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Methionine sulfoxide reductase (Msr) is a kind of antioxidant enzyme that can scavenge free radicals and repair oxidized proteins by reducing methionine sulfoxide to active methionine. Studies have shown that Msr play an important role in regulating ripening, senescence, and stress resistance of fruit and vegetable. In this paper, the classification of Msr is summarized. In addition, the research progresses on the substrates of Msr, gene families encoding Msr, and its role in regulating fruit and vegetable metabolism and stress response are reviewed. This paper would provide theoretical references for further studying the types and functions of Msr in fruit and vegetable crops, as well as improving the quality and stress resistance of fruit and vegetables by genetic engineering.

Density functional theory (DFT) and time-dependent DFT calculations have been performed to investigate the Raman scattering spectra of metal-molecule complex and metal-molecule-metal junction architectures interconnected with 4-aminothiophenol (PATP) molecule. The simulated profiles of normal Raman scattering (NRS) spectra for the two complexes (Ag2-PATP and PATP-Au2) and the two junctions (Ag2-PATP-Au2 and Au2-PATP-Ag2) are similar to each other, but exhibit obviously different Raman intensities. Due to the lager static polarizabilities of the two junctions, which directly influence the ground state chemical enhancement in NRS spectra, the calculated normal Raman intensities of them are stronger than those of two complexes by the factor of 102. We calculate preresonance Raman scattering (RRS) spectra with incident light at 1064 nm, which is much lower than the S1 electronic transition energy of complexes and junctions. Ag2-PATP-Au2 and Au2-PATP-Ag2 junctions yield higher Raman intensities than those of Ag2-PATP and PATP-Au2 complexes, especially for b2 modes. This effect is mainly attributed to charge transfer (CT) between the metal gap and the PAPT molecule which results in the occurrence of CT resonance enhancement. The calculated pre-RRS spectra strongly depend on the electronic transition state produced by new structures. With excitation at 514.5 nm, the calculated pre-RRS spectra of two complexes and two junctions are stronger than those of with excitation at 1064 nm. A charge difference densities methodology has been used to visually describe chemical enhancement mechanism of RRS spectrum. This methodology aims at visualizing intermolecular CT which provides direct evidence of the Herzberg–Teller mechanism. [ABSTRACT FROM AUTHOR]

The physiological responses of three edible canna cultivars (Canna edulis ker. cv. 'PLRF', 'Xingyu-1', and 'Xingyu-2') to continuous drought stress for 35 days were investigated by characterizing the water saturation deficit (WSD), relative electrical conductivity (REC), superoxidative radical content (SRC), ascorbic acid (AsA) content, glutathione (GSH) content and protein content. It was observed that WSD, REC, SRC progressively increased in the upper leaves of three cultivars under both control and drought treatments. The content changes of AsA, GSH and water soluble protein were lower in 'Xingyu-2' than in 'Xingyu-1' and 'PLRF', in upper leaves than in lower leaves. Compared with control, drought stress aggravated these physiological changes in all three cultivars. The correlation analysis showed that there were significant correlations between indexes except for protein content, which significantly correlated only with SRC. These indicated that drought stress directly led to water loss, and then the REC increased, while the GSH and AsA played major roles in removing the SRC. These results revealed that 'Xingyu-2' was more tolerant to drought stress than 'PLRF' and 'Xingyu-1' and the lower leaves were more sensitive than the upper leaves. The present study not only provides new insights into mechanisms of acclimation and tolerance to drought stress in edible canna but also provides clues for improving drought tolerance of edible canna through breeding or genetic engineering. [ABSTRACT FROM AUTHOR]