The effect of drought conditions on sweet orange (Citrus sinensis) plants infected with citrus tristeza virus (CTV)

Abstract

Brazil is one of the world's largest producers of citrus. However, production is challenged due to biotic and abiotic factors limiting crop health. The aim of this work was to evaluate the influence of water deficit in sweet orange (Citrus sinensis) cv. Pera Bianchi inoculated with citrus tristeza virus (CTV). Two isolates of CTV were used, one causing severe symptoms (Forte Rolândia) and the second causing mild symptoms (Pêra IAC), grafted on Rangpur lime (Citrus limonia) and Swingle citrumelo [Citrus paradisi x Poncirus trifoliata], and the indicator sweet orange Pêra Bianchi, free of virus, and healthy controls containing only the indicator budwood. The water regime for the plants was field capacity or 50% field capacity. After five months of controlled irrigation, biochemical variables were measured (protein, proline content and catalase activity), and real-time RT-PCR amplification of the virus was performed for detection and quantification of viral titer. Differences were observed in the total protein content and proline, with greater accumulation in plants maintained under water deficit. There was no effect of drought on the population of viral isolates, but the plants held at field capacity and inoculated with the severe isolate had a higher viral titer.

Identification of an Emaravirus in a Common Oak (Quercus robur L.) Conservation Seed Orchard in Germany: Implications for Oak Health

“…It was suggested that the protection may be due to a virus-induced accumulation of osmoprotectants and antioxidants such as anthocyanins [41]. Likewise, proline, a proteinogenic amino acid acting on osmotic adjustment that helps subcellular structure stabilization and the elimination of free radicals, invariably had a higher concentration in sweet orange (Citrus sinensis) infected with citrus tristeza virus [43]. Survival of infected plants under extreme drought stress represents a conditional difference in fitness, assuming the surviving virus-infected plants can subsequently produce offspring.…”