Redução da severidade da podridão-amarga de maçã em pós-colheita pela imersão de frutos em quitosana

Abstract

Resumo -O objetivo deste trabalho foi avaliar a aplicação de quitosana no controle da podridão-amarga da maçã em pós-colheita e seus efeitos sobre Colletotrichum acutatum e a atividade da peroxidase nos frutos. Frutos previamente infectados com o patógeno foram imersos em suspensões de quitosana com diferentes concentrações e pHs. Para estudar possíveis mecanismos de ação envolvidos no controle da doença, foram realizados testes in vitro, para avaliar o efeito da quitosana sobre a germinação de conídios de C. acutatum e sobre o crescimento micelial. Foi avaliada a capacidade da quitosana de induzir a síntese de enzimas relacionadas à defesa da planta (peroxidases), por meio de ensaio espectrofotométrico. Houve efeito de doses e de pH da quitosana sobre a redução da severidade da podridão-amarga em maçã. A suspensão de quitosana a 10 g L -1 e pH 4 foi a mais apropriada tecnicamente para o controle da doença, pois reduziu a severidade em 26%. O polissacarídeo não elevou a atividade de peroxidases nos frutos, mas reduziu a germinação de conídios e o crescimento micelial do patógeno. A quitosana aplicada em pós-colheita é uma medida alternativa aos fungicidas para o manejo da podridão-amarga.Termos para indexação: Colletotrichum acutatum, antibiose, controle alternativo, indução de resistência. Reduction of the severity of apple bitter rot by fruit immersion in chitosanAbstract -The objective of this work was to evaluate the aplication of chitosan on the control of apple bitter rot in postharvest conditions and its effects on Colletotrichum acutatum and fruit peroxidase activity. Apple fruit previously infected with the pathogen were immersed in chitosan suspensions with different concentrations and pHs. To study some possible action mechanisms, in vitro tests were carried out to evaluate the effect of chitosan on spore germination and mycelial growth of C. acutatum. The capacity of chitosan to induce the synthesis of defense enzymes (peroxidases) was evaluated in fruits by spectrofotometric assay. Different doses and pH of chitosan were found to be effective in the reduction of the disease severity. Chitosan at 10 g L -1 (pH 4) had the most technical viability for the control of the disease and reduced the severity in 26%. Considering the action mechanisms, chitosan did not increase peroxidase activity in the fruits; however, it reduced both spore germination and mycelial growth of the pathogen. Chitosan applied at postharvest is an alternative to reduce bitter rot severity.

Blue mold control and volatile compounds in “Fuji” apples treated with chitosan emulsion combined with essential oils

“…In both seasons, POD activity in the skin tissue was lower in fruit treated with CE + citronella EO and CE + clove EO than in the control (Table 1). Felipini and Di Piero (2009) also reported in apples treated with chitosan no increase of POD activity, but reduced severity of the disease caused by C. acutatum , through inhibition of conidia germination and mycelial growth of the fungus. However, in 2019/2020, fruit treated with CE had higher POD activity in the skin tissue than the control (Table 1).…”

Blue mold control and volatile compounds in “Fuji” apples treated with chitosan emulsion combined with essential oils

“…In both seasons, POD activity in the skin tissue was lower in fruit treated with CE + citronella EO and CE + clove EO than in the control (Table 1). Felipini and Di Piero (2009) also reported in apples treated with chitosan no increase of POD activity, but reduced severity of the disease caused by C. acutatum , through inhibition of conidia germination and mycelial growth of the fungus. However, in 2019/2020, fruit treated with CE had higher POD activity in the skin tissue than the control (Table 1).…”

Evaluation of chitosan for in vitro control of Colletotrichum tamarilloi and anthracnose on scarlet eggplant fruit

“…Chitosan's antimicrobial activity is affected by various factors, such as its molecular weight (Jing et al, 2007;Hernández-Lauzardo et al, 2008), degree of acetylation (Andres et al, 2007), temperature during interaction (Hefian et al 2010;Szymańska & Winnicka, 2015), and the pH of the medium (Felipini & Piero, 2009;Alburquenque et al, 2010). The local pH, specifically the pH of the coated produce, is also known to have an impact on chitosan's antifungal activity (Assis & Leoni, 2003).…”

Mangifera Indica Postharvest: Evaluation of the Potential of Alternative Treatments to Control Anthracnose

“…ex Tanaka) found that Chitosan ® at all concentrations did not show statistical differences for enzymatic activity of peroxidase. Felipini;Di Piero (2009), studying the application of Chitosan ® in the postharvest control of Malus domestica L. against Colletotrichum acutatum (Simmonds) and the peroxidase activity, observed that the application of Chitosan ® independent of pathogen inoculation did not change the activity of this enzyme.…”

Blue mold control and volatile compounds in “Fuji” apples treated with chitosan emulsion combined with essential oils

“…In both seasons, POD activity in the skin tissue was lower in fruit treated with CE + citronella EO and CE + clove EO than in the control (Table 1). Felipini and Di Piero (2009) also reported in apples treated with chitosan no increase of POD activity, but reduced severity of the disease caused by C. acutatum , through inhibition of conidia germination and mycelial growth of the fungus. However, in 2019/2020, fruit treated with CE had higher POD activity in the skin tissue than the control (Table 1).…”

Evaluation of chitosan for in vitro control of Colletotrichum tamarilloi and anthracnose on scarlet eggplant fruit

“…Chitosan's antimicrobial activity is affected by various factors, such as its molecular weight (Jing et al, 2007;Hernández-Lauzardo et al, 2008), degree of acetylation (Andres et al, 2007), temperature during interaction (Hefian et al 2010;Szymańska & Winnicka, 2015), and the pH of the medium (Felipini & Piero, 2009;Alburquenque et al, 2010). The local pH, specifically the pH of the coated produce, is also known to have an impact on chitosan's antifungal activity (Assis & Leoni, 2003).…”

Mangifera Indica Postharvest: Evaluation of the Potential of Alternative Treatments to Control Anthracnose

“…ex Tanaka) found that Chitosan ® at all concentrations did not show statistical differences for enzymatic activity of peroxidase. Felipini;Di Piero (2009), studying the application of Chitosan ® in the postharvest control of Malus domestica L. against Colletotrichum acutatum (Simmonds) and the peroxidase activity, observed that the application of Chitosan ® independent of pathogen inoculation did not change the activity of this enzyme.…”

Blue mold control and volatile compounds in “Fuji” apples treated with chitosan emulsion combined with essential oils

“…In both seasons, POD activity in the skin tissue was lower in fruit treated with CE + citronella EO and CE + clove EO than in the control (Table 1). Felipini and Di Piero (2009) also reported in apples treated with chitosan no increase of POD activity, but reduced severity of the disease caused by C. acutatum , through inhibition of conidia germination and mycelial growth of the fungus. However, in 2019/2020, fruit treated with CE had higher POD activity in the skin tissue than the control (Table 1).…”

Evaluation of chitosan for in vitro control of Colletotrichum tamarilloi and anthracnose on scarlet eggplant fruit

“…Chitosan's antimicrobial activity is affected by various factors, such as its molecular weight (Jing et al, 2007;Hernández-Lauzardo et al, 2008), degree of acetylation (Andres et al, 2007), temperature during interaction (Hefian et al 2010;Szymańska & Winnicka, 2015), and the pH of the medium (Felipini & Piero, 2009;Alburquenque et al, 2010). The local pH, specifically the pH of the coated produce, is also known to have an impact on chitosan's antifungal activity (Assis & Leoni, 2003).…”

Mangifera Indica Postharvest: Evaluation of the Potential of Alternative Treatments to Control Anthracnose

“…ex Tanaka) found that Chitosan ® at all concentrations did not show statistical differences for enzymatic activity of peroxidase. Felipini;Di Piero (2009), studying the application of Chitosan ® in the postharvest control of Malus domestica L. against Colletotrichum acutatum (Simmonds) and the peroxidase activity, observed that the application of Chitosan ® independent of pathogen inoculation did not change the activity of this enzyme.…”