Grapevine Phytoplasma Yellows And Their Quarantine Techniques

Plant disorder occurred on wild and cultivated grapevines caused by phytoplasmas infection is usually called grapevine yellows. The typical symptom of the disease is shown as yellow leaves on the infected plant. In order to distinguish the disease from the yellow symptoms caused by several viruses and nutrition deficiency, this disease is referred as grapevine phytoplasma yellows (GPY) in this research. Comprehensive systematic research including quarantine, risk assessment, detection and identification was conducted on GPYs in this research. The results are as follows:①Phytoplasma concentration inside dormant grapevine plants is extremely low, and its distribution is uneven. phytoplasmas mainly persist inside root and shoot tissues which are not completely suberized.②Different primer pairs have different detect sensitivities, the differences among them are possibly over thousand-fold.③The method of incubating leafhopper like insects inside Eppendorf tube is a highly effective method for the screening of phytoplasma insect vectors.④Leafhopper Aprodes makarovi Zachvatkin naturally infected by so-called"Vergilungskrankheit"phytoplasma (AY group) was detected for the first time.⑤Analysis of an extra 0.36 kb fragment amplified by P1/P7 (U5/P7) nested U5/U3 primers in grapevine yellow (Stolbur) phytoplasma detection revealed that this extra fragment located on phytoplasma 16SrRNA gene with a partial compliment site of U5 primer.⑥The results show that AFLP technique can be used in the classification and typing of phytoplasmas when properly designed.⑦It is unreasonable using"dissemination by S. titanus"as one of the preconditions to distinguish ALY phytoplasma from FD phytoplasma. ALY phytoplasma is actually FD phytoplasma, i.e. FD-C type of FD phytoplasma.⑧No GPY was observed or detected during a survey of GPY in Jiaodong peninsula viticulture region. No known insect vector of GPY was found while wild host plants of GPY was found in this region.