鼠李糖脂对梨采后黑斑病的抑制机理

Inhibition Mechanisms of Rhamnolipid on Black Spot of Postharvest Pear

摘要:

以梨果黑斑病菌 Alternaria alternate为研究对象，研究了鼠李糖脂（rhamnolipids，RLS）对抑制A. alternata的生长和控制黑斑病的作用，并进一步探讨了其抑菌作用机理。结果表明：RLS能显著抑制 A. alternata 的生长，且其抑制效果随质量浓度的增加而显著提高，其中30 mg/mL RLS处理的菌落培养7 d时直径仅为对照组的19.22%，且菌落呈白色、球状。同时，RLS处理能有效控制梨果黑斑病的扩展，其中50 mg/mL RLS处理的果实的病斑直径仅为对照的21.42%。进一步研究发现RLS处理严重破坏了A. alternata 细胞膜和线粒体的完整性，提高了膜电导率，促进了活性氧的产生与积累。超微观察发现RLS处理后A. alternata的菌丝形态、细胞结构均发生了明显改变。

Abstract:

The antifungal effect of rhamnolipids (RLS) on the vegetative growth of Alternaria alternata and on the black spot control were studied, and the possible mechanism of its antifungal activity was evaluated. The results showed that RLS significantly inhibited the growth of A. alternata, and the inhibition effect was significantly increased with the increase of RLS concentration. The mycelium diameters of A. alternata treated with 30 mg/mL RLS was only 19.22% of the control group after 7 days' incubation, and mycelium was white and ball in shape. The development of black spot in pear fruit treated with RLS was also inhibited, lesion diameter of 50 mg/mL RLS treatment group was only 21.42% of that in the control group. Further research showed that the RLS treatment severely damaged the integrity of A. alternata cell membranes and mitochondria, increased membrane conductivity, and promoted the generation and accumulation of reactive oxygen species. Ultramicroscopic observation showed that the hyphae morphology and cellular structure of A. alternata were significantly destroyed by RLS treatment.