Overexpression of the Panax ginseng CYP703 Alters Cutin Composition of Reproductive Tissues in Arabidopsis

The Dark Side of the pollen: BSA-seq identified genomic regions linked to male sterility in globe artichoke

Globe artichoke (Cynara cardunculus var. scolymus; 2n = 2x = 34) is a food crop consumed for its immature flower heads. Traditionally, globe artichoke varietal types are vegetatively propagated. However, seed propagation makes it possible to treat the crop as annual, increasing field uniformity and reducing farmers costs, as well as pathogens diffusion. Despite globe artichoke's significant agricultural value and the critical role of heterosis in the development of superior varieties, the production of hybrids remains challenging without a reliable system for large-scale industrial seed production. Male sterility (MS) presents a promising avenue for overcoming these challenges by simplifying the hybridization process and enabling cost-effective seed production. However, within the Cynara genus, genic male sterility has been linked to three recessive loci in globe artichoke, with no definitive genetic mechanism elucidated to date. A 250 offsprings F2 population, derived from a cross between a MS globe artichoke and a male fertile (MF) cultivated cardoon (C. cardunculus var. altilis) and fitting a monogenic segregation model (3:1), was analyzed through BSA-seq, aiming at the identification of genomic regions/genes affecting male sterility. Four QTL regions were identified on chromosomes 4, 12, and 14. By analyzing the sequence around the highest pick on chromosome 14, a cytochrome P450 (CYP703A2) was identified, carrying a deleterious substitution (R/Q) fixed in the male sterile parent. A single dCAPS marker was developed around this SNP, allowing the discrimination between MS and MF genotypes within the population, suitable for applications in plant breeding programs. A 3D model of the protein was generated by homology modeling, revealing that the mutated amino acid is part of a highly conserved motif crucial for protein folding.

Morphological and anatomical changes during dormancy break of the seeds of Fritillaria taipaiensis

Fritillaria taipaiensis P. Y. Li is the most suitable species planted at low altitudes among other species used as Tendrilleaf Fritillary Bulb, whose seeds embracing the morphological and physiological dormancy need to experience a long-dormant time from sowing to germination. In this study, the developmental changes of F. taipaiensis seeds during dormancy period were observed by morphological and anatomical observation, and the cause of long-term dormancy of seeds was discussed from the perspective of embryonic development. The process of embryonic organogenesis was revealed during the dormancy stage by the paraffin section. The effects of testa, endosperm and temperature on dormant seeds were discussed. Furthermore, we found that the mainly dormant reason was caused by the morphological dormancy, which accounted for 86% of seed development time. The differentiation time of the globular or pear-shaped embryo into a short-rod embryo was longer, which was one of the chief reasons for the morphological dormancy and played an important role in embryonic formation. Testa and endosperm with mechanical constraint and inhibitors involved in the dormancy of F. taipaiensis seeds. The seeds of F. taipaiensis, the average ambient temperature of 6-12°C for morphological dormancy and 11-22°C for physiological dormancy, were unsuitable for seed growth. Therefore, we suggested that the dormancy time of F. taipaiensis seeds could be shortened by shortening the development time of the proembryo stage and stratification for the different stages of dormancy.