Abstract
There is an urgent need for the improvement of drought-tolerant bread and durum wheat. The huge and complex genome of bread wheat (BBAADD genome) stands as a vital obstruction for understanding the molecular mechanism underlying drought tolerance. However, tetraploid wheat (Triticum turgidum ssp., BBAA genome) is an ancestor of modern bread wheat and offers an important model for studying the drought response due to its less complex genome. Additionally, several wild relatives of tetraploid wheat have already shown a significant drought tolerance. We sequenced root transcriptome of three tetraploid wheat varieties with varying stress tolerance profiles, and built differential expression library of their transcripts under control and drought conditions. More than 5,000 differentially expressed transcripts were identified from each genotype. Functional characterization of transcripts specific to drought-tolerant genotype, revealed their association with osmolytes production and secondary metabolite pathways. Comparative analysis of differentially expressed genes and their non-coding RNA partners, long noncoding RNAs and microRNAs, provided valuable insight to gene expression regulation in response to drought stress. LncRNAs as well as coding transcripts share similar structural features in different tetraploid species; yet, lncRNAs slightly differ from coding transcripts. Several miRNA-lncRNA target pairs were detected as differentially expressed in drought stress. Overall, this study suggested an important pool of transcripts where their manipulations confer a better performance of wheat varieties under drought stress.
Highlights
Wheat (Triticum ssp.) is one of the major sources of continuously increasing food demand, ranking third in crop production worldwide[1]
While the miRNAs and small interfering RNAs (siRNAs) are referred as small RNAs based on their small length ranging between 18 to 24 nucleotides, another type of ncRNAs longer than 200 nucleotides has been recently defined as long non-coding RNAs19, 20
RNA-dependent DNA Methylation (RdDM) in plants, for example, utilizes long non-coding RNAs (lncRNAs) acting as precursors of siRNAs which later target lncRNAs acting as scaffold RNAs recruiting siRNA-AGO4 complex together with RDM1 (RNA-directed DNA Methylation 1) to a target genomic loci for DNA methylation-mediated silencing[23]
Summary
Wheat (Triticum ssp.) is one of the major sources of continuously increasing food demand, ranking third in crop production worldwide[1]. Wild plants evolved sophisticated stress tolerance and adaptation mechanisms to drought where the domestication of modern wheat varieties has led to the loss of these valuable genes in the process of domestication[6]. Mechanisms of drought responses in wild progenitors of wheat might reveal such favorable regulatory elements lost during domestication and cultivation processes. Several studies evinced the functions of lncRNAs in the biogenesis and targeting process of small-noncoding RNAs by possessing miRNA-siRNA precursor potential and sRNA target mimicry[19]. LncRNAs have been identified as differentially expressed under several stress conditions and their regulation on both mRNA and sRNA pool detected as critical for stress tolerance and maintenance of vitality[25]; not that much effort has been done in drought responsive lncRNAs and their association with coding and other non-coding RNA species, in cereals. This study presents a brief method for precise identification and detailed characterization of lncRNAs for plants lacking both an annotated genome and a reference genome
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
