Genotypic variation in the response to embryogenic callus induction and regeneration inSaccharum spontaneum

Abstract

Embryogenic callus induction and regeneration are useful in many aspects of plant biotechnology, especially in the functional characterization of economically important genes. However, in sugarcane, callus induction and regeneration vary across genotypes. Saccharum spontaneum is an important wild germplasm that confers disease resistance and stress tolerance to modern sugarcane cultivars, and its genome has been completely sequenced. The aim of this study was to investigate the effect of genetic variations on embryogenic callus induction and regeneration in S. spontaneum and to screen genotypes having high tissue culture susceptibility. The study was performed using nine genotypes of S. spontaneum and the following five parameters were assessed to determine the response of genotypes to embryogenic callus induction and regeneration: callus induction, embryogenic callus ratio, embryogenic callus induction, embryonic callus regeneration and regeneration capacity. All the genotypes varied significantly (P < 0.01) in all the parameters, except for embryonic callus regeneration, which was high (>80%) for all the genotypes. High broad-sense heritability (86.1–96.8%) indicated that genetic differences are the major source of genotypic variations. Callus induction was found to be strongly positively correlated with embryogenic callus induction (r = 0.890, P < 0.01) and regeneration capacity (r = 0.881, P < 0.01). Among the nine tested genotypes, VN2 was found to be the most responsive to tissue culture and could therefore be used to characterize functional genes in S. spontaneum. We also suggested an approach with potential applications in facilitating the rapid identification of sugarcane genotypes susceptible to tissue culture.

CRISPR technology towards genome editing of the perennial and semi-perennial crops citrus, coffee and sugarcane

“…Considering the biological nature of these systems, as Agrobacterium -mediated transformation, they rely on compatible biological interactions with the explant. In wheat, the Barley stripe mosaic virus -based sgRNA delivery vector (BSMV-sg) is effective in performing heritable genome editing ( Li et al., 2021 ; Wang et al., 2022 ), thus raising potential applications in other monocot plants. The recombinant Sugarcane mosaic virus (SCMV) ( Beernink et al., 2021 ) and the Foxtail mosaic virus (FoMV) ( Mei et al., 2019 ) may also be other viable VIGE alternatives for testing in Saccharum spp.…”

“…plants. Nevertheless, these viral vector-based approaches do not support the efficient delivery of large Cas effectors (more than 1000 amino acids), such as Cas9 ( Baltes et al., 2014 ; Uranga et al., 2021 ), thus relying on Cas9-overexpressing plants ( Li et al., 2021 ). However, small Cas effectors have been unveiled as efficient tools for VIGE in plants, highlighting the miniature Cas12f ( Wu et al., 2021 ) and the hypercompact Cas12j2 ( Liu et al., 2022 ) as promising candidates.…”