Changes in nutrient concentrations and biochemical characteristics of Mexican lime (Citrus aurantifolia) infected by phytoplasma

Abstract

Witches’ broom disease of lime (WBDL), caused by ‘Candidatus Phytoplasma aurantifolia’, is a major limiting factor for Mexican lime (Citrus aurantifolia Swingle) production in southern Iran. Here, nutritional status and biochemical composition of healthy and infected Mexican lime in a greenhouse were compared between uninoculated (healthy) plants and plants 52 weeks after inoculation with the phytoplasma. Leaves from healthy and infected plants were sampled to measure total phenolics, antioxidant capacity, peroxidase and superoxide dismutase enzymatic activities, soluble carbohydrate, and starch. Macro- and microelements were also measured in leaves, stems, and roots of the plants. The results showed that phytoplasma infection led to a marked increase in soluble carbohydrates and starch in the leaves, but to a reduction in the roots. In leaves and roots, antioxidant capacity, phenolics, and peroxidase activity were enhanced after infection; nitrogen, calcium, boron, and manganese were significantly lower and phosphorus, magnesium, potassium, iron, zinc, and copper significantly higher in the infected leaves. This study provides new insights on metabolic and nutritional changes associated with WBDL in the greenhouse.