Transformation of rapid cycling cabbage (Brassica oleracea var. capitata) with Agrobacterium rhizogenes

Hairy CRISPR: Genome Editing in Plants Using Hairy Root Transformation

CRISPR/Cas-mediated genome editing is a powerful tool of plant functional genomics. Hairy root transformation is a rapid and convenient approach for obtaining transgenic roots. When combined, these techniques represent a fast and effective means of studying gene function. In this review, we outline the current state of the art reached by the combination of these approaches over seven years. Additionally, we discuss the origins of different Agrobacterium rhizogenes strains that are widely used for hairy root transformation; the components of CRISPR/Cas vectors, such as the promoters that drive Cas or gRNA expression, the types of Cas nuclease, and selectable and screenable markers; and the application of CRISPR/Cas genome editing in hairy roots. The modification of the already known vector pKSE401 with the addition of the rice translational enhancer OsMac3 and the gene encoding the fluorescent protein DsRed1 is also described.

Tissue culture and genetic transformation of cabbage (Brassica oleracea var. capitata): an overview

MAIN CONCLUSION

The main goal of this publication is an overview of the biotechnological achievements concerning in vitro cultures and transformation of Brassica oleracea var. capitata. Faced with the requirements of the global food market, intensified work on the genetic transformation of economically important plants is carried out in laboratories around the world. The development of efficient procedures for their regeneration and transformation could be a good solution for obtaining, in a shorter time than by traditional methods, plants with desirable traits. Furthermore, conventional breeding methods are insufficient for crop genetic improvement not only because of being time-consuming but also because they are severely limited by sexual incompatibility barriers. This problem has been overcome by genetic engineering, which seems to be a very good technique for cabbage improvement. Despite the huge progress that has been made in the field of plant regeneration and transformation methods, up to now, no routine transformation procedure has been developed in the case of cabbage. This problem stems from the fact that the efficiency of cabbage transformation is closely related to the genotype and some varieties are recalcitrant to transformation. It is obvious that it is not possible to establish one universal regeneration and transformation protocol for all varieties of cabbage. Therefore, it seems fully justified to develop the above-mentioned procedures for individual economically important cultivars. Despite the obstacles of cabbage transformation in laboratories of many countries, especially those where this vegetable is extremely popular (e.g., China, India, Korea, Malaysia, Pakistan), such attempts are made. This article reviews the achievements in the field of tissue culture and cabbage transformation from the last two decades.

Improvement of tissue culture, genetic transformation, and applications of biotechnology to Brassica

Development of in vitro plant regeneration method from Brassica explants via organogenesis and somatic embryogenesis is influenced by many factors such as culture environment, culture medium composition, explant sources, and genotypes which are reviewed in this study. An efficient in vitro regeneration system to allow genetic transformation of Brassica is a crucial tool for improving its economical value. Methods to optimize transformation protocols for the efficient introduction of desirable traits, and a comparative analysis of these methods are also reviewed. Hence, binary vectors, selectable marker genes, minimum inhibitory concentration of selection agents, reporter marker genes, preculture media, Agrobacterium concentration and regeneration ability of putative transformants for improvement of Agrobacterium-mediated transformation of Brassica are discussed.

Regeneration of transgenic vegetable brassicas (Brassica oleracea andB. campestris) via Ri-mediated transformation

A procedure for the production of fertile transgenic brassicas via Ri-mediated transformation is reported in this paper. Transgenic hairy root lines were selected for 12 vegetable brassica cultivars and lines representing six varieties: broccoli, Brussels sprouts, cabbage, cauliflower, rapid-cycling (allBrassica oleracea) and Chinese cabbage (B. campestris). Leaf explants or petioles of intact cotyledons were co-cultivated withAgrobacterium strain A4T harbouring various binary vectors. The T-DNA region of all binary vectors contained a neomycin phosphotransferase II gene for kanamycin resistance, in addition to other genes. Hairy root lines grew prolifically on hormone-free medium containing kanamycin. Transgenic shoots were regenerated from all cultivars either spontaneously or after transfer of hairy roots to a hormone-containing medium. Southern analysis confirmed that the plants were transgenic. Plants from all brassica types were successfully transferred to greenhouse conditions. Plants were fertile and segregation analysis confirmed transmission of traits to progeny.

Agrobacterium tumefaciens-mediated transformation of broccoli (Brassica oleracea var. italica) and cabbage (B. oleracea var. capitata)

Transgenic broccoli (Brassica oleracea var. italica) was produced by two Agrobacterium tumefaciens-mediated transformation methods. One used flowering stalk explants from mature plants; the other used hypocotyl and petiole explants from in vitro-grown seedlings. Several hundred transformants containing a Bacillus thuringiensis ∂-endotoxin gene (CryIA(c)-type) and the neomycin phosphotransferase gene were recovered. Rooted transformants were obtained in as little as 3 months using seedling explants. Transgenic cabbage was also obtained by the seedling explant method. Parameters important for high efficiency regeneration and transformation rates included use of a tobacco nurse cell layer, sealing of petri dishes with a porous surgical tape instead of Parafilm, preculture of seedling explants and appropriate length of co-cultivation with Agrobacterium. Advantages and disadvantages of each transformation procedure are discussed.

TL -DNA transformation decreases ABA level

The endogenous levels of ABA were measured in Agrobacterium rhizogenes A₄ T_l -DNA transformed oilseed rape (Brassica napus L. var. oleifera cv. Brutor and cv. Drakkar), cabbage (Brassica oleracea). A₄ transformed tobacco (Nicotiana tabacum cv. Xanthi) and their normal counterparts, using high performance liquid chromatography and enzyme-liked immunosorbent assay. Measurements were made on different plant tissues (i. e. floral stem, terminal bud, young leaf, mature leaf, root and root tips) and ABA levels were compared in unstressed and osmotically stressed oilseed rape plants (cv. Brutor). In unstressed Plants. in each of the 5 independent transformation events studied, a significant reduction (about 65% of control) in ABA concentration was observed in all transformed plants. When subjected to an osmotic stress, T_L transformed Brutor plants showed a higher ABA accumulation than untransformed plants. The change in ABA content as a consequence of T_L -DNA transformation is discussed with regard to phenotype, drought resistance and adaptability.