(273) Engineering Female Sterility for Horticultural Crops

Abstract

<jats:p>Female sterility is desirable in horticultural crops for many reasons, including decreasing invasiveness and weediness, reducing nuisance fruit production, promoting vegetative growth, and increasing flower longevity and number. This study tested a method of creating female sterility through genetic transformation of plants with a gene that ablates tissue necessary for female fertility and reproduction. A gene construct was created containing barnase, a cytotoxic RNAse, expressed with a transmitting tract specific promoter from the tobacco gene <jats:italic>sP41</jats:italic>. The <jats:italic>sP41</jats:italic>gene encodes a (1,3)-β-glucanase in the transmitting tract of the pistil of mature tobacco flowers. The construct also expressed barstar, a barnase inhibitor, driven by the CaMV 35S promoter to protect other plant tissues from unexpected barnase expression. Seed set data taken after controlled pollinations showed tobacco plants transformed with this construct had greatly reduced fertility in young flowers and female sterility in mature flowers relative to nontransformed controls. Light microscopy showed ablation of the transmitting tract tissue in transformed plants. The expression of barnase with a transmitting tract specific promoter is an effective way to reduce or eliminate female fertility. Due to the conservation of (1,3)-β-glucanase activity in the styles of other plant species, this construct has potential for producing female-sterile cultivars of other horticultural crops.</jats:p>