羧甲基纤维素诱导提高罗伦隐球酵母对采后砂糖橘抗青霉、绿霉病的生防效果

Carboxymethyl Cellulose Induced Improvement of the Biocontrol of Cryptococcus laurentii against Postharvest Penicillium and Green Mold in‘Shatangju’Mandarin

为研究羧甲基纤维素(carboxymethyl cellulose,CMC)诱导罗伦隐球酵母(Cryptococcus laurentii)对采后砂糖橘(Citrus reticulata cv.Shatangju)拮抗扩展青霉(Penicillium expansum)、指状青霉(Penicillium digitatum)所引起青霉和绿霉病的生防增效作用,本研究以市售的砂糖橘为试材,筛选0.5%(质量分数,下同)CMC培养C.laurentii抗砂糖橘果实青霉、绿霉病的最佳诱导时间,采用无菌水为对照组,0.5%CMC诱导/未诱导培养C.laurentii为处理组,探究其对砂糖橘果实抗青霉、绿霉病效果、诱导果实抗病防御体系形成及果实贮藏质量的影响。结果表明,0.5%CMC诱导C.laurentii处理抗砂糖橘果实青霉、绿霉病的最佳诱导时间为72 h,该诱导时间下,C.laurentii对青霉、绿霉病害发生的生防效果显著优于其他诱导时间(P<0.05)。经0.5%CMC诱导培养72 h的C.laurentii(0.5%CMC-C.laurentii)所处理砂糖橘果实与其他组相比P.expansum、P.digitatum的发病率、病斑直径显著降低(P<0.05)。此外,与对照组相比,0.5%CMC-C.laurentii浸泡处理诱导可在贮藏第8天显著提高砂糖橘果皮β-1,3-葡聚糖酶、几丁质酶、苯丙氨酸酶、多酚氧化酶活力和总酚、类黄酮含量(P<0.05),保持砂糖橘在贮藏期间的营养品质。因此认为,添加0.5%CMC诱导培养可提高C.laurentii生防效力,CMC培养C.laurentii处理诱导能够提高砂糖橘果实抗病防御酶活力、促进抗性物质的合成积累、抑制采后青霉、绿霉病害发生,进而维持果实贮藏品质。

We aimed to investigate the efficacy of carboxymethyl cellulose(CMC)in inducing C.laurentii to antagonize postharvest penicillium(Penicillium expansum)and green mold(Penicillium digitatum)in‘Shatangju’mandarin.In this study,the culture time of C.laurentii induced by 0.5%CMC(mass fraction)was optimized for improved antagonistic effect against blue and green mold in commercially available‘Shatangju’mandarin.Using sterile water as a control,the effect of C.laurentii cultures induced and not induced by 0.5%CMC on the resistance to blue and green mold,the induction of disease defense system formation and the storage quality of‘Shatangju’mandarin was explored.The results showed that the optimal induction time for C.laurentii against both molds was 72 h.The biocontrol of C.laurentii against the two molds was significantly better at 72 h than at other induction times(P<0.05).C.laurentii induced by 0.5%CMC for 72 h significantly inhibited the incidence and lesion diameter of blue and green mold(P<0.05).In addition,it increased the activities ofβ-1,3-glucanase,chitinase,phenylalamine ammonia lyase and polyphenoloxidase and the contents of total phenols and flavonoids in citrus fruit on the eighth day of storage compared to the control group,thereby maintaining the nutritional quality of‘Shatangju’mandarin during storage.Accordingly,it was concluded that the addition of 0.5%CMC to the culture medium can improve the biocontrol efficacy of C.laurentii.The CMC-induced culture of C.laurentii can increase disease defense related enzyme activities,promote the synthesis and accumulation of antioxidant substances in‘Shatangju’mandarin,inhibit the occurrence of postharvest blue and green mold,and consequently maintain the storage quality of the fruit.