Metabolic engineering of cassava to improve carotenoids.

Cassava is a staple food used in many countries around the world, despite deficiencies in micronutrients such as provitamin A carotenoids. Unfortunately, improvement of the cassava nutritional content by use of conventional breeding is slow and difficult. Therefore, there is an urgent need to develop and standardize protocols using biotechnological tools to improve cassava. The Alliance of Biodiversity International and the International Center for Tropical Agriculture (CIAT) have worked on cassava genetic transformation over the last 30 years. Here, we describe, step by step, the procedures used for genetic transformation of cassava variety TMS60444, to improve carotenoids and other traits. This protocol includes stock setup, reagents, media preparation, materials, and equipment, for the genetic transformation of embryogenic tissues. The main expected output in publishing this protocol is to provide the basis for a reproducible and reliable method to genetically modify and/or gene edit Latin American and Asian cassava varieties.