Root cultures of potato mutant lacking MSPI isoform, indispensable for photosynthetic light reactions, exhibit characteristics similar to intact plant roots

Abstract

Potato (Solanum tuberosum) mutant (ST) lacking one isoform of manganese-stabilizing protein (MSPI) of photosystem II exhibited besides spontaneous tuberization also growth changes with strongly impaired root system development. Previous studies revealed marked changes in carbohydrate levels and allocation within ST plant body. To verify causal relationship between changed carbohydrate balance and root growth restriction we engaged dark grown sucrose-supplied root organ-cultures of ST plants to exclude/confirm shoot effects. Unexpectedly, in ST root cultures we observed large alterations in growth and architecture as well as saccharide status similar to those found in the intact plant roots. The gene expression analysis, however, proved PsbO1 transcript (coding MSPI protein) neither in ST nor in WT root-organ cultures. Therefore, the results point to indirect effects of PsbO1 allele absence connected possibly with some epigenetic modulations.