Nodulation and nitrogen fixation in interspecies grafts of soybean and common bean is controlled by isoflavonoid signal molecules translocated from shoot

Abstract

Identification of common signals of nodulation control among legume species will facilitate progress in enhancing symbiotic nitrogen fixation of legumes in sustainable agriculture system. Grafting experiments between soybean and common bean were carried out to evaluate whether a common shoot signals control the expression of hypernodulation among the tow species. Grafting of a hypernodulating soybean mutant NOD1-3 shoots to three cultivars of normally nodulating common bean roots resulted in hypernodulation on roots of three tested cultivars of common bean. The shoot control of hypernodulation may be causally related to differential root isoflavonoid levels, which are also controlled by shoot factors. Isoflavonoid analysis from root extracts of grafted plants showed that NOD1-3 shoots had markedly higher root isoflavonoid concentrations in roots of both NOD1-3 and common bean cv. Adzuki compared with self-grafts of common bean Adzuki. Exogenous application of daidzein, genistein, coumestrol, glycitein and in combination at concentration of 10 µmol to the nutrient solution significantly increased the nodule numbers of common bean cv. Adzuki. Therefore, the control of hypernodulation expression by isoflavonoid signal molecules translocated from shoot is common among legume species.

Impact of Harsh Environmental Conditions on Nodule Formation and Dinitrogen Fixation of Legumes

“…The major findings are: (1) complete absence of or very weak institutions, policy and budgetary support for biotechnology research and lack of its integration into wider agricultural and overall development objectives, (2) limited knowledge of inoculation responses of both promiscuous and specifically nodulating legume varieties as well as the other factors that inhibit BNF, hence a weak basis for decision-making on biotechnology issues, (3) limited capacity and lack of sustainable investment, (4) poorly developed marketing channels and infrastructure, and limited involvement of the private sector in the distribution of inoculants, and (5) limited farmer awareness about and access to (much more than price) inoculants. The lessons learned in-clude the need: (1) to increase investment in Rhizobium inoculation technology development, and strengthen policy and institutional support, (2) for public private partnership in the development, deployment and dissemination of BNF technologies, (3) to develop effective BNF dissemination strategies (including participatory approach) to reach farmers, and (4) for greater emphasis on capacity building along the BNF value chain. According to an FAO report, production of N fertilizer for 2007 was 130 million tons of N, and this should further increase in the coming years (FAO 2008).…”

“…Low temperature inhibits inter-organismal signaling between the two symbiotic partners. It has been shown that low temperature inhibits the biosynthesis and rhizosecretion of plant to-bacteria signal molecules (for example genistein from soybean roots, which are necessary for the induction of the nod genes of B. japonicum (Zhang and Smith 1997;Abd-Alla 2001, 2011. Low temperature also inhibit the induction of bacterial nodulation genes (nod gene) required for the biosynthesis of bacteriato-plant signaling molecules, lipo-chitooligosaccarides (LCOs), the so-called Nod factors ).…”

Alleviating the inhibitory effect of salinity stress on nod gene expression in Rhizobium tibeticum – fenugreek (Trigonella foenum graecum) symbiosis by isoflavonoids treatment

“…Evidence exist that the introduction of exogenous nod gene inducers increases nodulation and N 2 fixation of some legume species. Pretreatment of B. japonicum with genistein increased nodulation and N 2 fixation of soybean and common bean (Zhang and Smith 1996;Abd-Alla 1999, 2011; and preinduction of R. leguminosarum with hesperetin and naringenin was found to stimulate nodulation and plant dry matter accumulation of pea and lentil plants (Begum et al 2001). Flavonoid inducers act in low concentrations and the pre-activation of rhizobia used as inoculants (biofertilizers) in undoubtedly economically justified (Hassan & Mathesius 2012).…”

“…The early interaction between flavonoids and NodD regulatory protein activates nod gene transcription and the synthesis of Nod factor that initiates nodule primordium (Maj et al 2010;Abd-Alla 2011).…”

Genome‐wide identification and in silico characterisation of microRNAs, their targets and processing pathway genes in Phaseolus vulgaris L.

“…The common bean ( Phaseolus vulgaris L.) is an important legume for global food security and is an essential staple crop for more than 400 million people. In addition, it plays an important role in sustainable agriculture by fixing atmospheric nitrogen (Abd‐Alla ). The common bean stands out for its high nutritional value, containing proteins, carbohydrates, fibre, vitamins and minerals such as iron, phosphorus, calcium and magnesium.…”