[Description and evaluation of transformation approaches used in wheat]

Genetic transformation is a valuable tool for direct crop improvement and functional genomics study. Unfortunately, wheat is considered as a recalcitrant plant to genetic transformation due to its low efficiency and genotype dependency. To overcome these problems, various transformation methods such as biolistic bombardment, Agrobacterium tumefaciens, pollen-tube pathway, ion implantation, laser microbeams puncture, treatment with polyethylene glycol and ultrasonic wave, and electroporation have been reported in wheat using various types of explants including immature embryos, mature embryos, anthers derived calluses, inflorescences, apical meristems, and other floral organs. In this review, several major transformation approaches and their applications in wheat are reviewed, and potential strategies for the development of safe transgenic wheat plants are discussed. The objective of this review is to provide an update on current status of wheat trans-formation, and to stimulate further research for improving transformation efficiency in wheat.