Abstract
Adventitious rooting is the most important mechanism underlying vegetative propagation and an important strategy for plant propagation under environmental stress. The present study was conducted to obtain transcriptomic data and examine gene expression using RNA-Seq and bioinformatics analysis, thereby providing a foundation for understanding the molecular mechanisms controlling adventitious rooting. Three cDNA libraries constructed from mRNA samples from mung bean hypocotyls during adventitious rooting were sequenced. These three samples generated a total of 73 million, 60 million, and 59 million 100-bp reads, respectively. These reads were assembled into 78,697 unigenes with an average length of 832 bp, totaling 65 Mb. The unigenes were aligned against six public protein databases, and 29,029 unigenes (36.77%) were annotated using BLASTx. Among them, 28,225 (35.75%) and 28,119 (35.62%) unigenes had homologs in the TrEMBL and NCBI non-redundant (Nr) databases, respectively. Of these unigenes, 21,140 were assigned to gene ontology classes, and a total of 11,990 unigenes were classified into 25 KOG functional categories. A total of 7,357 unigenes were annotated to 4,524 KOs, and 4,651 unigenes were mapped onto 342 KEGG pathways using BLAST comparison against the KEGG database. A total of 11,717 unigenes were differentially expressed (fold change>2) during the root induction stage, with 8,772 unigenes down-regulated and 2,945 unigenes up-regulated. A total of 12,737 unigenes were differentially expressed during the root initiation stage, with 9,303 unigenes down-regulated and 3,434 unigenes up-regulated. A total of 5,334 unigenes were differentially expressed between the root induction and initiation stage, with 2,167 unigenes down-regulated and 3,167 unigenes up-regulated. qRT-PCR validation of the 39 genes with known functions indicated a strong correlation (92.3%) with the RNA-Seq data. The GO enrichment, pathway mapping, and gene expression profiles reveal molecular traits for root induction and initiation. This study provides a platform for functional genomic research with this species.
Highlights
Adventitious roots refer to roots that form from any tissue that is not a root, such as leaves and stems
To investigate gene expression changes during adventitious rooting, the primary roots of the seedlings were removed from the bases of the hypocotyls, and the resulting explants (10 per beaker) were cultured in 50-mL beakers containing 40 mL sterilized distilled water for 6 h (Wat6) or 24 h (Wat24) under the same aseptic conditions applied to the seedling culture
Total RNA extraction and cDNA synthesis were performed from three samples: hypocotyls (Con), hypocotyls after primary root excision and incubation in water for 6 h (Wat6, root induction stage), and hypocotyls after primary root removal and incubation in water for 24 h (Wat24, root initiation stage)
Summary
Adventitious roots refer to roots that form from any tissue that is not a root, such as leaves and stems. The formation of adventitious roots has been associated with an important aspect of tissue dedifferentiation that involves shifting cells from normal morphogenetic pathways to functions associated with the development of root primordia [3]. This shift leads to de novo root formation and a multitude of metabolic changes involving the enzymes and macromolecules associated with the induction, initiation, and development of root primordia in plant cuttings [4]. The physiological and biochemical changes that occur during adventitious root formation have been extensively studied, the molecular mechanisms involved remain less well understood
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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
