Nitrogen deficit decreases seed Cry1Ac endotoxin expression in Bt transgenic cotton

Bt insecticidal efficacy variation and agronomic regulation in Bt cotton

“…High N fertilizer rates enhanced the leaf Bt protein content by 14% compared with light nitrogen rates. Nitrogen metabolic physiology had close relationships with Bt protein concentration in Bt cotton (Chen et al 2005;Chen et al 2013;Chen et al 2019). Nitrogen metabolic strength influenced the Bt protein concentration of cotton organs (Chen et al 2004;Chen et al 2017aChen et al , 2017b, and nitrogen deficit reduced the content of Bt protein in Bt cotton (Chen et al 2018;Chen et al 2019).…”

“…Nitrogen metabolic physiology had close relationships with Bt protein concentration in Bt cotton (Chen et al 2005;Chen et al 2013;Chen et al 2019). Nitrogen metabolic strength influenced the Bt protein concentration of cotton organs (Chen et al 2004;Chen et al 2017aChen et al , 2017b, and nitrogen deficit reduced the content of Bt protein in Bt cotton (Chen et al 2018;Chen et al 2019). The concentration of Bt protein in plant tissues was significantly correlated with the content of total soluble protein and total nitrogen (Oosterhuis and Brown 2004;Dong et al 2007;Wang et al 2012;Chen et al 2018).…”

“…In addition, variation of Bt protein expression was also observed between leaves of different ages, for a seven to nine leafstage plant, the fully expanded leaves on main stem exhibited much higher Bt protein content than older basal leaves, while the young leaves on the top part had the lowest level (Chen et al 2000). The variation of Bt toxin concentration in growth period (temporal) and different parts/organs (spatial) might enhance the pests surviving probability, which has been paid the close attention by cotton farmers and related researchers (Gutierrez et al 2006;Chen et al 2018;Chen et al 2019).…”

“…Wherever an environmental stress happened, the plants response was induced and changed their metabolic level, which might be able to keep the critical toxin level (Mahon et al 2002). Moreover, under some circumstances, the Bt protein content was markedly decreased (Chen et al 2012a;Chen et al 2019), but the Bt protein level did not drop below the threshold level, which was still high enough to against pests. Kranthi et al (2005) thought the threshold value as 1.9 ng•g − 1 , and toxin level would fall below the critical level only after 110 days after planting.…”

“…There are some reports on the improvement of Cry1Ac protein expression in Bt cotton through agronomic practices like high doses of N fertilizer (Pettigrew and Adamczyk 2006). Chen et al (2019) reported that the fertilizer application rates influenced the Bt toxin expression, and the efficacy of Bt cotton reduced markedly if nitrogen rates were low during cotton growth. The recovery was further proved that nitrogen fertilizer enhanced Bt protein expression and insect resistance (Oosterhuis and Brown 2004;Wang et al 2012;Chen et al 2018).…”