The tomato HIGH PIGMENT1/DAMAGED DNA BINDING PROTEIN 1 gene contributes to regulation of fruit ripening

Fleshy fruit ripening is governed by multiple external and internal cues and accompanied by changes in color,texture,volatiles,and nutritional quality traits.While extended shelf-life and increased phytonutrients are desired,delaying ripening via genetic or postharvest means can be accompanied by reduced nutritional value.Here we report that the high pigment 1(hp1)mutation at the UV-DAMAGED DNA BINDING PROTEIN 1(DDB1)locus,previously shown to influence carotenoid and additional phytonutrient accumulation via altered light signal transduction,also results in delayed ripening and firmer texture,resulting at least in part from decreased ethylene evolution.Transcriptome analysis revealed multiple ethylene biosynthesis and signaling-associated genes downregulated in hp1.Furthermore,the hp1 mutation impedes softening of the pericarp,placenta,columella as well as the whole fruit,in addition to reduced expression of the FRUITFUL2(FUL2)MADS-box transcription factor and xyloglucan endotransglucosylase/hydrolase 5(XTH5).These results indicate that DDB1 influences a broader range of fruit development and ripening processes than previously thought and present an additional genetic target for increasing fruit quality and shelf-life.

Tomato fruit as a model for tissue-specific gene silencing in crop plants

Use of CRISPR-Cas9(Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)-CRISPR-associated 9)-mediated genome editing has proliferated for use in numerous plant species to modify gene function and expression,usually in the context of either transient or stably inherited genetic alternations.While extremely useful in many applications,modification of some loci yields outcomes detrimental to further experimental evaluation or viability of the target organism.Expression of Cas9 under a promoter conferring gene knockouts in a tissue-specific subset of genomes has been demonstrated in insect and animal models,and recently in Arabidopsis.We developed an in planta GFP(green fluorescent protein)assay system to demonstrate fruit-specific gene editing in tomato using a phosphoenolpyruvate carboxylase 2 gene promoter.We then targeted a SET-domain containing polycomb protein,SlEZ2,previously shown to yield pleiotropic phenotypes when targeted via ^(35)S-driven RNA interference and we were able to characterize fruit phenotypes absent additional developmental perturbations.Tissue-specific gene editing will have applications in assessing function of essential genes otherwise difficult to study via germline modifications and will provide routes to edited genomes in tissues that could not otherwise be recovered when their germline modification perturbs their normal development.

Determination of luminous color gamut of continuous emissions in visible waveband

Regarding objects of monotonic emissivities in the visible waveband, the concept of color-kernel body is put forward. With this concept, the luminous color of actual objects is found out to be the mixture of the radiative colors of a blackbody and a color-kernel body with different weights. The locus of the isothermal radiative colors is a straight-line segment in the chromaticity diagram. The whole color gamut of continuous emissions is about 17% of the entire gamut of natural colors and at its bottom.