007). However, this symptom is not consistently expressed in all infected vines in every season (Mundy & Manning 2011). Vines with mixed infections of both diseases were commonly detected during surveys when isolations were made from symptomatic vines (Mundy et al 2009).…”

The response to stress treatments of potted grapevines inoculated with <i>Eutypa lata</i> and <i>Botryosphaeria lutea</i> fungi associated with trunk disease

“…The pathogens of interest have been identified as wound invaders (Mundy & Manning 2010) and stress on the vines at the time of wounding has been reported as one possible factor that could influence vine response to pathogen invasion (Rudelle et al 2005;Desprez-Loustau et al 2006;Petit et al 2006;Mundy & Manning 2011). Carbohydrates are important both to the vine's defence mechanisms against wounding and to the wound invading process of many pathogens (Mundy & Manning 2011). If carbohydrate stress can influence pathogen invasion of the wound and trigger latent endophytic infections to become pathogenic, this has implications for the management of the vineyard in terms of risk of trunk diseases.…”

“…Leaf removal and girdling have also been reported to change the availability of sugars within the vine (Caspari et al 1998). Decreases in carbohydrate reserves (starch) or changes in allocation to different sinks such as roots and fruit have been hypothesised to reduce the rate of wound healing and decrease fungal colonisation of wounds (Mundy & Manning 2011).…”