Identification of BELL Transcription Factors Involved in Nodule Initiation and Development in the Legumes Pisum sativum and Medicago truncatula.

Alexandra V Dolgikh,Elizaveta S Rudaya,Elena A Dolgikh

doi:10.3390/plants9121808

Alexandra V Dolgikh, Elizaveta S Rudaya + Show 1 more

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https://doi.org/10.3390/plants9121808

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Abstract

Single three-amino acid loop extension (TALE) homeodomain proteins, including the KNOTTED-like (KNOX) and BEL-like (BELL) families in plants, usually work as heterodimeric transcription factor complexes to regulate different developmental processes, often via effects on phytohormonal pathways. Nitrogen-fixing nodule formation in legumes is regulated by different families of homeodomain transcription factors. Whereas the role of KNOX transcription factors in the control of symbiosis was studied early, BELL transcription factors have received less attention. Here, we report the identification and expression analysis of BELL genes in the legume plants Medicago truncatula and Pisum sativum, which are involved in regulating symbiosis initiation and development. A more precise analysis was performed for the most significantly upregulated PsBELL1-2 gene in pea. We found that the PsBELL1-2 transcription factor could be a potential partner of PsKNOX9. In addition, we showed that PsBELL1-2 can interact with the PsDELLA1 (LA) protein-regulator of the gibberellin pathway, which has a previously demonstrated important role in symbiosis development.

Highlights

The formation of symbiotic nitrogen-fixing nodules represents a process in which the development of new organs substantially depends on external factors [1,2]
To identify BELL genes in the genome of the model legume M. truncatula and the crop legume pea P. sativum, we searched for these genes using amino acid sequences of BEL1 and BEL-like genes of A. thaliana for BLASTP analysis [16]
A complex network of transcription factors and phytohormones is involved in the regulation of the shape of this organ and its position on the root

Summary

Introduction

The formation of symbiotic nitrogen-fixing nodules represents a process in which the development of new organs substantially depends on external factors [1,2]. In plants, such regulation can be achieved by means of a complex network of transcription factors and phytohormones. Three-amino acid loop extension (TALE) homeodomain transcription factors play a comprehensive role in the regulation of numerous biological processes, and members of this superfamily are highly conserved in different organisms [3]. The significant role of TALE proteins in meristem maintenance and morphogenesis regulation has been shown, but specific processes such as chloroplast development, cell wall modification, or leaf formation represent examples of TALE-regulated processes in plants [4,5,6]

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