特基拉芽胞杆菌KXF 6501对猕猴桃灰霉病的防控效果及诱导果实抗性研究

Biocontrol Efficiency and Mechanism of Bacillus tequilensis KXF 6501 against Grey Mold in Postharvest Kiwifruit

灰霉菌Botrytis cinerea引起的猕猴桃灰霉病是猕猴桃采后贮藏过程的主要病害之一,为更好防治猕猴桃采后灰霉病,本研究以健康草莓果实表面分离的特基拉芽胞杆菌KXF 6501为供试菌株,研究24 h和96 h的发酵液在平板对峙及猕猴桃果实上对灰霉病的防治效果,进而研究其对猕猴桃果实抗性物质、抗性防御酶活及果实品质的影响。结果表明,芽胞杆菌KXF 650124和96 h的发酵液在第5 d时,在平板上对灰霉菌的抑制率分别为75.96%和73.72%;在猕猴桃果实上处理4d时,与未处理的对照组相比,果实的发病率分别为65.00%和70.00%,显著低于对照组;11 d时的果实病斑直径分别为2.78和4.25 cm,小于对照组,其中以24 h的发酵液防治效果较好。与对照相比,芽胞杆菌KXF 650124 h的发酵液处理能更快诱导提高猕猴桃的抗性物质含量和抗病酶活,抗性物质总酚、类黄酮和花青素的含量,先于对照组在第7 d达到峰值,且为对照组的1.96、4.07和5.29倍;PAL、GLU和CHI酶活峰值分别为95.04、240.19和8.41 U/g,是对照组的2.40、2.03和1.15倍,PPO酶活在28d时显著高于对照组,为116.58U/g,是对照组的3.35倍。此外,KXF 650124 h发酵液处理降低了果实可溶性固形物含量和失重率,维持猕猴桃果实的营养品质。研究表明,特基拉芽胞杆菌KXF 6501对猕猴桃灰霉病病原菌具有很好的抑制作用,能降低发病率,可促使猕猴桃果实抗病相关物质和酶活性升高,诱导猕猴桃果实的系统抗性。

Kiwifruit gray mold disease caused by Botrytis cinerea is one of the main postharvest diseases.In order to better control postharvest gray mold in kiwifruit,this study used Bacillus tequilensis KXF 6501 isolated from healthy strawberry fruit surfaces as the test strain,its antagonistic effect against gray mold on plate and kiwifruit fruits was investigated,then its effect on kiwifruit fruits resistance substances,resistance defense enzyme activities and fruit quality were studied.The results showed that the 24 h-and 96 h-fermentation broths of KXF 6501 inhibited gray mold by 75.96%and 73.72%,respectively,at the 5th day on plate,and the fruit incidence of gray mold disease on kiwifruit was 65.00%and 70.00%,respectively,at the 4th day of storage,which significantly lower than the control fruits.The lesion diameters on the kiwifruit at 11d were 2.78 and 4.25 cm,respectively,which were smaller than those of the control fruits.The 24 h fermentation broth showed a better control effect.Compared with the control,24 h-fermentation broth of KXF 6501 induced a faster increase of resistance substance content and enzyme activity in kiwifruit.The content of total phenols,flavonoids,and anthocyanins reached their peak at 7 d,which were 1.96,4.07,and 5.29 times higher than those of the control group,respectively.The peak PAL,GLU and CHI enzyme activities were 95.04,240.19 and 8.41 U/g,respectively,which were 2.40,2.03 and 1.15 times higher than those of the control group,and the PPO enzyme activity was significantly higher than that of the control group at 28 d,which was 116.58 U/g,3.35 times higher than that of the control group.In addition,24 h-fermentation broth of KXF 6501 treatment reduced fruit soluble solids content and weight loss,maintained the nutritional quality of kiwifruit fruits.The study showed that Bacillus tequilensis KXF 6501 had a good inhibitory effect on the kiwifruit gray mold pathogen,reduced the incidence of the disease,and could increase the content and activities of disease resistance-related substances and enzymes in kiwifruit fruits,then induced the systemic resistance in kiwifruit fruits.