西瓜感染黄瓜绿斑驳花叶病毒后糖分代谢与倒瓤的关系

The relationships between sugar metabolism and blood-flesh of watermelon infected with Cucumber green mottle mosaic virus

为揭示人工接种黄瓜绿斑驳花叶病毒(Cucumber green mottle mosaic virus,CGMMV)后西瓜糖分代谢与倒瓤的关系,采用高效液相色谱法测定了接种CGMMV后西瓜的葡萄糖、果糖、蔗糖含量变化,采用比色法测定了糖酵解途径关键酶及蔗糖代谢相关酶活性的变化。结果显示,西瓜苗感染CGMMV后,果实中葡萄糖、果糖、蔗糖含量均较对照发生明显变化,接种处理后葡萄糖含量在授粉7~28 d显著高于对照,之后迅速下降,35 d时显著低于对照,仅为对照的24.87%;果糖含量仅在授粉后7~14 d高于对照,21~35 d显著低于对照;接种处理和对照的蔗糖含量在授粉后14~35 d均逐渐上升,但14~35 d接种处理显著低于对照。接种处理后己糖激酶、磷酸果糖激酶和果糖激酶活性均在授粉后7~14 d显著低于对照,21~28 d显著高于对照,35 d时显著低于对照;丙酮酸激酶活性授粉后7~21 d显著低于对照,35 d时显著高于对照;酸性转化酶和中性转化酶活性在授粉后7~21 d显著低于对照,35 d时高于对照;蔗糖磷酸合成酶和蔗糖合成酶活性均显著低于对照,其中蔗糖合成酶活性在授粉后28 d时仅为对照的21.32%。推断西瓜苗接种CGMMV后糖酵解的4个关键酶协同作用,调控糖酵解,进而调控葡萄糖和果糖的积累与代谢,同时蔗糖代谢相关酶活性降低,阻碍蔗糖合成,即西瓜苗感染CGMMV导致倒瓤与其糖分的合成与代谢密切相关。

To reveal the relationships between the variation of sugar contents, the activities of the key enzymes in glycometabolism and blood-flesh of watermelon after inoculated by Cucumber green mottle mosaic virus（CGMMV）, the contents of glucose, fructose and sucrose were analyzed with high-performance liquid chromatography and the activities of the key glycolytic enzymes and sucrose-metabolizing enzymes were measured with colorimetry. The results showed that the content of glucose, fructose and sucrose changed obviously compared with the control group. After inoculated by CGMMV, the content of glucose was significantly increased 7-28 d after pollination compared to that of the control, then reduced rapidly and was only 24.87% of the control at the 35 th day after pollination. The content of fructose was higher than the control 7-14 d after pollination, then decreased obviously, and it was significantly lower than the control after 21-35 d. In all cases, the content of sucrose increased in 14 to 35 d with the growth of watermelon. However, compared with the control, the sucrose content of watermelon inoculated with CGMMV was significantly lower after 14-35 d. After inoculation, the activities of hexokinase, phosphofructokinase and fructokinase were significantly lower than that of the control after7-14 d and at the 35 th day after pollination, and were significantly higher than the control after 21-28 d.The activity of pyruvate kinase was significantly lower than that of control 7-21 d after pollination, and significantly higher than the control at the 35 th day. The results of acid invertase and neutral invertase assay showed that the activities of these two enzymes were significantly lower than that of the control7-28 d after pollination, and it was higher than the control at the 35 th day. The activities of sucrose synthase and sucrose phosphate synthase were significantly lower than that of control during the test, and the activity of sucrose synthase was only 21.32% of the control at the 28 th day after pollination. It was concluded that the four key enzymes of EMP had synergistic effect with each other, and played an important role in the regulation of glycolysis and the accumulation of glucose and fructose after inoculated by CGMMV. The acid invertase, neutral invertase, sucrose synthase and sucrose phosphate synthase played an important role in the synthesis of sucrose, and the change of them may prevent the synthesis of sucrose. In summary, synthesis and metabolism of sugar was closely related to the blood-flesh of watermelon caused by CGMMV.