El-Raheem A, El-Shanshoury R, El-Sououd S M, Awadalla O A, El-Bandy N B
Botany Department, Tanta University, Egypt.
Acta Microbiol Pol. 1995;44(3-4):255-66.
Pretreatment of tomato seeds with pendimethalin or metribuzin and inoculation of seedlings with the antagonistic Streptomyces corchorusii or/and Streptomyces mutabilis were tested for the formation of tomatine in roots and stems of tomato, infested with Pseudomonas solancearum or/and Fusarium oxysporum f. sp. lycopersici. All treatments induced the formation of variable quantities of tomatine, compared with untreated control. The variation was proportional to: the pathogen, Fusarium was more stimulating than Pseudomonas; the antagonistic organism, S. corchorusii being more eliciting than S. mutabilis; the herbicide and its concentration, pendimethalin at 2 x 10(-3) M being the most eliciting of tomatine; and according to the soil, plants grown in non-sterilized soil accumulated more tomatine than did these grown in sterilized soil. In all treatments, stems had more tomatine than roots and non-sterilized soil was better than sterilized soil. The antagonistic streptomycetes induced accumulation of tomatine more than did the herbicides. The highest amounts of tomatine were detected in plants pretreated with pendimethalin at 2 x 10(-3) M, grown in non-sterilized soil, infested with F. oxysporum, and inoculated with S. corchorusii and S. mutabilis. The effect of the extracted tomatine on the growth of Fusarium and Pseudomonas was examined in vitro. The crude extract of tomatine from all treatments reduced growth and sporulation of F. oxysporum and growth of P. solanacearum in defined media. The reduction varied according to the treatment and was proportional to the quantities of extracted tomatine, the highest amounts being the most effective. The mechanism of phytoalexins in controlling tomato wilt pathogens was also discussed.
用二甲戊灵或嗪草酮预处理番茄种子，并接种拮抗链霉菌（Streptomyces corchorusii）或/和可变链霉菌（Streptomyces mutabilis），以检测番茄根和茎中番茄碱的形成情况，番茄植株受到青枯假单胞菌（Pseudomonas solancearum）或/和尖孢镰刀菌（Fusarium oxysporum f. sp. lycopersici）侵染。与未处理的对照相比，所有处理均诱导了不同数量番茄碱的形成。这种变化与以下因素成正比：病原体，镰刀菌比假单胞菌更具刺激作用；拮抗生物，corchorusii链霉菌比mutabilis链霉菌更能引发番茄碱的形成；除草剂及其浓度，2×10(-3) M的二甲戊灵对番茄碱的诱导作用最强；以及土壤，在未灭菌土壤中生长的植物比在灭菌土壤中生长的植物积累更多的番茄碱。在所有处理中，茎中的番茄碱含量高于根，未灭菌土壤优于灭菌土壤。拮抗链霉菌比除草剂更能诱导番茄碱的积累。在2×10(-3) M二甲戊灵预处理、生长在未灭菌土壤中、受到尖孢镰刀菌侵染并接种corchorusii链霉菌和mutabilis链霉菌的植物中，检测到的番茄碱含量最高。在体外研究了提取的番茄碱对镰刀菌和假单胞菌生长的影响。所有处理的番茄碱粗提物在特定培养基中均降低了尖孢镰刀菌的生长和孢子形成以及青枯假单胞菌的生长。这种降低因处理而异，并与提取的番茄碱量成正比，含量最高的效果最显著。还讨论了植保素控制番茄枯萎病病原体的机制。
