掘氏疫霉有性生殖行为的研究

THE BEHAVIOR OF SEXUAL REPRODUCTION IN THE CROSSES OF INTRASPECIFIC ISOLATES OF PHYTOPHTHORA DRECHSLERI

以抗药性为标记,采用双标记菌株为亲本,研究了掘氏疫霉有性生殖行为。配对亲本 Phy607(A_1)、Phy64(A_2)抗放线菌酮对新霉素敏感,Phy115(A_1)、Phy112(A_2)抗新霉素对放线菌酮敏感。在配对组合 Phy607x Phy112、Phy115x Phy64 F_1代单卵孢株群体中,均出现同时抗放线菌酮和新霉素的个体,分别占群体的37%和50%.这种双重抗药性在单游动孢子无性系后代可稳定遗传,在自交后代发生分离。上述4个亲本在相对交配型产生的激素刺激下均可自交产生卵孢子。因此认为,掘氏疫霉种内菌株配对有性生殖可能以配对亲本杂交和各自自交等3种方式产生卵孢子,以双亲杂交为主要方式.

The behavior of sexual reproduction of Phytophthora drechsleri was studied by the crosses ofwild type parents with double-marker(drug-resistantce).Parental isolates Phy 607(A-1)and Phy 64(A_2) were reisitant to actidione and sensitive to neomycin,and Phy115(A_1)and Phyll2(A_2)wereresistant to neomycin and sensitive to actidione.From the crosses of isolates Phy607xPhy112,Phy115xPhy64,single-oospore cultures resistant to both actidione and neomycin were 37% and 50% of the total iso-lates respectively in F_1 progenies.Results also showed that those four parental isolates formed oospores bythe stimulation of hormone from the opposite mating type isolates.It is suggested that,three manners ofoospore formation might be present in the cross of intraspecific isolates of P.drechsleri,includinghybridization,and self-fertilization of both parents.However,hyridization might play an important partin sexual reproduction.