Transcriptome analysis of purple pigment formation in Colocasia esculenta

Taro(Colocasia esculenta(L.)Schott)is an important crop in Africa,Southeast Asia,and subtropics and is used as a food and medicine.The purple color pigmentation is an appealing character in taro.We sampled taro corms of the cultivar‘Lipu Taro’at four developmental stages,including LPYS1(without purple pigment,50 days of development(DOD)),LPYS2(very few purple pigments,75 DOD),LPYS3(moderate purple pigments,115 DOD)and LPYS4(high purple pigments,205 DOD).The purpose of our study was to identify the key genes underpinning the purple pigmentation in taro based on RNA-sequencing.Through RNA-Seq,6453 differentially expressed transcripts(DETs)were identified between purple and non-purple pigmented samples.We identified 41 and 12 flavonoid and anthocyanin related DETs transcripts,respectively.These DETs were upregulated at LPYS2,LPYS3,and LPYS4 as compared to LPYS1,indicating their positive contribution to the color formation in taro.Moreover,we identified several DETs encoding for transcription factors,including MYB and bHLH,known to be major regulators of structural genes involved in the flavonoid-anthocyanin pathway.Finally,we reported several plant hormones(ethylene,auxin,gibberellin,jasmonic acid,and cytokinin)related DETs,which are predicted to play important roles in the corm coloration.Different regulation of transcripts representing the flavonoid-anthocyanin biosynthesis pathway,plant hormone transduction pathway,and transcription factors may have key roles in purple pigmentation in taro.Our findings will facilitate future research on improving the quality and appeal of taro.

Refractive Index Change and Color Center Formation in LiYF_4 Crystal Induced by a Femtosecond Laser

The refractive index change and color centers formation in LiYF4 crystal at room temperature are induced by a femtosecond laser irradiation. A mechanism for refractive index change and color centers formation is proposed.

Sucrose enhances the chromogenic ability of Staphylococcus xylosus by improving nitric oxide synthase activity

In this paper,the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated.The results showed that the highest a*value and the best coloring effect similar to those of nitrite were observed after the addition of 0.05 g/mL sucrose to stress the S.xylosus.UV-Vis and electron spin resonance spectra analysis showed that production of coloring product Mb-NO was significantly enhanced after 0.05 g/mL sucrose stress.The growth curve,reactive oxygen content,cell cycle,nitric oxide synthase(NOS)activity,zeta potential,cell size,and protein composition of S.xylosus were investigated to reveal the mechanism of sucrose stress to enhance the coloring effect of the strain.The result showed that sucrose inhibited the growth of S.xylosus,which changed the physiological state by activating the oxidative stress response.The stress altered the rate of intracellular metabolism of S.xylosus by delaying the cell cycle and increasing cell surface zeta potential and cell particle size.These changes altered the protein composition of the cells and significantly enhanced the activity of intracellular NOS,which could improve the chromogenic ability of S.xylosus.This study will provide theoretical support for sucrose stress on S.xylosus to enhance its coloring effect,and sucrose stress for S.xylosus might be a promising biological alternative to nitrite in meat products.