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

Noncoding RNAs in regulation of plant secondary metabolism

Plant secondary metabolites (PSMs) are a large class of structurally diverse molecules, mainly consisting of terpenoids, phenolic compounds, and nitrogen-containing compounds, which play active roles in plant development and stress responses. The biosynthetic processes of PSMs are governed by a sophisticated regulatory network at multiple levels. Noncoding RNAs (ncRNAs) such as microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs) may serve as post-transcriptional regulators for plant secondary metabolism through acting on genes encoding either transcription factors or participating enzymes in relevant metabolic pathways. High-throughput sequencing technologies have facilitated the large-scale identifications of ncRNAs potentially involved in plant secondary metabolism in model plant species as well as certain species with enriched production of specific types of PSMs. Moreover, a series of miRNA-target modules have been functionally characterized to be responsible for regulating PSM biosynthesis and accumulation in plants under abiotic or biotic stresses. In this review, we will provide an overview of current findings on the ncRNA-mediated regulation of plant secondary metabolism with special attention to its participation in plant stress responses, and discuss possible issues to be addressed in future fundamental research and breeding practice.

Multiomics and biotechnologies for understanding and influencing cadmium accumulation and stress response in plants

Cadmium (Cd) is one of the most toxic heavy metals faced by plants and, additionally, via the food chain, threatens human health. It is principally dispersed through agro-ecosystems via anthropogenic activities and geogenic sources. Given its high mobility and persistence, Cd, although not required, can be readily assimilated by plants thereby posing a threat to plant growth and productivity as well as animal and human health. Thus, breeding crop plants in which the edible parts contain low to zero Cd as safe food stuffs and harvesting shoots of high Cd-containing plants as a route for decontaminating soils are vital strategies to cope with this problem. Recently, multiomics approaches have been employed to considerably enhance our understanding of the mechanisms underlying (i) Cd toxicity, (ii) Cd accumulation, (iii) Cd detoxification and (iv) Cd acquisition tolerance in plants. This information can be deployed in the development of the biotechnological tools for developing plants with modulated Cd tolerance and detoxification to safeguard cellular and genetic integrity as well as to minimize food chain contamination. The aim of this review is to provide a current update about the mechanisms involved in Cd uptake by plants and the recent developments in the area of multiomics approach in terms of Cd stress responses, as well as in the development of Cd tolerant and low Cd accumulating crops.

Identification and expression analysis of the Xyloglucan transglycosylase/hydrolase (XTH) gene family under abiotic stress in oilseed (Brassica napus L.)

XTH genes are key genes that regulate the hydrolysis and recombination of XG components and plays role in the structure and composition of plant cell walls. Therefore, clarifying the changes that occur in XTHs during plant defense against abiotic stresses is informative for the study of the plant stress regulatory mechanism mediated by plant cell wall signals. XTH proteins in Arabidopsis thaliana was selected as the seed sequences in combination with its protein structural domains, 80 members of the BnXTH gene family were jointly identified from the whole genome of the Brassica napus ZS11, and analyzed for their encoded protein physicochemical properties, phylogenetic relationships, covariance relationships, and interoperating miRNAs. Based on the transcriptome data, the expression patterns of BnXTHs were analyzed in response to different abiotic stress treatments. The relative expression levels of some BnXTH genes under Al, alkali, salt, and drought treatments after 0, 6, 12 and 24 h were analyzed by using qRT-PCR to explore their roles in abiotic stress tolerance in B. napus. BnXTHs showed different expression patterns in response to different abiotic stress signals, indicating that the response mechanisms of oilseed rape against different abiotic stresses are also different. This paper provides a theoretical basis for clarifying the function and molecular genetic mechanism of the BnXTH gene family in abiotic stress tolerance in rapeseed.

MicroRNA-encoded regulatory peptides modulate cadmium tolerance and accumulation in rice

MicroRNAs (miRNAs) are small noncoding RNAs that play a vital role in plant responses to abiotic and biotic stresses. Recently, it has been discovered that some primary miRNAs (pri-miRNAs) encode regulatory short peptides called miPEPs. However, the presence of miPEPs in rice, and their functions in response to abiotic stresses, particularly stress induced by heavy metals, remain poorly understood. Here, we identified a functional small peptide (miPEP156e) encoded by pri-miR156e that regulates the expression of miR156 and its target SPL genes, thereby affecting miR156-mediated cadmium (Cd) tolerance in rice. Overexpression of miPEP156e led to decreased uptake and accumulation of Cd and reactive oxygen species (ROS) levels in plants under Cd stress, resulting in improved rice Cd tolerance, as observed in miR156-overexpressing lines. Conversely, miPEP156e mutants displayed sensitivity to Cd stress due to the elevated accumulation of Cd and ROS. Transcriptome analysis further revealed that miPEP156e improved rice Cd tolerance by modulating Cd transporter genes and ROS scavenging genes. Our study provides insights into the regulatory mechanism of miPEP156e in rice response to Cd stress and demonstrates the potential of miPEPs as an effective tool for improving crop abiotic stress tolerance.

Biocontrol fungi induced stem-base rot disease resistance of Morinda officinalis How revealed by transcriptome analysis

Introduction

Morinda officinalis How (MO) is a Rubiaceae plant, and its medicinal part is dried root, which is one of the "Four Southern Medicines" in China. At present, the plant MO breed seedlings mainly by cutting methods. Long-term asexual propagation makes pathogenic fungi accumulate in MO, leading to stem-base rot, which is caused by Fusarium oxysporum (Fon).

Methods

In this study, we used Trichoderma harzianum and Pestalotiopsis sp. as biocontrol fungi to investigate their antagonistic ability to Fon through in vitro antagonism and pot experiments, and combined with transcriptome sequencing to explore the mechanism of biocontrol.

Results

The results showed that both Trichoderma harzianum and Pestalotiopsis sp. could inhibit the growth of Fon. In addition, Trichoderma harzianum and Pestalotiopsis sp. could also enhance the basic immunity to Fon by increasing the activities of defensive enzymes such as POD and SOD, chlorophyll content, soluble sugar content, and oligosaccharide content of MO. The mechanism of biological control of stem-base rot of MO was discussed by transcriptome technology. MO was treated with two treatments, root irrigation with biocontrol fungi or inoculation with Fon after root irrigation with biocontrol fungi. Transcriptome sequencing revealed that nearly 11,188 differentially expressed genes (DEGs) were involved in the process of inducing MO systemic resistance to Fon by biocontrol fungi. Meanwhile, Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, as well as transcription factor (TFs) prediction showed that there were significant differences in the expression levels of MO roots under different treatments. Also, the genes of the "MAPK signaling pathway" and "plant hormone signaling pathway" were analyzed, in which the ERFs gene of the ethylene signal transduction pathway participated in the metabolism of glycosyl compounds. It is speculated that the ethylene signal may participate in the immune response of the sugar signal to the infection of Fon. After qRT-PCR verification of 10 DEGs related to the ethylene signal transduction pathway, the expression trend is consistent with the results of transcriptome sequencing, which proves the reliability of transcriptome sequencing.

Discussion

In conclusion, this study preliminarily identified the molecular mechanism of the biological control of MO stem-base rot and provided a scientific basis for further research on the prevention and control mechanism of MO stem-base rot.

Insights into heavy metal tolerance mechanisms of Brassica species: physiological, biochemical, and molecular interventions

Heavy metal (HM) contamination of soil due to anthropogenic activities has led to bioaccumulation and biomagnification, posing toxic effects on plants by interacting with vital cellular biomolecules such as DNA and proteins. Brassica species have developed complex physiological, biochemical, and molecular mechanisms for adaptability, tolerance, and survival under these conditions. This review summarizes the HM tolerance strategies of Brassica species, covering the role of root exudates, microorganisms, cell walls, cell membranes, and organelle-specific proteins. The first line of defence against HM stress in Brassica species is the avoidance strategy, which involves metal ion precipitation, root sorption, and metal exclusion. The use of plant growth-promoting microbes, Pseudomonas, Psychrobacter, and Rhizobium species effectively immobilizes HMs and reduces their uptake by Brassica roots. The roots of Brassica species efficiently detoxify metals, particularly by flavonoid glycoside exudation. The composition of the cell wall and callose deposition also plays a crucial role in enhancing HMs resistance in Brassica species. Furthermore, plasma membrane-associated transporters, BjCET, BjPCR, BjYSL, and BnMTP, reduce HM concentration by stimulating the efflux mechanism. Brassica species also respond to stress by up-regulating existing protein pools or synthesizing novel proteins associated with HM stress tolerance. This review provides new insights into the HM tolerance mechanisms of Brassica species, which are necessary for future development of HM-resistant crops.

Mapping and Identifying Candidate Genes Enabling Cadmium Accumulation in Brassica napus Revealed by Combined BSA-Seq and RNA-Seq Analysis

Rapeseed has the ability to absorb cadmium in the roots and transfer it to aboveground organs, making it a potential species for remediating soil cadmium (Cd) pollution. However, the genetic and molecular mechanisms underlying this phenomenon in rapeseed are still unclear. In this study, a 'cadmium-enriched' parent, 'P1', with high cadmium transport and accumulation in the shoot (cadmium root: shoot transfer ratio of 153.75%), and a low-cadmium-accumulation parent, 'P2', (with a cadmium transfer ratio of 48.72%) were assessed for Cd concentration using inductively coupled plasma mass spectrometry (ICP-MS). An F₂ genetic population was constructed by crossing 'P1' with 'P2' to map QTL intervals and underlying genes associated with cadmium enrichment. Fifty extremely cadmium-enriched F₂ individuals and fifty extremely low-accumulation F₂ individuals were selected based on cadmium content and cadmium transfer ratio and used for bulk segregant analysis (BSA) in combination with whole genome resequencing. This generated a total of 3,660,999 SNPs and 787,034 InDels between these two segregated phenotypic groups. Based on the delta SNP index (the difference in SNP frequency between the two bulked pools), nine candidate Quantitative trait loci (QTLs) from five chromosomes were identified, and four intervals were validated. RNA sequencing of 'P1' and 'P2' in response to cadmium was also performed and identified 3502 differentially expressed genes (DEGs) between 'P1' and 'P2' under Cd treatment. Finally, 32 candidate DEGs were identified within 9 significant mapping intervals, including genes encoding a glutathione S-transferase (GST), a molecular chaperone (DnaJ), and a phosphoglycerate kinase (PGK), among others. These genes are strong candidates for playing an active role in helping rapeseed cope with cadmium stress. Therefore, this study not only sheds new light on the molecular mechanisms of Cd accumulation in rapeseed but could also be useful for rapeseed breeding programs targeting this trait.

Comprehensive mechanisms of heavy metal toxicity in plants, detoxification, and remediation

Natural and anthropogenic causes are continually growing sources of metals in the ecosystem; hence, heavy metal (HM) accumulation has become a primary environmental concern. HM contamination poses a serious threat to plants. A major focus of global research has been to develop cost-effective and proficient phytoremediation technologies to rehabilitate HM-contaminated soil. In this regard, there is a need for insights into the mechanisms associated with the accumulation and tolerance of HMs in plants. It has been recently suggested that plant root architecture has a critical role in the processes that determine sensitivity or tolerance to HMs stress. Several plant species, including those from aquatic habitats, are considered good hyperaccumulators for HM cleanup. Several transporters, such as the ABC transporter family, NRAMP, HMA, and metal tolerance proteins, are involved in the metal acquisition mechanisms. Omics tools have shown that HM stress regulates several genes, stress metabolites or small molecules, microRNAs, and phytohormones to promote tolerance to HM stress and for efficient regulation of metabolic pathways for survival. This review presents a mechanistic view of HM uptake, translocation, and detoxification. Sustainable plant-based solutions may provide essential and economical means of mitigating HM toxicity.

Heavy Metals, Their Phytotoxicity, and the Role of Phenolic Antioxidants in Plant Stress Responses with Focus on Cadmium: Review

The current state of heavy metal (HM) environmental pollution problems was considered in the review: the effects of HMs on the vital activity of plants and the functioning of their antioxidant system, including phenolic antioxidants. The latter performs an important function in the distribution and binding of metals, as well as HM detoxification in the plant organism. Much attention was focused on cadmium (Cd) ions as one of the most toxic elements for plants. The data on the accumulation of HMs, including Cd in the soil, the entry into plants, and the effect on their various physiological and biochemical processes (photosynthesis, respiration, transpiration, and water regime) were analyzed. Some aspects of HMs, including Cd, inactivation in plant tissues, and cell compartments, are considered, as well as the functioning of various metabolic pathways at the stage of the stress reaction of plant cells under the action of pollutants. The data on the effect of HMs on the antioxidant system of plants, the accumulation of low molecular weight phenolic bioantioxidants, and their role as ligand inactivators were summarized. The issues of polyphenol biosynthesis regulation under cadmium stress were considered. Understanding the physiological and biochemical role of low molecular antioxidants of phenolic nature under metal-induced stress is important in assessing the effect/aftereffect of Cd on various plant objects-the producers of these secondary metabolites are widely used for the health saving of the world's population. This review reflects the latest achievements in the field of studying the influence of HMs, including Cd, on various physiological and biochemical processes of the plant organism and enriches our knowledge about the multifunctional role of polyphenols, as one of the most common secondary metabolites, in the formation of plant resistance and adaptation.

miRNA transcriptome reveals key miRNAs and their targets contributing to the difference in Cd tolerance of two contrasting maize genotypes

Soil cadmium (Cd) contamination is a global environmental and food safety production issue. microRNAs (miRNAs) are proven to be involved in plant growth and development, and abiotic/biotic stress response, but their role in Cd tolerance is largely unknown in maize. To understand the genetic basis of Cd tolerance, two maize genotypes differing in Cd tolerance (L42, a sensitive genotype and L63, a tolerant genotype) were selected, and miRNA sequencing was carried out at nine-day-old seedlings exposed to 24 h Cd stress (5 μM CdCl₂). A total of 151 differentially expressed miRNAs were identified, including 20 known miRNAs and 131 novel miRNAs. The results revealed that 90 and 22 miRNAs were up-regulated and down-regulated by Cd in Cd-tolerant genotype L63, and there were 23 and 43 miRNAs in Cd-sensitive genotype L42, respectively. Twenty-six miRNAs were up-regulated in L42 and unchanged or down-regulated in L63, or unchanged in L42 and down-regulated in L63. There were 108 miRNAs that were up-regulated in L63 and unchanged or down-regulated in L42, or unchanged in L63 and down-regulated in L42. Their target genes were enriched mainly in peroxisomes, glutathione (GSH) metabolism, ABC transporter, and ubiquitin-protease system. Among them, target genes involved in the peroxisome pathway and GSH metabolism might play key roles in Cd tolerance in L63. Besides, several ABC transporters which might involve in Cd uptake and transport were identified. The differentially expressed miRNAs or target genes could be used for breeding low grain Cd accumulation and high Cd tolerance cultivars in maize.

Temporal transcriptome analysis reveals several key pathways involve in cadmium stress response in Nicotiana tabacum L

Tobacco has a strong cadmium (Cd) enrichment capacity, meaning that it can absorb large quantities from the environment, but too much Cd will cause damage to the plant. It is not yet clear how the plant can dynamically respond to Cd stress. Here, we performed a temporal transcriptome analysis of tobacco roots under Cd treatment from 0 to 48 h. The number of differentially expressed genes (DEGs) was found to change significantly at 3 h of Cd treatment, which we used to define the early and middle stages of the Cd stress response. The gene ontology (GO) term analysis indicates that genes related to photosynthesis and fatty acid synthesis were enriched during the early phases of the stress response, and in the middle phase biological process related to metal ion transport, DNA damage repair, and metabolism were enriched. It was also found that plants use precursor mRNA (pre-mRNA) processes to first resist Cd stress, and with the increasing of Cd treatment time, the overlapped genes number of DEGs and DAS increased, suggesting the transcriptional levels and post-transcriptional level might influence each other. This study allowed us to better understand how plants dynamically respond to cadmium stress at the transcriptional and post-transcriptional levels and provided a reference for the screening of Cd-tolerant genes in the future.

Effects of Arbuscular Mycorrhizal Fungi on Alleviating Cadmium Stress in Medicago truncatula Gaertn

Heavy metal contamination is a global problem for ecosystems and human health. Remediation of contaminated soils has received much attention in the last decade. Aided mitigation of heavy metal phytotoxicity by arbuscular mycorrhizal fungi (AMF) is a cost-effective and environmentally friendly strategy. This study was carried out to investigate the mitigation effect of AMF inoculation on heavy metal toxicity in Medicago truncatula under soil cadmium stress. Therefore, a pot experiment was designed to evaluate the growth, chlorophyll fluorescence, Cd uptake and distribution, malondialdehyde (MDA) content, root soil physicochemical properties, and metabolite profile analysis of M. truncatula with/without AMF inoculation in Cd (20 mg/Kg)-contaminated soil. The results showed that inoculating AMF under Cd stress might enhance photosynthetic efficiency, increase plant biomass, decrease Cd and MDA content, and improve soil physicochemical properties in M. truncatula. Non-targeted metabolite analysis revealed that inoculation with AMF under Cd stress significantly upregulated the production of various amino acids in inter-root metabolism and increase organic acid and phytohormone synthesis. This study provides information on the physiological responses of mycorrhizal plants to heavy metal stress, which could help provide deeper insight into the mechanisms of heavy metal remediation by AMF.

Multiple Functions of MiRNAs in Brassica napus L

The worldwide climate changes every year due to global warming, waterlogging, drought, salinity, pests, and pathogens, impeding crop productivity. Brassica napus is one of the most important oil crops in the world, and rapeseed oil is considered one of the most health-beneficial edible vegetable oils. Recently, miRNAs have been found and confirmed to control the expression of targets under disruptive environmental conditions. The mechanism is through the formation of the silencing complex that mediates post-transcriptional gene silencing, which pairs the target mRNA and target cleavage and/or translation inhibition. However, the functional role of miRNAs and targets in B. napus is still not clarified. This review focuses on the current knowledge of miRNAs concerning development regulation and biotic and abiotic stress responses in B. napus. Moreover, more strategies for miRNA manipulation in plants are discussed, along with future perspectives, and the enormous amount of transcriptome data available provides cues for miRNA functions in B. napus. Finally, the construction of the miRNA regulatory network can lead to the significant development of climate change-tolerant B. napus through miRNA manipulation.

Plant responses to metals stress: microRNAs in focus

Metal toxicity can largely affect the growth and yield of numerous plant species. Plants have developed specific mechanisms to withstand the varying amounts of metals. One approach involves utilization of microRNAs (miRNAs) that are known for cleaving transcripts or inhibiting translation to mediate post-transcriptional control. Use of transcription factors (TFs) or gene regulation in metal detoxification largely depends on metal-responsive miRNAs. Moreover, systemic signals and physiological processes for plants response to metal toxicities are likewise controlled by miRNAs. Therefore, it is necessary to understand miRNAs and their regulatory networks in relation to metal stress. The miRNA-based approach can be important to produce metal-tolerant plant species. Here, we have reviewed the importance of plant miRNAs and their role in mitigating metal toxicities. The current review also discusses the specific advances that have occurred as a result of the identification and validation of several metal stress-responsive miRNAs.

Copper microRNAs modulate the formation of giant feeding cells induced by the root knot nematode Meloidogyne incognita in Arabidopsis thaliana

Root-knot nematodes (RKNs) are root endoparasites that induce the dedifferentiation of a few root cells and the reprogramming of their gene expression to generate giant hypermetabolic feeding cells. We identified two microRNA families, miR408 and miR398, as upregulated in Arabidopsis thaliana and Solanum lycopersicum roots infected by RKNs. In plants, the expression of these two conserved microRNA families is known to be activated by the SPL7 transcription factor in response to copper starvation. By combining functional approaches, we deciphered the network involving these microRNAs, their regulator and their targets. MIR408 expression was located within nematode-induced feeding cells like its regulator SPL7 and was regulated by copper. Moreover, infection assays with mir408 and spl7 knockout mutants or lines expressing targets rendered resistant to cleavage by miR398 demonstrated the essential role of the SPL7/MIR408/MIR398 module in the formation of giant feeding cells. Our findings reveal how perturbation of plant copper homeostasis, via the SPL7/MIR408/MIR398 module, modulates the development of nematode-induced feeding cells.

microRNAs: Key Players in Plant Response to Metal Toxicity

Environmental metal pollution is a common problem threatening sustainable and safe crop production. Heavy metals (HMs) cause toxicity by targeting key molecules and life processes in plant cells. Plants counteract excess metals in the environment by enhancing defense responses, such as metal chelation, isolation to vacuoles, regulating metal intake through transporters, and strengthening antioxidant mechanisms. In recent years, microRNAs (miRNAs), as a small non-coding RNA, have become the central regulator of a variety of abiotic stresses, including HMs. With the introduction of the latest technologies such as next-generation sequencing (NGS), more and more miRNAs have been widely recognized in several plants due to their diverse roles. Metal-regulated miRNAs and their target genes are part of a complex regulatory network. Known miRNAs coordinate plant responses to metal stress through antioxidant functions, root growth, hormone signals, transcription factors (TF), and metal transporters. This article reviews the research progress of miRNAs in the stress response of plants to the accumulation of HMs, such as Cu, Cd, Hg, Cr, and Al, and the toxicity of heavy metal ions.

Regulatory role of microRNAs (miRNAs) in the recent development of abiotic stress tolerance of plants

MicroRNAs (miRNAs) are a distinct groups of single-stranded non-coding, tiny regulatory RNAs approximately 20-24 nucleotides in length. miRNAs negatively influence gene expression at the post-transcriptional level and have evolved considerably in the development of abiotic stress tolerance in a number of model plants and economically important crop species. The present review aims to deliver the information on miRNA-mediated regulation of the expression of major genes or Transcription Factors (TFs), as well as genetic and regulatory pathways. Also, the information on adaptive mechanisms involved in plant abiotic stress responses, prediction, and validation of targets, computational tools, and databases available for plant miRNAs, specifically focus on their exploration for engineering abiotic stress tolerance in plants. The regulatory function of miRNAs in plant growth, development, and abiotic stresses consider in this review, which uses high-throughput sequencing (HTS) technologies to generate large-scale libraries of small RNAs (sRNAs) for conventional screening of known and novel abiotic stress-responsive miRNAs adds complexity to regulatory networks in plants. The discoveries of miRNA-mediated tolerance to multiple abiotic stresses, including salinity, drought, cold, heat stress, nutritional deficiency, UV-radiation, oxidative stress, hypoxia, and heavy metal toxicity, are highlighted and discussed in this review.

A Multi-Level Iterative Bi-Clustering Method for Discovering miRNA Co-regulation Network of Abiotic Stress Tolerance in Soybeans

Although growing evidence shows that microRNA (miRNA) regulates plant growth and development, miRNA regulatory networks in plants are not well understood. Current experimental studies cannot characterize miRNA regulatory networks on a large scale. This information gap provides an excellent opportunity to employ computational methods for global analysis and generate valuable models and hypotheses. To address this opportunity, we collected miRNA-target interactions (MTIs) and used MTIs from Arabidopsis thaliana and Medicago truncatula to predict homologous MTIs in soybeans, resulting in 80,235 soybean MTIs in total. A multi-level iterative bi-clustering method was developed to identify 483 soybean miRNA-target regulatory modules (MTRMs). Furthermore, we collected soybean miRNA expression data and corresponding gene expression data in response to abiotic stresses. By clustering these data, 37 MTRMs related to abiotic stresses were identified, including stress-specific MTRMs and shared MTRMs. These MTRMs have gene ontology (GO) enrichment in resistance response, iron transport, positive growth regulation, etc. Our study predicts soybean MTRMs and miRNA-GO networks under different stresses, and provides miRNA targeting hypotheses for experimental analyses. The method can be applied to other biological processes and other plants to elucidate miRNA co-regulation mechanisms.

The elemental defense effect of cadmium on Alternaria brassicicola in Brassica juncea

BACKGROUND

The elemental defense hypothesis states a new defensive strategy that hyperaccumulators defense against herbivores or pathogens attacks by accumulating heavy metals. Brassica juncea has an excellent ability of cadmium (Cd) accumulation. However, the elemental defense effect and its regulation mechanism in B. juncea remain unclear.

RESULTS

In this study, we profiled the elemental defense effect and the molecular regulatory mechanism in Cd-accumulated B. juncea after Alternaria brassicicola infection. B. juncea treated with 180 mg Kg^- 1 DW CdCl₂ 2.5H₂O exhibited obvious elemental defense effect after 72 h of infection with A. brassicicola. The expression of some defense-related genes including BjNPR1, BjPR12, BjPR2, and stress-related miRNAs (miR156, miR397, miR398a, miR398b/c, miR408, miR395a, miR395b, miR396a, and miR396b) were remarkably elevated during elemental defense in B. juncea.

CONCLUSIONS

The results indicate that Cd-accumulated B. juncea may defend against pathogens by coordinating salicylic acid (SA) and jasmonic acid (JA) mediated systemic acquired resistance (SAR) and elemental defense in a synergistic joint effect. Furthermore, the expression of miRNAs related to heavy metal stress response and disease resistance may regulate the balance between pathogen defense and heavy metal stress-responsive in B. juncea. The findings provide experimental evidence for the elemental defense hypothesis in plants from the perspectives of phytohormones, defense-related genes, and miRNAs.

Identification and Characterization of Csa-miR395s Reveal Their Involvements in Fruit Expansion and Abiotic Stresses in Cucumber

The miR395 plays an indispensable role in biochemical processes by regulating their target genes. However, little is known about the roles of miR395 in cucumber fruit expansion and response to abiotic stresses. Here, 4 Csa-miR395s and 8 corresponding target genes were identified in the cucumber genome. Csa-miR395s were all located on the same chromosome (Chr 5). Csa-miR395a/b/c and Csa-miR395d were distributed in different branches without a closer genetic relationship. Massive cis-acting elements, including light, phytohormone, and stress response elements, were detected in the promoter regions of Csa-MIR395s, indicating that Csa-miR395s might be involved in complex regulatory networks to control cucumber growth and development and stress response. In addition, Csa-miR395a/b/c shared the same target genes, and Csa-miR395d had its specific target genes. Tissue-specific expression analysis showed that Csa-miR395a/b/c were all expressed in the leaf, root, ovary, and expanded fruit of cucumber and highly expressed in the expanded fruits compared to the ovary, while Csa2G215520 and Csa1G502860 (target genes of Csa-miR395a/b/c) presented a downregulated trend in the expanded fruit compared to the ovary. Meanwhile, the protein co-expression network revealed that these target genes had interactions in sulfur metabolism. These results suggested that Csa-miR395a/b/c targeting Csa2G215520 and Csa1G502860 might promote cucumber fruit expansion by affecting sulfur metabolism. Additionally, Quantitative Real-time PCR analysis validated that Csa-miR395s could be regulated by NaCl stress, and Csa-miR395a/b/c could respond to PEG stress, which further confirmed the reliability of cis-acting elements data. Taken together, our results could be helpful for further exploration of the functions of miR395s in cucumber fruit expansion and response to abiotic stresses.

Comprehensive In Silico Characterization and Expression Profiling of TCP Gene Family in Rapeseed

TCP proteins are plant-specific transcription factors that have multipurpose roles in plant developmental procedures and stress responses. Therefore, a genome-wide analysis was performed to categorize the TCP genes in the rapeseed genome. In this study, a total of 80 BnTCP genes were identified in the rapeseed genome and grouped into two main classes (PCF and CYC/TB1) according to phylogenetic analysis. The universal evolutionary analysis uncovered that BnTCP genes had experienced segmental duplications and positive selection pressure. Gene structure and conserved motif examination presented that Class I and Class II have diverse intron-exon patterns and motifs numbers. Overall, nine conserved motifs were identified and varied from 2 to 7 in all TCP genes; and some of them were gene-specific. Mainly, Class II (PCF and CYC/TB1) possessed diverse structures compared to Class I. We identified four hormone- and four stress-related responsive cis-elements in the promoter regions. Moreover, 32 bna-miRNAs from 14 families were found to be targeting 21 BnTCPs genes. Gene ontology enrichment analysis presented that the BnTCP genes were primarily related to RNA/DNA binding, metabolic processes, transcriptional regulatory activities, etc. Transcriptome-based tissue-specific expression analysis showed that only a few genes (mainly BnTCP9, BnTCP22, BnTCP25, BnTCP48, BnTCP52, BnTCP60, BnTCP66, and BnTCP74) presented higher expression in root, stem, leaf, flower, seeds, and silique among all tested tissues. Likewise, qRT-PCR-based expression analysis exhibited that BnTCP36, BnTCP39, BnTCP53, BnTCP59, and BnTCP60 showed higher expression at certain time points under various hormones and abiotic stress conditions but not by drought and MeJA. Our results opened the new groundwork for future understanding of the intricate mechanisms of BnTCP in various developmental processes and abiotic stress signaling pathways in rapeseed.

The miR169n-NF-YA8 regulation module involved in drought resistance in Brassica napus L

As an ancient and conserved plant microRNA (miRNA) family, miR169 targets nuclear factor Y subunit alpha (NF-YA) family members. The miR169-NF-YA module is associated with plant development and various stress responses. However, the function of miR169 in response to drought stress in rapeseed (Brassica napus L.) is unclear. In the present study, we showed that miR169n acted as a negative regulator of drought resistance in rapeseed by targeting a nuclear factor Y-A gene, NF-YA8. miR169n was strongly down-regulated by drought stress. Expression of a miR169n target mimicry construct (MIM169n) which functioned as a sponge to trap miR169n resulted in enhanced resistance of transgenic plants to both osmotic stress at the post-germination stage and drought stress at the seedling stage. MIM169n plants had a higher relative water content (RWC) and proline content, lower relative electrolyte leakage (REL), and showed higher antioxidative capability compared with those of control (CK) plants under drought stress. Moreover, NF-YA8 was verified as a target of miR169n, and overexpression of NF-YA8 led to improved tolerance of rapeseed to osmotic stress at the post-germination stage. Overall, our findings implied that the miR169n-NF-YA8 regulatory module could serve as a potential target for genetic improvement of drought resistance in B. napus.

Identification of miRNAs and their target genes in genic male sterility lines in Brassica napus by small RNA sequencing

BACKGROUND

Brassica napus is the third leading source of edible oil in the world. Genic male sterility (GMS) lines provide crucial material for harnessing heterosis for rapeseed. GMS lines have been used successfully for rapeseed hybrid production in China. MicroRNAs (miRNAs) play crucial regulatory roles in various plant growth, development, and stress response processes. However, reports on miRNAs that regulate the pollen development of GMS lines in B. napus are few.

RESULTS

In this study, 12 small RNA and transcriptome libraries were constructed and sequenced for the flower buds from the fertile and sterile lines of two recessive GMS (RGMS) lines, namely, "6251AB" and "6284AB". At the same time, 12 small RNA and transcriptome libraries were also constructed and sequenced for the flower buds from the fertile and sterile lines of two dominant GMS (DGMS) lines, namely, "4001AB" and "4006AB". Based on the results, 46 known miRNAs, 27 novel miRNAs on the other arm of known pre-miRNAs, and 44 new conserved miRNAs were identified. Thirty-five pairs of novel miRNA-3p/miRNA-5p were found. Among all the identified miRNAs, fifteen differentially expressed miRNAs with over 1.5-fold change between flower buds of sterile and fertile lines were identified, including six differentially expressed miRNAs between "4001A" and "4001B", two differentially expressed miRNAs between "4006A" and "4006B", four differentially expressed miRNAs between "6251A" and "6251B", and ten differentially expressed miRNAs between "6284A" and "6284B". The correlation analysis of small RNA and transcriptome sequencing was conducted. And 257 candidate target genes were predicted for the 15 differentially expressed miRNAs. The results of 5' modified RACE indicated that BnaA09g48720D, BnaA09g11120D, and BnaCnng51960D were cleaved by bna-miR398a-3p, bna-miR158-3p and bna-miR159a, respectively. Among the differentially expressed miRNAs, miR159 was chosen to analyze its function. Overexpression of bna-miR159 in Arabidopsis resulted in decreased seed setting rate, and shortened siliques, illustrating that miR159 may regulate the fertility and silique development in rapeseed.

CONCLUSIONS

Our findings provide an overview of miRNAs that are potentially involved in GMS and pollen development. New information on miRNAs and their related target genes are provided to exploit the GMS mechanism and reveal the miRNA networks in B. napus.

Genome-Wide Characterization of Glutathione Peroxidase (GPX) Gene Family in Rapeseed (Brassica napus L.) Revealed Their Role in Multiple Abiotic Stress Response and Hormone Signaling

Plant glutathione peroxidases (GPXs) are the main enzymes in the antioxidant defense system that sustain H₂O₂ homeostasis and normalize plant reaction to abiotic stress conditions. To understand the major roles of the GPX gene family in rapeseed (Brassica napus L.), for the first time, a genome-wide study identified 25 BnGPX genes in the rapeseed genome. The phylogenetic analysis discovered that GPX genes were grouped into four major groups (Group I-Group IV) from rapeseed and three closely interrelated plant species. The universal investigation uncovered that the BnGPXs gene experienced segmental duplications and positive selection pressure. Gene structure and motifs examination recommended that most of the BnGPX genes demonstrated a comparatively well-maintained exon-intron and motifs arrangement within the identical group. Likewise, we recognized five hormones-, four stress-, and numerous light-reactive cis-elements in the promoters of BnGPXs. Five putative bna-miRNAs from two families were also prophesied, targeting six BnGPXs genes. Gene ontology annotation results proved the main role of BnGPXs in antioxidant defense systems, ROS, and response to stress stimulus. Several BnGPXs genes revealed boosted expression profiles in many developmental tissues/organs, i.e., root, seed, leaf, stem, flower, and silique. The qRT-PCR based expression profiling exhibited that two genes (BnGPX21 and BnGPX23) were suggestively up-regulated against different hormones (ABA, IAA, and MeJA) and abiotic stress (salinity, cold, waterlogging, and drought) treatments. In short, our discoveries provide a basis for additional functional studies on the BnGPX genes in future rapeseed breeding programs.

MicroRNAs: Tiny, powerful players of metal stress responses in plants

Metal contamination of the environment is a widespread problem threatening sustainable and safe crop production. Physio-biochemical and molecular mechanisms of plant responses to metal exposure have been studied to establish the best possible agronomical or biotechnological methods to tackle metal contamination. Metal stress tolerance is regulated by several molecular effectors among which microRNAs are one of the key master regulators of plant growth and stress responses in plants. MicroRNAs are known to coordinate multitude of plant responses to metal stress through antioxidant functions, root growth, hormonal signalling, transcription factors and metal transporters. The present review discusses integrative functions of microRNAs in the regulation of metal stress in plants, which will be useful for engineering stress tolerance traits for improved plant growth and productivity in metal stressed situations.

Genome-Wide Analysis and Expression Profile of Superoxide Dismutase (SOD) Gene Family in Rapeseed (Brassica napus L.) under Different Hormones and Abiotic Stress Conditions

Superoxide dismutase (SOD) is an important enzyme that acts as the first line of protection in the plant antioxidant defense system, involved in eliminating reactive oxygen species (ROS) under harsh environmental conditions. Nevertheless, the SOD gene family was yet to be reported in rapeseed (Brassica napus L.). Thus, a genome-wide investigation was carried out to identify the rapeseed SOD genes. The present study recognized 31 BnSOD genes in the rapeseed genome, including 14 BnCSDs, 11 BnFSDs, and six BnMSDs. Phylogenetic analysis revealed that SOD genes from rapeseed and other closely related plant species were clustered into three groups based on the binding domain with high bootstrap values. The systemic analysis exposed that BnSODs experienced segmental duplications. Gene structure and motif analysis specified that most of the BnSOD genes displayed a relatively well-maintained exon-intron and motif configuration within the same group. Moreover, we identified five hormones and four stress- and several light-responsive cis-elements in the promoters of BnSODs. Thirty putative bna-miRNAs from seven families were also predicted, targeting 13 BnSODs. Gene ontology annotation outcomes confirm the BnSODs role under different stress stimuli, cellular oxidant detoxification processes, metal ion binding activities, SOD activity, and different cellular components. Twelve BnSOD genes exhibited higher expression profiles in numerous developmental tissues, i.e., root, leaf, stem, and silique. The qRT-PCR based expression profiling showed that eight genes (BnCSD1, BnCSD3, BnCSD14, BnFSD4, BnFSD5, BnFSD6, BnMSD2, and BnMSD10) were significantly up-regulated under different hormones (ABA, GA, IAA, and KT) and abiotic stress (salinity, cold, waterlogging, and drought) treatments. The predicted 3D structures discovered comparable conserved BnSOD protein structures. In short, our findings deliver a foundation for additional functional investigations on the BnSOD genes in rapeseed breeding programs.

Genome-wide analysis and expression patterns of lipid phospholipid phospholipase gene family in Brassica napus L

BACKGROUND

Lipid phosphate phosphatases (LPP) are critical for regulating the production and degradation of phosphatidic acid (PA), an essential signaling molecule under stress conditions. Thus far, the LPP family genes have not been reported in rapeseed (Brassica napus L.).

RESULTS

In this study, a genome-wide analysis was carried out to identify LPP family genes in rapeseed that respond to different stress conditions. Eleven BnLPPs genes were identified in the rapeseed genome. Based on phylogenetic and synteny analysis, BnLPPs were classified into four groups (Group I-Group IV). Gene structure and conserved motif analysis showed that similar intron/exon and motifs patterns occur in the same group. By evaluating cis-elements in the promoters, we recognized six hormone- and seven stress-responsive elements. Further, six putative miRNAs were identified targeting three BnLPP genes. Gene ontology analysis disclosed that BnLPP genes were closely associated with phosphatase/hydrolase activity, membrane parts, phosphorus metabolic process, and dephosphorylation. The qRT-PCR based expression profiles of BnLPP genes varied in different tissues/organs. Likewise, several gene expression were significantly up-regulated under NaCl, PEG, cold, ABA, GA, IAA, and KT treatments.

CONCLUSIONS

This is the first report to describe the comprehensive genome-wide analysis of the rapeseed LPP gene family. We identified different phytohormones and abiotic stress-associated genes that could help in enlightening the plant tolerance against phytohormones and abiotic stresses. The findings unlocked new gaps for the functional verification of the BnLPP gene family during stresses, leading to rapeseed improvement.

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

The contamination of soil with high levels of cadmium (Cd) is of increasing concern, as Cd is a heavy metal element that seriously limits crop productivity and quality, thus affecting human health. (1) Background: Some miRNAs play key regulatory roles in response to Cd stress, but few have been explored in the highly Cd-enriched coefficient oilseed crop, Brassica juncea. (2) Methods: The genome-wide identification and characterization of miRNAs and their targets in leaves and roots of Brassica juncea exposed to Cd stress was undertaken using strand specific transcript sequencing and miRNA sequencing. (3) Results: In total, 11 known and novel miRNAs, as well as 56 target transcripts, were identified as Cd-responsive miRNAs and transcripts. Additionally, four corresponding target transcripts of six miRNAs, including FLA9 (Fasciclin-Like Arabinogalactan-protein 9), ATCAT3 (catalase 3), DOX1 (dioxygenases) and ATCCS (copper chaperone for superoxide dismutase), were found to be involved in the plant’s biotic stress pathway. We further validated the expression of three miRNA and six target genes in response to Cd, hydrargyrum (Hg), manganese (Mn), plumbum (Pb) or natrium (Na) stress and Mucor infection by qRT-PCR, and show that ATCCS and FLA9 were significantly and differentially regulated in the Cd-treated leaves. In addition, our results showed that DOX1 was obviously induced by Pb stress. Among the respective target miRNAs, bra-miR172b-3p (target for ATCCS) and ra-miR398-3p (target for FLA9) were down-regulated in Cd-treated leaves. (4) Conclusions: We identified bra-miR172b-3p as a potential Cd-specific resistant inhibitor, which may be negatively regulated in ATCCS in response to Cd stress. These findings could provide further insight into the regulatory networks of Cd-responsive miRNA in Brassica juncea.

Catalase (CAT) Gene Family in Rapeseed (Brassica napus L.): Genome-Wide Analysis, Identification, and Expression Pattern in Response to Multiple Hormones and Abiotic Stress Conditions

Catalase (CAT) is an antioxidant enzyme expressed by the CAT gene family and exists in almost all aerobic organisms. Environmental stresses induce the generation of reactive oxygen species (ROS) that eventually hinder plant growth and development. The CAT enzyme translates the hydrogen peroxide (H₂O₂) to water (H₂O) and reduce the ROS levels to shelter the cells’ death. So far, the CAT gene family has not been reported in rapeseed (Brassica napus L.). Therefore, a genome-wide comprehensive analysis was conducted to classify the CAT genes in the rapeseed genome. The current study identified 14 BnCAT genes in the rapeseed genome. Based on phylogenetic and synteny analysis, the BnCATs belong to four groups (Groups I–IV). A gene structure and conserved motif analysis showed that Group I, Group II, and Group IV possess almost the same intron/exon pattern, and an equal number of motifs, while Group III contains diverse structures and contain 15 motifs. By analyzing the cis-elements in the promoters, we identified five hormone-correlated responsive elements and four stress-related responsive elements. Further, six putative bna-miRNAs were also identified, targeting three genes (BnCAT4, BnCAT6, and BnCAT8). Gene ontology (GO) enrichment analysis showed that the BnCAT genes were largely related to cellular organelles, ROS response, stimulus response, stress response, and antioxidant enzymes. Almost 10 BnCAT genes showed higher expression levels in different tissues, i.e., root, leaf, stem, and silique. The expression analysis showed that BnCAT1–BnCAT3 and BnCAT11–BnCAT13 were significantly upregulated by cold, salinity, abscisic acid (ABA), and gibberellic acid (GA) treatment, but not by drought and methyl jasmonate (MeJA). Notably, most of the genes were upregulated by waterlogging stress, except BnCAT6, BnCAT9, and BnCAT10. Our results opened new windows for future investigations and provided insights into the CAT family genes in rapeseed.

Integration of mRNA and miRNA analysis reveals the molecular mechanism of potato (Solanum tuberosum L.) response to alkali stress

The continuing increase in the global saline-alkali land area has made saline-alkali stress the principal abiotic stress limiting plant growth. Potato is the most important non-grain crop, and its production is also severely limited by saline-alkali stress. However, few studies have addressed the mechanism of saline-alkali tolerance of potato with a focus on its response to neutral salt NaCl stress, or its response to alkali stress. Recently, miRNA-mRNA analyses have helped advance our understanding of how plants respond to stress. Here, we have characterized the morphological, physiological, and transcriptome changes of tissue culture seedlings of potato variety "Qingshu No. 9" treated with NaHCO₃ (for 0, 2, 6, and 24 h). We found that the leaves of tissue culture seedlings wilted and withered under alkali stress, and the contents of ABA, BRs, trehalose, and lignin in roots increased significantly. The contents of GAs decreased significantly. Subsequently, miRNA-seq analysis results identified 168 differentially expressed miRNAs (DEMIs) under alkali stress, including 21 exist miRNAs and 37 known miRNAs from 47 families and 110 novel miRNAs. The mRNA-seq results identified 5731 differentially expressed mRNAs (DEMs) under alkali stress. By miRNA-mRNA integrated analysis, were obtained 33 miRNA-target gene pairs composed of 20 DEMIs and 33 DEMs. Next, we identified the "phenylpropanoid biosynthesis", "plant hormone signal transduction", and "starch and sucrose metabolism" pathways as necessary for potato to respond to alkali stress. miR4243-x and novel-m064-5p were involved in the response of potato to alkali stress by their negative regulatory effects on shikimate O-hydroxycinnamoyltransferase (HCT) and sucrose-phosphate synthase (SPS) genes, respectively. The expression results of miRNA and mRNA were verified by quantitative real-time PCR (qRT-PCR). Our results clarify the mechanism of potato response to alkali stress at the miRNA level, providing new insights into the molecular mechanisms of potato's response to alkali stress. We report many candidate miRNAs and mRNAs for molecular-assisted screening and salt-alkali resistance breeding.

Plant miR397 and its functions

MicroRNAs (miRNAs) are noncoding, small RNAs of 20-24 nucleotides (nt) and function critically at the post-transcriptional level to regulate gene expression through cleaving mRNA targets or interfering with translation of the target mRNAs. They are broadly involved in many biological processes in plants. The miR397 family in plants contains several conserved members either in 21-nt or in 22-nt that mainly target the laccase (LAC) genes functioning in lignin synthesis and are involved in the development of plants under various conditions. Recent findings showed that miR397b in Arabidopsis could also target to Casein Kinase II Subunit Beta 3 (CKB3) and mediate circadian regulation and plant flowering. This review aims to summarise recent updates on miR397 and provides the available basis for understanding the functional mechanisms of miR397 in plant growth and development regulation and in response to external adverse stimulation.

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

A photoperiod- and thermo-sensitive genic male sterile (PTGMS) line is the basic material for two-hybrid rice and is an important genetic breeding resource. Peiai64S (PA64S) is an important germplasm resource of PTGMS rice, and it has been applied to two-line hybrid rice systems in China. Pollen fertility in PA64S is regulated by the temperature and photoperiod, but the mechanism of the fertility transition is unclear. In this study, we obtained the male fertile plant PA64S(F) and the male sterile plant PA64S(S) by controlling different temperatures under long light conditions and used the male fertile and sterile plants to investigate the role of microRNAs (miRNAs) in regulating male fertility in rice. We performed the small RNA library sequencing of anthers from PA64S(S) and PA64S(F). A total of 196 miRNAs were identified-166 known miRNAs among 27 miRNA families and 30 novel miRNAs. In the transcriptome analysis, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially expressed genes revealed significant enrichment in the synthesis and metabolism of fatty acids and some secondary metabolism pathways such as fatty acid metabolism and phenylalanine metabolism. With a comprehensive analysis of miRNA, transcriptome, and degradome sequencing, we identified that 13 pairs of miRNA/target genes regulated male fertility in rice by responding to temperature change, among which the miR156, miR5488, and miR399 affect the male fertility of PA64S by influencing SPLs, the lignin synthesis of anther walls, and the flavonoid metabolism pathway. The results provide a new understanding of PTGMS rice, which will help us better understand the potential regulatory mechanisms of male sterility in the future.

MicroRNA-Mediated Responses to Cadmium Stress in Arabidopsis thaliana

In recent decades, the presence of cadmium (Cd) in the environment has increased significantly due to anthropogenic activities. Cd is taken up from the soil by plant roots for its subsequent translocation to shoots. However, Cd is a non-essential heavy metal and is therefore toxic to plants when it over-accumulates. MicroRNA (miRNA)-directed gene expression regulation is central to the response of a plant to Cd stress. Here, we document the miRNA-directed response of wild-type Arabidopsis thaliana (Arabidopsis) plants and the drb1, drb2 and drb4 mutant lines to Cd stress. Phenotypic and physiological analyses revealed the drb1 mutant to display the highest degree of tolerance to the imposed stress while the drb2 mutant was the most sensitive. RT-qPCR-based molecular profiling of miRNA abundance and miRNA target gene expression revealed DRB1 to be the primary double-stranded RNA binding (DRB) protein required for the production of six of the seven Cd-responsive miRNAs analyzed. However, DRB2, and not DRB1, was determined to be required for miR396 production. RT-qPCR further inferred that transcript cleavage was the RNA silencing mechanism directed by each assessed miRNA to control miRNA target gene expression. Taken together, the results presented here reveal the complexity of the miRNA-directed molecular response of Arabidopsis to Cd stress.

Comprehensive In Silico Characterization and Expression Profiling of TCP Gene Family in Rapeseed

TCP proteins are plant-specific transcription factors that have multipurpose roles in plant developmental procedures and stress responses. Therefore, a genome-wide analysis was performed to categorize the TCP genes in the rapeseed genome. In this study, a total of 80 BnTCP genes were identified in the rapeseed genome and grouped into two main classes (PCF and CYC/TB1) according to phylogenetic analysis. The universal evolutionary analysis uncovered that BnTCP genes had experienced segmental duplications and positive selection pressure. Gene structure and conserved motif examination presented that Class I and Class II have diverse intron-exon patterns and motifs numbers. Overall, nine conserved motifs were identified and varied from 2 to 7 in all TCP genes; and some of them were gene-specific. Mainly, Class II (PCF and CYC/TB1) possessed diverse structures compared to Class I. We identified four hormone- and four stress-related responsive cis-elements in the promoter regions. Moreover, 32 bna-miRNAs from 14 families were found to be targeting 21 BnTCPs genes. Gene ontology enrichment analysis presented that the BnTCP genes were primarily related to RNA/DNA binding, metabolic processes, transcriptional regulatory activities, etc. Transcriptome-based tissue-specific expression analysis showed that only a few genes (mainly BnTCP9, BnTCP22, BnTCP25, BnTCP48, BnTCP52, BnTCP60, BnTCP66, and BnTCP74) presented higher expression in root, stem, leaf, flower, seeds, and silique among all tested tissues. Likewise, qRT-PCR-based expression analysis exhibited that BnTCP36, BnTCP39, BnTCP53, BnTCP59, and BnTCP60 showed higher expression at certain time points under various hormones and abiotic stress conditions but not by drought and MeJA. Our results opened the new groundwork for future understanding of the intricate mechanisms of BnTCP in various developmental processes and abiotic stress signaling pathways in rapeseed.