MicroRNA-mRNA expression profiles and their potential role in cadmium stress response in Brassica napus

Abstract

BackgroundOilseed rape is an excellent candidate for phytoremediation of cadmium (Cd) contaminated soils given its advantages of high biomass, fast growth, moderate metal accumulation, ease of harvesting, and metal tolerance, but the cadmium response pathways in this species (Brassica napus) have yet to be fully elucidated. A combined analysis of miRNA and mRNA expression to infer Cd-induced regulation has not been reported in B. napus.ResultsWe characterized concurrent changes in miRNA and mRNA profiles in the roots and shoots of B. napus seedlings after 10 days of 10 mg/L Cd2+ treatment. Cd treatment significantly affected the expression of 22 miRNAs belonging to 11 families in the root and 29 miRNAs belonging to 14 miRNA families in the shoot. Five miRNA families (MIR395, MIR397, MIR398, MIR408 and MIR858) and three novel miRNAs were differentially expressed in both tissues. A total of 399 differentially expressed genes (DEGs) in the root and 389 DEGs in the shoot were identified, with very little overlap between tissue types. Eight anti-regulation miRNA-mRNA interaction pairs in the root and eight in the shoot were identified in response to Cd and were involved in key plant stress response pathways: for example, four genes targeted by miR398 were involved in a pathway for detoxification of superoxide radicals. Cd stress significantly impacted the photosynthetic pathway. Transcription factor activation, antioxidant response pathways and secondary metabolic processes such as glutathione (GSH) and phenylpropanoid metabolism were identified as major components for Cd-induced response in both roots and shoots.ConclusionsCombined miRNA and mRNA profiling revealed miRNAs, genes and pathways involved in Cd response which are potentially critical for adaptation to Cd stress in B. napus. Close crosstalk between several Cd-induced miRNAs and mRNAs was identified, shedding light on possible mechanisms for response to Cd stress in underground and aboveground tissues in B. napus. The pathways, genes, and miRNAs identified here will be valuable targets for future improvement of cadmium tolerance in B. napus.

Integrated Analysis of Small RNA, Transcriptome, and Degradome Sequencing Reveals the MiR156, MiR5488 and MiR399 Are Involved in the Regulation of Male Sterility in PTGMS Rice

“…We also drew similar conclusions by comparing the distribution of sRNA richness in other plants such as peanuts, rapeseed, tomatoes, and radishes. However, we found that 18 nt sRNAs have the highest richness in wheat [ 31 , 33 , 48 , 49 , 50 ]. Such results indicated that the abundance of sRNAs may only slightly vary between species, regardless of experimental treatment and variety selection.…”

Plant miR397 and its functions

“…Some studies based on genome-wide transcriptome analysis showed that miR397 could be upregulated by other heavy metal stresses. It was reported that miR397 was upregulated by cadmium (Cd) stress in Brassica napus (Zhou et al 2012;Fu et al 2019), Brassica parachinensis (Zhou et al 2017;Liu et al 2020), and soybeans (Fang et al 2013), as well as by chromium (Cr) in rice (Dubey et al 2020). Gielen et al (2016) found that Cd-exposure led to a decrease in Cu levels in Arabidopsis plants compared with the control (Gielen et al 2016).…”

Analysis of Cadmium-Stress-Induced microRNAs and Their Targets Reveals bra-miR172b-3p as a Potential Cd2+-Specific Resistance Factor in Brassica juncea

“…Cadmium (Cd), is one of the most prevalent and poisonous elements in agricultural soil, and jeopardizes the environment and human health. Toxicology studies have been undertaken of Cd stress in plants affecting tissue morphological, biochemical and physiological changes, as well as altered gene expressions [3][4][5][6]. The presence of 40 mg L −1 Cd in soil has already been found to affect yield in some crops [7].…”