Natural endophytic association between Rhizobium leguminosarum bv. trifolii and rice roots and assessment of its potential to promote rice growth

摘要: For over 7 centuries, production of rice (Oryza sativa L.) in Egypt has benefited from rotation with Egyptian berseem clover (Trifolium alexandrinum) The nitrogen supplied by this replaces 25– 33% the recommended rate fertilizer-N application for production. This benefit to cannot be explained solely an increased availability fixed N through mineralization N- rich crop residues. Since normally supports a diverse microbial community internal root colonists, we have examined possibility that symbiont, Rhizobium leguminosarum by. trifolii colonizes roots endophytically fields where these crops are rotated, and if so, whether novel plant-microbe association benefits growth. MPN plant infection studies were performed on macerates surface-sterilized inoculated T alexandrinum as legume trap host. results indicated interior grown rotated Nile Delta contained ~106 clover-nodulating rhizobial endophytes g−1 fresh weight root. Plant tests plus microscopical, cultural, biochemical, molecular structure numerically dominant isolates represent 3 – 4 authentic strains R. Nod+ Fix+ clover. Pure cultures selected able colonize under gnotobiotic conditions. These reisolated shown methods same original inoculant strains, thus verifying Koch’s postulates. Two endophytic R significantly shoot growth chamber experiments, grain yield agronomic fertilizer N-use efficiency Giza-175 hybrid field inoculation experiment conducted Delta. Thus, been since antiquity contain naturally interior, true potential promote productivity laboratory