Endo-β-mannanase and β-tubulin gene expression during the final phases of coffee seed maturation

Abstract

Coffee seeds begin to develop shortly after fertilization and can take 6 to 8 months to complete their formation, a period during which all the characteristics of the mature seed are determined, directly influencing physiological quality. However, little is known about the molecular mechanisms that act during coffee seed maturation. The objective of the current study was to analyze expression of the β-tubulin (TUB) and endo-β-mannanase (MAN) genes during different phases at the end of development and in different tissues of Coffea arabica seeds. The transcription levels of the TUB and MAN genes were quantified in a relative manner using qRT-PCR in whole seeds, and dissected into embryos and endosperms at different developmental stages. Greater expression of MAN was observed in whole seeds and in endosperms during the green stage, and in the embryo during the over-ripe stage. High TUB gene expression was observed in whole seeds during the green stage and, in the embryos, there were peaks in expression during the over-ripe stage. In endosperms, the peak of expression occurred in both the green stage and in the cherry stage. These results suggest participation of endo-β-mannanase during the initial seed developmental stages, and in the stages of physiological maturity in the embryo tissues. TUB gene expression varied depending on the developmental stage and section of seed analyzed, indicating the participation of β-tubulin during organogenesis and coffee seed maturation.