Activity of Trichoderma asperellum Strain ICC 012 and Trichoderma gamsii Strain ICC 080 Toward Diseases of Esca Complex and Associated Pathogens.

Grapevine trunk diseases are widespread in all grape-growing countries. The diseases included in the Esca complex of diseases are particularly common in European vineyards. Their distinctive foliar symptoms are well known to be associated not only with losses in quantity, as with all grapevine wood diseases, but also with losses in the quality of the crop. Protection of pruning wounds is known to reduce infections in artificial inoculations and, to some extent, reduce the external leaf symptoms. The application of biological control agents in the field is typically started at the first appearance of symptoms. In this article, the two strains belonging to two different species, Trichoderma asperellum ICC 012 and T. gamsii ICC 080, which are present in a commercial formulation, were tested in vitro, in vivo in artificial inoculation, and in the field in long-term experiments where the wounds on four young asymptomatic vineyards were protected since 1 or 2 years after planting. The in vitro trials highlighted the different temperature requirements of the two strains, the direct mycoparasitizing activity of T. asperellum, and the indirect activity shown by both Trichoderma strains. The in vivo trials confirmed the ability of the two strains to reduce the colonization following artificial inoculations with the high, unnatural concentration of spores used in artificial infections, even if with variable efficacy, and with long persistence as they could be reisolated 7 months post-application. The preventive applications carried out over 9 years showed a very high reduction in symptom development in the treated vines, on annual and cumulated incidence and on the death of vines, with disease reduction varying from 66 to almost 90%. Early and annual application of protection to the pruning wounds appears to be the best method for reducing damages caused by grapevine leaf stripe disease (a disease of the Esca complex of diseases). Trichoderma appears to offer an efficient, environmentally friendly, and long-lasting protection in the presence of a natural inoculum concentration.

Genomic and transcriptomic analysis of the AP2/ERF superfamily in Vitis vinifera.

BACKGROUND: The AP2/ERF protein family contains transcription factors that play a crucial role in plant growth and development and in response to biotic and abiotic stress conditions in plants. Grapevine (Vitis vinifera) is the only woody crop whose genome has been fully sequenced. So far, no detailed expression profile of AP2/ERF-like genes is available for grapevine. RESULTS: An exhaustive search for AP2/ERF genes was carried out on the Vitis vinifera genome and their expression profile was analyzed by Real-Time quantitative PCR (qRT-PCR) in different vegetative and reproductive tissues and under two different ripening stages.One hundred and forty nine sequences, containing at least one ERF domain, were identified. Specific clusters within the AP2 and ERF families showed conserved expression patterns reminiscent of other species and grapevine specific trends related to berry ripening. Moreover, putative targets of group IX ERFs were identified by co-expression and protein similarity comparisons. CONCLUSIONS: The grapevine genome contains an amount of AP2/ERF genes comparable to that of other dicot species analyzed so far. We observed an increase in the size of specific groups within the ERF family, probably due to recent duplication events. Expression analyses in different aerial tissues display common features previously described in other plant systems and introduce possible new roles for members of some ERF groups during fruit ripening. The presented analysis of AP2/ERF genes in grapevine provides the bases for studying the molecular regulation of berry development and the ripening process.

Foliar Symptom Expression of Wood Decay in Actinidia deliciosa in Relation to Environmental Factors.

Kiwifruit vines (Actinidia deliciosa var. deliciosa) have recently been affected by a new form of decay caused by several fungi that produce different types of wood deterioration in the trunk and cordons. Surveys were conducted over a period of 5 years to investigate epidemiological aspects of the disease in a typical Italian growing area (Emilia-Romagna), where kiwifruit is widely cultivated and where the disease was noted for the first time. The disease was widespread over the kiwifruit growing area surveyed, and its incidence increased over the course of the survey. No relationship was found between vineyard soil characteristics or management methods and the annual incidence of symptomatic vines. Foliar symptoms did not consistently express every season even on obviously infected vines. The time of appearance and the development of the disease were correlated with plant phenology and temperature. In particular, from June to August, temperature seemed to affect the annual incidence of the disease in terms of both symptomatic shoots and symptomatic vines. The aspects in common between the decay of kiwifruit and esca of grapevine could be hypothesized and are discussed.