Plant non-specific lipid transfer proteins (nsLTPs) are encoded by a multigene family and support physiological functions,
which remain unclear. We adapted an efficient ligation-mediated polymerase chain reaction (LM-PCR) procedure that enabled
isolation of 22 novel
Triticum
aestivum
nsLtp (
TaLtp) genes encoding types 1 and 2 nsLTPs. A phylogenetic tree clustered the wheat nsLTPs into ten subfamilies comprising 1–7
members. We also studied the activity of four type 1 and two type 2
TaLtp gene promoters in transgenic rice using the β-Glucuronidase reporter gene. The activities of the six promoters displayed
both overlapping and distinct features in rice. In vegetative organs, these promoters were active in leaves and root vascular
tissues while no β-Glucuronidase (GUS) activity was detected in stems. In flowers, the GUS activity driven by the
TaLtp7.2a,
TaLtp9.1a,
TaLtp9.2d, and
TaLtp9.3e gene promoters was associated with vascular tissues in glumes and in the extremities of anther filaments whereas only the
TaLtp9.4a gene promoter was active in anther epidermal cells. In developing grains, GUS activity and GUS immunolocalization data evidenced
complex patterns of activity of the
TaLtp7.1a,
TaLtp9.2d, and
TaLtp9.4a gene promoters in embryo scutellum and in the grain epicarp cell layer. In contrast, GUS activity driven by
TaLtp7.2a,
TaLtp9.1a, and
TaLtp9.3e promoters was restricted to the vascular bundle of the embryo scutellum. This diversity of
TaLtp gene promoter activity supports the hypothesis that the encoded TaLTPs possess distinct functions in planta.
Keywords Gene regulation - Non-specific lipid transfer protein genes - Promoter analysis - Transgenic rice -
UidA reporter gene - Wheat