An optimized procedure for plant recovery from somatic embryos significantly facilitates the genetic improvement of Vitis. (11th June 2014)

• Record Type: Journal Article
• Authors: Li, Zhijian T; Kim, Kyung-Hee; Dhekney, Sadanand A; Jasinski, Jonathan R; Creech, Matthew R; Gray, Dennis J
• Is Part Of: Horticulture research. Volume 1(2014)
• Publication Date: 2014-06-11
• Subjects: Agricultural genetics; Horticulture -- Research -- Periodicals; 635.072
• DOI: 10.1038/hortres.2014.27
• Languages: English
• ISSNs: 2052-7276

Abstract

Abstract: Plant regeneration from grapevine ( Vitis spp.) via somatic embryogenesis typically is poor. Recovery of plants from Vitis rotundifolia Michx. (muscadine grape) is particularly problematic due to extremely low efficiency, including extended culture durations required for embryo–plant conversion. Poor plant recovery is an obstacle to the selection of improved genetically modified lines. Somatic embryos (SEs) of V. rotundifolia cultivar Delicious (Del-HS) and Vitis vinifera L cultivar Thompson Seedless (TS) were used to identify culture media and conditions that promoted embryo differentiation and plant conversion; this resulted in a two-step culture system. In comparative culture experiments, C2D medium containing 6% sucrose was the most effective, among four distinct formulae tested, for inducing precocious SE germination and cell differentiation. This medium, further supplemented with 4 µM 6-benzylaminopurine (C2D4B), was subsequently determined to enhance post-germinative growth of SE. MS medium supplemented with 0.5 µM 1-naphthaleneacetic acid (MSN) was then utilized to stimulate root and shoot growth of germinated SE. An average of 35% and 80% 'Del-HS' and 'TS' SE, respectively, developed into plants. All plants developed robust root and shoot systems and exhibited excellent survival following transfer to soil. Over 150 plants of 'Del-HS' were regenerated and established within 2.5 months, which is a dramatic reduction from the 6- to 12-month time period previously required. Similarly, 88 'TS' plant lines were obtained within the same time period. Subsequently, seven out of eight Vitis cultivars exhibited significantly increased plant conversion percentages, demonstrating broad application of the two-step culture system to produce the large numbers of independent plant lines needed for selection of desired traits. Tissue culture: Efficient regeneration of muscadine grapevines: A two-step strategy has dramatically improved the rate at which muscadine grapevinescan be regenerated from single cells by tissue culture. A team led by Dennis Gray from the University of Florida (USA)identified culture media and conditions that allowed them to mass-produce viable Vitis rotundifolia grapevine plants in 2.5 months rather than the 6 to 12 months needed using previous methods. Previous work had established how to coax a differentiated grapevine cell into forming a so-called somatic embryo. The researchers identified optimal conditions to first germinate these somatic embryos and then induce the regenerated shoots to form roots. The efficiency and reliability of the new system to regenerate plants in culture makes targeted genetic improvement a realistic alternative to traditional breeding, which is time-consuming and inprecise in enhancing the commercial potential of muscadine grapes. The system is also applicable to other table and wine grapevines.