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The development of floral organs, crucial for the establishment of floral symmetry and morphology in higher plants, is regulated by MADS-box genes. In sunflower, the capitulum is comprised of ray and disc florets with various floral organs. In the sunflower long petal mutant ( lpm ), the abnormal disc (ray-like) floret possesses prolongated petals and degenerated stamens, resulting in a transformation from zygomorphic to actinomorphic symmetry. In this study, we investigated the effect of MADS-box genes on floral organs, particularly on petals, using WT and lpm plants as materials. Based on our RNA-seq data, 29 MADS-box candidate genes were identified, and their roles on floral organ development, especially in petals, were explored, by analyzing the expression levels in various tissues in WT and lpm plants through RNA-sequencing and qPCR. The results suggested that HaMADS3 , HaMADS7 , and HaMADS8 could regulate petal development in sunflower. High levels of HaMADS3 that relieved the inhibition of cell proliferation, together with low levels of HaMADS7 and HaMADS8 , promoted petal prolongation and maintained the morphology of ray florets. In contrast, low levels of HaMADS3 and high levels of HaMADS7 and HaMADS8 repressed petal extension and maintained the morphology of disc florets. Their coordination may contribute to the differentiation of disc and ray florets in sunflower and maintain the balance between attracting pollinators and producing offspring. Meanwhile, Pearson correlation analysis between petal length and expression levels of MADS-box genes further indicated their involvement in petal prolongation. Additionally, the analysis of cis -acting elements indicated that these three MADS-box genes may regulate petal development and floral symmetry establishment by regulating the expression activity of HaCYC2c . Our findings can provide some new understanding of the molecular regulatory network of petal development and floral morphology formation, as well as the differentiation of disc and ray florets in sunflower., Competing Interests: The authors declare that they have no competing interests., (© 2024 Wang et al.)

Members of the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family play diverse roles in plant growth and development, including the guidance of inflorescence architecture and pedicel length. In this work, we identified and characterized the EFPL gene TaEPFL1 from the wheat pistillody mutant HTS-1. Sequence alignment and phylogenetic analysis indicated that TaEPFL1 belongs to the EPFL1 gene. Quantitative real-time RT-PCR analysis showed that the TaEPFL1 gene is expressed at an abnormally high level in pistillody stamens compared with that in pistils and stamens. Heterologous expression of the TaEPFL1 gene in Arabidopsis caused shortened filaments and pedicels and might reduce the level of AtACO2 gene expression. These results suggest that TaEPFL1 plays an important role in the development of stamen and that overexpression of TaEPFL1 results in abnormal stamens. We deduced that the overexpression of the TaEPFL1 gene may contribute to the homeotic transformation of stamens into pistils or pistil-like structures in wheat. These data offer insights into the molecular mechanism of pistillody mutation in wheat.

Transcription factors (TFs) regulate plant gene expression in different tissues. To investigate TF genes in rice ( L.), a genome-wide TF identification was conducted with the japonica rice genome. This study identified 3078 putative TFs in 59 families. The TF number of the top 10 TF families accounted for 58% of the 3078 rice TFs. The three largest TF families were the myeloblastosis (MYB) superfamily, basic helix-loop-helix (bHLH), and far-red-impaired response (FAR1), which contained 413, 228, and 210 TF members, respectively. The expression profiles of the 3078 TF genes were surveyed with the RNA sequencing (RNA-seq) data of 13 rice tissue types. Based on these expression profiles, we validated 1087 TFs expressed in 13 rice tissue types, which accounted for 35.32% of the 3078 putative TFs. We further analyzed the tissue-specific TFs in rice. In total, 28, 14, 14, 10, 9, 5, 5, 4, 3, 3, 2, 11, and 1 tissue-specific TF sequences were identified in the dry seed, pistil, spikelet, aleurone, anther, ovules, embryo 25 d after pollination (DAP), seed 5 DAP, root, leaf, seed 10 DAP, shoot, and endosperm 25 DAP, respectively. Moreover, we constructed RicetissueTFDB (), a comprehensive and public rice TF database that integrates tissue expression characters, genomic location, and Gene Ontology (GO) terms for each TF. The RicetissueTFDB database will facilitate the identification of target TFs and the functional studies about rice TFs., (Copyright © 2019 Crop Science Society of America.)

The common wheat line three-pistil (TP) is a valuable mutant for wheat breeding. The TP mutation has normal spike morphology; however, it only produces three pistils per floret. Therefore, it has potential to increase the grain number per spike. In order to determine the underlying molecular mechanism, an annealing control primer system was used to identify the different expressed genes in three-pistil mutation. Using 120 arbitrary ACP primers, we identified three differentially expressed genes in young spikes between two near-isogenic lines (i.e., Chuanmai 28 TP and Chinese Spring TP) and their recurrent parents. We tentatively designated the three differentially expressed genes as DETP-1, DETP-2, and DETP-3. DETP-1 showed similar function with maize cytoplasmic membrane protein, which is involved in cell division in bacteria. DETP-3 is homologous to maize endo-1, 4-beta-glucanase (EGases), which is associated with plant development, cell wall loosening, stem flowering, and root expansion. DETP-2 showed no significant hit with any sequence found in the database and translates unknown protein. These genes would likely play an important role in determining the three pistils trait in wheat., (Copyright © 2011 Elsevier B.V. All rights reserved.)