RESUMO
Calcium acts as a secondary messenger in plants and is essential for plant growth and development. However, studies on the pathway of aroma synthesis in 'Nanguo' pear (Pyrus ussriensis Maxim.) are scarce. In this study, a bioinformatics analysis of transcriptomic data from calcium-treated 'Nanguo' pear was performed, which identified two fatty acid desaturases, PuFAD2 and PuFAD3, and eight AP2/ERF transcription factors, all exhibiting the same expression patterns. Transient expression experiments showed overexpression of PuFAD2 and PuFAD3 significantly increased the levels of aromatic substrates linoleic acid, hexanal, linolenic acid, and (E)-2-hexenal, but RNAi (RNA interference) had the opposite expression. Promoter sequences analysis revealed that PuFAD2 and PuFAD3 have ERE (estrogen response element) motifs on their promoters. The strongest activation of PuFAD2 by PuERF008 was verified using a dual-luciferase reporting system. Additionally, yeast one-hybrid and electrophoretic mobility shift assays revealed PuERF008 could active PuFAD2. Transient overexpression and RNAi analyses of PuERF008 showed a strong correlation with the expression of PuFAD2. This study provides insights into the process of aroma biosynthesis in 'Nanguo' pear and offers a theoretical basis for elucidating the role of calcium signaling in aroma synthesis.
RESUMO
MAIN CONCLUSION: A total of 6763 proteins were identified in the developing pear flesh, which were further screened for differentially expressed proteins related to fruit quality and ATP-binding cassette transporters. To obtain further details on changes in protein levels during fruit ripening and to identify and evaluate changes in various metabolic pathways that affect fruit quality, a proteomic method using tandem mass tags was implemented at three developmental stages in Pyrus pyrifolia cv. "Hosui" that identified 6763 proteins. Subcellular localization and Gene Ontology enrichment analysis revealed major functions of all identified proteins. Kyoto Encyclopedia of Genes and Genomes pathway analysis suggested that all metabolic processes are reflected in the up- and downregulation of differentially expressed proteins during fruit development, which play predominant roles in cell division, cell expansion, and fruit ripening. Among the examined differentially expressed proteins, 160 related to fruit quality, and 14 ATP-binding cassette transporters related to fruit development were identified and analyzed. The quantitative data were validated by parallel reaction monitoring, which confirmed the reliability of the experimental results.
