Induced cassava mutations link more starch with less lignin

Researchers used two chemical and physical mutagens to generate cassava plants with markedly different compositions in their storage roots. In the cultivar SC205, atmospheric and room temperature plasma and ethyl methanesulfonate produced 184 regenerated lines, from which 16 vigorous mutants with stable storage-root formation were selected for further analysis. Across two consecutive planting years, starch accumulation was consistently negatively correlated with lignin content, revealing a compositional trade-off that also yielded a promising line called A18.

Cassava is a tropical crop whose storage roots accumulate large quantities of starch. Lignin, meanwhile, can reduce processing quality when it is deposited excessively in those roots. The study addressed whether induced genetic variation could create useful diversity in both traits. A18 accumulated more starch and contained less lignin than the wild-type SC205 plant, whereas the opposite combination was observed in another mutant, E27. The contrast between these lines provided the basis for investigating the biological processes associated with altered storage-root composition.

The researchers combined metabolomic profiling with quantitative PCR, or qPCR, to examine storage roots from A18, E27 and wild-type plants. A18 showed enhanced starch and sucrose metabolism together with increased expression of genes associated with starch biosynthesis. E27 instead showed activation of phenylpropanoid metabolism and elevated expression of genes linked to lignin biosynthesis. These measurements indicate that the two mutants differ not only in their final starch and lignin levels but also in the metabolic and transcriptional pathways associated with those traits.

The findings suggest that induced mutation can generate substantial variation in cassava storage-root composition while retaining a recurring inverse relationship between starch accumulation and lignification. That relationship was maintained in both planting years examined, although it does not establish that increased starch must always cause reduced lignin, nor does it identify the complete genetic mechanism behind the association. The work was conducted in one cultivar and relied on regenerated mutant lines, with compositional variation identified among 16 selected plants. The reported results therefore establish A18 as a genetic resource rather than demonstrate that the mutant will improve industrial performance, yield or crop performance under field conditions.

A18 nevertheless offers a useful experimental system for dissecting how starch accumulation and lignin biosynthesis are coordinated in cassava storage roots. By pairing compositional measurements with metabolomic and gene-expression data, the study presents A18 as a high-starch, low-lignin phenotype and E27 as a contrasting example with the reverse pattern. The research expands the pool of cassava germplasm available for studying induced genetic variation and may support future breeding aimed at improving starch content and processing characteristics, but any wider application would require evaluation beyond the cultivar and experimental setting reported here.

Subject of Research: In vitro mutagenesis identifies cassava mutants with high starch and low lignin

Article Title: Identification of cassava mutants with high-starch and low-lignin through in vitro mutagenesis

Article References: Liu, K., Xu, J., Cai, Z., Zhu, P., Li, Y., & Fan, X. (2026). Identification of cassava mutants with high-starch and low-lignin through in vitro mutagenesis. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09852-5

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09852-5

Keywords: cassava, ARTP, EMS, plant mutagenesis, starch accumulation, lignin biosynthesis, storage roots, metabolomics, gene expression, crop breeding, Identification, mutants