Transcriptome profiling reveals abnormal cell wall components in the cleistogamy mutant 1 (clm1) lodicule of foxtail millet.

The molecular mechanism of cleistogamy in foxtail millet was analyzed. We found that changes of cell wall components caused the abnormal development of the lodicule. Outcrossing between cultivated crops and their associated wild species may result in the loss of favorable agricultural traits in the progeny or the drift of genetically modified (GM) organisms in future generations. In this study, we found a cleistogamy mutant with an abnormal development of the lodicules. The lodicules were sampled when the florets just to bloom for RNA-seq analysis. Our results showed that, compared with the wild type, the mutant had more enriched pathways related to cell wall synthesis or decomposition. Staining of the lodicule cell wall showed that the mutant had relatively lower amounts of callose and cellulose than the wild type. The content of pectin methylation in the lodicule cell wall of the mutant was lower than that of the wild type. In summary, we analyzed the causes of cleistogamy phenotype in foxtail millet. Transcriptome data analysis revealed that this was probably caused by dysplasia of the lodicule cell wall. Cytochemical staining and immunofluorescence tests showed that the changes of the components in the cell wall caused the abnormal development of the lodicule. Overall, this study sheds light on the potential molecular mechanism of cleistogamy of foxtail millet and provides a theoretical basis for subsequent research.