Integrated Analysis of Small RNA, Transcriptome and Degradome Sequencing Provides New Insights into Floral Development and Abscission in Yellow Lupine (Lupinus luteus L.).

Paulina Glazińska,Waldemar Wojciechowski,Wojciech Glinkowski,Jan Kosiński,Milena Kulasek

doi:10.3390/ijms20205122

Abstract

The floral development in an important legume crop yellow lupine (Lupinus luteus L., Taper cv.) is often affected by the abscission of flowers leading to significant economic losses. Small non-coding RNAs (sncRNAs), which have a proven effect on almost all developmental processes in other plants, might be of key players in a complex net of molecular interactions regulating flower development and abscission. This study represents the first comprehensive sncRNA identification and analysis of small RNA, transcriptome and degradome sequencing data in lupine flowers to elucidate their role in the regulation of lupine generative development. As shedding in lupine primarily concerns flowers formed at the upper part of the inflorescence, we analyzed samples from extreme parts of raceme separately and conducted an additional analysis of pedicels from abscising and non-abscising flowers where abscission zone forms. A total of 394 known and 28 novel miRNAs and 316 phased siRNAs were identified. In flowers at different stages of development 59 miRNAs displayed differential expression (DE) and 46 DE miRNAs were found while comparing the upper and lower flowers. Identified tasiR-ARFs were DE in developing flowers and were strongly expressed in flower pedicels. The DEmiR-targeted genes were preferentially enriched in the functional categories related to carbohydrate metabolism and plant hormone transduction pathways. This study not only contributes to the current understanding of how lupine flowers develop or undergo abscission but also holds potential for research aimed at crop improvement.

Highlights

Yellow lupine is a crop plant with remarkable economic potential
Since (i) some micro RNAs and small interfering RNAs restrict the activity of certain ARFs [18,19] and members of the TAAR (TIR1/AFB AUXIN RECEPTOR) family encoding auxin receptors [20], and since (ii) we proved that the precursor of miR169 is accumulated in increased quantities in yellow lupine’s generative organs undergoing abscission [17], we predict that sRNAs play significant roles in orchestrating organ abscission in L. luteus
Flowers collected from the top and bottom parts of the inflorescence were separated into four categories based on the progression of their development, and : Stage 1—closed green buds, parts of which were still elongating

Summary

Introduction

Yellow lupine is a crop plant with remarkable economic potential. Because of the symbiotic bond with nitrogen-fixing Rhizobium bacteria it does not need fertilizers, and its protein-rich seeds may be an excellent source of protein for both human consumption and animal feed [1,2,3]. Precise control of flower emergence and development is crucial for plant’s reproductive cycle This is especially true for crop plants, as it is directly tied to potential yield. Numerous factors are involved in flower development, such as plant hormones (for example GA, IAA, JA [8]), numerous genes [9] and microRNAs, [10]. All of these components create a complex regulatory network, malfunction of which can cause a variety of abnormalities with the loss of fertility being the most detrimental [11,12]

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