The Accumulation of miRNAs Differentially Modulated by Drought Stress Is Affected by Grafting in Grapevine

Abstract

Grapevine (Vitis vinifera) is routinely grafted, and rootstocks inducing drought tolerance represent a source for adapting vineyards to climate change in temperate areas. Our goal was to investigate drought stress effects on microRNA (miRNA) abundance in a drought-resistant grapevine rootstock, M4 (Vitis vinifera 3 Vitis berlandieri), compared with a commercial cultivar, Cabernet Sauvignon, using their autografts and reciprocal grafts. RNA extracted from roots and leaves of droughted and irrigated plants of different graft combinations was used to prepare cDNA libraries for small RNA sequencing and to analyze miRNAs by quantitative real-time polymerase chain reaction (RT-qPCR). Measurements of leaf water potential, leaf gas exchange, and root hydraulic conductance attested that, under irrigation, M4 reduced water loss in comparison with cultivar Cabernet Sauvignon mostly through nonhydraulic, root-specific mechanisms. Under drought, stomatal conductance decreased at similar levels in the two genotypes. Small RNA sequencing allowed the identification of 70 conserved miRNAs and the prediction of 28 novel miRNAs. Different accumulation trends of miRNAs, observed upon drought and in different genotypes and organs, were confirmed by RT-qPCR. Corresponding target transcripts, predicted in silico and validated by RT-qPCR, often showed opposite expression profiles than the related miRNAs. Drought effects on miRNA abundance differed between the two genotypes. Furthermore, the concentration of drought-responsive miRNAs in each genotype was affected by reciprocal grafting, suggesting either the movement of signals inducing miRNA expression in the graft partner or, possibly, miRNA transport between scion and rootstock. These results open new perspectives in the selection of rootstocks for improving grapevine adaptation to drought.

Grapevine rootstocks shape underground bacterial microbiome and networking but not potential functionality

“…Since grapevine rootstocks and their hybrids have been selected by breeders over the last century for their ability to provide ecological services to grape scions, such as tolerance to environmental factors (e.g. drought, soil limestone content and salinity) [ 13 , 15 , 35 ], the differences among the bacterial microbiome structures of grafted plants may be related to the rootstock species domestication, as has been observed in crop plant species such as wild plants and cultivars of rice [ 36 ]. In our study, the root system type determines the differential distribution of a subset of common community members between the rhizosphere and the root tissues and, at the same time, selects specific bacterial OTUs as biomarkers for the different root genotypes.…”

Exogenous strigolactone interacts with abscisic acid-mediated accumulation of anthocyanins in grapevine berries

“…cDNA integrity and primer specificity were then checked by gradient PCR and agarose gel electrophoresis. RT–qPCR was conducted in triplicate using a StepOnePlus™ System (Applied Biosystems), and the SYBR Green method (Power SYBR ® Green PCR Master Mix, Applied Biosystems) was used for quantifying amplification results ( Giordano et al , 2016 ; Pagliarani et al , 2017 ). Each reaction contained 1 μl of 5 μM primer mix, 100 ng of template cDNA, 5 μl of 2× SYBR Green mix, and 3 μl of diethylpyrocarbonate (DEPC)-treated water for a total reaction volume of 10 μl.…”

Integrated Analysis of Small RNA, Transcriptome, and Degradome Sequencing Reveals the Water-Deficit and Heat Stress Response Network in Durum Wheat

“…Plant miRNAs can rapidly respond to different developmental and environmental signals and subsequently suppress the expression of their targets via mRNA cleavage or transcriptional inhibition [ 23 , 26 , 27 , 28 ]. These miRNA-target modules play significant roles in biological processes, such as signal transduction, nutrient transport, reproductive development, organ formation, and particularly, stress adaptation [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. In crop plants, upon abiotic stress, miRNAs can quickly reprogram the expression of downstream genes that tightly regulate adaptive physiological traits, such as altered flowering timing and increased root water uptake.…”