A lateral organ boundaries domain transcription factor acts downstream of the auxin response factor 2 to control nodulation and root architecture in Medicago truncatula.

Legume plants develop two types of root postembryonic organs, lateral roots and symbiotic nodules, using shared regulatory components. The module composed by the microRNA390, the Trans-Acting SIRNA3 (TAS3) RNA and the Auxin Response Factors (ARF)2, ARF3, and ARF4 (miR390/TAS3/ARFs) mediates the control of both lateral roots and symbiotic nodules in legumes. Here, a transcriptomic approach identified a member of the Lateral Organ Boundaries Domain (LBD) family of transcription factors in Medicago truncatula, designated MtLBD17/29a, which is regulated by the miR390/TAS3/ARFs module.

Identification of conserved and new miRNAs that affect nodulation and strain selectivity in the Phaseolus vulgaris-Rhizobium etli symbiosis through differential analysis of host small RNAs.

Phaseolus vulgaris plants from the Mesoamerican centre of genetic diversification establish a preferential and more efficient root nodule symbiosis with sympatric Rhizobium etli strains. This is mediated by changes in host gene expression, which might occur either at the transcriptional or at the post-transcriptional level. However, the implication of small RNA (sRNA)-mediated control of gene expression in strain selectivity has remained elusive.

Auxin Response Factor 2 (ARF2), ARF3, and ARF4 Mediate Both Lateral Root and Nitrogen Fixing Nodule Development in .

Auxin Response Factors (ARFs) constitute a large family of transcription factors that mediate auxin-regulated developmental programs in plants. , , and are post-transcriptionally regulated by the microRNA390 (miR390)/-acting small interference RNA 3 () module through the action of -derived acting small interfering RNAs (ta-siRNA). We have previously reported that constitutive activation of the miR390/ pathway promotes elongation of lateral roots but impairs nodule organogenesis and infection by rhizobia during the nitrogen-fixing symbiosis established between and its partner .