Biochemical changes in corn plants infected by the maize bushy stunt phytoplasma

The objective of the present work was to study biochemical alterations in corn plants infected by the maize bushy stunt phytoplasma. A resistant and a susceptible corn hybrid were used and changes in protein, phenolic compounds, chlorophyll and reducing sugars in infected plants were evaluated. The experiments were carried out inside greenhouse, and the corn plants were inoculated by using infective Dalbulus maidis leafhoppers 10 days after seeding. When symptoms started to appear, leaf samples were harvested at different times for the biochemical analyses. The results showed an increase in all biochemical parameters evaluated for both hybrids, with exception for the chlorophyll content that decreased. In a general way, the values observed for the level of the different compounds were higher in the susceptible hybrid when compared to the resistant one. The increases in protein, reducing sugar and phenolic compound contents in inoculated plants point out changes in host metabolism due to the phytoplasma, and the reduction in chlorophyll content shows that the phytoplasma can interfere in photosynthesis and perhaps speedy senescence in the leaf tissue.