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Legume plants host nitrogen-fixing endosymbiotic Rhizobium bacteria in root nodules. In Medicago truncatula, the bacteria undergo an irreversible (terminal) differentiation mediated by hitherto unidentified plant factors. We demonstrated that these factors are nodule-specific cysteine-rich (NCR) peptides that are targeted to the bacteria and enter the bacterial membrane and cytosol Obstruction of NCR transport in the dnf1-1 signal peptidase mutant correlated with the absence of terminal bacterial differentiation. On the contrary, ectopic expression of NCRs in legumes devoid of NCRs or challenge of cultured rhizobia with peptides provoked symptoms of terminal differentiation. Because NCRs resemble antimicrobial peptides, our findings reveal a previously unknown innovation of the host plant, which adopts effectors of the innate immune system for symbiosis to manipulate the cell fate of endosymbiotic bacteria. 10.1126/science.1184057

Polyelectrolyte multilayers were constructed through the alternation of mixed solutions of poly(L-glutamic acid) (PGA) and poly(L-aspartic acid) (PAA) polyanions and a solution of the polycation (poly(L-lysine) (PLL)) by using two independent techniques, Quartz crystal microbalance-dissipation (QCM-D) and Fourier transform infrared (FTIR) spectroscopy. Results reveal that the self-assembling capacity of polyelectrolyte multilayers acquire from the presence of more than one polyanion in the build-up solutions could lead to properties which could not be attained by multilayers constructed only from pure polyanion and polycation solutions.

Plant genetics plays a key role in determining root hair initiation and development. A complex network of genetic interactions therefore closely monitors and influences root hair phenotype and morphology. The significance of these genes can be studied by employing, for instance, loss-of-function mutants, overexpression plant lines, and fluorescently labeled constructs. Confocal laser scanning microscopy is a great tool to visually observe and document these morphological features. This chapter elaborates the techniques involved in handling of microscopic setup to acquire images displaying root hair distribution along the fully elongated zone of Arabidopsis thaliana roots. Additionally, we illustrate an approach to visualize early fate determination of epidermal cells in the root apical meristem, by describing a method for imaging YFP tagged transgenic plant lines., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)