The insect-protected CTC91087-6 sugarcane event expresses Cry1Ac protein preferentially in leaves and presents compositional equivalence to conventional sugarcane

Abstract

A Cry1Ac-expressing sugarcane cultivar, CTC91087-6, has been developed by Centro de Tecnologia Canavieira (CTC) to be resistant to the sugarcane borer (Diatraea saccharalis). This genetically modified event was developed using Agrobacterium-mediated transformation and the help of the selectable marker phosphinothricin N-acetyltransferase (PAT) expressed from bar gene. We describe here a detailed characterization of CTC91087-6 event with respect to protein expression, nutritional composition, and assessment of its derived DNA and proteins in raw sugar. Expression of the Cry1Ac and PAT (bar) proteins produced by CTC91087-6 was evaluated in different tissues and at different times during the growing season. The new proteins are preferentially expressed in leaves, are produced at low levels in stalks, and are near the limits of detection in root tissues. The levels of Cry1Ac were much higher than PAT in all evaluated tissues. Furthermore, Cry1Ac levels in CTC91087-6 leaves are stable at various times during sugarcane cultivation cycle, assuring borer control throughout the complete crop cycle.

Sugar derived from genetically modified sugarcane

“…DNA and protein were not detected in the clarified juice and downstream processed fractions of CTC20BT, including ethanol and raw sugar, indicating that protein and DNA are removed and/or degraded during the processing of this GM variety (Cheavegatti-Gianotto et al, 2018). Similarly, and not surprisingly, neither DNA nor protein was detected at significant levels in sugar produced from the CTC9001BT variety (Cheavegatti-Gianotto et al, 2019).…”

Improvementofsugarcane for borer resistance usingAgrobacteriummediated transformation ofcry1Acgene

“…29 Recently, Bt soybean varieties expressing the cry1Ac gene has been approved for commercial use in Latin America 30 and Bt sugarcane CTC175 has been approved for commercial use in Brazil. 31 The use of synthetic insecticides was significantly reduced by using commercialization Bt crops. 32 A lot numbers of cry genes have been tested and described against main insect pests.…”

Assessment of Gene Flow to Wild Relatives and Nutritional Composition of Sugarcane in Brazil

“…In the specific case of sugarcane, the OECD recommends that a new cultivar be analyzed in relation to its contents of main components (humidity, raw protein, lipids, ash, fibers, and sucrose) [Organization for Economic Co-operation and Development (OECD), 2011]. There is local literature on the topic (Azevêdo et al, 2003;Santos et al, 2006;Anjos et al, 2007), but most of the studies are about the use of sugarcane as silage and, more recently, about the release of transgenic cultivars (Gianotto et al, 2019). Nowadays there is no base-line information on nutritional composition of Brazilian sugarcane cultivars, as is required and recommended by the OECD.…”

“…The sugarcane culm can be fractioned into water-insoluble substances-fibers (10-16%)-, and sugarcane juice. On average, 80% of the sugarcane juice consists of water (moisture), and 20% of sugars (e.g., sucrose), lipids, protein, and minerals (Lavanholi, 2010;Kim and Day, 2011;Gianotto et al, 2019).…”

“…(C) Boxplot considering the phenotypic variation of the 20 varieties across all production environments (from left to right: CTC04, CTC09, CTC15, CTC17, CTC20, CTC21, CV7231, CV7870, IACSP955000, IACSP955094, RB835054, RB855156, RB855453, RB867515, RB92579, RB965902, RB965917, RB966928, SP813250, and SP832847). minimal risks to human and animal health (Gianotto et al, 2019).…”