Plant growth-promoting capabilities of diazotrophs from wild gramineous crops = 야생 벼과식물 유래 질소고정세균의 식물생장촉진 관련 특성

Abstract

Since there could be more and rather various diazotrophs in rhizosphere of wild crops than those in rhizosphere of cultivars, some wild gramineous crops grown in Korea were collected for isolating nitrogen-fixing bacteria. Six diazotrophs were purified from their roots using nitrogen-free media. The isolated bacteria were partially identified as 4 genera by 16S rDNA sequence analysis: Stenotrophomonas sp., Bosea sp., Klebsiella sp., and Azorhizobium sp. By PCR amplification and sequence analysis, DNA fragments extracted from all isolates turned out to have an individual nifH homologous gene. Five isolates (KNUC163, KNUC165, KNUC169, KNUC170, and KNUC171) showed auxin activity and four isolates (KNUC163, KNUC166, KNUC170, and KNUC171) produced siderophores. Especially, 3 strains of S. maltophilia showed both auxin and siderophore activities. In conclusion, the isolated nitrogen-fixing bacteria might have capabilities for plant growth promotion.