Function of the photosynthetic apparatus of oilseed winter rape under elicitation by Phoma lingam phytotoxins in relation to carotenoid and phenolic levels

Abstract

Stem canker (blackleg) caused by fungus Leptosphaeria maculans/L. biglobosa is one of the most damaging diseases of oilseed winter rape crops. Some winter oilseed rape varieties (Brassica napus L. var. oleifera 'Bojan', 'Lisek', 'Liclassic') that differ in blackleg resistance have been chosen for the experiment. In all tested cultivars during growth on a medium with a fungal elicitor, a distinct reduction in the length of the stems, the roots and the entire length of the seedlings was observed. However, only in the case of the 'Liclassic' cultivar, fresh and dry weight were reversibly affected during elicitation. The cultivar 'Liclassic', recognized as blackleg mildly resistant, was characterized by the most efficient photosynthetic apparatus under toxin elicitation. The efficient adaptation of photosynthetic apparatus in this cultivar was accompanied by an increase in the content of phenolics, chlorophyll and carotenoids. Only for 'Liclassic', did most of the measured parameters of chlorophyll fluorescence (F v 0 /F m 0 , U PSII , q P and q N ) exhibit a statistically significant correlation with regard to the level of carotenoids. Therefore, in'Liclassic', the observed increase in carotenoid content seems to be a significant biochemical factor which can raise the efficiency of the photosynthetic apparatus under elicitation by Phoma lingam toxins.

Biochemical defense mechanisms induced in winter oilseed rape seedlings with different susceptibility to infection with Leptosphaeria maculans

“…In the previous work we showed higher activity of the photosynthetic apparatus in 'Liclassic' plants inoculated with L. maculans spores, as compared to 'Bojan' cultivar [23]. This was also manifested in greater biomass production in 'Liclassic' seedlings.…”

“…The division of winter rape cultivars in terms of susceptibility to L. maculans infection was based on field trials carried out in Polish conditions, breeding observations and our own experiments, whose results have been partly published [23]. The seeds were obtained from the Plant Breeding Center Strzelce Sp.…”

“…Our previous works showed that the cultivar resistant to L. maculans was characterized by higher activity of the photosynthetic apparatus. This was also reflected in a more rapid biomass production during pathogenesis [23]. Higher activity of the photosynthetic apparatus may result in a more efficient primary carbohydrate metabolism, constituting the basis of the secondary metabolism related to e.g.…”

Effects of seed priming, salinity and methyl jasmonate treatment on bioactive composition of Brassica oleracea var. capitata (white and red varieties) sprouts

“…In Brassicaceae, phenolics and GLS are enhanced under biotic stress . The mechanisms involved in such a response have been related to jasmonic acid (JA) .…”

Early Detection of Phoma Lingam Infection in Oilseed Winter Rape Before Visible Symptoms Appear

“…In the case of a biotic stress this may yield additional information on the functioning of the photosynthetic apparatus at the point of inoculation with a fungal pathogen as well as in the immediate vicinity of the inoculated tissue before the first symptoms of the disease become visible (Lai et al, 2011 (Jędryczka, 2007). In our previous study we demonstrated differences in photosynthetic apparatus activity in winter rape seedlings grown on agar medium containing toxic culture of Phoma lingam filtrates at 4, 7 and 11 days after inoculation (Hura et al, 2014). Little is known about early disturbances (between days 1 and 4 post-inoculation) of photosynthetic apparatus activity in winter rape seedlings under Phoma lingam infection.…”