Sugar management and photosynthesis of sugar beet after infection by Cercospora beticola.

Sugar beet (Beta vulgaris L. subsp. vulgaris) is an important crop used not only in sugar production but also as the source of biogas and bioethanol, as a substrate in the petrochemical industry, and as a bio-resource for additional industrial and chemical feedstocks. Sugar beet is sensitive to environmental stress factors, including fungal infections such as Cercospora beticola (CLS-Cercospora leaf spot disease). Despite the introduction of plant cultivars with increased resistance to this disease, it causes a significant reduction in crop yield every year. The effect of infection is significant leaf loss in July and August, and the leaf rosette regeneration in September lasts until November. We examined three varieties of sugar beet with increased resistance to CLS. Using satellite images, we monitored the rate of leaf regeneration after CLS infection and studied in detail the gas exchange of plants, the efficiency of the photosynthetic apparatus, changes in the content of pigments and sugars in leaves, and sugar storage in roots. We showed for the first time that leaf regeneration after CLS infection seems independent of sugar accumulated in the roots. Sugar beetroot varieties were characterized by different strategies for managing sugar production and relocation. Moreover, the efficiency of CO assimilation and solar energy absorption were not correlated in time and space in sugar beet, which, in the context of autumn leaf regeneration and senescence, may also be an indication for earlier harvesting.