TREATMENT OF GRAPE BERRIES, A NONCLIMACTERIC FRUIT WITH A SYNTHETIC AUXIN, RETARDS RIPENING AND ALTERS THE EXPRESSION OF DEVELOPMENTALLY-REGULATED GENES
C. Davies et al., TREATMENT OF GRAPE BERRIES, A NONCLIMACTERIC FRUIT WITH A SYNTHETIC AUXIN, RETARDS RIPENING AND ALTERS THE EXPRESSION OF DEVELOPMENTALLY-REGULATED GENES, Plant physiology, 115(3), 1997, pp. 1155-1161
Treatment of grape (Vitis vinifera L.) berries with the synthetic auxi
n-like compound benzothiazole-2-oxyacetic acid (BTOA) caused a delay i
n the onset of ripening of approximately 2 weeks. This was manifested
as a retardation of the increases in berry weight, color, deformabilit
y, and hexose concentration. BTOA treatment also delayed by 2 weeks th
e increase in abscisic acid level that normally accompanies ripening a
nd altered the expression of a number of developmentally regulated gen
es. A putative vacuolar invertase, which is normally expressed from be
rry set until ripening and turned off after ripening commences, remain
ed expressed throughout development in BTOA-treated grape berries. Thi
s elevated expression resulted in increased levels of invertase activi
ty. In contrast, the up-regulation of four other genes normally switch
ed on at the time of ripening was delayed in BTOA-treated fruit. These
included chalcone synthase and UDP-glucose-flavonoid 3-O-glucosyl tra
nsferase, both of which are involved in anthocyanin synthesis, a chiti
nase, and a ripening-related gene of an unknown function. These observ
ations support the view that auxins (perhaps in conjunction with absci
sic acid) may have a role in the control of grape berry ripening by af
fecting the expression of genes involved in the ripening process.