PopW蛋白对黄瓜霜霉病的防病促生作用

Control and growth promotion of PopW to cucumber downy mildew under greenhouse and field conditions

前期研究发现来源于青枯菌(Ralstonia solanacearum,ZJ3721)的Harpin蛋白PopW对多种作物有较好的诱导抗病作用。本文研究PopW蛋白在温室和田间条件下对黄瓜霜霉病的生防和促生效果。温室试验结果表明:人工接种霜霉病病原菌后15 d,250 mg/L PopW蛋白水溶液对黄瓜霜霉病的防效最好(42.85%),PopW蛋白(250 mg/L)处理的黄瓜苗与对照相比生物量增加26.92%,叶绿素含量显著提高。2010年,PopW蛋白(250 mg/L)间隔15 d喷雾1次,共使用3次。初次喷雾后8、25、35和48 d,对黄瓜霜霉病的生防效果分别为41.87%、48.36%、53.21%和50.85%;2011年,等量的PopW蛋白间隔10 d使用1次,共使用3次。初次喷雾后的第8、15、22和27 d,生防效果分别为47.07%、48.17%、50.59%和54.48%。试验结果表明,250 mg/L PopW蛋白水溶液可作为黄瓜霜霉病的潜在生防因子,且其抗病作用有一定的持效期,可保持10～15 d,甚至更长时间。分析PopW蛋白处理对黄瓜的促生作用及其对黄瓜品质的影响,结果显示:PopW蛋白处理组黄瓜单株增产达33.01%。PopW蛋白处理的黄瓜果实可溶性蛋白、可溶性糖、游离氨基酸和维生素C含量分别为18.07 mg/g、6.80 mg/g、60.20 mg/100 g、68.27μg/g,均显著高于对照(10.21 mg/g、5.30 mg/g、59.06 mg/100 g、49.55μg/g),结果表明PopW蛋白处理可显著提高黄瓜产量、改善黄瓜品质。

The PopW, a new harpin protein, was isolated from the bacterium Ralstonia solanacearum ZJ3721and showed induced resistance to various plant diseases. In this study, the biocontrol efficacy of PopW against cucumber downy mildew caused by Pseudoperonospora cubensis was investigated and evaluated. The PopW at the concentration of 250 mg/L obtained the best biocontrol efficacy of 42.85% than the other con- centration at the 15th day after pathogen inoculation under the greenhouse experiment. Meanwhile, PopW（250 mg/L） promoted the growth of cucumber and increased the content of chlorophyll in leaves of the plant. In the field experiments, the PopW with the same concentration was applied every 15 days and used three times in 2010. The biocontrol efficacy reached 41.87%, 48.36%, 53.21% and 50.85% at the 8, 25, 35 and 48 d after the first treatment of PopW, respectively. In 2011, the same treatment was applied every 10 days and the biocontrol efficacy reached 47.07%, 48.17%, 50.59% and 54.48% at the day of 8, 15, 22 and 27 d after the first application of PopW, respectively. The results indicated that the PopW had the potential to be an ef- fective biocontrol agent against Pseudoperonospora cubensis and the resistance induced could keep 10 - 15 days, even more. Furthermore, PopW increased the yield with 33.01% per individual plant and significantly improved the quality of cucumber fruit with increased content of soluble sugar, soluble protein, free amino acids and vitamin C with 18.07 mg/g, 6.80 mg/g, 60.20 mg/100 g, 68.27 μg/g, in PopW treatment and 10.21 mg/g, 5.30 mg/g, 59.06 mg/100 g and 49.55μg/g in control respectively.