Análise de fatores de ferroptose em Vigna unguiculata [L.] Walp durante resposta a infecção pelo Vírus do Mosaico Severo do Caupi.

Abstract

The search for more tolerant and resistant cultivars has gained prominence due to ongoing climate changes, which are affecting global agricultural production. Cowpea (Vigna unguiculata [L.] Walp.) stands out as a relevant alternative to address these issues, given its ability to tolerate adverse environmental conditions, such as water deficit and high temperatures. However, cowpea is specially affected by pathogen attacks, with Cowpea Severe Mosaic Virus (CPSMV) being the main infectious agent affecting Brazilian production. As sessile organisms, plants have developed sophisticated defense mechanisms to cope with environmental challenges, among which programmed cell death (PCD) stands out as a form of resistance to pathogen action associated with the hypersensitive response. Among various PCD pathways, ferroptosis was recently discovered and described in plant models as an Fe²⁺-dependent form of cell death mediated by lipid hydroperoxides, resulting in oxidative stress induced cell death. This study aimed to investigate evidence of ferroptosis during the compatible plant-pathogen interaction between V. unguiculata and CPSMV. Plants of Pitiúba cultivar (CE-31) were inoculated with CPSMV on the first expanded trefoil and 12 hours later treated with ferrostatin-1 (Fer-1), a ferroptosis inhibitor, follow by collection 2 days after inoculation. Results of qualitative analysis of ferric ion (Fe³⁺) detection indicates that infected plants treated with the inhibitor had lower Fe³⁺ content compared to the control. Observing oxidative damage parameters, the inhibitor also affected hydrogen peroxide (H₂O₂) content, significantly reducing H₂O₂ levels in treated plants, but it did not alter malondialdehyde (MDA) content. In addition to biochemical markers of oxidative stress, the total enzyme activity of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) was measured. While CAT and APX exhibited reduced activity in infected plants treated with Fer-1, SOD activity remained unchanged. Thus, it can be concluded that the susceptible cultivar's response to CPSMV occurs late and is not modulated by ferroptosis.