Study On Callose Fluorescence Labeling And Function In The Different Soybean-soybean Mosaic Virus Combinations

The role played by callose (β-1,3-Glucan) to protect plants against virus has gained more and more attentions, however, its exact effect to keep soybean away from soybean mosaic virus (SMV) infection is relatively little known. In this experiment, the selected eight varieties of soybean and four different strains of soybean mosaic virus(SMV) are divided into twenty-three combinations that respond on different resistance levels. Through the symptom observation of inoculated leaves and the upper leaves, aniline blue staining followed by fluorescence microscopy, and pharmacological experiment we want to study the characteristics of callose (β–1,3–glucan ) accumulation in combinations of different resistance levels and the function of callosein in the process of soybean and SMV interaction.The results show that,in the earlier period of time after inoculation (6-72 h ), callose fluorescence in the mesophyll cells of different combinations, which resistance levels ranges from 0 to 3, were observed at different time depending on different resistant levels of combinations and the emergence time of callose fluorescence is closely related to the resistance levels. In another word, the variety more strongly resisting to SMV can earlier be found the callose fluorescen at the sites of inoculation. However, callose fluorescence has not been observed in the combination that responds in resistance level 5 . In addition, 2-deoxy-D-glucose, necrosis in the upper leaves was observed and the viral RNA of specific coat protein(CP-RNA) was detected by RT-PCR analysis following pre-injection of DDG ( an inhibitor of callose synthesis). Therefore, the deposition of callose at the sites of inoculation can limit the transportation of SMV in mesophyll cells, indicating that callose plays an important role in the resistance of soybean to the infection of SMV. In the combination that responds in resistance level 0,there are callose accumulation in leaf vein、leaf stalk and stems after frictional inoculation. All the results above indicated that,the variety more strongly resisting to SMV can earlier be found the callose accumulation at the sites of inoculation .Callose accumulation relates closely to the resistance of soybean to SMV.