Winegrowers face agronomic and environmental challenges that affect grapevine health and wine quality, including pathogen pressure, nutrient deficiencies, drought stress, and the ecological impact of intensive practices. Microorganisms play a key role in plant development and resilience, influencing grapevine performance through interactions in the rhizosphere, vegetative tissues, and fruit cuticle, ultimately shaping grape and wine characteristics.
This study has two main objectives. First, using 16S rRNA amplicon sequencing, we compare the rhizosphere microbiome of Vitis vinifera cv. Cabernet Sauvignon across four Israeli terroirs – Elrom (Golan Heights), Even Menachem (Western Galilee), Beit Zait (Jerusalem Mountains), and Mizpe Ramon (Negev Desert) – each representing distinct soil types. Second, we evaluate physiological and fruit quality responses to three commercial microbial inoculants: a bacteria-nutrient mix (Mix), mycorrhiza (Myc), and a bacteria-fungi blend (Micro). Each was applied to 40 vines in Beit Zait and Mizpe Ramon.
Measured physiological parameters included midday stem water potential, leaf area index (LAI), berry count per cluster, ripe cluster weight, cane weight, and mineral uptake. Fruit quality assessments encompassed total soluble solids (TSS), pH, berry weight (three time points), malic acid, titratable acidity, and primary amino acids.
Preliminary results show significant differences in ripe cluster weight between treatments. Control vines produced heavier clusters than Myc and Mix in Beit Zait (p=0.0133) and heavier than Mix in Mizpe Ramon (p=0.0308). These trends suggest microbial inoculation influences fruit development, though integration with native microbiomes requires time. This ongoing three-year study (initiated 2023) will also assess rhizosphere microbiome shifts and wine composition.
