甜瓜抗枯萎病资源筛选及抗病生理指标相关性分析

Screening of melon resources resistant to Fusarium wilt and correlation analysis of physiological indexes of disease resistance

为明确黑龙江地区甜瓜枯萎病生理小种,探究枯萎病胁迫下甜瓜生理指标变化,完善甜瓜枯萎病抗病评价体系,利用表型鉴定结合分子标记辅助选择(MAS,marker-assisted selection)对24份甜瓜资源进行抗病筛选。结果表明,黑龙江省尖孢镰刀菌甜瓜专化型Fm-1为1号生理小种。分子标记辅助选择共筛选出抗病资源15份,感病资源9份,具有较高的筛选效率。其中野生型资源1314抗性最强,发病率仅为10%;栽培种22-152的感病程度最高。利用筛选的两个抗性极端材料在幼苗期接种病原菌并于根部取样,测定抗病生理指标并进行相关性分析。结果表明,枯萎病胁迫下的抗病和感病材料生理指标响应差异显著,过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性与发病率呈极显著负相关;丙二醛含量和相对电导率与发病率呈极显著正相关。综上,利用功能性分子标记可在早期实现精准筛选甜瓜抗枯萎病品种,相对电导率和CAT及PAL活性可作为抗枯萎病评价的首选指标。

In order to identify the physiological race of melon Fusarium wilt in Heilongjiang province,and improve the evaluation system of melon Fusarium wilt disease resistance,24 melon varieties were screened for disease resistance using phenotype identification combined with marker-assisted selection(MAS).The results showed that the specific type Fm-1 of Fusarium oxysporum from Heilongjiang province was physiological race No.1.A total of 15 resistant resources and 9 susceptible resources were screened by marker-assisted selection with high screening efficiency.The wild-type resource 1314 had the most resistant,the incidence of which was only 10%.The cultivated-type 22-152 had the highest degree of infection.Two resources with extreme resistance were inoculated with pathogens at seedling stage and sampled at root.The physiological indexes of resistance were determined and the correlation analysis was carried out.The results showed that the physiological indexes of resistant and susceptible materials were significantly different under wilt stress,and the activities of catalase(CAT),phenylalanine aminolyase(PAL),superoxide dismutase(SOD)and peroxidase(POD)were significantly negatively correlated with incidence rate.Malondialdehyde content and relative conductivity were significantly positively correlated with incidence rate.In conclusion,functional molecular markers can be used to accurately screen melon varieties resistance to Fusarium wilt at an early stage,and relative conductivity and CAT and PAL activities can be used as the preferred indicators for evaluation of Fusarium wilt resistance.