Genetic Transformation of Recalcitrant Cassava by Embryo Selection and Increased Hormone Levels.

Genetic engineering is considered to be an important tool for the improvement of cassava. Cassava is a highly heterozygous crop species for which conventional breeding is a lengthy and tedious process. Robust transformation is based on Agrobacterium-mediated transformation of friable embryogenic callus (FEC).

Cassava geminivirus agroclones for virus-induced gene silencing in cassava leaves and roots.

Aim: We report the construction of a Virus-Induced Gene Silencing (VIGS) vector and an agroinoculation protocol for gene silencing in cassava ( Crantz) leaves and roots. The African cassava mosaic virus isolate from Nigeria (ACMV-[NOg]), which was initially cloned in a binary vector for agroinoculation assays, was modified for application as VIGS vector. The functionality of the VIGS vector was validated in and subsequently applied in wild-type and transgenic cassava plants expressing the gene under the control of the CaMV 35S promoter in order to facilitate the visualization of gene silencing in root tissues.