This transformation procedure generates, with high efficiency (70-90%), hairy roots in cultivars, landraces and accessions of Phaseolus vulgaris (common bean) and other Phaseolus spp. Hairy roots rapidly develop after wounding young plantlets with Agrobacterium rhizogenes, at the cotyledon node, and keeping the plants in high-humidity conditions. Callogenesis always precedes hairy-root formation, and after 15 days, when roots develop at wounded sites, the stem with the normal root is cleaved below the hairy root zone. Transgenic roots and nodules co-transformed with a binary vector can be easily identified using a reporter gene. This procedure, in addition to inducing robust transgenic hairy roots that are susceptible to being nodulated by rhizobia and to fixing nitrogen efficiently, sets the foundation for a high-throughput functional genomics approach on the study of root biology and root-microbe interactions. This protocol can be completed within 30 days.

A fast, reproducible, and efficient transformation procedure employing Agrobacterium rhizogenes was developed for Phaseolus vulgaris L. wild accessions, landraces, and cultivars and for three other species belonging to the genus Phaseolus: P. coccineus, P. lunatus, and P. acutifolius. Induced hairy roots are robust and grow quickly. The transformation frequency is between 75 and 90% based on the 35-S promoter-driven green fluorescent protein and beta-glucuronidase expression reporter constructs. When inoculated with Rhizobium tropici, transgenic roots induce normal determinate nodules that fix nitrogen as efficiently as inoculated standard roots. The A. rhizogenes-induced hairy root transformation in the genus Phaseolus sets the foundation for functional genomics programs focused on root physiology, root metabolism, and root-microbe interactions.

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Polycrystalline manganites within the compositional variation La0.72(Ca1−xSrx)0.28MnO3 (x = 0, 0.25, 0.50, 0.75, 1.0) were synthesized by solid-state reaction method. An initial orthorhombic structure was observed at x = 0, with a subsequent change to rhombohedral structure for x ≥ 0.25. The Curie temperature of the compounds exhibited a marked dependence with the Sr content, with general variations between 190 K (x = 0) and 364 K (x = 1.0), while the saturation magnetization at room temperature showed a small variation between the range 0.30 and 0.38 T. The magnetocaloric effect, measured through heat capacity experiments, showed a maximum entropy variation of −2.56 J/kg · K at x = 0.25, besides a maximum adiabatic temperature variation of 1.13 K. Results are interpreted in terms of the structural transition observed and its effect on the radius of the A-site of the perovskite structure.