Root-zone waterproof cultivation advanced coloring by accumulation anthocyanins and modulated epiphytic bacteria...

In Shandong Peninsula, the hygrothermal and rainy climate leads to unstable wine color and insufficient aroma of wine grapes. Plant cultivation patterns play a crucial role with various advantages. Root-zone waterproof cultivation is a cultivation technique by restricting the external water entering the root-zone during the rainy season. This study aims to investigate the berry quality, rhizospheric and epiphytic bacterial communities, the anthocyanins contents and the correlation analysis between anthocyanins and bacterial community under the root-zone waterproof treatment.

Compared to normal conditions, the root zone waterproof cultivation advanced coloring at early veraison and accumulated more total soluble solids at maturity stage. LC-MS data showed that the root zone waterproof cultivation reduced the procyanidin contents and accumulated more anthocyanin 3-O-glucosides/galactosides at early veraison. There were significant differences in the diversity and relative abundance of epiphytic microorganisms between the normal conditions and the root zone waterproof treatment at maturity stage. Moreover, correlation network between anthocyanin profiles and microorganisms showed that petunidin-3-O-(6''-O-caffeoyl)-galactoside, petunidin-3-O-(6''-O-malonyl)galactoside, malvidin-3-O-(6''-O-acetyl)galactoside and delphinidin at early veraison were more closely related to the the bacterial community at maturity stage. Thus the changed specific anthocyanins modulated the structure of grape epiphytic bacterial communities. At the same time, the berries at S3 stage exhibated higher total antioxidant capacity to alleviate plant stress during the rainy season.

The root zone waterproof cultivation pattern emerges as a potential alternative choice for the sustainable management of wine grapes in Shandong Peninsula.