The propagation of cultivated garlic relies on vegetative cloves, thus flowers become non-essential for reproduction in this species, driving the evolution of reproductive feature-derived traits. To obtain insights into the evolutionary alteration of reproductive traits in the clonally propagated garlic, the evolutionary histories of two main reproduction-related traits, bolting and flower differentiation, were explored by genome analyses using 134 accessions displaying wide diversity in these two traits. Resequencing identified 272.8 million variations in the garlic genome, 198.0 million of which represent novel variants. Population analysis identified five garlic groups that have evolved into two clades. Gene expression, single-cell transcriptome sequencing, and genome-wide trait association analyses have identified numerous candidates that correlate with reproductive transition and flower development, some of which display distinct selection signatures. Selective forces acting on the B-box zinc finger protein-encoding Asa2G00291.1, the global transcription factor group E protein-encoding Asa5G01527.1, and VERNALIZATION INSENSITIVE 3-like Asa3G03399.1 appear to be representative of the evolution of garlic bolting. Plenty of novel genomic variations and trait-related candidates represent valuable resources for biological studies of garlic. Numerous selective signatures from genes associated with the two chosen reproductive traits provide important insights into the evolutionary history of reproduction in this clonally propagated crop.

The KNOX transcription factor plays crucial roles in regulating fiber growth in plants. Although the genome of ramie, an important fiber crop in China, is available, knotted related homeobox (KNOX) genes have not been systematically explored in this crop. In this study, seven members of the KNOX gene from the ramie genome were identified and assigned to two groups, Class I and II. The intron–exon structure, conserved domain architecture, cis-regulating elements, and expression pattern showed distinct differences among the seven KNOX regulators. One of the genes, Bnt07G011994, encodes an ortholog of Arabidopsis fiber-growth-related KNAT7, and is differentially expressed among barks undergoing different stages of fiber growth. The overexpression of Bnt07G011994 dramatically decreases the fiber number in transgenic Arabidopsis, indicating a negative role played by this gene in modulating fiber growth. Further transcriptome analysis of transgenic Arabidopsis revealed that the overexpression of Bnt07G011994 resulted in an expression change in 14 pectin biosynthesis-/metabolism-related genes. These findings provide a useful foundation for further investigating the function of KNOX genes in ramie, and provide an important insight into the involvement of the ramie KNOX gene in fiber growth.

NAM, ATAF, and CUC (NAC) proteins are plant-specific transcription factors that play crucial roles in fiber growth by regulating the secondary wall thickening. In this study, a systematical investigation of NAC genes was performed in the genome of ramie, an important fiber crop, resulting in a total of 60 ramie NAC genes identified. Phylogenetic analysis of these 60 NAC members in conjunction with 111 Arabidopsis NAC proteins identified 11 subfamilies, three of which showed considerable contraction in the ramie genome. Ten ramie NAC genes were identified to encode the orthologs of Arabidopsis NAC regulators involved in the control of secondary wall biosynthesis. Of these ten genes, most showed relatively high expression in the stems, and eight displayed a differential expression between the barks from the top and middle section of the stems where fiber growth is under different stages. Furthermore, the overexpression of three of these ten NAC genes significantly promoted fiber growth in transgenic Arabidopsis. These results indicated that these ten NAC genes were associated with the fiber growth of ramie. This study provided an important basis for researching the regulatory mechanism of fiber growth.

Quantitative real-time PCR (qRT-PCR) is a widely used technique for quantifying gene expression. However, accurate data normalization requires stable reference genes that exhibit constant expression levels across different experimental conditions. To date, no suitable reference genes have been validated for atemoya fruits (Annona cherimola Mill × A. squamosa L.). This study aimed to evaluate the expression stability of candidate reference genes in atemoya across distinct tissues, postharvest storage stages, and various treatment conditions. To this end, we designed specific primers for six reference genes: ubiquitin carrier-like protein (UBC), actin 7 (ACT7), actin 11 (ACT11), elongation factor 1α (EF1α), 18S ribosomal RNA (18S), and β-tubulin (TUB). Total RNA was extracted from atemoya tissues (e.g., petals, young fruits, and roots), for pulp across three post-harvest time points (0, 2, and 4 days) and under different conditions: 28 °C, 15 °C, ethylene, or 1-MCP treatment. The geNorm tool was subsequently used to identify the most stable reference transcripts under each experimental condition. ACT7 was the most stable reference gene across atemoya tissues, while UBC ranked first under all postharvest conditions tested (28 °C storage, 15 °C cold storage, ethylene, and 1-MCP). Furthermore, the suitability of these reference genes under ethylene and 1-MCP treatments was validated by examining the expression patterns of AaPG and AaERF. Collectively, the combined use of ACT7, UBC, and 18S proved to be the most reliable normalization strategy across all experimental conditions. This validated multi-gene approach provides a robust foundation for future investigations into gene expression and the postharvest ripening mechanisms of atemoya.