In the present work we studied the effect of inoculating corn plants with the maize bushy stunt phytoplasma on the activity of the enzymes peroxidase, -1,3 glucanase and chitinase. The experiments were ca rried ou t inside a greenhou se. Pla nts of a resistant a nd a susceptible corn hybrid were inoculated by using infective Dalbulus maidis leafhoppers 10 days after sowing. When symptoms started to appear, leaf samples were collected at different periods to quantify enzyme activity. The resu lts showed a n increa se in the activity of Junqueira, A.C.B.; Bedendo, I.P.; Pascholati, S.F. Effect of phytoplasma infection on activity of peroxidase, -1,3 glucanase and chitinase in corn plants. Summa Phytopathologica, v.37, n.4, p.194-198, 2011. the three enzymes in inoculated plants of both hybrids. In genera l, the values observed for the level of the different enzymes were higher in the susceptible hybrid when compared to the resistant one. Thus, the increases in peroxidase, -1,3 glucanase and chitina se levels in inocula ted pla nts are evidence of cha nges in the host meta bolism ca used by the phytopla sma . On the other hand, since the increases could not be correlated with plant resistance further studies are needed to explain such changes.Keywords: maize stunt, pr-protein, Mollicutes, yellows.
ABSTRACTJunqueira, A.C.B.; Bedendo, I.P.; Pascholati, S.F. Efeito da infecção de fitoplasma sobre a atividade de peroxidase, -1,3 glucanase e quitinase em plantas de milho. Summa Phytopathologica, v.37, n.4, p.194-198, 2011.
RESUMOPalavras-chave adicionais: enfezamento do milho, pr-proteína, Mollicutes, amarelos Phytoplasmas are associated with important diseases in several hundreds of plant species (19). Although well known as pathogens, little information is available concerning biochemical and physiological changes that occur in infected plants. Some reports have shown that the association between plants and phytoplasmas can result in changes in compounds present in plant tissue, but basically few ones are found related to the activities of peroxidases, -1,3 glucanases and chitinases in these interactions. In corn hybrids infected with maize bushy stunt phytoplasma, changes were observed in protein, reducing sugar, phenolic compound and chlorophyll content (12). Corn plants inoculated with phytoplasma and spiroplasma agents of corn stunt showed lower protein content than non-inoculated plants (24). In plants of tobacco and Catharanthus roseus infected with phytoplasmas accumulation of carbohydrates in the leaves and lower levels in the roots of the same plants were observed (15).Maize bushy stunt has caused significant damage to corn crops in Brazil, reaching high levels of incidence and losses (18; 25). Thus, a comparative analysis revealed a yield reduction of up to 30% in fields without treatment insecticide for control of the vector (18). In some fields naturally infected, incidences of almost 100% were observed, resulting in total losses for the crop (25). Typical symptoms are foliar reddening, shortening ...
