自毒物质胁迫下不同草莓品种枯萎病抗性变化的研究

通过盆栽试验研究了17个亲本不同的草莓品种在自毒物质—对羟基苯甲酸胁迫下对枯萎病的抗性变化及其与抗病性相关生理指标的影响,采用HPLC法分析了3种抗病类型的草莓品种根系分泌物中氨基酸成分的差异。结果表明:不同抗性品种在自毒物质胁迫下发病程度均加重,病情指数上升最多的是‘红玫瑰’和‘丰香’,分别为24.44和24.86,上升幅度高达77%和69%;病情指数变化较小的为‘石莓1号’和‘土特拉’,上升幅度均小于4。对羟基苯甲酸处理使不同抗性草莓品种根系分泌物中氨基酸的含量和种类发生变化,表现为降低了对枯萎病菌"抑制型"氨基酸如天冬氨酸含量,提高了"促进型"氨基酸种类和含量。对羟基苯甲酸处理后,‘土特拉’根系分泌物中天冬氨酸含量降低了0.009mg/gDW,而‘丰香’根系分泌物中"促进型"丝氨酸含量却升高0.114mg/gDW。总之,自毒物质胁迫下根系保护酶活性和分泌氨基酸的差异可能是不同草莓品种抗枯萎病强弱的重要原因。

Wilt disease resistance of different strawberry cultivars under root autotoxins stress

A total of 17 different strawberry cultivars were evaluated for their resistance to wilt disease,and the mechanism on disease resistance under autotoxins-p-hydroxybenzoic acid stress was studied with a pot culture experiment.The amino acids variation in the root exudates of different strawberry cultivars was analyzed with high performance liquid chromatography(HPLC).The results showed that,Fusarium wilt symptom was exacerbated when inoculated with pathogens onto different strawberry cultivars during autotoxins stress.The highest increse in disease index were found in ’Red rose’ and ’Toyonoka’,with increased values of 24.44(77%) and 24.86(69%),respectively,and ’Shimei number 1’ and ’Tutela’ were found slightly increased in disease index,both lower than 4.All the strawberry cultivars were divided into three different categories according to their performances against Fusarium wilt,represented by ’Tutela’,’Toyonoka’ and ’All star’,respectively.The variation of amino acids detected in root exudates of different strawberry cultivars and the change of antioxidant enzyme activities during autotoxins-p-hydroxybenzoic acid stress were proved to have close relationship with their resistance.The content of proline,serine and threonine in root exudates of sensitive varieties was significantly higher than that of resistant varieties.Some amino acids that could promote spore germination of F.oxysporum Schl.f.sp.fragariae were increased and other amino acids restraining spore germination were reduced after autotoxins-p-hydroxybenzoic acid stress.Asp content in root exudates in ’Tutela’ was reduced by 0.009 mg/g DW,while Ser content in’Toyonoka’ was increased by 0.114 mg/g DW.