Ácido salicílico na indução de resistência a escaldadura em cana-de-açúcar em condições de deficiência hídrica
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Data
2022-05-31
Autores
Souza, Lucas da Silva
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A produção brasileira de cana-de-açúcar encontra-se estagnada desde 2010 em função de problemas fitossanitários. Uma das doenças que afeta substancialmente a cana-de- açúcar é conhecida como escaldadura da folha, causada pela bactéria Xanthomonas albilineans. Atualmente, o único método de controle efetivo é o uso de cultivares resistentes. Entretanto, este método é passível de erros. Por conta disso, a busca por meios alternativos de controle torna-se de suma importância, como a indução da resistência, e entre estes indutores encontra-se o ácido salicílico (AS). Assim, o presente trabalho teve como objetivo avaliar a eficiência da aplicação do AS no controle da escaldadura em duas cultivares de cana-de-açúcar, sendo uma suscetível a Xanthomonas albilineans, cultivar SP78-4467, e a outra, considerada resistente à doença, cultivar SP80-3280. Diferentes concentrações de AS (0 μmol L−1 e 72 μmol L−1) foram aplicadas por um período de 90 dias, e em seguida as plantas foram transplantadas para vasos maiores contendo solo. Após um período de 30 dias, as plantas foram inoculadas com a bactéria Xanthomonas albilineans, e após 10 dias depois da inoculação foi realizada a deficiência hídrica até o CRA atingir 40%, em seguida as plantas foram coletadas para análises laboratoriais. Ambos os estresses causaram uma queda na concentração de clorofila e carotenoides. Os tratamentos que passaram por déficit hídrico apresentaram menor potencial hídrico foliar, mas o AS promoveu um aumento nesse potencial na cultivar SP80-3280, isto pois o AS está relacionado com genes exclusivos de cultivares resistentes a seca. O AS também causou um aumento na concentração da prolina, e atividade da SOD, GPOX e GSH-Px em diferentes cultivares quando as plantas foram inoculadas e sob deficiência hídrica. De modo geral, a aplicação de AS promoveu atenuação nos danos causados pela bactéria, sendo a cultivar susceptível a mais responsiva a aplicação do AS.
The Brazilian production of sugarcane has been stagnant since 2010 due to phytosanitary problems. One of the diseases that substantially affects sugarcane is known as leaf scald caused by the bacterium Xanthomonas albilineans. Currently, the only effective control method is the use of resistant cultivars. However, this method is prone to error. Because of this, the search for alternative means of control becomes important, such as the the use of elicitors like salicylic acid (SA). Thus, the present work aimed to evaluate the efficiency of the application of SA in the control of leaf scald in two sugar cane cultivars, SP78-4467 (susceptible to Xanthomonas albilineans) and, SP80 -3280 (resistant to Xanthomonas albilineans). Different concentrations of SA (0 μmol L−1 and 72 μmol L−1) were used for a period of 90 days, and then the plants were transplanted to larger pots containing soil. After a period of 30 days, the plants were inoculated with the bacterium Xanthomonas albilineans, and 10 days after inoculation, water deficit was performed until the CRA reached 40%, then the plants were collected for laboratory analysis. Both stresses caused a drop in the concentration of chlorophyll and carotenoids. The treatments that underwent water deficit had lower leaf water potential, but SA promoted an increase in this potential in cultivar SP80-3280, this because SA is related to genes exclusive to drought-resistant cultivars. AS also caused an increase in proline concentration, and SOD, GPOX and GSH-Px activity in different cultivars when plants were inoculated and under water deficit. In overall results, SA promoted attenuation of the damages caused by the bacteria, with the susceptible cultivar being the most responsive to the application of SA.
The Brazilian production of sugarcane has been stagnant since 2010 due to phytosanitary problems. One of the diseases that substantially affects sugarcane is known as leaf scald caused by the bacterium Xanthomonas albilineans. Currently, the only effective control method is the use of resistant cultivars. However, this method is prone to error. Because of this, the search for alternative means of control becomes important, such as the the use of elicitors like salicylic acid (SA). Thus, the present work aimed to evaluate the efficiency of the application of SA in the control of leaf scald in two sugar cane cultivars, SP78-4467 (susceptible to Xanthomonas albilineans) and, SP80 -3280 (resistant to Xanthomonas albilineans). Different concentrations of SA (0 μmol L−1 and 72 μmol L−1) were used for a period of 90 days, and then the plants were transplanted to larger pots containing soil. After a period of 30 days, the plants were inoculated with the bacterium Xanthomonas albilineans, and 10 days after inoculation, water deficit was performed until the CRA reached 40%, then the plants were collected for laboratory analysis. Both stresses caused a drop in the concentration of chlorophyll and carotenoids. The treatments that underwent water deficit had lower leaf water potential, but SA promoted an increase in this potential in cultivar SP80-3280, this because SA is related to genes exclusive to drought-resistant cultivars. AS also caused an increase in proline concentration, and SOD, GPOX and GSH-Px activity in different cultivars when plants were inoculated and under water deficit. In overall results, SA promoted attenuation of the damages caused by the bacteria, with the susceptible cultivar being the most responsive to the application of SA.
Descrição
Palavras-chave
Ácido salicílico, Saccharum spp., Xanthomonas albilineans, Deficiência hídrica, Cana-de-açúcar, Bactérias, Fisiologia vegetal