Abstract: In order to integrate the excellent characteristics of biocontrol streptomyces strain ML27 and endophytic actinomycetes strain P3Y2 from citrus, the protoplast fusion between strain ML27 and P3Y2 were studied in this paper. The results showed that protoplasts with sufficient number and strong regeneration ability were obtained when ML27 and P3Y2 were cultured separately in culture medium containing 20% and 10% sucrose as well as 1.5% and 1.0% glycin, and sensitive mycelia were treated with 5 mg/mL lysozyme for 90 min and 120 min separately. The protoplasts were inactivated in 60℃ water for 10 min for ML27 and 15 min for P3Y2, or under 20W ultraviolet lamp for 7 min and 5 min.Based on the above, the protoplast fusion between P3Y2 and ML27 was executed, and one fused strain ML45 was screened preliminarily according to the cultural characteristics and the inhibition effect and the colonization ability. The experimental results were able to lay a foundation for the reform and full utilization of strain P3Y2 and ML27 with the ability of controlling the citrus diseases.

Key words: endophyte, citrus disease, protoplast, regeneration, fusion

摘要： 为了将生防链霉菌ML27和柑橘内生放线菌P3Y2的优良特性整合在一起，对两株菌进行了原生质体融合研究。结果表明，菌株ML27和P3Y2的种子液分别转移到蔗糖浓度为20%和10%以及甘氨酸浓度为1.5%和1.0%的培养液中培养，收获的菌丝体对原生质体形成和再生最有利；分别选用5 mg/mL、90 min，及5 mg/mL、120 min的溶菌酶浓度与酶解时间制备ML27与P3Y2的原生质体能达到较高的形成率和再生率；在60℃条件下，菌株ML27和P3Y2的原生质体热灭活时间分别以10 min和15 min适宜；在20 W紫外灯下15 cm处分别照射7 min和5 min时，菌株ML27和P3Y2原生质体的灭活程度适宜。在此基础上，进行菌株ML27和P3Y2的原生质体融合，根据形态学特征、抑菌活性检测和定殖能力测定初步筛选出1株融合菌株MP45。试验结果可为这两株柑橘病害生防菌株的改良和充分利用奠定基础。

关键词: 内生菌, 柑橘病害, 原生质体, 再生, 融合