LACK OF EVIDENCE FOR A ROLE OF ANTIFUNGAL METABOLITE PRODUCTION BY PSEUDOMONAS-FLUORESCENS PF-5 IN BIOLOGICAL-CONTROL OF PYTHIUM DAMPING-OFF OF CUCUMBER
LACK OF EVIDENCE FOR A ROLE OF ANTIFUNGAL METABOLITE PRODUCTION BY PSEUDOMONAS-FLUORESCENS PF-5 IN BIOLOGICAL-CONTROL OF PYTHIUM DAMPING-OFF OF CUCUMBER
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DOI：
10.1094/phyto-82-264
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发表时间：
1992-03-01
期刊：
影响因子：
3.2
通讯作者：
LOPER, JE
中科院分区：
文献类型：
--
作者：
KRAUS, J;LOPER, JE
荧光假单胞菌PF-5能保护黄瓜免受最终腐霉的苗前立枯病的侵染，并在培养过程中产生一系列抗真菌代谢产物，包括荧光铁载体(吡咯烷酮)、吡咯烷酮、吡咯硝酮、氰化物和一种未知化合物抗生素3。对Pf-5的Tn5插入突变体进行了Pf-5插入突变体的筛选，以检测Pf-5的溶血素产生(Plt-)和吡喃脱氢酶(PVD-)产生的损失。共鉴定出13株plt突变体、13株pvd突变体和6株抗生素产物(apd-)突变体，它们都缺乏吡咯菌素、吡咯硝酸根和抗生素3的产生。鉴定出三个Plt++突变体，它们在培养中产生比Pf-5更多的溶血素。亲本菌株Pf-5在培养上抑制了P.ultimum的菌丝生长，而Plt-和APd-突变体在某些生长介质上不抑制P.ultimum。相反，Plt++突变体对P.ultimum产生的抑制区大于Pf-5在琼脂培养上产生的抑制区。而Plt-、Pvd-、Ad-和Plt++突变体对黄瓜腐霉立枯病的抑制作用与Pf-5相似。这些结果与PF-5产生的抗真菌代谢产物对其对黄瓜腐霉立枯病的生防活性没有实质性贡献的说法是一致的。
Pseudomonas fluorescens Pf-5 protected cucumber from preemergence damping-off caused by Pythium ultimum and produced a number of antifungal metabolites in culture, including a fluorescent siderophore (pyoverdine), pyoluteorin, pyrrolnitrin, cyanide, and an uncharacterized compound termed antibiotic 3. Of these, the roles of pyoluteorin and pyoverdine in the biocontrol activity of Pf-5 against Pythium damping-off of cucumber were investigated. Tn5 insertion mutants of Pf-5 were screened for loss of pyoluteorin production (Plt-) or pyoverdine production (Pvd-). Thirteen Plt- mutants, 13 Pvd mutants, and six antibiotic production (Apd-) mutants, which were deficient in pyoluteorin, pyrrolnitrin, and antibiotic 3 production, were identified. Three Plt++ mutants, which produced greater quantities of pyoluteorin in culture than did Pf-5, were identified. The parental strain, Pf-5, inhibited hyphal growth of P. ultimum in culture, whereas the Plt- and Apd- mutants did not inhibit P. ultimum on certain growth media. In contrast, the Plt++ mutants produced inhibition zones against P. ultimum that were larger than those produced by Pf-5 on an agar medium. Nevertheless, the Plt-, Pvd-, Apd-, and Plt++ mutants were similar to Pf-5 in suppression of Pythium damping-off of cucumber. These results are consistent with the suggestion that antifungal metabolite production by Pf-5 did not contribute substantially to its biocontrol activity against Pythium damping-off of cucumber.