Fungal contaminants observed during micropropagation of Lilium candidum L. and the effect of chemotherapeutic substances applied after sterilization

Lilium candidum L. is a species which grows in the South West Anatolia region of Turkey. It is a bulbous plant with beautifully scented flowers and is used in the floral industry. The bulbs are produced by using traditional propagation and in vitro techniques. Micropropagation is a rapid propagation technique, but the greatest problem is contamination with fungi and bacteria. Antibiotic and fungicide treatments were done after sterilization for micropropagation of L. candidum. Fungal contaminants formed during the culture were determined. Bulb scales were used as explants (5 - 10 mm width) and were cultured in photoperiodic conditions (16 h light, 8 h dark) or complete darkness. Bulb scales rinsed in water were surface sterilized, then solutions containing chemotherapeutic substances (Benomyl, Nystatin, Streptomycin, Penicillin) in different combinations were applied for 30 min and subsequently were cultured in MS medium with supplement 0.1 mg dm-3 NAA + 0.01 mg dm-3 BA. During the experiment, fungal contaminants were observed in full treatments. Determined contaminants were identified according to their morphological and cultural characteristics by cultivation and were comprised of: Fusarium, Penicillium, Alternaria, Rhizopus, Cylindrocarpon and Aspergillus species. The most effective treatment against fungal contaminations was achieved by utilizing a Benomyl (100 mg dm-3) + Nystatin (100 mg dm-3) treatment combination

Differential expression analysis of boron transporters and some stress-related genes in response to 24-epibrassinolide and boron by semi-quantitative RT-PCR in Arabidopsis thaliana (L.) Heynh

Plant steroidal hormones, brassinosteroids (BRs), promote plant developmental processes and enhance tolerance to several abiotic stresses including high boron (B) stress. To examine the possible role of BR in high B-induced stress at the transcriptional level, we investigated the response of B transporter genes (BOR1-4), high B-induced genes (MATE, Hsp-like), BR-induced genes (Hsp70-4, Hsp90-1) and other stress-related genes (LTI/COR78, LEA4-5) upon exogenous treatments of 24-epibrassinolide (EBL) on Arabidopsis thaliana (L.) Heynh exposed to high concentrations of boric acid (BA) using semi-quantitative RT-PCR. BA treatments led to down regulation of BOR1 and BOR3 genes in leaf and root tissues and higher concentration of EBL further decreased expression of these genes in roots. The expression of high B-induced genes was observed to be upregulated by 1 μM EBL treatment under high B stress in both tissues of the seedlings. The upregulation of BR-induced genes were clearly evident in root tissues co-treated with 1 μM EBL and BA as compared to BA alone. Higher concentration of EBL was found to be more effective in increasing expression of LTI/COR78 gene in root and LEA4-5 gene in shoot tissues. To our knowledge, this is the first report how exogenous application of EBL modulates high B stress responses at molecular level in model plant Arabidopsis thaliana