Engineered ACC deaminase-expressing free-living cells of Mesorhizobium loti show increased nodulation efficiency and competitiveness on Lotus spp.

The Journal of General and Applied Microbiology

Valeria P. Conforte¹  Mariela Echeverria¹  Ana B. Menéndez¹  Viviana C. Lepek¹  Cintia Sánchez¹  Rodolfo A. Ugalde¹ 

[1] Instituto de Investigaciones Biotecnológicas, INTECH, Universidad Nacional de General San Martín

关键词: ACC deaminase;    competitiveness;    ethylene;    lotus;    Mesorhizobium loti;   

DOI  :  10.2323/jgam.56.331

学科分类：微生物学和免疫学

来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation

【 摘 要 】

Ethylene inhibits the establishment of symbiosis between rhizobia and legumes. Several rhizobia species express the enzyme ACC deaminase, which degrades the ethylene precursor 1-cyclopropane-1-carboxilate (ACC), leading to reductions in the amount of ethylene evolved by the plant. M. loti has a gene encoding ACC deaminase, but this gene is under the activity of the NifA-RpoN-dependent promoter; thus, it is only expressed inside the nodule. The M. loti structural gene ACC deaminase (acdS) was integrated into the M. loti chromosome under a constitutive promoter activity. The resulting strain induced the formation of a higher number of nodules and was more competitive than the wild-type strain on Lotus japonicus and L. tenuis. These results suggest that the introduction of the ACC deaminase activity within M. loti in a constitutive way could be a novel strategy to increase nodulation competitiveness of the bacteria, which could be useful for the forage inoculants industry.

【 授权许可】

Unknown