Nitrogen in the defense system of Annona emarginata (Schltdl.) H. Rainer

Abstract

The concentration of nitrogen can generate different strategies in plants in response to stress. In this study, we investigated how nitrogen concentration interferes with the defense system of Annona emarginata . Low concentrations of nitrogen increased the allocation of photosynthetic resources to carbon metabolism, resulting in an increase in the synthesis of volatile substances involved in signaling and defense that contributed to antioxidant enzymes in overcoming stress. The availability of nitrogen at 5.62 mM concentration might have helped to induce increased resistance in the plants because at this concentration, signaling substances and defense substances (monoterpenes and sesquiterpenes) were observed. Plants cultivated with the highest nitrate concentration displaced energy for the reduction of this ion, likely forming nitric oxide, a signaling molecule. This condition, together with the decrease in carbon skeletons, may have contributed to the lower synthesis of volatile substances of the specialized metabolism that are also involved with signaling. Varying the nitrogen in Annona emarginata cultivation revealed that depending on the concentration, volatile substances show higher or lower synthesis and participation in the system of signaling and defense in the plant. These results may suggest that volatile substances participate in resistance to pests and diseases, which is a necessary condition for Annona emarginata to be preferentially used as rootstock for Annona x atemoya .

Metabolic Adjustment of Glycine max (L.) Merril in the Presence of Nitrate and Bradyrhizobium japonicum

“…Nitrate supply to Glycine resulted in decreased water use efficiency, which can be explained by greater transpiration (E), indicating greater water consumption, as already observed in Manihot esculenta [31]. In addition, Glycine with nitrate had reduced carbon assimilation rate (Anet), carboxylation efficiency of the Ru-BisCO enzyme (Anet/Ci), and concentrations of total soluble sugars, reducing sugars, and starch, indicative of competition between nitrogen and carbon metabolisms, as verified in previous studies [32]. Less photosynthetic activity in the absence of nitrogen and greater starch accumulation suggest that energy resources were used for the synthesis of reserve carbohydrates; these results are in agreement with those in the literature that report that nitrogen metabolism works with a carbon skeleton drain [7].…”

Unravelling the Roles of Nitrogen Nutrition in Plant Disease Defences

“…These antioxidant enzymes reduce ROS under stresses to less toxic compounds [126]. N fertilization generally increases the activities of these enzymes, thereby enhancing plant antioxidant capacity and reducing cell membrane injury [127,128]. The N deficient-triggered H 2 O 2 or superoxide anion accumulation in rice leaves [129], Matricaria chamomilla roots [130] and wheat peduncles [131] further support these observations.…”

“…Thus, NO 3 − nutrition can enhance NO generation via Nr activity, while the NO signal is inhibited under NH 4 + condition [150]. Further, NO 3 − nutrition can regulate NO-mediated responses to pathogen infection, such as stomatal closure or the kinetics of the HR [128]. Thus, the Nr-deficient double mutant (nia1 nia2) of Arabidopsis thaliana exhibited an impaired HR against avirulent Pseudomonas [151].…”

Comparative Transcriptome Analysis Reveals Common and Developmental Stage-Specific Genes That Respond to Low Nitrogen in Maize Leaves

“…Indeed, the trade-off between growth and defense response has been widely observed in many plant species. The inhibition of growth by LN may lead to resource fluxes that enter into defense-related pathways rather than growth by producing more secondary metabolites, which help plants to overcome adverse conditions [23,31,41]. However, among CGs, only a few genes were assigned to these two CMs, suggesting that these processes are highly stage-specific.…”