Regulation of the Later Stages of Nodulation Stimulated by IPD3/CYCLOPS Transcription Factor and Cytokinin in Pea Pisum sativum L.

Elizaveta S Rudaya,Elena A Dolgikh,Olga A Pavlova,Polina Yu Kozyulina,Alexandra V Dolgikh,Alexandra N Ivanova

doi:10.3390/plants11010056

Abstract

The IPD3/CYCLOPS transcription factor was shown to be involved in the regulation of nodule primordia development and subsequent stages of nodule differentiation. In contrast to early stages, the stages related to nodule differentiation remain less studied. Recently, we have shown that the accumulation of cytokinin at later stages may significantly impact nodule development. This conclusion was based on a comparative analysis of cytokinin localization between pea wild type and ipd3/cyclops mutants. However, the role of cytokinin at these later stages of nodulation is still far from understood. To determine a set of genes involved in the regulation of later stages of nodule development connected with infection progress, intracellular accommodation, as well as plant tissue and bacteroid differentiation, the RNA-seq analysis of pea mutant SGEFix--2 (sym33) nodules impaired in these processes compared to wild type SGE nodules was performed. To verify cytokinin’s influence on late nodule development stages, the comparative RNA-seq analysis of SGEFix--2 (sym33) mutant plants treated with cytokinin was also conducted. Findings suggest a significant role of cytokinin in the regulation of later stages of nodule development.

Highlights

Accepted: 22 December 2021Signal exchange between legume plants and rhizobial bacteria from the Rhizobiaceae family results in the development of specialized organs on roots, the nitrogen-fixing nodules
In legumes with the determinate type of nodules such as Lotus japonicus, the complex of LjNFR5/LjNFR1 receptors perceives Nod factors [1,2,3], while in legumes with indeterminate nodule type, such as Medicago truncatula and Pisum sativum L., several receptor complexes can be involved in the control of early plant responses to Nod factors and infection development [4,5,6,7,8,9]
It was previously shown that concentrations of cytokinin BAP in the range of 1–10 μM may stimulate the nodulation in M. sativa and pea plants, while inhibition of nodule formation was shown in the range of

Summary

Introduction

Accepted: 22 December 2021Signal exchange between legume plants and rhizobial bacteria from the Rhizobiaceae family results in the development of specialized organs on roots, the nitrogen-fixing nodules. In legumes with the determinate type of nodules such as Lotus japonicus, the complex of LjNFR5/LjNFR1 receptors perceives Nod factors [1,2,3], while in legumes with indeterminate nodule type, such as Medicago truncatula and Pisum sativum L., several receptor complexes can be involved in the control of early plant responses to Nod factors and infection development [4,5,6,7,8,9]. Receptor complex MtNFP/MtLYK3, MtLYK4 is involved in the control of infection process in M. truncatula [5,6], whereas in pea P. sativum L. the complex consists of PsSym10/PsSym and, probably, PsSym (PsLykX) [8,9,10]. Responses can be controlled by the PsSym10/PsK1 receptor complex in pea [1,9,12], while it remains unknown whether the MtNFP can function in complex with an additional receptor kinase in

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Conclusion