柑桔裂皮病类病毒感染的柑桔树中同工酶的变化

CHANGES OF ISOENZYMES FROM CITRUS TREES INFECTED BY CITRUS EXOCORTIS VIROID

柑桔裂皮病是由柑枯裂皮病类病毒(Citrus exocortis viroid,CEV)引起的病害,它的主要症状是砧木韧皮部纵向裂皮,鳞片化剥落,植株矮化,生长缓慢。因为症状有无十分明显,故病树和未发病树肉眼可辨,无需再作其它诊断。实践上的困难在于多数带有类病毒的慢性感染植株在什么条件下发病?如何预测?能否预防?因此,本研究特以慢性感染树作对照,与病树进行同工酶的对比研究。寻找发病的先兆,以期找到早期诊断的参考指标,并为进一步研究病害的预防打下基础。

Rootstock phloem tissue of exocortic citrus trees caused by citrus exo-cortis viroid ( CEV ) and chronic CEV-infected citrus trees were collected from citrus orchards. Peroxidase, esterase and glutamic oxalacetic transami-nase ( GOT ) iscenzymes were extracted and analyzed by means of PAGE method, at the same time, the activity of peroxidase was measured. The results showed that the activity of peroxidase from the exocortic citrus trees was higher than that of the chronic CEV-infected citrus trees, the exocortic citrus trees had one extra band of peroxidase that was missing inthe chronic CEV-infected citrus trees, some bands of esterase isoenzymes from the exocortic citrus trees became less distinct; the exocortic citrus trees lost the large molecular band of GOT isoenZymes but showed small molecular bands. The possible relationship between the changes of enzyme activity and the mechanism of CEY pathogenesis is discussed.