Osmopriming-associated genes in Poincianella pyramidalis

Cimille G.C Antunes,Saulo A Aflitos,Valdir G Neto,Daniele Takahashi,Henk W.M Hilhorst,Luzimar G Fernandez,Renato D De Castro,Wilco Ligterink,Alexandre C.S.S Marques,Claudinéia R.P Cruz,Peter Toorop

doi:10.1016/j.envexpbot.2020.104345

Abstract

Osmopriming of seeds can increase seed vigour, allowing faster germination and field emergence, especially under adverse field conditions. The restricted imbibition during priming treatments reactivates metabolism although germination will be prevented. In order to identify and characterize genes that are involved in the improvement of vigour of Poincianella pyramidalis (Catingueira) seeds upon priming, we produced two different Suppression Subtractive Hybridization (SSH) cDNA libraries. These were a Forward and Reverse subtraction of cDNA samples isolated from untreated dry seeds (unprimed) and osmoprimed seeds. The two different libraries were sequenced by Illumina GAII next generation sequencing, resulting in almost 20 million reads that could be assigned to 5298 different contigs. Of these, 999 were only found in the unprimed seeds library and 2711 were specific for osmoprimed seeds. The contigs were annotated and subjected to gene set enrichment analysis and differential expression of several genes was confirmed by qRT-PCR analysis. The identified differentially expressed genes might play an important role in vigour improvement upon priming and may be potential markers for tolerance to water stress in P. pyramidalis seeds.

Highlights

Priming is a commercially used technique to improve seed germi nability and seedling emergence
They may encode proteins involved in signaling cascades and subsequent transcriptional control to regulate target genes, such as Mitogen-Activated Protein Ki nases (MAPKs), Calcium-Dependent Protein Kinases (CDPKs), Salt Overly Sensitive (SOS) Independent Protein Kinases, phospholipases
The osmopriming treatment was done by incubating the P. pyramidalis seeds for 7 days in PEG solution (-1.2 MPa) under constant light and agitation, followed by re-drying the seeds to their original moisture content for 4 days at 20 ◦C and 30 % RH (Fig. 1A)

Summary

Introduction

Priming is a commercially used technique to improve seed germi nability and seedling emergence. Osmotic stress response genes code for proteins that protect plant cells against several abiotic stresses such as Heat Shock proteins (HSPs), Late Embryogenesis Abundant (LEA) pro teins, osmoprotectants, antifreeze proteins, detoxification enzymes, free-radical scavengers, aquaporins and ion transporters (Blumwald, 2000; Bray et al, 2015; Ligterink et al, 2007) They may encode proteins involved in signaling cascades and subsequent transcriptional control to regulate target genes, such as Mitogen-Activated Protein Ki nases (MAPKs), Calcium-Dependent Protein Kinases (CDPKs), Salt Overly Sensitive (SOS) Independent Protein Kinases, phospholipases and multiple transcription factors (Ludwig et al, 2004; Rudrabhatla and Rajasekharan, 2002; Shinozaki and Yamaguchi-Shinozaki, 2000; Shi nozaki et al, 2003; Zhu, 2001)

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Conclusion