Effects of Bacillus thuringiensis (Bt) gene on potassium efficiency of cotton (Gossypium hirsutum L.)

Abstract Potassium (K) deficiency became a common field production problem following the widespread adoption of Bacillus thuringiensis (Bt) transgenic cotton (Gossypium hirsutum L.) worldwide. The purpose of this study was to clarify whether the introduction of Bt gene directly reduces the K-use efficiency of cotton to cause K deficiency. The cotton variety, Jihe 321 (wild type, WT) and its two Bt (Cry1Ac)-transgenic lines (OE-29317, OE-29312) were studied in growth chamber and field with low soil-test K+ (47.8 mg kg− 1). When silencing of Bt gene (~ 70%) in OE-29317 and OE-29312 plants by virus-induced gene silencing (VIGS), VIGS-Bt plants did not produce more biomass than VIGS-Ctrl plants. In the field with low soil-test K+, OE-29317 but not OE-29312 had less biomass and K+ accumulation than those of WT at some growth stages. Moreover, both Bt lines produced similar or even greater seed cotton yield than WT in the field. Taken together, the introduction of Bt gene did not necessarily hinder the K use efficiency of the cotton lines under study.