Functional characterisation of genetic elements regulating bunch morphology in grapevine

Undesirable compounds in wine, like OTA, biogenic amines, and pesticide residues, can negatively affect its quality and pose health risks to consumers. In addition, an excess of tannins can lead to an unpleasant rise in astringency and bitterness, which makes tannins another target of reduction.

Ochratoxin A (OTA) is a mycotoxin produced by several filamentous fungi infecting grape bunches (Penicillium and Aspergillus spp.), this toxin pass to must when grapes are crushed and later it is found in wine. Following the evaluations of the toxicity of OTA, European Commission Regulations have been promulgated introducing upper limits for OTA concentrations in various commodities (cereals, cereal products, dried vine fruit, coffee, wine, grape juice, baby foods and dietary foods for special medical purposes).

Numerous studies have demonstrated the importance of irrigation in improving the grape yield and quality in areas with arid and semiarid climates, particularly in the context of ongoing climate changes. However, the introduction of irrigation in vineyards of the Mediterranean basin is a matter of debate, in particular in those of the Douro Demarcated Region (DDR), due to the limited number of available studies in this region. The present study aimed to evaluate how different irrigation deficits for 6 years would influence production and must quality in Touriga Francesa (TF) and Touriga Nacional (TN) varieties.

Vineyard exposure to smoke can lead to grapes and wine which exhibit objectionable smoky and ashy aromas and flavours, more commonly known as ‘smoke taint’ [1, 2]. In the last decade, significant bushfires have occurred around the world, including near wine regions in Australia, Canada, South Africa and the USA, as a consequence of the warmer, drier conditions associated with climate change. Considerable research has subsequently been undertaken to determine the chemical, sensory and physiological consequences of grapevine exposure to smoke. The sensory attributes associated with smoke-tainted wine have been linked to the presence of several smoke-derived volatile phenols, such as guaiacols, syringols and cresols [2].

Atypical ageing (ATA) is a wine aroma fault occurring in white wines characterised by an early loss of varietal aroma as well as nuances of wet mop, acacia blossom, shoe polish and dirty rag among others. 2-aminoacetophenone (2AAP) – a degradation product of indole-3-acetic acid (IAA) – has been described as the major odour-active compound and chemical marker responsible for this off-flavour. Depending on the aroma intensity of wines, its odour threshold varies from 0.5 to 10.5 μg/L. It seems that a stress reaction in the vineyard triggered by climatic, pedological and viticultural factors can ultimately cause ATA development in wines and therefore shorten their shelf-life.