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Almond [Prunus dulcis (Mill.) D.A. Webb] is an economically important, specialty nut crop grown almost exclusively in the United States. Breeding and improvement efforts worldwide have led to the development of key, productive cultivars, including 'Nonpareil,' which is the most widely grown almond cultivar. Thus far, genomic resources for this species have been limited, and a whole-genome assembly for 'Nonpareil' is not currently available despite its economic importance and use in almond breeding worldwide. We generated a 571X coverage genome sequence using Illumina, PacBio, and optical mapping technologies. Gene prediction revealed 49,321 putative genes using MinION Oxford nanopore and Illumina RNA sequencing, and genome annotation found that 68% of predicted models are associated with at least one biological function. Furthermore, epigenetic signatures of almond, namely DNA cytosine methylation, have been implicated in a variety of phenotypes including self-compatibility, bud dormancy, and development of noninfectious bud failure. In addition to the genome sequence and annotation, this report also provides the complete methylome of several almond tissues, including leaf, flower, endocarp, mesocarp, exocarp, and seed coat. Comparisons between methylation profiles in these tissues revealed differences in genome-wide weighted % methylation and chromosome-level methylation enrichment. [ABSTRACT FROM AUTHOR]

Abstract: The ultraviolet (UV) component of sunlight is the main cause of skin cancer. More than 50% of all non-melanoma skin cancers and >90% of squamous cell carcinomas in the US carry a sunlight-induced mutation in the p53 tumor suppressor gene. These mutations have a strong tendency to occur at methylated cytosines. Ligation-mediated PCR (LMPCR) was used to compare at nucleotide resolution DNA photoproduct formation at dipyrimidine sites either containing or lacking a methylated cytosine. For this purpose, we exploited the fact that the X chromosome is methylated in females only on the inactive X chromosome, and that the FMR1 (fragile-X mental retardation 1) gene is methylated only in fragile-X syndrome male patients. Purified genomic DNA was irradiated with UVC (254nm), UVB (290–320nm) or monochromatic UVB (302 and 313nm) to determine the effect of different wavelengths on cyclobutane pyrimidine dimer (CPD) formation along the X-linked PGK1 (phosphoglycerate kinase 1) and FMR1 genes. We show that constitutive methylation of cytosine increases the frequency of UVB-induced CPD formation by 1.7-fold, confirming that methylation per se is influencing the probability of damage formation. This was true for both UVB sources used, either broadband or monochromatic, but not for UVC. Our data prove unequivocally that following UVB exposure methylated cytosines are significantly more susceptible to CPD formation compared with unmethylated cytosines. [Copyright &y& Elsevier]