Bud dormancy is crucial for winter survival and is characterized by the inability of the bud meristem to respond to growth-promotive signals before the chilling requirement (CR) is met. However, our understanding of the genetic mechanism regulating CR and bud dormancy remains limited. This study identified PpDAM6 (DORMANCY-ASSOCIATED MADS-box) as a key gene for CR using a genome-wide association study analysis based on structural variations in 345 peach (Prunus persica (L.) Batsch) accessions. The function of PpDAM6 in CR regulation was demonstrated by transiently silencing the gene in peach buds and stably overexpressing the gene in transgenic apple (Malus × domestica) plants. The results showed an evolutionarily conserved function of PpDAM6 in regulating bud dormancy release, followed by vegetative growth and flowering, in peach and apple. The 30-bp deletion in the PpDAM6 promoter was substantially associated with reducing PpDAM6 expression in low-CR accessions. A PCR marker based on the 30-bp indel was developed to distinguish peach plants with non-low and low CR. Modification of the H3K27me3 marker at the PpDAM6 locus showed no apparent change across the dormancy process in low- and non-low- CR cultivars. Additionally, H3K27me3 modification occurred earlier in low-CR cultivars on a genome-wide scale. PpDAM6 could mediate cell–cell communication by inducing the expression of the downstream genes PpNCED1 (9-cis-epoxycarotenoid dioxygenase 1), encoding a key enzyme for ABA biosynthesis, and CALS (CALLOSE SYNTHASE), encoding callose synthase. We shed light on a gene regulatory network formed by PpDAM6-containing complexes that mediate CR underlying dormancy and bud break in peach. A better understanding of the genetic basis for natural variations of CR can help breeders develop cultivars with different CR for growing in different geographical regions.

Methyl jasmonate (MeJA) plays a vital role in plant disease resistance and also induces the expression of disease resistance genes in plants. In this study, a transcriptome analysis was performed on grapevine leaves after 12, 24 and 48 h of MeJA-100 μM treatment. A total of 1242 differentially expressed genes (DEGs) were identified from the transcriptome data, and the analysis of the DEGs showed that genes related to phytohormone signal transduction, jasmonic acid-mediated defense, Mitogen-activated protein kinase (MAPK), and flavonoid biosynthetic pathways were upregulated. As Pathogenesis-related gene 1 (PR1) is an important marker gene in plant defense also upregulated by MeJA treatment in RNA-seq data, the VvPR1 gene was selected for a promoter analysis with β-glucuronidase (GUS) through transient expression in tobacco leaves against abiotic stress. The results showed that the region from −1837 bp to −558 bp of the VvPR1 promoter is the key region in response to hormone and wound stress. In this study, we extended the available knowledge about induced defense by MeJA in a grapevine species that is susceptible to different diseases and identified the molecular mechanisms by which this defense might be mediated.

Yield and Nutrients Uptake of Avena sativa as Influenced by Vesicular Arbuscular Mycorrhizal (VAM)