N. Matsuda et al., PARTIAL MALE-STERILITY IN TRANSGENIC TOBACCO CARRYING ANTISENSE AND SENSE PAL CDNA UNDER THE CONTROL OF A TAPETUM-SPECIFIC PROMOTER, Plant and Cell Physiology, 37(2), 1996, pp. 215-222
Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) catalyzes the first step
in the synthesis of phenylpropanoids. An antisense or sense PAL cDNA
of sweet potato under the control of a tapetum-specific promoter of ri
ce was introduced into tobacco. A reduction in pollen fertility was ob
served in two out of seventeen antisense PAL transformants and in six
out of nineteen sense PAL transformants. The pollen fertility of these
plants ranged from 8% to 60%. The distorted pollen grains that did no
t germinate lacked starch and flavonols. PAL activity in anthers at th
e microspore stage was also reduced to some extent and the level of PA
L activity was positively correlated with the number of fertile pollen
grains at the flowering stage. Although it was unclear how the antise
nse or sense transgene affected the PAL activity in anthers, our resul
ts clearly demonstrate that the PAL activity in the anther tapetum has
a significant effect on the development of microspores.