Molluscs for sale: Assessment of freshwater gastropods and bivalves in the ornamental pet trade

10.1371/journal.pone.0161130PLoS ONE118e016113

The ethylene response factor VaERF092 from Amur grape regulates the transcription factor VaWRKY33, improving cold tolerance

Cold stress is a major limiting factor in grape (Vitis) productivity. In this study, we characterized a cold-responsive ethylene response factor (ERF) transcription factor, VaERF092, from Amur grape (Vitis amurensis). VaERF092 expression was induced by both low temperatures and the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC), but was suppressed by treatment with the ethylene inhibitor aminoethoxyvinylglycine (AVG) under cold conditions. Ectopic expression of VaERF092 in Arabidopsis thaliana enhanced cold tolerance. Co-expression network analysis of V. vinifera genes indicated that WRKY33 might be a downstream target of VaERF092. This hypothesis was supported by the fact that VaWRKY33 was expressed temporally after VaERF092 expression and could also be induced by cold and ACC, and inhibited by AVG. Yeast one-hybrid, transient beta-glucuronidase (GUS) and dual-luciferase reporter assays provided evidence for an interaction between VaERF092 and a GCC-box element in the VaWRKY33 promoter. In addition, heterologous overexpression of VaWRKY33 in A. thaliana resulted in enhanced cold tolerance. VaERF092- and VaWRKY33 overexpressing grape calli showed lower low-temperature exothermic values than the empty vector (EV) calli, indicating enhanced tolerance to cold. Together, these results indicated that VaERF092 regulates VaWRKY33 through binding to its promoter GCC-box, leading to enhanced cold stress tolerance

Genetic, epigenetic and genomic effects on variation of gene expression among grape varieties

The transcriptional regulatory structure of plant genomes is still relatively unexplored and little is known about factors that influence expression variation in plants. We used a genetic system consisting of 10 heterozygous grape varieties with high consanguinity and high haplotypic diversity to: (i) identify regions of haplotype sharing through whole genome resequencing and SNP genotyping; (ii) analyse gene expression through RNA-seq in four stages of berry development; (iii) associate gene expression variation with genetic and epigenetic properties. We found that haplotype sharing in and around genes was positively correlated with similarity in expression and negatively correlated with the fraction of differentially expressed genes. Genetic and epigenetic properties of the gene and the surrounding region showed significant effects on the extent of expression variation, with negative associations for the level of gene body methylation and the mean expression level and positive ones for nucleotide diversity, structural diversity and ratio of non-synonymous to synonymous nucleotide diversity. We also observed a spatial dependency of covariation of gene expression among varieties. These results highlight relevant roles for cis-acting factors, selective constraints and epigenetic features of the gene and the regional context in which the gene is located in the determination of expression variation. This article is protected by copyright. All rights reserved