Inoculation of soybean (Glycine max. (L.) Merr.) with genistein-preincubated Bradyrhizobium japonicum or genistein directly applied into soil increases soybean protein and dry matter yield under short season conditions

Abstract

Inoculation of soybean (Glycine max. (L.) Merr.) with genistein-preincubatedBradyrhizobiumjaponicum or genistein directly applied into soil increases soybean protein and dry matter yield under short season conditions Abstract In short-season soybean production areas, low soil temperature is the major factor limiting plant growth and yield. The decreases in soybean yield at low temperatures are mainly due to nitrogen limitation. Genistein, the most effective plant-to-bacterium signal in the soybean (Glycine max (L.) Merr.) nitrogen fixation symbiosis, was used to pretreat Bradyrhizobium japonicum. We have previously reported that this increased soybean nodulation and nitrogen fixation in growth chamber studies. Two field experiments were conducted on two adjacent sites in 1994 to determine whether the incubation of B. japonicum with genistein, prior to application as an inoculant, or genistein, without B. japonicum, applied onto seeds in the furrow at the time of planting, increased soybean grain yield and protein yield in short season areas. The results of these experiments indicated that genistein-preincubated bradyrhizobia increased the grain yield and protein yield of AC Bravor, the later maturing of the two cultivars tested. Genistein without B. japonicum, applied onto seeds in the furrow at the time of planting also increased both grain and protein yield by stimulation of native soil B. japonicum. Interactions existed between genistein application and soybean cultivars, and indicated that the cultivar with the greatest yield potential responded more to genistein addition.Abbreviations: DAP-days after planting; RZT-root zone temperature.

The effect of biotic and physical factors on the competitive ability of Rhizobium leguminosarum

“…Interestingly, such a positive correlation was not observed in the two-step outdoor experiments, which, together with an increased positive correlation between metabolic potential and competitiveness, might be interpreted as the replacement of one bacterial feature (responsiveness to flavonoid induction) by another (metabolic potential). The flavonoid treatment of rhizobia was reported to increase symbiotic parameters of the host plants [49][50][51]. The higher expression of nod genes resulted in an increase of the Nod factor production.…”

Using signal molecule genistein to alleviate the stress of suboptimal root zone temperature on soybean-Bradyrhizobium symbiosis under different soil textures

“…In the first experiment genistein 20 mM (p 0 0.1) at different temperatures and in the second experiment genistein 5 mM (p 00.05) at 148C significantly increased leaf area and shoot dry weight (Zhang and Smith 1996;Mabood and Smith 2005) (Tables 1 and 5). These results are also in accordance with Pan and Smith (2000) in a clay-loam soil and Miransari and Smith (2007).…”

“…is between 258C and 308C. Hence, in cold areas with short growing seasons, like Canada, temperature may adversely affect the process of symbiosis between soybean and Bradyrhizobium japonicum (Lynch and Smith 1993a) and growth and dry matter accumulation of soybean (Zhang and Smith 1996).…”

Signals in Soybean's Inoculants

“…Then, another important characteristic of a culture medium is the possibility to contain natural substances which induce the nod genes in the bacteria to increase the nodulation factors concentration in the inoculum. A positive effect of genistein addition, as a nod gene inducer to B. japonicum inoculants on soybean grain and protein yield (Zhang & Smith, 1996), nodulation efficiency (Pan et al, 1998), N2 fixation and total N yield at low root zone temperatures (Zhang & Smith, 1997) has been reported.…”