Project description:<p>BACKGROUND: In China, a majority of apple orchards were initially planted under arboriculture. Noteworthy, as the trees age, there is an increase in the number of branches and the degree of orchard depression and deterioration of the canopy light conditions. This phenomenon results in in blockage of bud differentiation, causing yield decrease and overall deterioration in fruit quality. Intercropping is an effective strategy for addressing the issue of orchard depression. However, the impact of intercropping on bud differentiation remains unclear. This study thus analyzed the physiological and metabolic aspects of flower bud differentiation after thinning and reshaping an overcrowded orchard. METHODS: A series of physiological and metabolomic analyses were conducted on terminal flower bud samples collected during early (T1) and late (T2) bud differentiation following thinning and reshaping alongside their controls CK1 and CK2. RESULTS: The T1 group had significantly higher amounts of sucrose, glucose, fructose and sorbitol compared to its control. Metabolomic analyses yielded 845 metabolites. Among these metabolites, 72 were significantly different in CK1 vs T1. In contrast, 73 metabolites were different in CK2 vs T2, while 26 metabolites were common between the two comparison groups. CK1 vs T1 and CK2 vs T2 had 20 and 16 enhanced metabolic pathways, respectively. Bud differentiation was closely associated with the phenylpropane and flavonoid biosynthesis pathways. CONCLUSIONS: Thinning and reshaping of the apple orchard improved light penetration and increased the content of coumarins and eriodictyol, thereby promoting flower bud differentiation. This study provides new insights into how orchard management practices, such as thinning, pruning and shaping, promote flower bud development in apple trees.</p>
Project description:Gene expression associated with apple fruit ripening and postharvest treatments was studied to identify transcripts that are regulated by ethylene signaling.
Project description:New mechanisms-of-action of anthocyanins (ACNs) provided by a red-fleshed apple compared with a white-fleshed apple ACN-poor, and with an ACN-rich extract on the proteome profile of aorta and heart as cardiovascular key tissues were determined. Hypercholesterolemic Wistar rats were separated into the corresponding groups to analyze the proteomic profile of the aorta and heart tissues using nano-liquid chromatography coupled to mass-spectrometry. Red-fleshed apple downregulated CRP, C1QB and CFP related-inflammation. White-fleshed apple reduced C1QB, CFB, CFD, C3, and C9 related to the complement system, reduced MB and CP related to iron metabolism, and increased ME1, PKM, and PC related to energy homeostasis. ACN-rich extract increased FMOD, TAGLN, and CAP1 related to cellular structure and decreased PRKACA, IQGAP1, and HSP90AB1 related to cellular signaling. Red-fleshed apple rich in ACNs suggested an anti-inflammatory effect while white-fleshed apple reduced the complement system protein-related. An apple matrix effect reduced inflammatory proteins regardless their ACN content.
Project description:Fire blight (FB) is a bacterial disease affecting plants from Rosaceae family, including apple and pear. FB develops after the infection of Erwinia amylovora, gram-negative enterobacterium, and results in burnt-like damages and wilting, which can affect all organs of the plant. Although the mechanisms underlying disease response in apples are not elucidated yet, it has been well described that FB resistance depends on the rootstock type. The main objective of this work was to identify miRNAs involved in response to bacterial infection in order to better explain apple defense mechanisms against fire blight disease. We performed deep sequencing of eighteen small RNA libraries obtained from inoculated and non-inoculated Gala apple leaves. 233 novel plant mature miRNAs were identified together with their targets and potential role in response to bacterial infection. We identify three apple miRNAs responding to inoculation (mdm-miR168a,b, mdm-miR194C and mdm-miR1392C) as well as miRNAs reacting to bacterial infection in a rootstock-specific manner (miR395 family). Our results provide insights into the mechanisms of fire blight resistance in apple.
Project description:Winter dormancy is an adaptative mechanism that temperate and boreal trees have developed to protect their meristems against low temperatures. In apple trees (Malus domestica), cold temperatures induce bud dormancy at the end of summer/beginning of the fall. Apple buds stay dormant during winter until they are exposed to a period of cold, after which they can resume growth (budbreak) and initiate flowering in response to warm temperatures in spring. It is well-known that small RNAs modulate temperature responses in many plant species, but however, how small RNAs are involved in genetic networks of temperature-mediated dormancy control in fruit tree species remains unclear. Here, we have made use of a recently developed ARGONAUTE (AGO)-purification technique to isolate small RNAs from apple buds. A small RNA-seq experiment resulted in the identification of small RNAs that change their pattern of expression in apple buds during dormancy.