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Tissue culture is preferred for solving the shortcomings of low efficiency of conventional propagation in tree peony (Paeonia sect. Moutan), an economically important woody plant in China with various uses. Paeonia ostii ‘Feng Dan’ is one of the varieties with strong adaptability and high oil productivity. However, in vitro regeneration via organogenesis is hard to obtain. For instance, the indirect organogenesis from callus is a lengthy process, and the direct organogenesis is lacked. This study presents a protocol of direct organogenesis using cotyledon explant for in vitro regeneration of P. ostii ‘Feng Dan’, and includes two pathways. The explants need pretreated in the optimal dedifferentiation induction medium (DIM) [Murashige and Skoog (MS) medium with 2.27 µM thidiazuron (TDZ) + 5.37 µM α-naphthylacetic acid (NAA)] for 10 days, and then the cotyledons without callus induced were transferred to differentiation medium (DM) with 6 subcultures, 90 days in total. The best DM for the frequency of leaf clusters induction (66.67%) was Woody plant medium (WPM) containing 4.04 µM N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) + 4.54 µM TDZ, and for the frequency of MNs induction (41.67%) was WPM containing 2.02 µM CPPU + 2.27 µM TDZ. For two pathways, mean number of regenerated shoots (≈ 4 shoots per explant), the frequency of root induction (≈ 50%) and the frequency of survival (≈ 40%) were similar. Histological studies confirmed the process of direct organogenesis, and revealed that shoots and MNs were originated from the increased division of meristematic cells under cortical tissue, as well as from actively dividing meristematic cells around the vascular center. Moreover, shoots regenerated through MNs differentiation were originated from the epidermal and subepidermal cells. This study is supplements in the field of in vitro regeneration in tree peony, and is an improvement to current protocols of clonal micropropagation, at the same time facilitating fundamental studies of developmental biology and genetic transformation.Key message: Plant regeneration through two pathways of direct organogenesis using cotyledon explant was first presented in Paeonia ostii ‘Feng Dan’. [ABSTRACT FROM AUTHOR]

Herb genomics, at the forefront of traditional Chinese medicine research, combines genomics with traditional practices, facilitating the scientific validation of ancient remedies. This integration enhances public understanding of traditional Chinese medicine's efficacy and broadens its scope in modern healthcare. Stachys species encompass annual or perennial herbs or small shrubs, exhibiting simple petiolate or sessile leaves. Despite their wide-ranging applications across various fields, molecular data have been lacking, hindering the precise identification and taxonomic elucidation of Stachys species. To address this gap, we assembled the complete chloroplast (CP) genome of Stachys geobombycis and conducted reannotation and comparative analysis of seven additional species within the Stachys genus. The findings demonstrate that the CP genomes of these species exhibit quadripartite structures, with lengths ranging from 14,523 to 150,599 bp. Overall, the genome structure remains relatively conserved, hosting 131 annotated genes, including 87 protein coding genes, 36 tRNA genes, and 8 rRNA genes. Additionally, 78 to 98 SSRs and long repeat sequences were detected , and notably, 6 highly variable regions were identified as potential molecular markers in the CP genome through sequence alignment. Phylogenetic analysis based on Bayesian inference and maximum likelihood methods strongly supported the phylogenetic position of the genus Stachys as a member of Stachydeae tribe. Overall, this comprehensive bioinformatics study of Stachys CP genomes lays the groundwork for phylogenetic classification, plant identification, genetic engineering, evolutionary studies, and breeding research concerning medicinal plants within the Stachys genus. [ABSTRACT FROM AUTHOR]

Insertion and Deletion (InDel) are common features in genomes and are associated with genetic variation. The whole-genome re-sequencing data from two parents (X1 and X2) of the elite cucumber (Cucumis sativus) hybrid variety Lvmei No.1 was used for genome-wide InDel polymorphisms analysis. Obtained sequence reads were mapped to the genome reference sequence of Chinese fresh market type inbred line '9930' and gaps conforming to InDel were pinpointed. Further, the level of cross-parents polymorphism among five pairs of cucumber breeding parents and their corresponding hybrid varieties were used for evaluating hybrid seeds purity test efficiency of InDel markers. A panel of 48 cucumber breeding lines was utilized for PCR amplification versatility and phylogenetic analysis of these markers. In total, 10,470 candidate InDel markers were identified for X1 and X2. Among these, 385 markers with more than 30 nucleotide difference were arbitrary chosen. These markers were selected for experimental resolvability through electrophoresis on an Agarose gel. Two hundred and eleven (211) accounting for 54.81% of markers could be validated as single and clear polymorphic pattern while 174 (45.19%) showed unclear or monomorphic genetic bands between X1 and X2. Cross-parents polymorphism evaluation recorded 68 (32.23%) of these markers, which were designated as cross-parents transferable (CPT) InDel markers. Interestingly, the marker InDel114 presented experimental transferability between cucumber and melon. A panel of 48 cucumber breeding lines including parents of Lvmei No. 1 subjected to PCR amplification versatility using CPT InDel markers successfully clustered them into fruit and common cucumber varieties based on phylogenetic analysis. It is worth noting that 16 of these markers were predominately associated to enzymatic activities in cucumber. These agarose-based InDel markers could constitute a valuable resource for hybrid seeds purity testing, germplasm classification and marker-assisted breeding in cucumber. [ABSTRACT FROM AUTHOR]

Metasequoia glyptostroboides is an endangered relict plant native to China that has been widely introduced into many countries and areas around the world. However, its seeds germinate at a very low percentage. Consequently, population regeneration by seed is low under natural conditions, which probably contributes to the endangered status of this plant species. The present study aimed to describe the aging mechanism of M. glyptostroboides seeds. Our objective was to elucidate causes of the low germination rate in an effort to enhance potential for conservation of the species. We used germination tests, relative electrical conductivity and malondialdehyde content determination, ultrastructural observation of embryo cells, and analysis of superoxide dismutase, catalase, ascorbate peroxidase, and dehydroascorbate reductase activities during accelerated aging treatment. We found that M. glyptostroboides seeds have a low level of vigor and poor ability to maintain vigor, which is probably associated with the inefficiency of its enzymatic antioxidative system. [ABSTRACT FROM AUTHOR]

Genomic simple sequence repeat (SSR) markers were used to fingerprint and determine genetic similarity (GS) of the watermelon breeding lines, as well as the purity of their hybrid derivatives. Cluster analysis and Jaccard's distance coefficients using the unweighted pair group method with arithmetic mean (UPGMA) have classified these lines into three major groups. Notwithstanding, the genetic background of these lines is narrow as revealed by the restricted GS coefficients. Fifty-five sets of SSR markers were employed in this study. Fourteen of these markers were polymorphic between the breeding lines and were used for assessing hybrid purity. Cross-checking assay validated nine SSR markers as informative SSR markers for purity detection of these hybrids. To confirm the accuracy and efficiency of these markers, their derived PCR products were further sequenced, and ClSSR09643, ClSSR18153 and ClSSR01623 were selected as high-efficiency SSR markers. Interestingly, SSR markers ClSSR09643 and ClSSR18153 were broadly applied for purity detection of more than two different hybrids, while SSR marker ClSSR01623 behaved as a specific marker for purity detection in this study. Genetic purity of six commercial watermelon hybrids was definitely evaluated using these SSR markers. Genetic purity of all tested hybrids exceeded 96% while the field purity was above 98%. Genetic purity test was an emergency for identifying off-types and selfed female in a lot of hybrid seeds. Here, we elucidated the potential of nine SSR markers including three with higher breeding selection efficiency. We recommended them to seed company for purity improvement of watermelon commercial hybrid varieties. [ABSTRACT FROM AUTHOR]

We investigated the effect of working memory load on the SNARC (spatial-numerical association of response codes) effect under different number judgment tasks (parity judgment and magnitude comparison), using a novel dual task. Instead of exerting load over the whole block of number judgment trials, in this dual task, number judgment trials were inserted into each interstimulus interval of an n-back task, which served as the working memory load. We varied both load type (verbal and spatial) and amount (1-load, 2-load, and 3-load). The results indicated that the SNARC effect disappeared even under the 1-load condition for a parity judgment, regardless of the type of load. However, during the magnitude comparison task, the SNARC effect increased with increasing load amounts under spatial load conditions; under verbal load conditions, the SNARC effect decreased with increasing amounts of load, and disappeared during the 3-load task. The difference between the parity and magnitude tasks was not attributable to the interval stimuli or task switching. These findings confirm that different spatial-numerical associations for comparing numerical magnitudes and judgments of parity have different needs with respect to working memory resources. [ABSTRACT FROM AUTHOR]