一株地黄茎部致病菌的鉴定及防治药剂筛选

 在河南省温县地黄(Rehmannia glutinosa)种植园采集茎部感病的地黄植株,从感病部位分离、纯化出4株病原菌。通过对分离菌的形态学观察、致病性检测及ITS、EF1-α、TUB、CAL、HIS多基因核酸序列分析,鉴定其中1株分离菌为扁桃腐皮壳菌(Diaporthe amygdali),为地黄茎部病害的新型致病菌。生物学特性研究表明,最适宜该致病菌生长的为PDA培养基;菌丝生长的最佳温度为25 ℃、最适pH值为6、对光照不敏感;最适碳氮源分别是麦芽糖和蛋白胨。药剂抑菌活性筛选结果表明,选用的10种杀菌剂对D. amygdali生长都有一定的抑制作用,其中500 g·L^-1氟啶胺悬浮剂活性最高,EC₅₀为0.092 5 mg·L^-1。上述结果为D. amygdali引起的地黄茎部病害防治提供了科学依据。

Identification and screening of fungicides against a pathogenic fungi from the stem of Rehmannia glutinosa

Rehmannia glutinosa plants with diseased stems were collected from a R. glutinosa plantation in Wen County, Henan Province, and 4 strains were isolated from the diseased stem samples. Morphological observation, pathogenicity test and phylogenetic analysis of internal transcribed spacer (ITS), elongation factor 1-α (EF1-α), β-tublin (TUB), calmodulin (CAL) and histone H3 (HIS) genomic loci were conducted to identify the pathogen. The results indicated that one of the strains was identified as Diaporthe amygdali, which was a new pathogen of R. glutinosa stem diseases. The study of biological characteristics showed that PDA was the most suitable medium for the growth of D. amygdali. The optimal temperature for the mycelium growth was 25 ℃, and the optimal pH value was 6. D. amygdali was not sensitive to light. The optimal carbon and nitrogen sources for mycelium growth were maltose and peptone, respectively. The bioassays were carried out and the results showed that all of the ten tested fungicides had inhibitory effects on the mycelium growth of D. amygdali, where 500 g·L^-1 Fluazinam SC had the highest activity (EC₅₀=0.092 5 mg·L^-1). The results presented herein provide potentially useful information toward developing effective management strategies to control R. glutinosa stem diseases caused by D. amygdali.