一株抗香蕉枯萎病DSE菌株的筛选鉴定及抗病机理初探

通过平皿和盆栽共生对抗法,筛选到1株对香蕉枯萎病具有防治作用的深色有隔内生真菌L-14,2种方法的防效分别达到72.4%和56.5%,接种该菌株可显著提高香蕉幼苗的鲜重。形态观察和28S r DNA序列比对分析结果表明,该菌株为裂壳菌(Schizothecium sp.)。使用该菌株浸根处理接种香蕉苗后,植株系列抗氧化保护酶如苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)及超氧化物歧化酶(SOD)的活性均显著高于对照,而菌株L-14与香蕉枯萎病菌混合接种处理样品的PPO和SOD活性显著高于单独接种处理,表明接种该生防菌能增强香蕉的抗氧化防护系统,提高其对香蕉枯萎病的抗性。

Screening and Identification of Dark Septate Endophyte Strain L-14 and Its Mechanism of Banana Fusarium Wilt Disease Resistance

A dark septate endophytic (DSE) fungus L-14 was screened for further activity among the ten DSEs.The disease control efficacies of L-14 against the Fusarium wilt was found up to 72.4％ in the culture dish and 56.5％ in the pot culture method.After inoculation of this strain into the banana seedling,the fresh weight of banana seedlings significantly increased over the control plant.Morphological observation and 28S rDNA sequence alignment analysis showed that the strain belonged to the genus Schizothecium.After inoculation of L-14 with banana seedlings,the antioxidant enzymes such as phenylalanine ammonia lyase (PAL),peroxidase (POD),polyphenol oxidase (PPO) and superoxide dismutase (SOD) were significantly higher over the control.The activity of PPO and SOD was found to be higher in case of mix inoculation of L-14 strain and banana Fusarium wilt disease pathogen.The results suggested that DSE strain L-14 could improve the resistance to banana Fusarium wilt disease of the seedling by triggering the over expression of antioxidative defense system.