Transgenic apple plants overexpressing the chalcone 3-hydroxylase gene of Cosmos sulphureus show increased levels of 3-hydroxyphloridzin and reduced susceptibility to apple scab and fire blight

Main conclusionOverexpression of chalcone-3-hydroxylase provokes increased accumulation of 3-hydroxyphloridzin inMalus. Decreased flavonoid concentrations but unchanged flavonoid class composition were observed. The increased 3-hydroxyphlorizin contents correlate well with reduced susceptibility to fire blight and scab.The involvement of dihydrochalcones in the apple defence mechanism against pathogens is discussed but unknown biosynthetic steps in their formation hamper studies on their physiological relevance. The formation of 3-hydroxyphloretin is one of the gaps in the pathway. Polyphenol oxidases and cytochrome P450 dependent enzymes could be involved. Hydroxylation of phloretin in position 3 has high similarity to the B-ring hydroxylation of flavonoids catalysed by the well-known flavonoid 3′-hydroxylase (F3′H). Using recombinant F3′H and chalcone 3-hydroxylase (CH3H) from Cosmos sulphureus we show that F3′H and CH3H accept phloretin to some extent but higher conversion rates are obtained with CH3H. To test whether CH3H catalyzes the hydroxylation of dihydrochalcones in planta and if this could be of physiological relevance, we created transgenic apple trees harbouring CH3H from C. sulphureus. The three transgenic lines obtained showed lower polyphenol concentrations but no shift between the main polyphenol classes dihydrochalcones, flavonols, hydroxycinnamic acids and flavan 3-ols. Increase of 3-hydroxyphloridzin within the dihydrochalcones and of epicatechin/catechin within soluble flavan 3-ols were observed. Decreased activity of dihydroflavonol 4-reductase and chalcone synthase/chalcone isomerase could partially explain the lower polyphenol concentrations. In comparison to the parent line, the transgenic CH3H-lines showed a lower disease susceptibility to fire blight and apple scab that correlated with the increased 3-hydroxyphlorizin contents.Austrian Sci-ence Fund (FWF

Flow Cytometric DNA c-Value and Ploidy Variation in some Iranian Apple Cultivars

Introduction: Apple (Malus Miller) belongs to Rosacease family and the subfamily of Pomoideae. This fruit is at first place among fruits of temperate zones. The cultivated apple (Malus × domestica Borkh.) is a complex hybrid of the apple species. Chromosomal basis of this subfamily are x = 17 and the ploidy levels have been reported for diploid (2n=2x = 34), triploid (2n =3x= 51) and tetraploid (2n= 4x= 68). Since Iran is close to the apple diversity region (Central Asia), it has a good variation of apple varieties. Despite the high levels of variation in apple cultivars and species in Iran, there is not still a database of genome size. Classification of plants according to their genome size, especially at lower taxonomic levels is important for breeders. Over the past years, several methods for estimation of nuclear DNA content (genome size) was common, but recently, the use of flow cytometry (FCM) has been increasingly used. Flow cytometry is the best method to estimate DNA c-value and ploidy levels in apples. In this study, DNA c-Value and ploidy level of Iranian apple varieties has been estimated by flow cytometry and propidum iodide staining. Materials and Methods: Fully expanded young leaves of all apple varieties were collected in the summer 2013. Nuclear extraction was performed using Partec kit as following: 1 cm2 apple leaf and 1 cm2 parsley leaf (as internal standard) were co-chopped with razor blade after adding 500 µl of nuclear extraction buffer. Then, the extract was filtered by two kind of filters (50 and 30 um). One ml of staining buffer, 4 µl of RNAase and 4 µl ofpropidium iodide was added for 15 min at room temperature. Finally, nuclei were counted using flow cytometry (BD FACSCanto II, USA) at Tarbiat Modarres University. The genome size was estimated according to bellow formula: DNA 2C-value sample = Also, given the high levels of phenolic compounds in apples, treating with PVP and PVP 1% were performed to evaluate the effect of phenolic compounds on estimation of genome size. Finally, Histogram analysis and DNA c-value estimation were done with Partec Flow Max software. The difference between means was obtained by SAS software ver. 9.2 and LSD tests. Results and Discussion: The results showed that genome size obtained from Partec Flow Max software and ranged from 1.57 pg for ‘Golab- Bastam’ to 1.73 pg for ‘Golab- Kermanshah’. Histogram analysis was demonstrated that all studied cultivars are diploid. The average genome size in this study was 1.62 pg. Research conducted on foreign apple varieties have showed that the genome size of diploid species from was obtained 1.45 for M. fusca to1.68 pg for M. ransitoria. The genome size for triploid species was ranged from 2.37 to 2.57 pg. In this study, genome size was calculated in terms of mega base pairs and was different from 748 Mbp in ‘Golab- Bastam’ to 846 Mbp in ‘Golab- Kermanshah’. Thus, the size of the genome was closed to M. ransitoria (1.68 pg). This species is native to China, which is a Crab apple and used as an ornamental tree. It has been reported that Iranian apple are M. domestica Borkh. In another study, genome size was identified in the range from1.245 pg for diploid species of M. tschonoskii to 1.653 pg for M. florentina. M. florentina species is native to Balkans and Italy, that is an ornamental tree and its genome size is close to M. domestica Borkh. (1.653 pg). Conclusion: Classification of plants according to their genome size seems to be important, especially at lower taxonomic. Genome size, even in very close species can also be different, for example, northern corn with more heterochromatin has larger genomes than those who are located in south (less heterochromatin). This study appears the variation of DNA 2C-value in Golab cultivars, even though Golab cultivars are known clones with low genetic diversity. Therefore, it is likely that Iranian apple varieties, with the same ploidy level, have been had difference in genome size. There are various ploidy level in apple, including diploid (2n = 34), triploid (2n = 51), tetraploid (2n = 68) and hexaploid (2n = 102). Thus, it is expected that current apple M. × domestica Borkh., have been contributed some several species such as M. prunifolia (Willd.) Borkh., M. baccata (L.) Borkh., M. sieboldii (Regel) Rehder, M. sylvestris, ،M. orientalis Uglitzk and M. sieversii

Polyphenols vs. Coronaviruses: How Far Has Research Moved Forward?

The epidemic, caused by SARS-CoV-2 at the beginning of 2020, led us to a serious change in our lifestyle that for about three months has confined us to our homes, far from our laboratory routine. In this period, the belief that the work of a researcher should never stop has been the driving force in writing the present paper. It aims at reviewing the recent scientific knowledge about in vitro experimental data that focused on the antiviral role of phenols and polyphenols against different species of coronaviruses (CoVs), pointing up the viral targets potentially involved. In the current literature scenario, the papain-like and the 3-chymotrypsin-like proteases seem to be the most deeply investigated and a number of isolated natural (poly)phenols has been screened for their efficacy

Differential Radiomodulating Action of Olea europaea L. cv. Caiazzana Leaf Extract on Human Normal and Cancer Cells: A Joint Chemical and Radiobiological Approach

The identification of a natural compound with selectively differential radiomodulating activity would arguably represent a valuable asset in the striving quest for widening the therapeutic window in cancer radiotherapy (RT). To this end, we fully characterized the chemical profile of olive tree leaf polyphenols from the Caiazzana cultivar (OLC), autochthonous to the Campania region (Italy), by ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HR-MS). Oleacein was the most abundant molecule in the OLC. Two normal and two cancer cells lines were X-ray-irradiated following 24-h treatment with the same concentration of the obtained crude extract and were assessed for their radioresponse in terms of micronucleus (MN) induction and, for one of the normal cell lines, of premature senescence (PS). Irradiation of pre-treated normal cells in the presence of the OLC reduced the frequency of radiation-induced MN and the onset of PS. Conversely, the genotoxic action of ionising radiation was exacerbated in cancer cells under the same experimental conditions. To our knowledge, this is the first report on the dual action of a polyphenol-rich olive leaf extract on radiation-induced damage. If further confirmed, these findings may be pre-clinically relevant and point to a substance that may potentially counteract cancer radioresistance while reducing RT-associated normal tissue toxicity

Evidence of an additional center of apple domestication in Iran, with contributions from the Caucasian crab apple Malus orientalis Uglitzk. to the cultivated apple gene pool. Running head: Apple domestication in the Caucasus and Iran

International audienceDivergence processes in crop-wild fruit tree complexes in pivotal regions for plant domestication such as the Caucasus and Iran remain little studied. We investigated anthropogenic and natural divergence processes in apples in these regions using 26 microsatellite markers amplified in 550 wild and cultivated samples. We found two genetically distinct cultivated populations in Iran that are differentiated from Malus domestica, the standard cultivated apple worldwide. Coalescentbased inferences showed that these two cultivated populations originated from specific domestication events of Malus orientalis in Iran. We found evidence of substantial wild-crop and crop-crop gene flow in the Caucasus and Iran, as has been described in apple in Europe. In addition, we identified seven genetically differentiated populations of wild apple (M. orientalis), not introgressed by the cultivated apple. Niche modeling combined with genetic diversity estimates indicated that these wild populations likely resulted from range changes during past glaciations. This study identifies Iran as a key region in the domestication of apple and M. orientalis as an additional contributor to the cultivated apple gene pool. Domestication of the apple tree therefore involved multiple origins of domestication in different geographic locations and substantial cropwild hybridization, as found in other fruit trees. This study also highlights the impact of climate change on the natural divergence of a wild fruit tree and provides a starting point for apple conservation and breeding programs in the Caucasus and Iran