Regulation of the Bud Dormancy Development and Release in Micropropagated Rhubarb 'Malinowy'.

Agnieszka Wojtania,Monika Markiewicz,Piotr Waligórski

doi:10.3390/ijms23031480

Abstract

Culinary rhubarb is a vegetable crop, valued for its stalks, very rich in different natural bioactive ingredients. In commercial rhubarb stalk production, the bud dormancy development and release are crucial processes that determine the yields and quality of stalks. To date, reports on rhubarb bud dormancy regulation, however, are lacking. It is known that dormancy status depends on cultivars. The study aimed to determine the dormancy regulation in a valuable selection of rhubarb ‘Malinowy’. Changes in carbohydrate, total phenolic, endogenous hormone levels, and gene expression levels during dormancy development and release were studied in micropropagated rhubarb plantlets. Dormancy developed at high temperature (25.5 °C), and long day. Leaf senescence and dying were consistent with a significant increase in starch, total phenolics, ABA, IAA and SA levels. Five weeks of cooling at 4 °C were sufficient to break dormancy, but rhizomes stored for a longer duration showed faster and more uniformity leaf growing, and higher stalk length. No growth response was observed for non-cooled rhizomes. The low temperature activated carbohydrate and hormone metabolism and signalling in the buds. The increased expression of AMY3, BMY3, SUS3, BGLU17, GAMYB genes were consistent with a decrease in starch and increase in soluble sugars levels during dormancy release. Moreover, some genes (ZEP, ABF2, GASA4, GA2OX8) related to ABA and GA metabolism and signal transduction were activated. The relationship between auxin (IAA, IBA, 5-Cl-IAA), and phenolic, including SA levels and dormancy status was also observed.

Highlights

Perennial herbaceous plants from temperate climate regions, such as rhubarb (Rheum; Polygonacea family), have an adaptive mechanism that alters active growth and bud dormancy that allows them to survive in adverse conditions during winter
The balance between abscisic acid (ABA) and GA significantly influences dormancy regulation [51,52,53]. These results indicated that the decreased expression of ABA precursor (ZEP) and increased levels of acid responsive elements-binding factor 2 (ABF2) involved in ABA s1i1gonfa1l7 transduction and metabolism were consistent with the reduced levels of ABA in the rhubarb buds during dormancy release
These results indicated that the decreased expression of ABA precursor (ZEP) and increased levels of ABF2 involved in ABA signal transduction and metabolism were consistent with the reduced levels of ABA in the rhubarb buds during dormancy release

Summary

Introduction

Perennial herbaceous plants from temperate climate regions, such as rhubarb (Rheum; Polygonacea family), have an adaptive mechanism that alters active growth and bud dormancy that allows them to survive in adverse conditions during winter. These plants use cyclically changing environmental signals, such as temperature and day-length, to coordinate their growth and development with seasonal climate changes [1,2,3]. Reports on rhubarb in this area, are lacking

Methods

Results

Conclusion