Expression of miRNAs Regulates Growth and Development of French Bean (Phaseolus Vulgaris) under Salt and Drought Stress Conditions

Identification of stress-regulated miRNAs is crucial for understanding how plants respond to environmental stimuli. We are interested in the identification of miRNAs in French bean (Phaseolus vulgaris) to uncover different plant strategies to cope with adverse conditions and because of its relevance as a crop in developing countries. In this study, we investigated the effect of salt and drought stress in expression of small regulatory RNAs. Both salt and drought stresses altered the expression pattern of miRNA in a dose-dependent manner. However, each miRNA responded to drought stress in a different pattern. Salt and drought stress changed the expression level of miRNAs mainly from 0.9-fold up-regulation to 0.7-fold down-regulation. Micro RNAs were less sensitive to drought than salinity, as evidenced by the narrow fold change in expression levels. Although the range of change in expression level of miRNAs was similar under salt and drought stress, no miRNAs displayed significant change in expression level under all tested salt conditions. Micro RNAs, miR156 and miR162, showed significant change in expression level under high drought stress. This suggests that miR156 and miR162 may attribute to the adaption to drought stress and are good candidates for improving the vegetable crop by transgenic technology

Expression of miRNAs Confers Enhanced Tolerance to Drought and Salt Stress in Finger Millet (Eleusine coracona)

Plants respond to the environmental cues in various ways, recent knowledge of RNA interference in conferring stress tolerance had become a new hope of developing tolerant varieties. Here we attempt to unfold the molecular mechanism of stress tolerance through miRNA profiling and expression analysis in Finger millet (Eleusine coracona) under salt and drought stress conditions. The expression analysis of 12 stress specific conserved miRNAs was studied using semi-quantitative real time PCR and Northern blot assay. Our studies revealed that, although most of the miRNAs responded to the stresses, the expression of particular miRNA differed with the nature of stress and the tissue. The expression analysis was correlated with the existing data of their target genes. Abiotic stress up-regulated miRNAs are expected to target negative regulators of stress responses or positive regulators of processes that are inhibited by stresses. On the other hand, stress down-regulated miRNAs may repress the expression of positive regulators and/or stress up-regulated genes. Thus the current study of miRNAs and their targets under abiotic stress conditions displays miRNAs may be good candidates to attribute the stress tolerance in plants by transgenic technology

Response of Plant miRNAs Under Abiotic Stress Conditions

ABSTRACT MicroRNAs (miRNAs) are endogenous approximate 22 nucleotide (nt) small non-coding regulatory RNAs that play important roles in plants by targeting mRNAs for cleavage or translational repression. Plant miRNAs were described 10 years later than animal miRNAs did; there are some differences between them in terms of biogenesis and mechanism of function. Furthermore, plant miRNAs have been shown to be involved in various stress responses, such as oxidative, mineral nutrient deficiency, dehydration, and even mechanical stimulus. In this review, we focus on the current understanding of biogenesis and regulatory mechanisms of plant miRNAs. We also highlight specific examples of miRNAs, which are important regulators for plant abiotic stress responses

Expression of miRNAs confers enhanced tolerance to drought and salt stress in Finger millet (Eleusine coracona)

Plants respond to the environmental cues in various ways, recent knowledge of RNA interference in conferring stress tolerance had become a new hope of developing tolerant varieties. Here we attempt to unfold the molecular mechanism of stress tolerance through miRNA profiling and expression analysis in Finger millet (Eleusine coracona) under salt and drought stress conditions. The expression analysis of 12 stress specific conserved miRNAs was studied using semi-quantitative real time PCR and Northern blot assay. Our studies revealed that, although most of the miRNAs responded to the stresses, the expression of particular miRNA differed with the nature of stress and the tissue. The expression analysis was correlated with the existing data of their target genes. Abiotic stress up-regulated miRNAs are expected to target negative regulators of stress responses or positive regulators of processes that are inhibited by stresses. On the other hand, stress down-regulated miRNAs may repress the expression of positive regulators and/or stress up-regulated genes. Thus the current study of miRNAs and their targets under abiotic stress conditions displays miRNAs may be good candidates to attribute the stress tolerance in plants by transgenic technology

Response of plant miRNAs under abiotic stress conditions

MicroRNAs (miRNAs) are endogenous approximate 22 nucleotide (nt) small non-coding regulatory RNAs that play important roles in plants by targeting mRNAs for cleavage or translational repression. Plant miRNAs were described 10 years later than animal miRNAs did; there are some differences between them in terms of biogenesis and mechanism of function. Furthermore, plant miRNAs have been shown to be involved in various stress responses, such as oxidative, mineral nutrient deficiency, dehydration, and even mechanical stimulus. In this review, we focus on the current understanding of biogenesis and regulatory mechanisms of plant miRNAs. We also highlight specific examples of miRNAs, which are important regulators for plant abiotic stress responses

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Not AvailableGroundnut (Arachis hypogaea L.), is an important subsistence oil yielding crop of the semi-arid tropics and often exposed to several environmental cues (high temperature, drought & heavy metal). The WRKY transcription factor (TF) is one of the master regulator, and play vital role in stress responses. However, far less information is available on functional characterization and tolerance mechanism of stress responsive WRKY genes in groundnut till date. In this study, a comprehensive phylogenetic, protein features, gene structure and motif analysis of WRKY TF gene family was carried out. We conducted expression profiling of 10 WRKY genes under high temperature, drought and heavy metal (CdCl2) in various tissues. Majority of the AhWRKY (Arachis hypogaea WRKY) proteins were clustered and share close relationship with Arabidopsis and Glycine max. RT- qPCR analysis of AhWRKY genes revealed differential expression either in their transcript abundance or in their expression patterns in response to at least one abiotic stress. In particular, AhWRKY41 expression level was found to be maximum in all the stress conditions. On the other hand, AhWRKY20 and AhWRKY22 were down regulated. The obtained data demonstrate that AhWRKY41 may act as a positive regulator in drought/ high temperature/ heavy metal and would exhibit stress tolerance mechanism by activation of stress-associated gene expression.SER

Computational identification of conserved miRNAs and their potential targets in French bean (Phaseolus vulgaris)

MicroRNAs (miRNAs) are a novel growing family of endogenous, small, non- coding, single-stranded RNA molecules directly involved in regulating gene expression at the posttranscriptional level. High conservation of miRNAs in plant provides the foundation for identification of new miRNAs in other plant species through homology alignment. Here, previously known plant miRNAs were BLAST against the Expressed Sequence Tag (EST) database of French bean (Phaseolus vulgaris), and according to a series of filtering criteria, a total of 10miRNAs were identified, and 24potential target genes of them were subsequently predicted, most of which seemed to encode transcription factors or enzymes participating in regulation of development, growth and other physiological processes. Overall, our findings lay the foundation for further researches of miRNAs function inFrench bean