Simultaneous inhibition of two tomato fruit cell wall hydrolases, pectinmethylesterase and polygalacturonase, with antisense gene constructs.

The cloning and sequencing of two cDNAs representing pectinmethylesterase (PME) RNAs from tomato fruit is reported. The clones were used to construct chimeric antisense PME genes designed for high-level constitutive expression in plants. A full-length antisense PME gene construct, in conjunction with a chimeric antisense polygalacturonase gene, was introduced into tomato plants via Agrobacterium-mediated transformation. Simultaneous and significant reduction in the mRNA and protein levels of these normally highly abundant cell wall hydrolases of the pectin degradation pathway were observed in ripe fruit of transformants. Thus, antisense gene constructs in plants can be used to block multiple steps in metabolic pathways simultaneously.