Physiological and biochemical responses of tomato plants to white mold affected by manganese phosphite

Abstract

Considering the potential of white mold, caused by the fungus Sclerotinia sclerotiorum, to reduce tomato production, this study aimed to determinate the effect of manganese (Mn) phosphite on the resistance of tomato plants to this disease by assessing the photosynthetic performance (gas exchange and chlorophyll a fluorescence), the activities of defence enzymes and those related to the antioxidant metabolism as well as the concentrations of photosynthetic pigments, malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2−). The in vitro assays showed that S. sclerotiorum mycelial growth was inhibited by Mn phosphite in a dose‐response manner. The spray of Mn phosphite reduced white mold severity on the leaves of tomato plants. Additionally, there was a higher foliar Mn concentration for plants sprayed with Mn phosphite. The negative effects of S. sclerotiorum infection in the photosynthetic process were mitigated by Mn phosphite application as noticed by the net carbon assimilation rate, stomatal conductance to water vapour, transpiration rate, maximal photosystem II quantum yield values and concentration of photosynthetic pigments. The concentrations of MDA, H2O2 and O2‐ on inoculated leaves were lower upon Mn phosphite spray. In general, the activities of defence enzymes and those related to the antioxidant metabolism were higher for water‐sprayed plants inoculated with S. sclerotiorum in comparison to those inoculated and sprayed with Mn phosphite. Based on the present study results, the application of Mn phosphite may represent a feasible alternative for white mold management in tomato plants.

Selenium Promotes Sunflower Resistance to Sclerotinia Sclerotiorum by Regulating Redox Homeostasis and Hormonal Signaling Pathways

“…In a previous study, upregulation of cat in dun ower was found to be able toimprove resistance to S. sclerotiorum (Na et al 2018). In another study, the downregulation of pod and apx in tomato by the treatment of manganese phosphit could reduce the disease severity caused by S. sclerotiorum (Chaves et al 2021). The downregulation of sod expression was previously found to improve soybean resistance to S. sclerotiorum after sprayed with calcium (Arfaoui et al 2018).…”

Potentiation of soybean resistance against Phakopsora pachyrhizi infection using phosphite combined with free amino acids

“…Interestingly, the effect of the IR stimulus in reducing ASR symptoms was strikingly similar to that in studies reporting the use of ASM to establish SAR in some cash crops (Lyon, 2007). In soybean, the spray of ASM reduced soybean severity (Cruz et al, 2013) (12,13,14,15,16,17,18,19,20,21,22,23 and 24,respectively,to PAL1.1,PAL1.3,PAL2.1,PAL3. and suppression of spore germination (Chaves et al, 2020;Fagundes-Nacarath et al, 2018;Mohammad et al, 2021). Interestingly, the IR stimulus used in the present study had no effect on inhibiting urediniospore germination in vitro, highlighting its prominent role in triggering soybean resistance against P. pachyrhizi infection.…”

“…In soybean, the spray of ASM reduced soybean severity (Cruz et al, 2013). The phosphites can inhibit in vitro different physiological events in plant pathogens (e.g., Colletotrichum lindemuthianum , Sclerotinia sclerotiorum and different species of oomycetes) that will result in less mycelial growth and suppression of spore germination (Chaves et al, 2020; Fagundes‐Nacarath et al, 2018; Mohammad et al, 2021). Interestingly, the IR stimulus used in the present study had no effect on inhibiting urediniospore germination in vitro, highlighting its prominent role in triggering soybean resistance against P .…”

“…White mould symptoms were reduced in leaflets of common bean plants sprayed with Zn and Cu phosphites, resulting in higher F v / F m , Y(II) and ETR values associated with decreases in Y(NPQ) and Y(NO) (Fagundes‐Nacarath et al, 2018). Moreover, the functionality of the photosynthetic apparatus of tomato leaves sprayed with Mn phosphite was preserved due to lower white mould severity (Chaves et al, 2020). Reduced ASR symptoms for IR stimulus‐sprayed plants contributed to preserving the pool of photosynthetic pigments (Chl a + b and carotenoids), in contrast to results obtained for infected leaflets from ASM‐sprayed plants.…”

“…After germination, a total of four seedlings were left per pot. Plants were grown in a greenhouse (25 ± 3°C, relative humidity of 80% ± 5% and natural photosynthetically active radiation for 13 h), fertilized with nutrient solution (100 ml per pot weekly) prepared according to Chaves et al (2020) and watered as needed.…”