Morphological Characterization and Transcriptome Analysis of New Dwarf and Narrow-Leaf (dnl2) Mutant in Maize

Abstract

Lodging is the primary factor limiting high yield under a high plant density. However, an optimal plant height and leaf shape can effectively decrease the lodging risk. Here we studied an ethyl methanesulfonate (EMS)-induced dwarf and a narrow-leaf mutant, dnl2. Gene mapping indicated that the mutant was controlled by a gene located on chromosome nine. Phenotypic and cytological observations revealed that dnl2 showed inhibited cell growth, altered vascular bundle patterning, and disrupted secondary cell wall structure when compared with the wild-type, which could be the direct cause of the dwarf and narrow-leaf phenotype. The phytohormone levels, especially auxin and gibberellin, were significantly decreased in dnl2 compared to the wild-type plants. Transcriptome profiling of the internodes of the dnl2 mutant and wild-type revealed a large number of differentially expressed genes enriched in the cell wall biosynthesis, remodeling, and hormone biosynthesis and signaling pathways. Therefore, we suggest that crosstalk between hormones (the altered vascular bundle and secondary cell wall structure) may contribute to the dwarf and narrow-leaf phenotype by influencing cell growth. These results provide a foundation for DNL2 gene cloning and further elucidation of the molecular mechanism of the regulation of plant height and leaf shape in maize.

Analysis of Photosynthetic Characteristics and Screening High Light-Efficiency Germplasm in Sugarcane

“…Our results indicated significant chlorophyll content and fluorescence variations across years, leaf positions, and interactions. Previous research has shown that environmental factors, leaf traits, and internal structures significantly affect plant photosynthetic activity, thereby emphasizing the importance of season, climate, and canopy structure on photosynthetic efficiency [ 38 , 39 , 40 , 41 ]. The weight for genetic components in sugarcane photosynthetic efficiency varied between 15.055% and 28.498%, indicating that genetic factors primarily control photosynthetic traits in sugarcane [ 42 ].…”

Characterization and genetic dissection of maize ear leaf midrib acquired by 3D digital technology

“…For TipTop and DeviationTip, two traits that were significantly and negatively correlated ( Figure 9 ), Dwf4 is a common candidate gene for both traits. Previous studies showed that Dwf4 encoding putative cytochrome P450 superfamily protein was associated with changes in leaf angle in cereal crop species, such as maize ( Mantilla-Perez and Salas Fernandez, 2017 ; Dzievit et al., 2019 ; Han et al., 2022 ). TipTop indicated whether the leaf tip is the highest point of the leaf midrib curve, and DeviationTip represents the ratio of drooping length to LeafLength, and the drooping length is the length from the highest point to the leaf tip along the leaf midrib, both of them could have an effect on the leaf angle.…”

Characterization of a barley (Hordeum vulgare L.) mutant with multiple stem nodes and spikes and dwarf (msnsd) and fine-mapping of its causal gene

“…The known dwarfing genes Rht-B1b and Rht-D1b in wheat were considered GA-insensitive dwarfing genes due to their reduced response to GA (Peng et al, 1999), whereas the plant height of wheat Rht12 dwarf lines increased by more than 50% in the GA 3 treatment (Chen et al, 2014) and the wheat dwarf mutant DD399 also had significantly longer seedling and coleoptile lengths in the GA treatment than the non-treated control (Wu et al, 2021). Some dwarf mutants in plants, like the dwarf and narrow-leaf mutant dnl2 in maize, are GA biosynthesis-deficient mutants, with significantly lower GA concentrations than the wild-type mutant (Han et al, 2022). Inhibition of UI parenchyma cell extension in barley SS1 was possibly related to insufficient amounts of endogenous bioactive gibberellins (Pu et al, 2021).…”

“…In wheat, peduncle tissues of DD399 comprised shorter cells than the wild-type ND399, which may have reduced its plant height (Wu et al, 2021). Likewise, the length of parenchyma cells significantly decreased in the maize dwarf mutant dnl2 (Han et al, 2022). In barley, the significantly reduced length of the uppermost internode in the mutant Sheathed Spike 1 (SS1) was attributed mainly to suppressed cell elongation (Pu et al, 2021).…”