Regulation of α-expansins genes in Arabidopsis thaliana seeds during post-osmopriming germination

Abstract

Seed osmopriming is a pre-sowing treatment that involves limitation of the seed water imbibition, so that pre-germinative metabolic activities proceed without radicular protrusion. This technique is used for improving germination rate, uniformity of seedling growth and hastening the time to start germination. In Arabidopsis thaliana, seed germination has been associated with the induction of enzymes involved in cell wall modifications, such as expansins. The a-expansins (EXPAs) are involved in cell wall relaxation and extension during seed germination. We used online tools to identify AtEXPA genes with preferential expression during seed germination and RT-qPCR to study the expression of five EXPA genes at different germination stages of non-primed and osmoprimed seeds. In silico promoter analysis of these genes showed that motifs similar to cis-acting elements related to abiotic stress, light and phytohormone responses are the most overrepresented in promoters of these AtEXPA genes, showing that their expression is likely be regulated by intrinsic developmental and environmental signals during Arabidopsis seed germination. The osmopriming conditioning had a decreased time and mean to 50% germination without affecting the percentage of final seed germination. The dried PEG-treated seeds showed noticeable high mRNA levels earlier at the beginning of water imbibition (18 h), showing that transcripts of all five EXPA isoforms were significantly produced during the osmopriming process. The strong up-regulation of these AtEXPA genes, mainly AtEXPA2, were associated with the earlier germination of the osmoprimed seeds, which qualifies them to monitor osmopriming procedures and the advancement of germination.

Hormone analysis and candidate genes identification associated with seed size in Camellia oleifera

“…XTH9 was highly expressed in the T1 period of C. oleifera seeds and then decreased, which may be related to vigorous cell expansion. Additionally, Expansins genes were involved in cell wall relaxation and extension in Arabidopsis seeds [ 50 ]. Suppression of EXPA1 and EXPA10 altered chemical composition of the cell wall [ 51 ].…”

AtSYP71 Is Important for Plant Cell Wall Biosynthesis and Stress Adaptation.

“…For example, AT4G01700-encoding protein belongs to Chitinase family which is related to cellulose biosynthesis and cell wall remodeling [128]. The EXPA proteins are responsible for controlling cell wall extension and developmental processes, including cell dissociation and separation [129][130][131][132]. LTP1 and LTP2 belong to a family of lipid transfer proteins, and LTP2 plays a role in maintaining the integrity of the cuticle-cell wall interface [133].…”

Seed Priming Technology as a Key Strategy to Increase Crop Plant Production under Adverse Environmental Conditions

“…Routinely used by seed companies to enhance the vigor of seeds, osmopriming techniques have shown promising germination and plant growth performance 38,39 under several adverse environmental conditions, such as chilling 40 , salinity 41,42 and drought 12 . In this method, seeds are immersed in an osmotic solution with low water potential (ψ) through the use of polyethylene glycol (PEG), mannitol, sorbitol, glycerol, or inorganic substances, such as NaCl, KCl, K2SiO3, KNO3, MgSO4, and CaCl2.…”