Abstract
BackgroundSugarcane (Saccharum spp. hybrids) is considered the most globally important sugar-producing crop and raw material for biofuel. Insect attack is a major issue in sugarcane cultivation, resulting in yield losses and sucrose content reductions. Stem borer (Diatraea saccharalis F.) causes serious yield losses in sugarcane worldwide. However, insect-resistant germplasms for sugarcane are not available in any collections all over the world, and the molecular mechanism of insect resistance has not been elucidated. In this study, cry1Ac transgenic sugarcane lines were obtained and the biological characteristics and transgene dosage effect were investigated and a global exploration of gene expression by transcriptome analysis was performed.ResultsThe transgene copies of foreign cry1Ac were variable and random. The correlation between the cry1Ac protein and cry1Ac gene copies differed between the transgenic lines from FN15 and ROC22. The medium copy lines from FN15 showed a significant linear relationship, while ROC22 showed no definite dosage effect. The transgenic lines with medium copies of cry1Ac showed an elite phenotype. Transcriptome analysis by RNA sequencing indicated that up/down regulated differentially expressed genes were abundant among the cry1Ac sugarcane lines and the receptor variety. Foreign cry1Ac gene and endogenous borer stress-related genes may have a synergistic effect. Three lines, namely, A1, A5, and A6, were selected for their excellent stem borer resistance and phenotypic traits and are expected to be used directly as cultivars or crossing parents for sugarcane borer resistance breeding.ConclusionsCry1Ac gene integration dramatically improved sugarcane insect resistance. The elite transgenic offspring contained medium transgene copies. Foreign cry1Ac gene integration and endogenous borer stress-related genes may have a synergistic effect on sugarcane insect resistance improvement.
Highlights
Sugarcane (Saccharum spp. hybrids) is considered the most globally important sugar-producing crop and raw material for biofuel
Transgene copies via particle bombardment are variable and random To estimate the copy number of the foreign cry1Ac gene, a quantitative TaqMan real-time PCR method was established. This method was based on double-standard curves of cry1Ac and CYC/adenosine-5- phosphosulfate reductase (APRT)/P4H gene, which were integrated into the multi-target recombined plasmid pG1AcAPC0229 (p1AAPC)
Variance analysis indicated that there was no significant difference between the cycle threshold (Ct) value of all of the transgenic and control lines
Summary
Sugarcane (Saccharum spp. hybrids) is considered the most globally important sugar-producing crop and raw material for biofuel. Stem borer (Diatraea saccharalis F.) causes serious yield losses in sugarcane worldwide. Insect-resistant germplasms for sugarcane are not available in any collections all over the world, and the molecular mechanism of insect resistance has not been elucidated. Sugarcane (Saccharum spp. hybrids) is considered the most important crop for sugar production globally and is a valued raw material for the biofuel industry [1, 2]. One significant sugarcane pest is stem borer (Diatraea saccharalis F., Lepidoptera, Crambridae), which affects sugarcane throughout the entire growing season and causes serious yield losses of nearly 25–30% [3, 4]. Insect-resistant sugarcane germplasms are not available in any collections [3]. Genetic engineering is expected to play an important role in improving the insect resistance of sugarcane [6,7,8] and could facilitate the development of insect-resistant sugarcane varieties or germplasms for use in cross-breeding
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
