铜绿假单胞菌株CR56在黄瓜和番茄根围的定殖能力

Colonization of Pseudomonas aeruginosa CR56 in the rhizosphere of cucumber and tomato

铜绿假单胞菌株 Pseudomonas aeruginosa CR56作为种子处理时 ,能有效地防治由腐霉 Pythiumspp.和茄丝核菌 Rhizoctonia solania引起的黄瓜和番茄的苗期猝倒病 ,利用该菌的抗利福平突变菌株CR56 R9和 lac ZY标记菌株 CR56 RL4 ,研究其在黄瓜和番茄根围的定殖能力、种群动态和在根区的分布 .研究表明 ,黄瓜根围比番茄根围更适合于该菌的定殖 ,其种群数量下降的幅度在番茄根围比在黄瓜根围更快 .播后 2 8d,菌株 CR56 R9和 CR56 RL4在黄瓜根围种群数量分别由 7.6 3× 10 7CFU/粒和4 .88× 10 7CFU/粒下降到 9.85× 10 6CFU/株和 8.87× 10 6CFU/株 ,在番茄根围则分别由 3.0× 10 7CFU/粒和 2 .13× 10 7CFU/粒下降到 4 .4 8× 10 5CFU/株和 4 .37× 10 5CFU/株 ;该菌主要分布在猝倒病的发生部位——根基部 ,在根尖处检测不到该菌的存在 .lac ZY标记菌株 CR56 RL4与抗利福平突变菌株 CR56 R9。

Pseudomonas aeruginosa strain CR56 is effective to control cucumber and tomato seedlings damping off disease caused by Pythium spp and Rhizoctonia solania as a seed treatment A strain resistant to rifampin, CR56R9, and a lacZY marked derivative of wild strain CR56, CR56RL4, which were used to study the colonization ability, fluctuation of populations and distribution pattern on the rhizosphere of cucumber and tomato The studies indicated the rhizosphere of cucumber was more suitable for the strains CR56R9 and CR56RL4 to colonize than the rhizosphere of tomato The fluctuation of the two strains population was declined more quickly in the rhizosphere of tomato than that of cucumber For 28 days after planting, the populations of CR56R9 and CR56RL4 in the rhizosphere of cucumber were declined from inoculum level 7 63×10 7 and 4 88×10 7 CFU per seed to 9 85×10 6 and 8 87×10 6 CFU per plant,respectively, and the populations in the rhizosphere of tomato were declined from inoculum level 3 0×10 7 and 2 13×10 7 CFU per seed to 4 48×10 5 and 4 37×10 5 CFU per plant The fluctuation of the introduced bacteria population was declined more quickly in the rhizosphere of tomato than of cucumber It was found that the introduced bacteria were mainly in the location where damping off disease occurred, namely in the base of roots The introduced bacteria weren't detected in the tip of root The living ability in the rhizosphere of cucumber and tomato between a lacZY gene marked strain and a rifampin resistant strain was very similar