S. Nontachaiyapoom

Agrobacterium rhizogenes-mediated transformation of soybean to study root biology.

This protocol is used to induce transgenic roots on soybean to study the function of genes required in biological processes of the root. Young seedlings with unfolded cotyledons are infected at the cotyledonary node and/or hypocotyl with Agrobacterium rhizogenes carrying the gene construct to be tested and the infection sites are kept in an environment of high humidity. When the emerged hairy roots can support the plants, the main roots are removed and the transgenic roots can be tested. Using this method, almost 100% of the infected plants form hairy roots within 1 month from the start of the experiments.

Nodulation Control in Legumes

Nodulation and concomitant symbiotic nitrogen fixation are critical for the productivity of the legume, yielding food, feed and fuel. The nodule number in legumes is regulated by numerous factors including the number and efficiency of the interacting Rhizobium bacteria and abiotic stresses as well as endogenous processes involving phytohormones, nodulation reception systems and autoregulation of nodulation (AON; Kinkema et al., 2006). The original discovery of the AON-controlling LRR receptor kinases, GmNARK/ LjHAR1/MtSUNN, which is active in leaf tissue of several legu-mes, now has led to an analysis of the mechanism underlying the signal transduction.

Functional Genomics of the Regulation of Nodule Number in Legumes

Peter M. Gresshoff, Gustavo Gualtieri, Titeki Laniya, Arief Indrasumunar, Akira Miyahara, Sureeporn Nontachaiyapoom, Tim Wells, Bandana Biswas, Pick Kuen Chan, Paul Scott, M. Kinkema, M. Djordjevic, Dana Hoffmann, Lisette Pregelj, Diana M. Buzas, Dong Xi Li, Artem Men, Qunyi Jiang, Cheol-Ho Hwang and Bernard J. Carroll ARC Centre of Excellence for Integrative Legume Research; School of Life Sciences, and School of Molecular and Microbial Sciences and LAFS, The University of Queensland, St. Lucia, Brisbane QLD 4072, AGRF; Genome Interaction Group, RSBS, ANU, Canberra, ACT, Australia.