). Although classical methodologies have been used to overcome such barriers ( Hermsen and Ramanna, 1973 ), the desire to incorporate more than one source of resistance presents increased challenges for the potato breeder. Plant transformation offers an
Joseph C. Kuhl, Kelly Zarka, Joseph Coombs, William W. Kirk, and David S. Douches
Gilles Galopin, Laurent Crespel, Jean C. Mauget, and Philippe Morel
flower bloom. The flowering axis develops over 2 years of growth ( Galopin, 1995 ). Continuous plant growth over the first year ensures the formation of the stem. It is followed by floral transformation that is morphologically identifiable by the
Tao Dong, Fang-cheng Bi, Yong-hong Huang, Wei-di He, Gui-ming Deng, Hui-jun Gao, Ou Sheng, Chun-yu Li, Qiao-song Yang, Gan-jun Yi, and Chun-hua Hu
conventional breeding is severely hampered because of the long life cycle, sterility, and polyploidy of most cultivated varieties ( Khanna et al., 2004 ). The development of genetic transformation in recent decades may be able to overcome these shortcomings and
Grace Q. Chen
made to improve the agronomics of L. fendleri through plant breeding ( Dierig et al., 1993 , 2004 , 2006 ; Isbell et al., 2008 ). Genetic transformation, on the other hand, provides an alternative means to improve this crop. It has been shown that
Yu-Tsung Lin, Chia-Wei Lin, Chien-Hung Chung, Mei-Hsiu Su, Hsiu-Yin Ho, Shi-Dong Yeh, Fuh-Jyh Jan, and Hsin-Mei Ku
et al., 1990 ). In addition, no information on transformation of C. metuliferus is available so far, although ample transformation systems for melon, watermelon, squash, muskmelon, and cucumber have been developed by Agrobacterium tumefaciens
Xiaojuan Zong, Brandon J. Denler, Gharbia H. Danial, Yongjian Chang, and Guo-qing Song
from leaf explants of the ‘Hansen 536’ rootstock has not been reported. Peach and peach rootstocks are among the most recalcitrant plants for genetic transformation, although some efforts using particle bombardment or Agrobacterium -mediated
Luping Qu, James Polashock, and Nicholi Vorsa
Putative transgenic cranberry plants have been achieved via Agrobacterium-mediated transformation. Leaf explants were transformed with a supervirulent Agrobacterium tumefaciens strain EHA 105, harboring the binary vector P35SGUSint and nptII selectable marker genes. Inoculation of precultured explants (≈10 days on regeneration medium) coupled with sonicasion improved transformation efficiency significantly. Adventitious shoots were directly regenerated from explants. Putative transformed shoots were identified by being kanamycin-resistant and GUS-positive. Stable GUS gene expression (turning blue) could be detected within 1 h of incubation at 37 °C. Confirmation of transformation by molecular analysis is in progress. Eight putative transgenic cranberry plants were obtained. All appeared morphologically normal. This appears to be the first success in achieving cranberry transformed plants by Agrobacterium-mediated method. Optimizing the transformation system is ongoing.
Manjul Dutt, Dennis J. Gray, Zhijian T. Li, Sadanand Dhekney, and Marilyn M. Van Aman
A major drawback to the use of embryogenic cultures for transformation of grapevine is that their ability to undergo genetic transformation is cultivar-dependent. Also, depending on cultivar, embryogenic cultures are difficult to impossible to maintain over time, reducing their utility for use in genetic transformation. An alternative to the use of embryogenic cultures for transformation of grapevine is the use of micropropagation cultures, which are easier to initiate from a wide range of grapevine cultivars and can be maintained over time without loss of function. Vitis vinifera `Thompson Seedless' was used as a model for genetic transformation using micropropagation cultures. In vitro cultures were initiated from apical meristems of actively growing vines and maintained in C2D medium containing 4 μM of 6-benzylaminopurine (C2D4B). Shoot tips and nodes were collected from proliferating in vitro cultures for transformation studies. A variety of wounding techniques, including nicking, sonication, and fragmenting of meristematic tissues was employed in order to enable Agrobacterium infection. We used a construct containing a bidirectional 35S promoter complex with a marker gene composed of a bifunctional fusion between an enhanced green fluorescent protein (EGFP) gene and a neomycin phosphotransferase (NPTII) gene in one direction and a hybrid lytic peptide gene in the other. Transgenic shoots growing in C2D4B medium containing 200 mg·L-1 each of carbenicillin and cefotaxime and 20 mg·L-1 of kanamycin were selected based on GFP fluorescence. Transgenic shoots were rooted and transferred to a greenhouse. To date, 18 transgenic lines have been generated. Details on the transformation procedure will be discussed.
Xiuli Shen, Vladimir Orbović, Manjul Dutt, William S. Castle, and Frederick G. Gmitter Jr.
asiaticus , the presumed pathogen that causes Huanglongbing (HLB), the most devastating disease in citrus ( Halbert and Manjunath, 2004 ). Genetic transformation of M. paniculata with genes encoding insecticidal products that are deadly on ingestion by ACP
Keun H. Cho, Joo Young Kim, Maria I. Alvarez, Veronica Y. Laux, Lauren K. Valad, Joshua M. Tester, Thomas A. Colquhoun, and David G. Clark
). DsRed was originally cloned from a reef coral ( Discosoma sp.). Due to the creation of visible precipitates in cells upon transformation, a nonaggregating mutant, DsRed2 , became widely used as a red fluorescent protein ( Katayama et al., 2008 ; Matz