Spatio-temporal localization of LlBOP following early events of floral abscission in yellow lupine

Agata Kućko,Juan De Dios Alché,Aleksandra Florkiewicz,Emilia Wilmowicz,Dariusz Smoliński

doi:10.1007/s00709-019-01365-3

Agata Kućko, Juan De Dios Alché + Show 3 more

Open Access

https://doi.org/10.1007/s00709-019-01365-3

Copy DOI

Abstract

The phenomenon of excessive flower abscission in yellow lupine is a process of substantial interest to the agricultural industries, because it substantially affects the yield. The aim of this work was to provide an analysis of the changes taking place precisely in the abscission zone (AZ) during early stages of flower separation. We put particular emphasis on mRNA accumulation of BOP (BLADE ON PETIOLE) gene encoding a transcriptional factor so far considered to be essential for AZ formation. Our results show that the AZ displays a particular transcriptional network active in the specific stages of its function, as reflected by the expression profile of LlBOP. Noteworthy, spatio-temporal LlBOP transcript accumulation in the elements of pedicel vascular tissue reveals divergent regulatory mechanism of its activity. We have also found that AZ cells accumulate reactive oxidative species following abscission and what is more, become active due to the increasing amount of uridine-rich small nuclear RNA, accompanied by poly(A) mRNA intensive synthesis. Our paper is a novel report for BOP involvement in the AZ functioning in relation to the whole transcriptional activity of AZ and overall discussed regarding BOP role as a potential mobile key regulator of abscission.

Highlights

The current state of knowledge on organ abscission in plants excludes the functioning of a single, universal mechanism for Handling Editor: Burkhard BeckerElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Wu et al 2012; Frankowski et al 2015a; Couzigou et al 2016)
To determine the time of L. luteus Blade-OnPetiole (LlBOP) activity, we examined the distribution of its transcript accumulation in the floral abscission zone (AZ) after artificial activation
The relative expression of the LlBOP rapidly upregulated during the hours subsequent to the artificial activation of AZ (Fig. 1)

Summary

Introduction

Among the legume (Fabaceae) family, yellow lupine (Lupinus luteus L.) is a highly significant crop, commercially cultivated in Eastern Europe, Southern Africa, Australia, and many Mediterranean countries. This species is characterized by high nutritional value and functional properties, e.g., the ability to fulfill nitrogen fixation, which is a sustainable alternative to chemical fertilizers. Despite the great economic potential of yellow lupine, still little is known about the physiological and molecular basis of flower abscission in this plant. Our initial results showed that detachment of lupine flowers occurs in the AZ positioned at a predetermined site, located at the boundary between the flower and stem (Frankowski et al 2015a). We have found that during the differentiation of floral AZ, the expression of newly identified LlBOP was correlated with the changes at the cellular level (Frankowski et al 2015a, 2015b)

Objectives

Methods

Results

Conclusion