Comparative Proteomics Profiling Illuminates the Fruitlet Abscission Mechanism of Sweet Cherry as Induced by Embryo Abortion

Abstract

Sweet cherry (Prunus avium L.) is a delicious nutrient-rich fruit widely cultivated in countries such as China, America, Chile, and Italy. However, the yield often drops severely due to the frequently-abnormal fruitlet abscission, and few studies on the metabolism during its ripening process at the proteomic level have been executed so far. To get a better understanding regarding the sweet cherry abscission mechanism, proteomic analysis between the abscising carpopodium and non-abscising carpopodium of sweet cherry was accomplished using a newly developed Liquid chromatography-mass spectrometry/mass spectrometry with Tandem Mass Tag (TMT-LC-MS/MS) methodology. The embryo viability experiments showed that the vigor of the abscission embryos was significantly lower than that of retention embryo. The activity of cell wall degrading enzymes in abscising carpopodium was significantly higher than that in non-abscising carpopodium. The anatomy results suggested that cells in the abscission zone were small and separated. In total, 6280 proteins were identified, among which 5681 were quantified. It has been observed that differentially accumulated proteins (DAPs) influenced several biological functions and various subcellular localizations. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that plenty of metabolic pathways were notably enriched, particularly those involved in phytohormone biosynthesis, cell wall metabolism, and cytoskeletal metabolism, including 1-aminocyclopropane-1-carboxylate oxidase proteins which promote ethylene synthesis, and proteins promoting cell wall degradation, such as endoglucanases, pectinase, and polygalacturonase. Differential expression of proteins concerning phytohormone biosynthesis might activate the shedding regulation signals. Up-regulation of several cell wall degradation-related proteins possibly regulated the shedding of plant organs. Variations of the phytohormone biosynthesis and cell wall degradation-related proteins were explored during the abscission process. Furthermore, changes in cytoskeleton-associated proteins might contribute to the abscission of carpopodium. The current work represented the first study using comparative proteomics between abscising carpopodium and non-abscising carpopodium. These results indicated that embryo abortion might lead to phytohormone synthesis disorder, which effected signal transduction pathways, and hereby controlled genes involved in cell wall degradation and then caused the abscission of fruitlet. Overall, our data may give an intrinsic explanation of the variations in metabolism during the abscission of carpopodium.

Cross-talk between transcriptome, phytohormone and HD-ZIP gene family analysis illuminates the molecular mechanism underlying fruitlet abscission in sweet cherry (Prunus avium L) 

“…In recent research, the genes of cellulase, pectinase, polygalacturonase, expansin, xyloglucan endotransglucosylase/hydrolase, and peroxidase were found to be signi cantly up-regulated in the abscising carpopodium. In addition, previous proteomic studies have also shown the same results [49]. These results suggested that the remodeling of cell walls might promote the sweet cherry fruitlet shedding.…”

“…This result implies that the formation of plant cells is hindered, which in turn leads to programmed cell death and the shedding of plant organs. In addition, the proteomics at the early stage of this research group also showed that a close relationship existed between the cytoskeleton and the shedding of sweet cherry fruit [49].…”

The Sequenced Genomes of Non-Flowering Land Plants Reveal the (R)Evolutionary History of Peptide Signaling

“…In addition to angiosperms, RGFs have been suggested to be present in the lycophyte S. moellendorffii (Ghorbani et al, 2015). RGFs can signal through RGF RECEPTOR (RGFR)/ROOT GROWTH FACTOR INSENSITIVE (RGI) receptors, which were discovered a few years ago (Shinohara et al, 2016; Song et al, 2016; Qiu et al, 2020).…”

“…A double mutant of the closely related receptors HAE and HSL2 was needed to disclose their involvement in floral organ abscission, like their peptide ligand IDA (Butenko et al, 2003; Cho et al, 2008; Stenvik et al, 2008). Furthermore, triple to quintuple mutants were necessary to disclose the involvement of the RGI receptors in root development, with RGFs peptides as ligands (Shinohara et al, 2016; Song et al, 2016; Qiu et al, 2020). Thus, functional redundancy on the receptor side as well as the peptide side has made it complicated to identify ligand-receptor pairs through genetics.…”

Plant Proteomic Research 3.0: Challenges and Perspectives

“…Olivares-García et al [ 22 ] suggested that in the embryogenic culture of avocados, there is an enhanced phenylpropanoid metabolism for the production of the building blocks of lignin having a role in cell wall reinforcement for tolerating stress response. Qiu et al [ 23 ] indicated that embryo abortion might lead to phytohormone synthesis disorder, which effected signal transduction pathways, and hereby controlled genes involved in cell wall degradation and then caused the abscission of fruitlets in sweet cherry trees. Wu et al [ 24 ] revealed by using iTRAQ that plastid pigment metabolism contributes to leaf color changes in Nicotiana tabacum during curing.…”