Postharvest role of jasmonic acid and wounding on expression of defense related metabolism in sugar beet roots

• Ano de defesa: 2016
• Autor(a) principal: Oliveira, Lucilene Silva de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Beterraba açucareira; Beta vulgaris; Expressão gênica; Ácido jasmônico; Fisiologia Vegetal
• Link de acesso: http://www.locus.ufv.br/handle/123456789/8354

Jasmonate (JA) can act as an inducer expression of defense genes against biotic and abiotic stress by process of priming plant. Exogenous application of JA has been shown to reduce rotted tissue and control postharvest pathogen in sugarbeet roots. However, the mechanism involved in the postharvest induction of defense by JA in sugarbeet roots is unknown. Consequently, we investigated the JA-induced mechanisms which protect roots from storage pathogens by identifying and characterizing genes that are altered by JA treatment. JA (10 μM) treatment to sugarbeet roots resulted alteration significant of unigenes expression. RNA-Seq data showed that 30 and 49 putative defense genes were upregulated at 2 and 60 days after JA-treatment, respectively. In sugarbeet roots, peroxidases, cinnamate-4-hydroxilase, chitinase acid, laccases, nbs-Irr resistant, pathogen-related thaumatin family protein, proteinase inhibitor and β- glucosidase were found at higher levels (fold change ranged from 1.8 to 8.3) in treated than control roots at 2 d subsequent to JA-application. At 60 days after JA treatment observed that peroxidase, chitinase, cinnamate-4 hydroxilase and cc-nbs-Irr resistant protein were also up-regulated. These upregulated unigenes are related with biosynthesis of secondary metabolites, cell wall reinforcement, as well as for plant- pathogen interaction. Thus, the present study suggests that JA treatment could prime sugarbeet inducting a series of defense genes, including defense-related proteins and key enzymes related secondary metabolites. JA also increased the ability of sugarbeet cells to recognize pathogen which may result faster activation of immune response and then reduction of infection and susceptibility. In addition to rotted losses in rot storage it is extremely importance to avoid losses during sugarbeet growth. Insect attack by sugarbeet root magoot is one of damage that significantly reduces root yield and sucrose content and can devastate individual fields. Thus, study of resistance mechanism is essential to provide new control strategies and reduce insecticides spray. We investigated if resistance of some genotypes is achieved through activation of chitinase, peroxidase and polyphenoloxidase. Root of nine genotypes sugarbeet, susceptible and resistant to maggot fly, were wounding 4 weeks after planting to mimic maggot attack. The results showed neither peroxidase nor polyphenol oxidase activity is correlated to maggot fly resistant in sugarbeet roots. We observed that chitinase activity was significantly reduced for some genotypes after wounding, although no significance difference was found between resistant and susceptible sugarbeet genotypes.