Flavonoids and darkness lower PCD in senescing Vitis vinifera suspension cell cultures.

Alberto Bertolini,Marco Zancani,Angelo Vianello,Carlo Peresson,Valentino Casolo,Enrico Braidot,Elisa Petrussa,Sonia Patui

doi:10.1186/s12870-016-0917-y

Abstract

BackgroundSenescence is a key developmental process occurring during the life cycle of plants that can be induced also by environmental conditions, such as starvation and/or darkness. During senescence, strict control of genes regulates ordered degradation and dismantling events, the most remarkable of which are genetically programmed cell death (PCD) and, in most cases, an upregulation of flavonoid biosynthesis in the presence of light.Flavonoids are secondary metabolites that play multiple essential roles in development, reproduction and defence of plants, partly due to their well-known antioxidant properties, which could affect also the same cell death machinery. To understand further the effect of endogenously-produced flavonoids and their interplay with different environment (light or dark) conditions, two portions (red and green) of a senescing grapevine callus were used to obtain suspension cell cultures. Red Suspension cell Cultures (RSC) and Green Suspension cell Cultures (GSC) were finally grown under either dark or light conditions for 6 days.ResultsDarkness enhanced cell death (mainly necrosis) in suspension cell culture, when compared to those grown under light condition. Furthermore, RSC with high flavonoid content showed a higher viability compared to GSC and were more protected toward PCD, in accordance to their high content in flavonoids, which might quench ROS, thus limiting the relative signalling cascade. Conversely, PCD was mainly occurring in GSC and further increased by light, as it was shown by cytochrome c release and TUNEL assays.ConclusionsEndogenous flavonoids were shown to be good candidates for exploiting an efficient protection against oxidative stress and PCD induction. Light seemed to be an important environmental factor able to induce PCD, especially in GSC, which lacking of flavonoids were not capable of preventing oxidative damage and signalling leading to senescence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0917-y) contains supplementary material, which is available to authorized users.

Highlights

Senescence is a key developmental process occurring during the life cycle of plants that can be induced by environmental conditions, such as starvation and/or darkness
Limberger) and characterization of their flavonoid profile Grapevine cell cultures were grown under light on a solid medium
Red and green clusters from the same callus piece were chosen as inoculum for the subculture into liquid medium in order to study the effects of endogenous flavonoid at the onset of senescence

Summary

Introduction

Senescence is a key developmental process occurring during the life cycle of plants that can be induced by environmental conditions, such as starvation and/or darkness. Strict control of genes regulates ordered degradation and dismantling events, the most remarkable of which are genetically programmed cell death (PCD) and, in most cases, an upregulation of flavonoid biosynthesis in the presence of light. To understand further the effect of endogenously-produced flavonoids and their interplay with different environment (light or dark) conditions, two portions (red and green) of a senescing grapevine callus were used to obtain suspension cell cultures. Plant senescence is a multifactorial process involving several signalling pathways, which require an active regulation by nuclear genes. Those related to flavonoid synthesis could be differentially regulated, depending on the type of senescence, since in cell cultures the developmental- and starvationinduced senescence differs from that induced by darkness [1]

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