椰子茎基腐病病原菌的鉴定及致病性测定

Identification and Pathogenicity of Pathogen Causing Basal Stem Rot on Coconut

椰子(Cocos nucifera L.)茎基腐病对椰树的生长影响极其严重,为明确椰子茎基腐病的病原菌,预防海南椰子茎基腐病暴发,采用组织分离法和担子果分离对海南省文昌市椰子树的茎基腐病进行病原菌分离,并进行致病性测定、形态学和分子生物学鉴定。结果表明,分离得到的菌株在PDA培养基上恒温培养5 d后,菌落呈白色,近圆形,中心菌丝致密性高,向外辐射逐渐稀疏,显微结构下,菌丝呈树状分支且相互交错,外壁光滑,无刺透明,担孢子为长椭圆形,外壁无色透明,内壁为淡黄色;将分离的菌株回接于椰子幼苗上,叶柄接种处呈现出黑褐色病斑,内部组织白腐,并且组织坏死,已逐渐向上和向下扩展,叶片营养不良,生长缓慢,叶片泛黄,逐渐干枯,与田间症状一致;经过2个引物(ITS/LSU)合并系统发育分析,分离菌株与狭长孢灵芝(G.boninens)聚集在同一分支。综上可知,引起椰子茎基腐病的病原菌为狭长孢灵芝(G.boninens),这是狭长孢灵芝(G.boninens)侵染海南椰子引起椰子茎基腐病的首次报道。本研究结果确定狭长孢灵芝会引起椰子的茎基腐病,可为病害防治提供理论基础。

The growth effect of Cocos nucifera stalk rot disease was very serious.In order to identify the pathogenic bacteria and prevent the outbreak of Cocos nuciferastalk rot disease.The pathogenic of stalk rot disease of Cocos nucifera from Wenchang City in Hainan Province was isolated by tissue separation method,and pathogenic bacteria were identified by pathogenicity assay,morphological and molecular biological identification.The results show that one strain isolated from the Cocos nucifera disease tissues was white hyphae on PDA medium for 5 days and the central mycelia had high density and gradually sparse outward radiation.Under the microscopic structure,the mycelia presented tree-like branches and interlaced with each other,the outer wall was smooth and transparent without spines,the basidiospore was long oval,the outer wall was colorless and transparent,and the inner wall was light yellow.When it was connected back to the young coconut plant,the petiole inoculation site showed black brown lesions,white rot in the internal tissue,and tissue necrosis,has gradually expanded upward and downward,leaf malnutrition,slow growth,leaf yellow,gradually dry,which was consistent with the field symptoms.Based on the phylogenetic analysis of multiple(ITS/LSU),Ganoderma boninense clustered in the same clade.It was confirmed that the pathogen of stalk rot disease of Cocos nucifera was Ganoderma boninense.This was the first report that Ganoderma boninense infected the Cocos nucifera in Hainan Province and caused stalk rot disease.The results of this study confirmed that Ganoderma boninense could cause stem base rot of coconut and provided a theoretical basis for disease control.