槟榔根腐病菌拮抗菌株的筛选与鉴定

为获得对槟榔根腐病菌具有生防作用的菌株，以发病槟榔园健康植株根及根部土为材料，采用平板对峙培养法对尖孢镰刀菌（F.oxysporum）、可可毛色二孢菌（Lasiodiplodia theobromae）和奇异根串珠霉菌（Thielaviopsis paradoxa）3种槟榔根腐病菌的拮抗菌株进行筛选。从分离到的247株细菌中，获得了1株对尖孢镰刀菌、可可毛色二孢菌和奇异根串珠霉菌拮抗效果好且稳定性高的菌株brj-21，抑菌率分别为68%、73.66%和74.33%。经形态学观察和生理生化特征、16S rDNA碱基序列分析，brj-21被鉴定为粪产碱菌（Alcaligenes faecalis）。采用单因素及正交实验对拮抗菌（brj-21）的培养基组分进行优化，确定最佳培养基配方为酵母浸粉2.5 g、葡萄糖1 g、七水合硫酸镁0.4 g、水100 mL。室内实验结果表明，菌株brj-21对由可可毛色二孢菌引起的槟榔根腐病具有较好的防治效果，可作为潜在的生防菌株开发利用。

Screening and identification of antagonistic bacterial strains against pathogens causing Arecanut root rot

An attempt was made to select biocontrol strains against the pathogens of areca root rot, the roots and rhizosphere soil of healthy arecanut palms (Areca catechu L.) in the arecanut plantation infected with root rot disease were collected to isolate antagonistic bacterial strains against the root rot pathogens Lasiodiplodia theobromae, F.oxysporum and Thielaviopsis paradoxa by dual culture method. There were 247 bacterial strains isolated, of which a bacterial strain brj-21 was found to have good stable antagonistic effects against F. oxysporum, L. theobromae and T. paradoxa with inhibition rates of 68% ,73.66% and 74.33%, respectively. Based on morphological observation, physiological and biochemical characteristics as well as 16S rDNA sequence analysis, the strain brj-21 was identified as Alcaligenes faecalis. Furthermore, the culture medium for the strain brj-21 was optimized by single factor and orthogonal experiments, and the optimal medium was composed of 2.5 g yeast extract powder, 1 g glucose, 0.4 g MgSO₄ · 7H₂O and 100 mL water. The laboratory experiments showed preliminarily that the strain brj-21 had good control effect on areca root rot caused by L. theobromae, which can be developed and utilized as a potential biocontrol bacterial strain.