Profiling of N6-Methyladenosine (m6A) Modification Landscape in Response to Drought Stress in Apple (Malus prunifolia (Willd.) Borkh)

Drought stress is a significant environmental factor limiting crop growth worldwide. Malus prunifolia is an important apple species endemic to China and is used for apple cultivars and rootstocks with great drought tolerance. N6-methyladenosine (m6A) is a common epigenetic modification on messenger RNAs (mRNAs) in eukaryotes which is critical for various biological processes. However, there are no reports on m6A methylation in apple response to drought stress. Here, we assessed the m6A landscape of M. prunifolia seedlings in response to drought and analyzed the association between m6A modification and transcript expression. In total, we found 19,783 and 19,609 significant m6A peaks in the control and drought treatment groups, respectively, and discovered a UGUAH (H: A/U/C) motif. In M. prunifolia, under both control and drought conditions, peaks were highly enriched in the 3′ untranslated region (UTR) and coding sequence (CDS). Among 4204 significant differential m6A peaks in drought-treated M. prunifolia compared to control-treated M. prunifolia, 4158 genes with m6A modification were identified. Interestingly, a large number of hypermethylated peaks (4069) were stimulated by drought treatment compared to hypomethylation. Among the hypermethylated peak-related genes, 972 and 1238 differentially expressed genes (DEGs) were up- and down-regulated in response to drought, respectively. Gene ontology (GO) analyses of differential m6A-modified genes revealed that GO slims related to RNA processing, epigenetic regulation, and stress tolerance were significantly enriched. The m6A modification landscape depicted in this study sheds light on the epigenetic regulation of M. prunifolia in response to drought stress and indicates new directions for the breeding of drought-tolerant apple trees.

Phloretin attenuates hepatic steatosis via improvement of mitochondrial dysfunction by activating AMPK-dependent signaling pathways

Phloretin, a dihydrochalcone, widely exists in the fruits of apple and Malus prunifolia with multiple biological activities. Presently, we studied the function of phloretin on the attenuation of hepatic steatosis...

Melatonin promotes adventitious root formation in apple by promoting the function of MdWOX11

Background Melatonin (MT) is important for plant growth and development; however, it is not known whether MT is involved in apple adventitious root (AR) development. In this study, we treated Malus prunifolia (MP) at four different stages of AR development, and analyzed the level of the endogenous hormones MT, auxin (IAA), zeatin-riboside (ZR), abscisic acid (ABA), and gibberellins (GA1 + 3) in all four treatment groups and the untreated control group. The expression of MT, IAA biosynthesis, transport and signal transduction, the cell cycle, and root development related genes were quantified by RT-qPCR. The function of MdWOX11 was analyzed in transgenic apple plants. Results The promotion of AR development by MT was dependent on the stage of AR induction between 0 and 2 d in apple rootstocks. MT-treatment increased the level of IAA and crosstalk existed between MT and IAA during AR formation. The expression of MdWOX11 was induced by MT treatment and positively regulated AR formation in apple. Furthermore, transgenic lines that overexpressed MdWOX11 lines produced more ARs than ‘GL3’. Phenotypic analysis indicated that MdWOX11 overexpression lines were more sensitive to exogenous MT treatment than ‘GL3’, suggesting that MdWOX11 regulates AR formation in response to MT in apple rootstock. Conclusions MT promotes AR formation mainly during the AR induction stage by inducing IAA levels and upregulating MdWOX11.

Melatonin promotes adventitious root formation in apple by promoting the function of MdWOX11

Background: Melatonin (MT) is important for plant growth and development; however, it is not known whether MT is involved in apple adventitious root (AR) development. In this study, we treated Malus prunifolia (MP) at four different stages of AR development, and analyzed the level of the endogenous hormones MT, auxin (IAA), zeatin-riboside (ZR), abscisic acid (ABA), and gibberellins (GA1+3) in all four treatment groups and the untreated control group. The expression of MT, IAA biosynthesis, transport and signal transduction, the cell cycle, and root development related genes were quantified by RT-qPCR. The function of MdWOX11 was analyzed in transgenic apple plants.Results: The promotion of AR development by MT was dependent on the stage of AR induction between 0–2 d in apple rootstocks. MT-treatment increased the level of IAA and crosstalk existed between MT and IAA during AR formation. The expression of MdWOX11 was induced by MT treatment and positively regulated AR formation in apple. Furthermore, transgenic lines that overexpressed MdWOX11 lines produced more ARs than ‘GL3’. Phenotypic analysis indicated that MdWOX11 overexpression lines were more sensitive to exogenous MT treatment than ‘GL3’, suggesting that MdWOX11 regulates AR formation in response to MT in apple rootstock.Conclusions: MT promotes AR formation mainly during the AR induction stage by inducing IAA levels and upregulating MdWOX11.

Melatonin promotes adventitious root formation in apple by promoting the function of MdWOX11

Background: Melatonin (MT) is important for plant growth and development; however, it is not known whether MT is involved in apple adventitious root (AR) development. In this study, we treated Malus prunifolia (MP) at four different stages of AR development, and analysed the level of the endogenous hormones MT, auxin (IAA), zeatin-riboside (ZR), gibberellins (GA1+3) and abscisic acid (ABA) in all four treatment groups and in the untreated control group. The expression of genes related to MT, IAA biosynthesis, transport and signal transduction, the cell cycle, and root development was quantified by RT-qPCR, and the function of MdWOX11 was analysed in transgenic apple plants.Results: The promotion of AR development by MT was dependent on the stage of AR induction between 0–2 d in apple rootstocks. MT-treatment increased the level of IAA and crosstalk existed between MT and IAA during AR formation. The expression of MdWOX11 was induced by MT treatment and positively regulated AR formation in apple. Furthermore, transgenic lines that overexpressed MdWOX11 lines produced more ARs than ‘GL3’. Phenotypic analysis indicated that MdWOX11 overexpression lines were more sensitive to exogenous MT treatment than ‘GL3’, suggesting that MdWOX11 regulates AR formation in response to MT in apple rootstock.Conclusions: MT promotes AR formation mainly during the AR induction stage by inducing IAA levels and upregulating MdWOX11.

The Fruit Malus prunifolia (Malus micromalus Mak.): A Minireview of Current Knowledge of Fruit Composition and Health Benefits

The fruit Malus prunifolia (Malus micromalus Mak.), which belongs to the Rosaceae family, grows mostly in the upper-middle reaches of the Yellow River area. It has long been popular as a fruit commodity and as a natural remedy. Its main biologically active components include vitamin C, phenolics, flavonoids, polysaccharides, and triterpenic acids. Recent phytochemical studies on the fruit have shed some light on its biological activities, such as anticancer, immunomodulatory, antioxidant, immunostimulating, hepatoprotective, and gastrointestinal protective activities. A stronger focus on clinical studies and phytochemical characterization of the fruit will be essential for future research efforts. This minireview could be useful for predicting its other medicinal uses and its potential drug or food interactions, and it could be beneficial for people living in areas where the fruit is endemic and where healthcare resources are scarce.