Identification and comparison of oligopeptides during withering process of White tea by ultra-high pressure liquid chromatography coupled with quadrupole-orbitrap ultra-high resolution mass spectrometry.

Peptides could have specific tastes or bioactivities depending on the length and sequence of amino acids. Till date it remains unknown what peptides are formed during the white tea manufacturing process and whether they contribute to the flavor or bio-activities of white tea. As a first step to address these questions, we applied ultra-high pressure liquid chromatography coupled with quadrupole-orbitrap ultra-high resolution mass spectrometry (UPLC-Quadrupole-Orbitrap-UHRMS) to monitor peptides dynamic changes during the withering process. A total of 196 abundant peptides were identified. Most of them were oligopeptides within a molecular weight of 1000 Da. Four of them were randomly selected, synthesized peptides were applied for further confirmation and quantification. Sequence analysis suggested that some of them were potential taste contributors. Proteinase cleave site analysis identified two separate periods of active proteins degradation at 0-12 h and 30-42 h of the withering processes. Further analysis of cleavage sites also suggested that protein degradation during withering steps were random rather than a stepwise reaction.

A transient expression system in soybean mesophyll protoplasts reveals the formation of cytoplasmic GmCRY1 photobody-like structures.

Soybean (Glycine max (L.) Merr.), grown for its plant oils and proteins, is one of the most important crops throughout the world. Generating stable and heritable transgenic soybeans is relatively inefficient; therefore, there is an urgent need for a simple and high-efficient transient transformation method by which to enable the investigation of gene functions in soybeans, which will facilitate the elucidation and improvement of the molecular mechanisms regulating the associated agronomic traits. We established a system of transient expression in soybean mesophyll protoplasts and obtained a high level of protoplast transfection efficiency (up to 83.5%). The subcellular activity of the protoplasts was well preserved, as demonstrated by the dynamic formation of GmCRY nucleus photobodies (NPs) and/or cytoplasmic photobody-like structures (CPs) in response to blue light. In addition, we showed that GmCRY1b CPs colocalized with GmCOP1b, a co-ortholog of Arabidopsis thaliana CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), which provided new insight into the potential roles of GmCRY1s in the cytoplasm.