KEY MESSAGE : Agrobacterium tumefaciens strains differ not only in their ability to transform tomato Micro-Tom, but also in the number of transgene copies that the strains integrate in the genome. The transformation efficiency of tomato (Solanum lycopersicum L.) cv. Micro-Tom with Agrobacterium tumefaciens strains AGL1, EHA105, GV3101, and MP90, harboring the plasmid pBI121 was compared. The presence of the nptII and/or uidA transgenes in regenerated T(0) plants was determined by PCR, Southern blotting, and/or GUS histochemical analyses. In addition, a rapid and reliable duplex, qPCR TaqMan assay was standardized to estimate transgene copy number. The highest transformation rate (65 %) was obtained with the Agrobacterium strain GV3101, followed by EHA105 (40 %), AGL1 (35 %), and MP90 (15 %). The mortality rate of cotyledons due to Agrobacterium overgrowth was the lowest with the strain GV3101. The Agrobacterium strain EHA105 was more efficient than GV3101 in the transfer of single T-DNA insertions of nptII and uidA transgenes into the tomato genome. Even though Agrobacterium strain MP90 had the lowest transformation rate of 15 %, the qPCR analysis showed that the strain MP90 was the most efficient in the transfer of single transgene insertions, and none of the transgenic plants produced with this strain had more than two insertion events in their genome. The combination of higher transformation efficiency and fewer transgene insertions in plants transformed using EHA105 makes this Agrobacterium strain optimal for functional genomics and biotechnological applications in tomato.
• Premise of the study: Leaf morphogenesis, including that of compound leaves, provides the basis for the great diversity of leaf form among higher plants. Leaf form is an important character by which plants adapt to their environment. The common garden pea provides a developmental model system for understanding leaf development in the legumes and a contrasting one for other groups of plants.
• Methods: We used genetic, tissue culture, and physiological methods, as well as DR5::GUS expression and qRT‐PCR, to explore the interactions between the hormones gibberellic acid (GA) and auxin and Unifoliata (UNI) gene expression that control leaf morphogenesis in pea.
• Key results: Rate of increase in leaf complexity during shoot ontogeny (i.e., heteroblasty) and adult leaf complexity are controlled by GA through UNI. Leaves on greenhouse‐grown uni‐tac mutants are rescued by weekly GA or auxin applications. Auxin responsiveness is reduced in uni‐tac shoot and root tips and in wild‐type shoot tips treated with auxin transport inhibitors. GA and auxin increase UNI mRNA levels in uni‐tac as well as that of other transcription factors.
• Conclusions: GA and auxin positively promote leaf dissection during leaf morphogenesis in pea by prolonging the time during which acropetally initiated pinna pairs are produced. GA‐generated elaboration of leaf morphogenesis is in distinct contrast to that in other species, such as tomato and Cardamine. Instead, GA and auxin play common and supportive roles in pea leaf morphogenesis as they do in many other aspects of plant development.
Auxin concentration and response differences characterize the antagonistic relationship between AF and UNI in pea leaf development. The mechanism involves modulation of auxin mediated by one or both genes; UNI is expressed in and promotes high auxin levels, and AF suppresses auxin levels.
The CRISPA gene of pea suppresses KNOX1 genes and UNI and functions to (1) maintain proximal-distal regions in their appropriate positions, (2) restrict excessive adaxial cell proliferation, and (3) promote laminar expansion.
Agrobacterium-mediated transformation is the most common method for the incorporation of foreign genes into the genome of potato as well as many other species in the Solanaceae family. This chapter describes protocols for the genetic transformation of three species of potato: Solanum tuberosum subsp. tuberosum (Desiréé), S. tuberosum subsp. andigenum (Blue potato), and S. tuberosum subsp. andigena using internodal segments as explants.
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