Genes and genome editing tools for breeding desirable phenotypes in ornamentals

We review the main genes underlying commercial traits in cut flower species and critically discuss the possibility to apply genome editing approaches to produce novel variation and phenotypes. Promoting flowering and flower longevity as well as creating novelty in flower structure, colour range and fragrances are major objectives of ornamental plant breeding. The novel genome editing techniques add new possibilities to study gene function and breed new varieties. The implementation of such techniques, however, relies on detailed information about structure and function of genomes and genes. Moreover, improved protocols for efficient delivery of editing reagents are required. Recent results of the application of genome editing techniques to elite ornamental crops are discussed in this review. Enabling technologies and genomic resources are reviewed in relation to the implementation of such approaches. Availability of the main gene sequences, underlying commercial traits and in vitro transformation protocols are provided for the world's best-selling cut flowers, namely rose, lily, chrysanthemum, lisianthus, tulip, gerbera, freesia, alstroemeria, carnation and hydrangea. Results obtained so far are described and their implications for the improvement of flowering, flower architecture, colour, scent and shelf-life are discussed.

Occurrence of Lily mottle virus on Lilium in Italy

Lily mottle virus (LMoV), a member of the genus Potyvirus, is one of the main viruses infecting lily. Symptoms on lily differ according to the susceptibility and sensitivity of different cultivars and hybrids. They range from leaf mottle or mosaic, vein clearing, chlorotic and yellow streaking, leaf curling, and necrotic spots, to milder forms of leaf symptoms. Plants may even be symptomless at some stages of growth. A varietal collection of Lilium from the early 1990s is held in Pistoia Province (Tuscany, Italy) and is composed of Asian hybrids obtained from intraspecific breeding of commercial cultivars. During a survey conducted from May to June 2010, several plants showing vein clearing, leaf mottle, leaf mosaic, and reddish brownish necrotic spots were observed. Leaf samples from 60 symptomatic or symptomless lily plants, belonging to 20 cultivars, were collected and tested for the presence of LMoV. Samples were assayed by double-antibody sandwich (DAS)-ELISA and eight of them, belonging to four different cultivars, tested positive. Total RNA was extracted from 2 g of leaf tissue of every collected sample according to the protocol described earlier (3) and cDNA synthesis was performed with an iScript cDNA Synthesis Kit (Bio-Rad, Hercules, CA). Samples were tested by reverse transcription (RT)-PCR and real-time PCR assays using primers LMoV1 (5'-GCAAATGAGACACTCAATGCTG-3') and LMoV2 (5'-CGTGCGTGAAGTAACTTCATAG-3') designed to amplify 651 bp of the coat protein (CP) gene of LMoV (1). Results obtained with RT-PCR and real-time PCR exactly matched those achieved with ELISA assay, and the eight positive samples showed amplicons of the expected size. PCR products from five infected samples were directly sequenced from both directions and submitted in GenBank (Accessions Nos. JQ655106 to JQ655110). Our isolates share more than 99% nucleotide identity among each other. Comparison with other LMoV-CP gene sequences present in GenBank showed nucleotide identities ranging from 93 to 94% with LMoV isolates from South Korea (GenBank Accession Nos. GQ150683 to GQ150686), China (GenBank Accession Nos. EU348826, AJ748256, AJ564636, and AJ564637), Australia (GenBank Accession No. JN127341), and Japan (GenBank Accession No. AB570195). To our knowledge, this is the first report of LMoV on Lilium in Italy where this virus was already reported to infect escarole (2). Considering the economic importance of Lilium production as a flowering plant in Pistoia Province, and in several other areas of Italy, the report of LMoV present on lilies suggests the use of healthy propagation material and the adoption of preventive measures to avoid its diffusion. References: (1) J.-H. Lim et al. Korean J. Microbiol. 45:251, 2009. (2) V. Lisa et al. Plant Dis. 86:329, 2002. (3) D. J. MacKenzie et al. Plant Dis. 81:222, 1997.

Body composition, sex steroids, IGF-1, and bone mineral status in aging men

BACKGROUND

Bone loss in elderly men is associated with changes in body composition and reduced secretion of endogenous anabolizing hormones. The independent influences of body composition and endocrine factors on male bone metabolism, however, are unclear.

METHODS

Bone mass density (BMD) (bone mass content [BMC, g]/projected bone area [BA, cm2]) at different skeletal sites, skeletal muscle, and body fat mass were measured by dual-energy X-ray absorptiometry in 129 men aged 20 to 95 years. Free testosterone, 17-beta-estradiol, dehydroepiandrosterone-sulfate, and insulin-like growth factor 1 (IGF-1) serum concentrations were measured. Because BMD may fail to control for differences in skeletal size, the associations of bone mass with body composition and hormones were studied by comparing BMD regression models incorporating age and knee height only with BMC regression models also incorporating BA.

RESULTS

Skeletal muscle had close associations (p at least < .01) with BMD and BMC at almost all skeletal sites, but the strength of these associations was generally reduced in BMC with respect to BMD models. Weak associations (p < .05) were found in both models for fatness with femoral bone and for 17-beta-estradiol with total body and femoral bone. The association of 17-beta-estradiol with spinal bone was significant (p < .05) in the BMD but not in the BMC model. No association of BMC or BMD with androgens and IGF-1 reached significancy.

CONCLUSIONS

Skeletal muscle may be more important than fatness and anabolizing hormones in preserving bone mass in elderly men. In contrast to traditional belief, estrogens may be more important than androgens and IGF-1 in male bone metabolism.

Blood micronutrient and thyroid hormone concentrations in the oldest-old

Several micronutrients are involved in thyroid hormone metabolism, but it is unclear whether their marginal deficits may contribute to the alterations in thyroid function observed in extreme aging. The relationships among blood concentrations of thyroid hormones and selenium, zinc, retinol, and alpha-tocopherol were studied in 44 healthy Northern Italian oldest-old subjects (age range, 90-107 yr), selected by the criteria of the SENIEUR protocol. Control groups included 44 healthy adult (age range, 20-65 yr) and 44 SENIEUR elderly (age range, 65-89 yr) subjects. Oldest-old subjects had higher TSH (P < 0.01) and lower free T3 (FT3)/freeT4 (FT4) ratio, zinc, and selenium serum values (P < 0.001) than adult and elderly control subjects. No significant difference was found for plasma retinol and a-tocopherol values. The associations between micronutrients and thyroid hormones were evaluated by multivariate analysis. In oldest-old subjects, plasma retinol was negatively associated with FT4 (P = 0.019) and TSH serum levels (P = 0.040), whereas serum zinc was positively associated with serum FT3 (P = 0.010) and FT3/FT4 ratio (P = 0.011). In younger subjects, no significant association was found among thyroid variables and micronutrients. In conclusion, blood levels of specific micronutrients are associated with serum iodothyronine levels in extreme aging.

Prevalence and severity of dementia among northern Italian centenarians

Using diagnostic criteria from the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, dementia was clinically diagnosed in 57 (62%) of 92 centenarians living in two northern Italian provinces. The condition was severely disabling in approximately 70% of the demented patients. Although clinically diagnosed AD accounted for 79% of dementia cases, almost one third of patients with AD had risk factors for vascular dementia, suggesting that the aging brain may be susceptible to multiple additive factors that impair cognition.