Osmotic stress-induced somatic embryo maturation of coffee Coffea arabica L., shoot and root apical meristems development and robustness

Eliana Valencia-Lozano,Jorge E Ibarra,Humberto Herrera-Ubaldo,José L Cabrera-Ponce,Stefan De Folter

doi:10.1038/s41598-021-88834-z

Eliana Valencia-Lozano, Jorge E Ibarra + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-88834-z

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Abstract

Somatic embryogenesis (SE) is the most important plant biotechnology process for plant regeneration, propagation, genetic transformation and genome editing of coffee, Coffea arabica L. Somatic embryo (SEs) conversion to plantlets is the principal bottleneck for basic and applied use of this process. In this study we focus on the maturation of SEs of C. arabica var. Typica. SEs conversion to plantlet up to 95.9% was achieved under osmotic stress, using 9 g/L gelrite, as compared with only 39.34% in non-osmotic stress. Mature SEs induced in osmotic stress developed shoot and root apical meristems, while untreated SEs were unable to do it. C. arabica regenerated plants from osmotic stress were robust, with higher leaf and root area and internode length. To understand a possible regulatory mechanism, gene expression of key genes of C. arabica, homologous to sequences in the Arabidopsis thaliana genome, were analyzed. A set of two component system and cytokinin signaling-related coding genes (AHK1, AHK3, AHP4 and ARR1) which interact with WUSCHEL and WOX5 homedomains and morphogenic genes, BABY-BOOM, LEC1, FUS3 and AGL15, underwent significant changes during maturation of SEs of C. arabica var. Typica. This protocol is currently being applied in genetic transformation with high rate of success.

Highlights

Abbreviations SE Somatic embryogenesis SEs Somatic embryos shoot apical meristem (SAM) Shoot apical meristem root apical meristem (RAM) Root apical meristem BAP 6-Benzylaminopurine 2,4-D 2,4-Dichlorophenoxyacetic acid
We detected important changes in the expression of genes involved in the two-component system and cytokinin signaling pathway (AHK1, AHK3, AHP4 and ARR1), homeodomain transcription factors (WUSCHEL and WOX5), auxin response factor 5 (ARF5, Monopteros) and other key regulators of SE BABY-BOOM (BBM), LEAFY COTYLEDON1 (LEC1), FUSCA3 (FUS3), and AGAMOUS-LIKE 15 (AGL15)
Direct SE was induced from leaf explants of C. arabica var

Summary

Introduction

Abbreviations SE Somatic embryogenesis SEs Somatic embryos SAM Shoot apical meristem RAM Root apical meristem BAP 6-Benzylaminopurine 2,4-D 2,4-Dichlorophenoxyacetic acid. Conversion is defined as root and epicotyl growth with new leaf d evelopment[10] This is most likely due to a poor shoot and root apical meristem (SAM and RAM, respectively) development or defects in the meristem organization during SE. In the presence of high content of gelrite, mature SEs developed SAM and RAM demonstrated by histological analysis and were able of embryo to plantlet conversion and produce robustness plants compared to untreated SEs. We detected important changes in the expression of genes involved in the two-component system and cytokinin signaling pathway (AHK1, AHK3, AHP4 and ARR1), homeodomain transcription factors (WUSCHEL and WOX5), auxin response factor 5 (ARF5, Monopteros) and other key regulators of SE BABY-BOOM (BBM), LEAFY COTYLEDON1 (LEC1), FUSCA3 (FUS3), and AGAMOUS-LIKE 15 (AGL15)

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