A novel approach for rapid micropropagation of maspine pineapple (Ananas comosus L.) shoots using liquid shake culture system

Maspine (Ananas comosus L.) is currently the most preferred pineapple variety in Malaysia due to its pleasant aroma and applicability in caning. Large quantities of plant materials are needed to fulfill the market demand which could not be obtained from the conventional breeding method. Hence, in vitro procedure was developed as an alternative method to improve the multiplication rate of this special variety. Sterilized explants were cultured on solidified Murashige and Skoog (MS) medium supplemented with various combinations of 6-benzylaminopurine (BAP) (1 to 5 mg/l) and ∝-naphthaleneacetic acid (NAA) (1 to 5 mg/l) hormones. Pineapple plant cultures required 5 mg/l BAP to significantly increase the shoot development during the in vitro stage. In addition, explants were subsequently sub-cultured on medium with 1 mg/l BAP which produced highest number of proliferated in vitro plantlets. The optimization of the conditions for shoot propagation was carried out in both liquid and solid medium by supplementing with 1 or 5 mg/l of BAP. MS liquid medium supplemented with 1 mg/l BAP produced the highest number of shoots (31) after 4 weeks. The number of shoots formed was increased to 204 after third sub-culture in liquid medium. Shoot proliferation was increased up to nine-fold in liquid medium when compared to the cultures maintained on solid medium. This improved method of Maspine in vitro multiplication will serve as an alternative source of planting materials of this cultivar for subsistence and large-scale pineapple farmers.Key words: Pineapple, in vitro, 6-benzylaminopurine, ∝-naphthaleneacetic acid, liquid medium

Potential of microneedle-assisted micro-particle delivery by gene guns: a review

This article was published in the journal Drug Delivery [© Informa Healthcare USA, Inc]. The definitive version is available at: http://dx.doi.org/10.3109/10717544.2013.864345Abstact Context: Gene guns have been used to deliver deoxyribonucleic acid (DNA) loaded micro-particle and breach the muscle tissue to target cells of interest to achieve gene transfection. Objective: This article aims to discuss the potential of microneedle (MN) assisted micro-particle delivery from gene guns, with a view to reducing tissue damage. Methods: Using a range of sources, the main gene guns for micro-particle delivery are reviewed along with the primary features of their technology, e.g. their design configurations, the material selection of the micro-particle, the driving gas type and pressure. Depending on the gene gun system, the achieved penetration depths in the skin are discussed as a function of the gas pressure, the type of the gene gun system and particle size, velocity and density. The concept of MN-assisted micro-particles delivery which consists of three stages (namely, acceleration, separation and decoration stage) is discussed. In this method, solid MNs are inserted into the skin to penetrate the epidermis/dermis layer and create holes for particle injection. Several designs of MN array are discussed and the insertion mechanism is explored, as it determines the feasibility of the MN-based system for particle transfer. Results: This review suggests that one of the problems of gene guns is that they need high operating pressures, which may result in direct or indirect tissue/cells damage. MNs seem to be a promising method which if combined with the gene guns may reduce the operating pressures for these devices and reduce tissue/cell damages. Conclusions: There is sufficient potential for MN-assisted particle develivery systems

Biolistic DNA delivery and its applications in Sorghum bicolor

Biolistic DNA delivery has been considered a universal tool for genetic manipulation to transfer exotic genes to cells or tissues due to its simplicity, versatility, and high efficiency. It has been a preferred method for investigating plant gene function in most monocot crops. The first transgenic sorghum plants were successfully regenerated through biolistic DNA delivery in 1993, with a relatively low transformation efficiency of 0.3%. Since then, tremendous progress has been made in recent years where the highest transformation efficiency was reported at 46.6%. Overall, the successful biolistic DNA delivery system is credited to three fundamental cornerstones: robust tissue culture system, effective gene expression in sorghum, and optimal parameters of DNA delivery. In this chapter, the history, application, and current development of biolistic DNA delivery in sorghum are reviewed, and the prospect of sorghum genetic engineering is discussed