Attila Hegedus

New self-incompatibility alleles in apricot (Prunus armeniaca L.) revealed by stylar ribonuclease assay and S-PCR analysis

Apricot (Prunus armeniaca L.) shows gametophytic self-incompatibility controlled by a single locus with several allelic variants. An allele for self-compatibility (SC) and seven alleles for self-incompatibility (S1–S7) were described previously. Our experiments were carried out to ascertain whether the number of allelic variants of apricot S-locus was indeed so small. Twenty-seven apricot accessions were analysed for stylar ribonucleases by non-equilibrium pH gradient electrofocusing (NEpHGE) to determine their S-genotype. To validate the results of electrofocusing, the applicability of the S-gene-specific consensus PCR primers designed from sweet cherry sequences was tested. NEpHGE revealed 12 bands associated with distinct S-alleles in newly genotyped cultivars. Cherry consensus primers amplified 11 alleles out from 16 ones, which indicated that these primers could also recognize most of the S-RNase sequences in apricot, and provided an efficient tool to confirm or reject NEpHGE results. By combining the protein and DNA-based methods, complete or partial S-genotyping was achieved for 23 apricot accessions and nine putatively new alleles (provisionally labelled S8–S16) were found. Their identity needs to be confirmed by pollination tests or S-allele sequencing. This study provides evidence that similarly to other Prunus species, the S-locus of apricot is more variable than previously believed.

The Effect of Cd on Chlorophyll and Light-Harvesting Complex II Biosynthesis in Greening Plants

The effect of Cd on chlorophyll (Chl) as well as on light-harvesting complex II (LHCII) accumulation, has been examined during the early stages of development in etiolated Phaseolus vulgaris leaves exposed to intermittent light-dark cycles. We found that at the Cd concentrations studied, both Chl and LHCII accumulation were drastically reduced, although the LDS-solubilized total leaf protein level remained unaffected. However, on the basis of total chlorophyll present, the amount of stabilized LHCII was similar in both Cd-treated and nontreated samples. Additionally, the thylakoid-bound protease known to degrade LHCII, was found to be inhibited by Cd treatment both in vivo and in vitro. Finally, Northern hybridization analysis indicated that Cd affects LHCII accumulation by reducing drastically the steadystate level of Lhcb transcripts

Accumulation of overproduced ferritin in the chloroplast provides protection against photoinhibition induced by low temperature in tobacco plants

Wild-type tobacco plants (Nicotiana tabacum L. cv. Petit Havanna line SR1) and plants transformed with full-length alfalfa ferritin cDNA with the chloroplast transit peptide under the control of a Rubisco small subunit gene promoter (C3 and C8) were cold-treated at 0 degrees C with continuous light (250 micromol m(-2)s(-1)). These transgenic plants had higher chlorophyll content and higher F(v)/F(m) chlorophyll-a fluorescence induction parameters than wild-type plants after 2 or 3d of cold treatment in C3 and C8 transgenic plants, respectively. Thermoluminescence studies on the high-temperature bands suggest that these plants suffered less oxidative damage in comparison to the wild-type genotype. The present experiments provide evidence that transgenic tobacco lines overexpressing alfalfa ferritin, which is accumulated in the chloroplasts, may show higher tolerance to various stress factors, generating ROS including low temperature-induced photoinhibition.

Zirconium induced physiological alterations in wheat seedlings

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 µM Zr-ASC (Zr10, Zr33etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase) showed that Zr-ASC was only harmful at and over a concentration limit of 100 µM. Chlorophyll (Chl) content of plants was only decreased by Zr550. Zr-ASC at lower concentrations was beneficial for plant development: Zr10 and Zr33 enhanced root elongation, Zr55 induced about 30 % increase in the total Chl content, while the activity of antioxidant enzymes was not elevated indicating that no oxidative stress was generated by the intracellularly accumulated Zr4+ ions.

Bioactive content and antioxidant characteristics of wild (Fragaria vesca L.) and cultivated strawberry (Fragaria × ananassa Duch.) fruits from Turkey

In this study, some biochemical (total soluble solid content, pH, acidity and vitamin C) and in vitro antioxidant activity, total phenolic content, total ellagic acid and concentration of anthocyanins of fifteen wild strawberry genotypes ( Fragaria vesca L.) and one commercial strawberry cultivar Camarosa ( Fragaria × ananassa Duch.) sampled in Northeastern Turkey were determined. Antioxidant activity of fruit samples was determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (Ferric reducing antioxidant power) assays. Notable differences were found both among wild strawberries and also between wild strawberries and cv. Camarosa. Among the strawberry accessions tested, the total phenolics ranged from 138 mg to 228 mg gallic acid equivalent per 100 g fresh fruit. The total monomeric anthocyanin content was the highest in wild genotype FV-2 (53.51 mg/100 g) while the lowest in FV-6 as 25.11 mg per 100 g fresh weight basis. The total ellagic acid content was between 15.18 and 26.36 mg per 100 g. All wild strawberries had higher antioxidant activity than cv. Camarosa. Thus, it can be concluded that wild strawberry is a good source of polyphenols, ellagic acid and antioxidants.

Identification of self-(in)compatibility S-alleles and new cross-incompatibility groups in Tunisian apricot (Prunus armeniaca L.) cultivars

Summary Local Tunisian apricot (Prunus armeniaca L.) cultivars are characterised by having abundant flowering and floral self-incompatibility. In this study, PCR amplification provided definitive data on the S-genotypes of eight local and four new Tunisian apricot cultivars. These results were confirmed by field evaluations. Eight local cultivars (‘Oud Rhayem’, ‘Oud Hmida’, ‘Bouthani Ben Friha’, ‘Bedri Ahmar’, ‘Oueld El Oud’, ‘Hamidi’, ‘Bouk Ahmed’, and ‘Adedi Ahmar’) were found to be self-incompatible and three of four INRAT cultivars (‘Sayeb’, ‘Asli’, and ‘Raki’) were self-compatible, as described previously. The INRAT cultivar ‘Ouardi’ was self-incompatible, although it was previously described as a self-compatible cultivar.We also propose three new cross-incompatibility (CIG) groups: CIG XV (S7S8), CIG XVI (S7S11), and CIG XVII (S8S12) which include Tunisian and other cultivars.

Self-(in)compatibility and fruit set in 19 local Moroccan apricot (Prunus armeniaca L.) genotypes

Summary Self-compatibility and fruit set were assessed in 19 local apricot (Prunus armeniaca L.) genotypes identified in four different oasis ecosystems in southern Morocco. Observations on pollen tube growth, as well as examinations of the fruit-set percentages obtained after self-pollination in the field, established the compatibility of their pollen. Fourteen genotypes from different geographical origins were self-compatible, with fruit set percentages ranging from 14.8 – 42.2%, whereas five were self-incompatible, with no fruit set. Consequently, almost all the local apricot genotypes propagated by seed in oasis ecosystems in southern Morocco proved to be self-compatible. In addition, the fruit-set percentages after open-pollination showed high variability among genotypes from the same oasis, among locations, and in the 2 years of study, with medium-to-high fruit set percentages for all genotypes, ranging from 11.9 – 30.1%. Self-compatibility has therefore been identified for the first time, not only in Moroccan apricot genotypes, but also in the North African Prunus gene pool.

EFFECT OF ZIRCONIUM TREATMENT ON WHEAT SEEDLINGS DEVELOPMENT, AMINO ACID COMPOSITION, AND BORON CONTENT

The effects of zirconium ascorbate (Zr-ASC) were examined on wheat seedlings (Triticum aestivum L. cv. ‘MV. 20’). Plants grown hydroponically for nine days were exposed to solutions having various concentrations of Zr-ASC. The investigated plants were able to take up the Zr-ASC complex, accumulation and translocation of the metal has also been observed. Translocation mechanisms seem to be working efficiently to a certain concentration limit where from the translocation between root and shoot is limited. An interesting phenomenon was noticed in the case of boron, namely that the concentration change tendencies of boron and Zr were similar. A significant change was observed in the case of amino acid content, the total amino acid content increase was pronounced both in roots and shoots.