拟茎点霉一新种——油橄榄拟茎点霉

Phomopsis olea-europaea a New Species of Phomopsis

在甘肃陇南油橄榄种植区发生一种叶部新病害,叶片感病后,产生褐色斑点,病斑不断扩大,后期渐变为纶纹状,叶部有单个病斑,也有多个病斑相连,叶背症状不明显。叶片受害部位周围渐失绿,后期变黄,大面积干枯,继而引起早期落叶。通过组织分离、菌株纯化,显微观察,记录了病原的载孢体为椭圆形,大小为286~504μm×132~375μm,产生2种分生孢子,甲型孢子多为椭圆形,具2个油球,大小为4.3~7.6×1.6~3.4μm,乙型分生孢子线状或端部成钩状,大小为13~24×0.4~1.2μm。对病原物r DNA-ITS序列进行同源性分析得出,菌株A1（a3、a4、a5、a7）与Diaporthe eres菌株遗传距离最近,与Phomopsis属的多个种及该属的有性型Diaporthe sp.位于系统发育树的同一分支,与同源率最高的Phomopsis amygdali遗传距离相对较远。通过对病原物分子生物学分析及形态学观察,确定引起该病害的病原菌为一新种,初步定为拟茎点霉,经查文献,此病原菌在油橄榄上没有记载。

A new leaf disease was found in the producing area of Olea europaea in Longnan Gansu province. After leaves infected, causing small brown spots, and the scab continuously extend, gradual change into circular shapes later period, the affected leaves have single scab, also have several scab converged, back of leaf has no symptom, around the part of the affected leaves chlorina gradually, turn into yellow in later period, dry-rot in large area, then cause the serious fallen leaves in early phase. Brief description of the species was provided. After we make Homology comparison analysis of the rDNA-ITS sequenece of the pathogen and morphological observation, we think the pathogen which causes this disease is a new species, we tentative set as Phomopsis, after check the literature, there is no record about these pathogenic bacteria in the Olea europaea.