Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China.
World J Microbiol Biotechnol. 2012 Mar;28(3):1155-62. doi: 10.1007/s11274-011-0918-9. Epub 2011 Oct 22.
Two 1-aminocyclopropane-1-carboxylate deaminase-producing bacterial strains (DP24 and XG32) were isolated from surface-sterilized tomato roots and rizhospere soil. The strains were identified as Pseudomonas fluorescens biovar. IV (XG2) and Erwinia herbicola (DP24) by physiological and biochemical tests, and 16S rRNA gene analysis. Both strains showed positive plant growth-promoting activity when inoculated into cucumber (Cucumis sativus), tomato (Lycopersicon esculentum), pepper (Capsicum annuum) and rapeseed (Brassica napus L.). Colonization ability and behavior of these two strains were determined by treating mutant strains with rifampicin and fluorescence in situ hybridization (FISH) assay with rRNA targeted probes, respectively. Both strains were endophytic colonizers of pepper plants. The behavior of the two strains was not identical. Strain XG32 only colonized the root and reached the max level of 27.7 × 10(7) c.f.u./g (fresh weight), after 12 days postinoculation, while strain DP24 was able to colonize the roots, stems and leaves. The max level was reached at 40.87 × 10(7) c.f.u./g (fresh weight) in the roots, 17 × 10(7) c.f.u./g in the stems after 7 days postinoculation and 44.84 × 10(7) c.f.u./g in the leaves after 12 days postinoculation.
从表面消毒的番茄根和根际土壤中分离到两株 1-氨基环丙烷-1-羧酸脱氨酶产生菌（DP24 和 XG32）。通过生理生化试验和 16S rRNA 基因分析，将两株菌鉴定为荧光假单胞菌生物型 IV（XG2）和欧文氏菌（DP24）。当将两株菌接种到黄瓜（Cucumis sativus）、番茄（Lycopersicon esculentum）、辣椒（Capsicum annuum）和油菜（Brassica napus L.）中时，均表现出正向的植物促生作用。通过用利福平处理突变株和用 rRNA 靶向探针进行荧光原位杂交（FISH）试验，分别确定了这两株菌的定殖能力和行为。两株菌均为辣椒植物的内生定殖菌。两株菌的行为并不相同。菌株 XG32 仅定植于根，在接种后 12 天达到最大水平 27.7×10(7) c.f.u./g（鲜重），而菌株 DP24 能够定植于根、茎和叶。在接种后 7 天，根中最大水平达到 40.87×10(7) c.f.u./g（鲜重），茎中达到 17×10(7) c.f.u./g，叶中达到 44.84×10(7) c.f.u./g。
