Abstract

Grapevine rupestris stem pitting-associated virus (GRSPaV) is one of the most prevalent viruses that infects grapevines and belongs to the genus Foveavirus, in the Betaflexiviridae family. We have shown previously that plants of V. vinifera cv Bosco infected by the GRSPaV-1 sequence variant exerted a very moderate decrease in physiological efficiency and yield. Importantly, this response overlapped with molecular responses to water and salinity stress. These considerations prompted us to investigate possible interactions between GRSPaV and abiotic stress. The molecular basis of these interactions is still poorly understood; however, it is reasonable to hypothesise an involvement of RNA silencing, which is a natural defence against invading viruses in plants. Both miRNAs and siRNAs are involved in several developmental processes in defence responses to biotic and abiotic stresses and in genome stability maintenance, as reviewed in many studies. We analysed the ecophysiological and molecular interactions between GRSPaV infection and drought in grapevine. During the progressive drying of soil, the stomatal conductance (gs) and net photosynthesis (Pn) of both infected and GRSPaV-free sets of plants decreased in response to water stress; however, this response was delayed in infected plants Prolonged drought conditions are known to reduce or block growth. However, in both irrigated and water stress conditions, infected plants showed a greater leaf area, height, and stem growth diameter compared to GRSPaV-free plants. In the small endogenous RNAs libraries produced from leaves of infected and GRSPaV-free plants under WW and SWS, we identified members of almost all known miRNAs and 25 novel miRNA candidates. The analysis of the data revealed that the accumulation of some known miRNAs was clearly associated with GRSPaV infection. In addition, when GRSPaV-infected plants were subjected to water stress, the ratio of miRNA accumulation between infected and GRSPaV-free grapevines changed significantly. Interestingly, this study clearly shows that the sanitary status of the plants may play a determinant role in miRNA regulation during abiotic stress. Our data support the idea of mutual adaptation between GRSPaV and grapevine, resulting in beneficial effects for the host under water stress conditions. Therefore, GRSPaV might represent the first example of a plant virus that is more appropriately defined by the categories of 'conditional mutualism' and 'beneficial virus'.

Autore Pugliese

• Pantaleo Vitantonio

Tutti gli autori

• Pantaleo V.; Vitali M.; Boccacci P.; Miozzi L.; Cuozzo D.; Chitarra W.; Mannini F.; Lovisolo C.; Gambino G.

Titolo volume/Rivista

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Anno di pubblicazione

2015

ISSN

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ISBN

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Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

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Settori ERC

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Codici ASJC

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