Summary: AN1 is a regulatory gene that promotes anthocyanin biosynthesis in potato tubers and encodes a R2R3 MYB transcription factor. However, no clear evidence implicates AN1 in anthocyanin production in leaves, where these pigments might enhance environmental stress tolerance. In our study we found that AN1 displays intraspecific sequence variability in both coding/non‐coding regions and in the promoter, and that its expression is associated with high anthocyanin content in leaves of commercial potatoes. Expression analysis provided evidence that leaf pigmentation is associated to AN1 expression and that StJAF13 acts as putative AN1 co‐regulator for anthocyanin gene expression in leaves of the red leaf variety ‘Magenta Love,’ while a concomitant expression of StbHLH1 may contribute to anthocyanin accumulation in leaves of ‘Double Fun.’ Yeast two‐hybrid experiments confirmed that AN1 interacts with StbHLH1 and StJAF13 and the latter interaction was verified and localized in the cell nucleus by bimolecular fluorescence complementation assays. In addition, transgenic tobacco (Nicotiana tabacum) overexpressing a combination of either AN1 with StJAF13 or AN1 with StbHLH1 showed deeper purple pigmentation with respect to AN1 alone. This further confirmed AN1/StJAF13 and AN1/StbHLH1 interactions. Our findings demonstrate that the classical loci identified for potato leaf anthocyanin accumulation correspond to AN1 and may represent an important step to expand our knowledge on the molecular mechanisms underlying anthocyanin biosynthesis in different plant tissues.

Cryptochromes are flavin-containing blue light photoreceptors, present in most kingdoms, including archaea, bacteria, plants, animals and fungi. They are structurally similar to photolyases, a class of flavoproteins involved in light-dependent repair of UV-damaged DNA. Cryptochromes were first discovered in Arabidopsis thaliana in which they control many light-regulated physiological processes like seed germination, de-etiolation, photoperiodic control of the flowering time, cotyledon opening and expansion, anthocyanin accumulation, chloroplast development and root growth. They also regulate the entrainment of plant circadian clock to the phase of light–dark daily cycles. Here, we review the molecular mechanisms by which plant cryptochromes control the synchronisation of the clock with the environmental light. Furthermore, we summarise the circadian clock-mediated changes in cell cycle regulation and chromatin organisation and, finally, we discuss a putative role for plant cryptochromes in the epigenetic regulation of genes.

Inherited prion diseases are neurodegenerative pathologies related to genetic mutations in the prion protein (PrP) gene, which favour the conversion of PrPC into a conformationally altered pathogenic form, PrPSc. The molecular basis of PrPC/PrPSc conversion, the intracellular compartment where it occurs and how this process leads to neurological dysfunction are not yet known. We have studied the intracellular synthesis, degradation and localization of a PrP mutant associated with a genetic form of Creutzfeldt-Jakob disease (CJD), PrPT182A, in transfected FRT cells. PrPT182A is retained in the endoplasmic reticulum (ER), is mainly associated with detergent-resistant microdomains (DRMs) and is partially resistant to proteinase K digestion. Although an untranslocated form of this mutant is polyubiquitylated and undergoes ER-associated degradation, the proteasome is not responsible for the degradation of its misfolded form, suggesting that it does not have a role in the pathogenesis of inherited diseases. On the contrary, impairment of PrPT182A association with DRMs by cholesterol depletion leads to its accumulation in the ER and substantially increases its misfolding. These data support the previous hypothesis that DRMs are important for the correct folding of PrP and suggest that they might have a protective role in pathological scrapie-like conversion of PrP mutants.

Polyploidy is a very common phenomenon in the plant kingdom, where even diploid species are often described as paleopolyploids. The polyploid condition may bring about several advantages compared to the diploid state. Polyploids often show phenotypes that are not present in their diploid progenitors or exceed the range of the contributing species. Some of these traits may play a role in heterosis or could favor adaptation to new ecological niches. Advances in genomics and sequencing technology may create unprecedented opportunities for discovering and monitoring the molecular effects of polyploidization. Through this review, we provide an overview of technologies and strategies that may allow an in-depth analysis of polyploid genomes. After introducing some basic aspects on the origin and genetics of polyploids, we highlight the main tools available for genome and gene expression analysis and summarize major findings. In the last part of this review, the implications of next generation sequencing are briefly discussed. The accumulation of knowledge on polyploid formation, maintenance, and divergence at whole-genome and subgenome levels will not only help plant biologists to understand how plants have evolved and diversified, but also assist plant breeders in designing new strategies for crop improvement.