The Agrobacterium-mediated transformation of common wheat (Triticum aestivum L.) and triticale (x Triticosecale Wittmack): role of the binary vector system and selection cassettes

The influence of two binary vector systems, pGreen and pCAMBIA, on the Agrobacterium-mediated transformation ability of wheat and triticale was studied. Both vectors carried selection cassettes with bar or nptII driven by different promoters. Two cultivars of wheat, Kontesa and Torka, and one cultivar of triticale, Wanad, were tested. The transformation rates for the wheat cultivars ranged from 0.00 to 3.58% and from 0.00 to 6.79% for triticale. The best values for wheat were 3.58% for Kontesa and 3.14% for Torka, and these were obtained after transformation with the pGreen vector carrying the nptII selection gene under the control of 35S promoter. In the case of the bar selection system, the best transformation rates were, respectively, 1.46 and 1.79%. Such rates were obtained when the 35S::bar cassette was carried by the pCAMBIA vector; they were significantly lower with the pGreen vector. The triticale cultivar Wanad had its highest transformation rate after transformation with nptII driven by 35S in pCAMBIA. The bar selection system for the same triticale cultivar was better when the gene was driven by nos and the selection cassette was carried by pGreen. The integration of the transgenes was confirmed with at least three pairs of specific starters amplifying the fragments of nptII, bar, or gus. The expression of selection genes, measured by reverse transcriptase polymerase chain reaction (RT-PCR) in relation to the actin gene, was low, ranging from 0.00 to 0.63 for nptII and from 0.00 to 0.33 for bar. The highest relative transcript accumulation was observed for nptII driven by 35S and expressed in Kontesa that had been transformed with pGreen

Induction of androgenesis and production of haploid embryos in anther cultures of borage (Borago officinalis L.)

[EN] Borage (Borago officinalis L.) is an important medicinal plant with different culinary, pharmaceutical and industrial properties. Unfortunately, there are no published reports on the establishment of protocols to produce DHs in this species up to now. In this work, we show for the first time the induction of borage microspores to become embryogenic calli, from which haploid embryos are produced. In addition, we evaluated the effect of using different flower bud sizes, carbon sources, concentrations of 2,4-D and BAP, cold (4 A degrees C) pretreatments and heat shock treatments. Production of total calli, embryogenic calli and callus-derived embryos was differently affected by the different parameters studied. Our results showed that the use of 5-7 mm-long flower buds, a cold (4 A degrees C) pretreatment during 4 days, a 32 A degrees C heat shock for 3 days, and the addition of 3 % maltose and 2 mgl(-1) 2,4-D and 1 mgl(-1) BAP to the culture medium, was beneficial for embryo production. Overall, this work demonstrates that DH technology is possible in borage, and opens the door for future improvements needed to finally obtain borage DH plants.Eshaghi, ZC.; Abdollahi, MR.; Moosavi, SS.; Deljou, A.; Seguí-Simarro, JM. (2015). Induction of androgenesis and production of haploid embryos in anther cultures of borage (Borago officinalis L.). Plant Cell, Tissue and Organ Culture. 122:321-329. doi:10.1007/s11240-015-0768-5S321329122Abdollahi MR, Moieni A, Javaran MJ (2004) Interactive effects of shock and culture density on embryo induction in isolated microspore culture of Brassica napus L. cv. 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Plant Cell Tissue Organ Cult 104:301–309Ferrie AMR, Bethune T, Mykytyshyn M (2011) Microspore embryogenesis in the Apiaceae. Plant Cell Tissue Organ Cult 104:399–406Forster BP, Heberle-Bors E, Kasha KJ, Touraev A (2007) The resurgence of haploids in higher plants. Trends Plant Sci 12:368–375Gamborg OL, Miller RA, Ojiwa K (1968) Nutrient requirements of suspension culture of soybean root callus. Exp Cell Res 50:151–158Guil-Guerrero JL, García-Maroto F, Vilches-Ferrón MA, López-Alonso D (2003) Gamma-linolenic acid from fourteen Boraginaceae species. Ind Crop Prod 18:85–89Horrobin DF (1983) The regulation of prostaglandin biosynthesis by the manipulation of essential fatty acid metabolism. Rev Pure Appl Pharmacol Sci 4:339–383Irikova T, Grozeva S, Rodeva V (2011) Anther culture in pepper (Capsicum annuum L.) in vitro. 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In: Mazza G (ed) Functional foods, biochemical and processing aspects. Technomic Publ Co. Inc, Lancaster, pp 265–291Ozkum D, Tipirdamaz R (2002) The effects of cold treatment and charcoal on the in vitro androgenesis of pepper (Capsicum annuum L.). Turk J Bot 26:131–139Parra-Vega V, González-García B, Seguí-Simarro JM (2013a) Morphological markers to correlate bud and anther development with microsporogenesis and microgametogenesis in pepper (Capsicum annuum L.). Acta Physiol Plant 35:627–633Parra-Vega V, Renau-Morata B, Sifres A, Seguí-Simarro JM (2013b) Stress treatments and in vitro culture conditions influence microspore embryogenesis and growth of callus from anther walls of sweet pepper (Capsicum annuum L.). Plant Cell Tissue Organ Cult 112:353–360Raquin C (1983) Utilization of different sugars as carbon sources for in vitro cultures of Petuina. 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Archon Books, Hamden, CTSkrzypek E, Czyczyło-Mysza I, Marcińska I, Wędzony M (2008) Prospects of androgenetic induction in Lupinus spp. Plant Cell Tissue Organ Cult 94(2):131–137Snape JW (1989) Doubled haploid breeding: theoretical basis and practical applications. In: Mujeeb-Kazi A, Sitch LA (eds) Review of advances in plant biotechnology, 1985–1988: 2nd international symposium genetic manipulation in crops. Mexico and Manila, CIMMYT and IRRI, pp 19–30Tipirdamaz R, Ellialtioğlu Ş (1998) The effects of cold treatments and activated charcoal on ABA contents of anthers and in vitro androgenesis in eggplant (Solanum melongena L.). In: Tsekos I, Moustakas M (eds) Progress in botanical research, Proceedings of the 1st Balkan botanical congress. Kluwer Academic Publishers, The NetherlandsVagera J, Havranek P (1985) In vitro induction of androgenesis in Capsicum annuum L. and its genetic aspests. 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Phytosulfokine stimulates cell divisions in sugar beet (Beta vulgaris L.) mesophyll protoplast cultures

The aim of this work was to improve plating efficiency of sugar beet mesophyll protoplast cultures. Preliminary experiments showed that cultures of good quality, viable protoplasts were obtained in rich media based on the Kao and Michayluk formulation and with the calcium alginate as an embedding matrix. Nevertheless, in these cultures cell divisions were either not observed or very seldom confirming earlier reported recalcitrance of sugar beet protoplasts. The recalcitrant status of these cultures was reversed upon application of exogenous phytosulfokine (PSK)—a peptidyl plant growth factor. The highest effectiveness of PSK was observed at 100 nM concentration. Plating efficiencies obtained in the presence of PSK reached approximately 20% of the total cultured cells. The stimulatory effect of phytosulfokine was observed for all tested breeding stocks of sugar beet. Our data indicate that PSK is a powerful agent able to overcome recalcitrance of plant protoplast cultures

Agrobacterium-mediated transformation systems of Primula vulgaris

Background: Genetic transformation is a valuable tool and an important procedure in plant functional genomics contributing to gene discovery, allowing powerful insights into gene function and genetically controlled characteristics. Primulaceae species provide one of the best-known examples of heteromorphic flower development, a breeding system which has attracted considerable attention, including that of Charles Darwin. Molecular approaches, including plant transformation give the best opportunity to define and understand the role of genes involved in floral heteromorphy in the common primrose, Primula vulgaris, along with other Primula species. Results: Two transformation systems have been developed in P. vulgaris. The first system, Agrobacterium-mediated vacuum infiltration of seedlings, enables the rapid testing of transgenes, transiently in planta. GUS expression was observed in the cotyledons, true leaves, and roots of Primula seedlings. The second system is based on Agrobacterium tumefaciens infection of pedicel explants with an average transformation efficiency of 4.6%. This transformation system, based on regeneration and selection of transformants within in vitro culture, demonstrates stable transgene integration and transmission to the next generation. Conclusion: The two transformation systems reported here will aid fundamental research into important traits in Primula. Although, stable integration of transgenes is the ultimate goal for such analyses, transient gene expression via Agrobacterium-mediated DNA transfer, offers a simple and fast method to analyse transgene functions. The second system describes, for the first time, stable Agrobacterium-mediated transformation of Primula vulgaris, which will be key to characterising the genes responsible for the control of floral heteromorphy

DNA Methylation and Histone Modifications Regulate De Novo Shoot Regeneration in Arabidopsis by Modulating WUSCHEL Expression and Auxin Signaling

Plants have a profound capacity to regenerate organs from differentiated somatic tissues, based on which propagating plants in vitro was made possible. Beside its use in biotechnology, in vitro shoot regeneration is also an important system to study de novo organogenesis. Phytohormones and transcription factor WUSCHEL (WUS) play critical roles in this process but whether and how epigenetic modifications are involved is unknown. Here, we report that epigenetic marks of DNA methylation and histone modifications regulate de novo shoot regeneration of Arabidopsis through modulating WUS expression and auxin signaling. First, functional loss of key epigenetic genes—including METHYLTRANSFERASE1 (MET1) encoding for DNA methyltransferase, KRYPTONITE (KYP) for the histone 3 lysine 9 (H3K9) methyltransferase, JMJ14 for the histone 3 lysine 4 (H3K4) demethylase, and HAC1 for the histone acetyltransferase—resulted in altered WUS expression and developmental rates of regenerated shoots in vitro. Second, we showed that regulatory regions of WUS were developmentally regulated by both DNA methylation and histone modifications through bisulfite sequencing and chromatin immunoprecipitation. Third, DNA methylation in the regulatory regions of WUS was lost in the met1 mutant, thus leading to increased WUS expression and its localization. Fourth, we did a genome-wide transcriptional analysis and found out that some of differentially expressed genes between wild type and met1 were involved in signal transduction of the phytohormone auxin. We verified that the increased expression of AUXIN RESPONSE FACTOR3 (ARF3) in met1 indeed was due to DNA demethylation, suggesting DNA methylation regulates de novo shoot regeneration by modulating auxin signaling. We propose that DNA methylation and histone modifications regulate de novo shoot regeneration by modulating WUS expression and auxin signaling. The study demonstrates that, although molecular components involved in organogenesis are divergently evolved in plants and animals, epigenetic modifications play an evolutionarily convergent role in this process