A carotenogenic mini-pathway introduced into white corn does not affect development or agronomic performance

Abstract

High-carotenoid corn (Carolight®) has been developed as a vehicle to deliver pro-vitamin A in the diet and thus address vitamin A deficiency in at-risk populations in developing countries. Like any other novel crop, the performance of Carolight® must be tested in different environments to ensure that optimal yields and productivity are maintained, particularly in this case to ensure that the engineered metabolic pathway does not attract a yield penalty. Here we compared the performance of Carolight® with its near isogenic white corn inbred parental line under greenhouse and field conditions, and monitored the stability of the introduced trait. We found that Carolight® was indistinguishable from its near isogenic line in terms of agronomic performance, particularly grain yield and its main components. We also established experimentally that the functionality of the introduced trait was indistinguishable when plants were grown in a controlled environment or in the field. Such thorough characterization under different agronomic conditions is rarely performed even for first-generation traits such as herbicide tolerance and pest resistance, and certainly not for complex second-generation traits such as the metabolic remodeling in the Carolight® variety. Our results therefore indicate that Carolight® can now be incorporated into breeding lines to generate hybrids with locally adapted varieties for further product development and assessment.

Breeding for provitamin A biofortification of maize (Zea mays L.)

“…Total carotenoid contents were comparable under greenhouse and field studies showed the mean ~106 ± 7 μg/g which was significantly higher than 86 ± 0.65 μg/g as reported in another study on T 1 generation of Carolight ® line (Farre′ et al., ; Zanga et al., ). Carotenoid profile of Carolight ® line was also comparable under greenhouse and field conditions, particularly at physiological maturity whereas slight differences were observed during earlier growth stages (Zanga et al., ). Zanga et al.…”

“…Carotenoid profile of Carolight â line was also comparable under greenhouse and field conditions, particularly at physiological maturity whereas slight differences were observed during earlier growth stages (Zanga et al, 2016). Zanga et al (2016) also reported that high temperature and high light intensity negatively affect b-carotene contents in Carolight â line. Real-time RT-PCR-based transcript profiling of the introduced genes showed that ZMPSY1 mRNA was significantly higher than PACRTI mRNA in maize endosperm.…”

“…Zanga et al. () also reported that high temperature and high light intensity negatively affect β‐carotene contents in Carolight ® line. Real‐time RT‐PCR‐based transcript profiling of the introduced genes showed that ZMPSY1 mRNA was significantly higher than PACRTI mRNA in maize endosperm.…”

“…High‐carotenoid corn (Carolight ® ) was developed by introducing the PSY1 gene from corn and CRT1 gene from Pantoea annatis in the genetic background of M37W, a white endosperm variety (Zanga, Capell, Slafer, Christou & Savin, ). Total carotenoid contents were comparable under greenhouse and field studies showed the mean ~106 ± 7 μg/g which was significantly higher than 86 ± 0.65 μg/g as reported in another study on T 1 generation of Carolight ® line (Farre′ et al., ; Zanga et al., ). Carotenoid profile of Carolight ® line was also comparable under greenhouse and field conditions, particularly at physiological maturity whereas slight differences were observed during earlier growth stages (Zanga et al., ).…”

Transgenic Pro-Vitamin A Biofortified Crops for Improving Vitamin A Deficiency and Their Challenges

“…In 2014, the European Commission granted consent for experimental release of the transgenic maize (Carolight TM ) in Spain to measure its agronomic and other characteristics [56]. Recently, reported Carolight TM was indistinguishable from its near isogenic line for agronomic performance including yield [57]. Rice has made similar ( [58].…”