Crosstalk between grapevine leafroll-associate virus-3 (GLRaV-3) and NaCl-induced salt stress in in vitro cultures of the red grape 'Cabernet Sauvignon'

Viral diseases (biotic stress) and salt stress (abiotic stress) are the two major stress factors limiting the sustainable development of the grape industry. These two stresses often occur simultaneously in many grape-growing regions. The present study investigated crosstalk between grapevine leafroll-associated virus-3 (GLRaV-3) and NaCl-induced salt stress in in vitro plantlets of the red-fruited grape 'Cabernet Sauvignon'. Results showed that although the healthy plantlets had greater vegetative growth than the virus-infected plantlets when grown without salt stress, the latter produced better vegetative growth than the former when cultured under salt stress, indicating that the virus-infected plantlets were more tolerant to NaCl-induced salt stress than the healthy ones. Analyses of physiological metabolites found that contents of total soluble sugar and free proline were generally much higher in the latter than in the former under salt stress. The virus-infected plantlets responded to salt stress by significantly increasing activities of SOD, POD and CAT, compared with the healthy ones. Salt stress induced much higher levels of ABA in the virus-infected plantlets than the healthy ones. To the best of our knowledge, this is the first study reporting virus infection improves plant tolerance to salt stress. The results reported here provide new insights into better understanding of improvement of plant salt tolerance by virus infection. Key message The red-fruited grape 'Cabernet Sauvignon' infected with grapevine leafroll-associated virus-3 improved salt tolerance of the infected in vitro plantlets. In vitro culture system provided an alternative strategy for studying crosstalk between plants and combined stresses by abiotic and biotic factors.

Automated summary

Viral infection can enhance salt tolerance of red-fruited grape 'Cabernet Sauvignon' in vitro plantlets, as virus-infected plantlets showed better growth and higher levels of physiological metabolites under salt stress compared to healthy ones. This study provides new insights into the crosstalk between virus infection and plant response to salt stress.