Preincubation of Rhizobium leguminosarum bv. phaseoli with Jasmonate and Genistein Signal Molecules Increases Bean (Phaseolus vulgaris L.) Nodulation, Nitrogen Fixation

The objective of this research work was to study the effect of Rhizobium leguminosarum pre-induced with genistein (G) and methyl jasmonate (MJ) on nodulation, nitrogen fixation and early growth of the common bean (Phaseolus vulgaris L.). Four day-old seedlings were transferred to pots, containing sterilized sand and turface (2:1 v:v) mixture and, receiving Hoagland’s nutrient solution, without nitrogen. The plants were grown in a growth chamber using a randomized complete block design with six replications. The rhizobia were cultured in TY medium and incubated with G, and/or MJ. The incubated rhizobia were used after 24 hours to inoculate the bean seedlings. The results showed that both G and MJ enhanced the nodule number, nitrogen content per plant, and plant dry matter. Genistein and MJ, when applied together to cultures, showed synergistic effects on all the characters studied. The results of this study indicated that MJ alone, or in combination with G, can be used to promote bean nodulation, nitrogen fixation and early plant growth.