海洋放线菌A3202的分离鉴定及其对柑橘采后病害的防效

为获得用于防治柑橘采后病害的海洋放线菌，以柑橘青霉病菌Penicillium italicum、柑橘绿霉病菌P.digitatum和柑橘炭疽病菌Colletotrichum gloeosporioides为指示菌，对分离到的25株海洋放线菌进行筛选。通过平板对峙法测定拮抗菌株的抑菌谱，并测定其发酵产物粗提物对柑橘果实采后病害的防效，根据形态特征、培养特征、生理生化特征及16S rDNA序列对其进行鉴定。结果表明，分离自鳞笠藤壶Tetraclita squamosa的菌株A3202对3种指示菌均具有强抑菌活性，对供试13种植物病原菌的菌丝生长具有不同程度的抑制作用，尤其对柑橘青霉病菌和柑橘绿霉病菌的抑制作用最强，抑菌带宽度分别可达2.33±0.05 cm和2.32±0.10 cm。该菌株800 mg/L粗提物溶液对接种后7 d的柑橘青霉病、柑橘绿霉病和柑橘炭疽病的相对防效均可达100%。初步鉴定该菌株为放线菌中的米修链霉菌Streptomyces misionensis。

Isolation and identification of marine actinomyces A3202 and its control efficacy against postharvest citrus diseases

In order to obtain marine actinomyces used for controlling postharvest citrus diseases, Penicillium italicum, P.digitatum and Colletotrichum gloeosporioides were taken as indicative fungi to screen antagonistic bacteria from 25 strains. The inhibition spectrum of the screened antagonistic strain was tested by using plate stand-opposite culture method, and the efficacy of its crude extracts to citrus postharvest diseases was investigated. The strain was identified according to the morphological characteristics, cultural characteristics, physiological and biochemical characteristics, combined with 16S rDNA sequence analysis. The results revealed that the strain A3202 isolated from Tetraclita squamosa exhibited strong antimicrobial activity against 3 indicative fungi, and could inhibit mycelial growth of 13 tested phytopathogens to different degrees, especially to P.italicum and P.digitatum with inhibition zone diameters of 2.33±0.05 cm and 2.32±0.10 cm, respectively. The relative control efficacy of 800 mg/L crude extracts against citrus blue mold, citrus green mold and citrus anthracnose could reach 100% 7 days after inoculation. The strain A3202 was identified as Streptomyces misionensis.