Abstract
Chinese cork oak (Quercus variabilis) is a widely distributed and highly valuable deciduous broadleaf tree from both ecological and economic perspectives. Seeds of this species are recalcitrant, i.e., sensitive to desiccation, which affects their storage and long-term preservation of germplasm. However, little is known about the underlying molecular mechanism of desiccation sensitivity of Q. variabilis seeds. In this study, the seeds were desiccated with silica gel for certain days as different treatments from 0 (Control) to 15 days (T15) with a gradient of 1 day. According to the seed germination percentage, four key stages (Control, T2, T4, and T11) were found. Then the transcriptomic profiles of these four stages were compared. A total of 4,405, 4,441, and 5,907 differentially expressed genes (DEGs) were identified in T2 vs. Control, T4 vs. Control, and T11 vs. Control, respectively. Among them, 2,219 DEGs were overlapped in the three comparison groups. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that these DEGs were enriched into 124 pathways, such as “Plant hormone signal transduction” and “Glycerophospholipid metabolism”. DEGs related to hormone biosynthesis and signal transduction (ZEP, YUC, PYR, ABI5, ERF1B, etc.), stress response proteins (LEA D-29, HSP70, etc.), and phospholipase D (PLD1) were detected during desiccation. These genes and their interactions may determine the desiccation sensitivity of seeds. In addition, group specific DEGs were also identified in T2 vs. Control (PP2C62, UNE12, etc.), T4 vs. Control (WRKY1-like, WAK10, etc.), and T11 vs. Control (IBH1, bZIP44, etc.), respectively. Finally, a possible work model was proposed to show the molecular regulation mechanism of desiccation sensitivity in Q. variabilis seeds. This is the first report on the molecular regulation mechanism of desiccation sensitivity of Q. variabilis seeds using RNA-Seq. The findings could make a great contribution to seed storage and long-term conservation of recalcitrant seeds in the future.
Highlights
Vegetative propagation is an extremely useful method for tree propagation
These results indicate that Q. variabilis seeds are highly sensitive to desiccation
The results showed that these differentially expressed genes (DEGs) covered three Gene Ontology (GO) categories: “Molecular function (MF)”, “Cellular component (CC)”, and “Biological progress (BP)”
Summary
Vegetative propagation is an extremely useful method for tree propagation. It can capture the superior phenotypes of selected trees and propagates uniform clones (Pacholczak et al, 2017). Seed desiccation sensitivity is considered as an important functional and secondary evolutionary characteristic with a series of molecular processes being involved, such as gene expression regulation at the transcriptional level, phytohormone signaling transduction, and accumulation of late embryogenesis abundant proteins (LEAs) (Marques et al, 2018; Kijak and Ratajczak, 2020). Genes related to abscisic acid (ABA) biosynthesis and signal transduction, as well as LEAs and heat shock proteins (HSPs) were found to be differentially expressed during desiccation (Wei et al, 2017; Jin et al, 2018; Marques et al, 2018). Desiccation tolerance acquisition of Coffea arabica seed was concomitant with a decrease of indole-3-acetic-acid (IAA) content (Dussert et al, 2018). It has been reported that the UDP-glucosyltransferase UGT74E2 modulate water stress tolerance in Arabidopsis (Tognetti et al, 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
