Identification of microRNAs and Their Expression in Leaf Tissues of Guava (Psidium guajava L.) under Salinity Stress

Abstract

Superfruit guava (Psidium guajava L.) is one of the healthiest fruits due to its high antioxidant dietary fiber and vitamin content. However, the growth and development of this plant are severely affected by salinity stress, mostly at the seedling stage. MicroRNAs (miRNAs) are small, noncoding, endogenous, highly conserved RNA molecules that play key regulatory roles in plant development, organ morphogenesis, and stress response signaling. In this study, applying computational approaches and following high stringent filtering criteria, a total of 40 potential microRNAs belonging to 19 families were characterized from guava. The identified miRNA precursors formed stable stem-loop structures and exhibited high sequence conservation among diverse and evolutionarily distant plant species. Differential expression pattern of seven selected guava miRNAs (pgu-miR156f-5p, pgu-miR160c-5p, pgu-miR162-3p, pgu-miR164b-5p, pgu-miR166t, pgu-miR167a-5p, and pgu-miR390b-5p) were recorded under salinity stress and pgu-miR162-3p, pgu-miR164b-5p as well as pgu-miR166t were found to be the most affected ones. Using the psRNATarget tool, a total of 49 potential target transcripts of the characterized guava miRNAs were identified in this study which are mostly involved in metabolic pathways, cellular development, and stress response signaling. A biological network has also been constructed to understand the miRNA mediated gene regulation using the minimum free energy (MFE) values of the miRNA-target interaction. To the best of our knowledge, this is the first report of guava miRNAs and their targets.

miR166h Directed Cleavage of Target Upon PGPR Inoculation Under Drought Stress and Tissue-Specific Expression Analysis Under Abiotic Stresses in Chickpea.

“…NaCl treated leaves showed signi cant downregulation of miR166h with gradual increase in the expression of its target as discussed in previous reports on maize, chickpea and guava (Ding et al 2009;Kohli et al 2014;Sharma et al 2020). The tissue-speci c expression in shoot followed the same expression patterns of miR166h and its target as observed in leaves.…”

Conservation and Diversity of miR166 Family Members From Highbush Blueberry (Vaccinium corymbosum) and Their Potential Functions in Abiotic Stress

“…The abundance of miR166a-5p and miR166j-3p was upregulated in soybean roots, while that of miR166a-5p was downregulated in barley roots ( Wang et al, 2020 ; Kuang et al, 2021 ). However, miR166 family members were upregulated in roots and downregulated in leaves of sweet potato ( Ipomoea batatas ) ( Yang et al, 2020 ), while Pgu-miR166t was also downregulated in the leaves of common guava ( Psidium guajava ) ( Sharma et al, 2020 ). In our study, the levels of Vco-miR166e-3p, Vco-miR166f-5p, and Vco-miR166i-3p were downregulated in highbush blueberry leaves, while those of Vco-miR166d-5p and Vco-miR166h-3p were upregulated upon exposure to salt stress relative to controls.…”

microRNA 166: an evolutionarily conserved stress biomarker in land plants targeting HD-ZIP family

“…The downregulated expression of miR166 has been reported in other plants as well like maize, chickpea, safflower with inverse correlation with its target HD-ZIP III genes. Upregulation was also observed in sweet potato roots and leaves keenly involved in salinity adaptation (Sharma et al 2020).…”