Effects of brassinosteroid on cotton regeneration via somatic embryogenesis

Brassinolide (BR), which is the most biologically active brassinosteroid, was used to examine the potential effect of hormone on cotton somatic embryogenesis. Ten-day-old cotton (Gossypium hirsutum L, cv. Cooker) seedlings were used for explant source and hypocotyls were removed and cultured on MS basal medium with 135 vitamins supplemented with 1 mg/L 6-benzylaminopurine + 0.5 mg/L kinetin for callus induction. After one month proliferating calli pieces were collected and cultured on MS basal medium containing various concentrations of BR (0.1, 0.5, 1.0 AM) with their controls. BR treatments were negatively effective on the fresh weight of calli when compared to control. Differential somatic embryogenesis maturation rates due to BR treatment were observed. Somatic embryogenesis was stimulated especially for transition to cotyledonary phase at 0.5 mg/L BR. Histological preparations from embryogenic calli and somatic embryos at different stages of development revealed the spontaneous polyploidisation during early somatic embryogenesis on BR-treated calli. Present results suggest that BR negatively effected calli growth, however, had a stimulating role in maturation of somatic embryos

Yr10 gene polymorphism in bread wheat varieties

Yellow rust resistance locus Yr10 located on chromosome 1B in Moro and originated from the Turkish line PI178383 was investigated in terms of polymorphism in seven winter type bread wheat cvs.(Triticum aestivum ssp. Aestivum) Altay2000, zgi2001, Sönmez2001 (yellow rust resistant), Aytýn98, ES14, Harmankaya99 (yellow rust susceptible) and PI178383 as control. Exon 1 (1 - 833 bp) and Exon 2 (1989 - 3630 bp) parts of Yr10 were amplified with three primers. Amplification was not observed with E2A primers in Harmankaya99, zgi2001 and Sönmez2001 cvs, while amplification products were observable at all tested varieties with the other primers. PCR results showed that E2A reverse primer is not able to anneal to the three varieties mentioned above. Sequence analysis and bioinformaticsanalysis proved that there has been single nucleotide changes especially in the second exon. The most similar sequences to the first exon of Harmankaya99, zgi01 and Sönmez2001 are AF509535 (Aegilops tauschii NBS-LRR-like gene), AF509534 (A. tauschii NBS-LRR-like gene sequence) and AF509534, respectively. These results could be helpful in revealing divergence between resistant and susceptible varieties

Transformation of Potato (Solanum Tuberosum L.) using Tuber Discs and Stem Explants

Transformation of three potato cultivars (Desiree, Isola and Anac) was achieved using tuber discs and callus tissue derived from cultured stems via co-cultivation with Agrobacterium tumafaciens Ti plasmid based vectors. Neomycin phosphotransferase (NPT II) marker and beta-glucuronidase (GUS) reporter genes were used in transfer-optimization studies. First selection of transgenics was done on selective Murashige and Skoog (MS) media containing 100 mg/l kanamycin and 500 mg/l cefotaxime. Histochemical assays were done for GUS activity using X-Gluc substrat. In addition polymerase chain reaction based Southern blot analyses revealed the existence of the transferred genes. The highest transformation frequency (10%) was obtained with cultivar Desiree in MS media supplied with 5 mg/l zeatin riboside and 1.5 mg/l indolacetic acid However; Anac gave the lowest frequency using tuber discs (3% and stem explants (2%). This protocol could be useful for the improvement of potato through gene manipulation