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The plant mitochondria play a crucial role in various cellular energy synthesis and conversion processes and are essential for plant growth. Watercress (Oenanthe javanica) is a fast-growing vegetable with strong adaptability and wide cultivation range, and it possesses high nutritional value. In our study, we assembled the O. javanica mitochondrial genome using the Illumina and Nanopore sequencing platforms. The results revealed that the mitochondrial genome map of watercress has a circular structure of 384,074 bp, containing 28 tRNA genes, 3 rRNA genes, and 34 protein-coding genes. A total of 87 SSR (simple sequence repeat) loci were detected, with 99% composed of palindrome repeats and forward repeats, while no complementary repeats were identified. Codon preference analysis indicated that watercress prefers to use codons encoding leucine, isoleucine, and serine with a preference for A/U-ending codons. Phylogenetic analysis showed that watercress is closely related to species of Bupleurum, Apium, Angelica, and Daucus, with the closest evolutionary relationship observed with Saposhnikovia divaricata and Apium graveolens. This study provides a valuable resource for the study of the evolution and molecular breeding of watercress. [ABSTRACT FROM AUTHOR]

This study sequenced and assembled the chloroplast (cp) genome of Brasenia schreberi cv. 'Mahu Chuncai', a novel variety of B. schreberi rich in nutrients with distinctive characteristics, unlike other varieties in China. The cpDNA genome of 'Mahu Chuncai' has a typical quadripartite structure, with a full length of 158,973 bp, including 88 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The phylogenetic analysis revealed that all species can be divided into three main clades. Results from inverted repeats (IR) boundary analysis revealed substantial differences between Brasenia and Cabomba species. The cpDNA genome of B. schreberi identified was strongly related to Brasenia species but appeared to be a distant relative of Cabomba aquatica more than other species in Cabombaceae. In contrast with the species from Cabombaceae, 'Mahu Chuncai' was a close relative of B. schreberi MN315507.1, which was a distant relative of C. aquatica MG720559.1. Furthermore, we found four potential molecular markers, i.e., ycf1 in the IR region, psbT in the LSC region, and ndhF and rps15 in the SSC region. Collectively, our findings confirm the phylogenetic evolution and cultivation origin of B. schreberi. We identified genetic characteristics and nucleotide diversity hotspots, which provides a theoretical basis for additional research on variety identification, germplasm resources, and molecular breeding of the precious vegetable. [ABSTRACT FROM AUTHOR]

Wasabi (Eutrema japonicum) is a vegetable of Brassicaceae family, currently cultivated in East Asia. It is rich in nutritional and has a spicy flavour. It is regarded as a rare condiment worldwide. Its genetic profile for yield improvement and the development of E. japonicum germplasm resources remains unknown. Cognizant of this, this study sequenced and assembled the chloroplast (cp) genome of E. japonicum to enrich our genomic information of wasabi and further understand genetic relationships within the Eutrema species. The structural characteristics, phylogeny, and evolutionary relationship of cp genomes among other Brassicaceae plants were analyzed and compared to those of Eutrema species. The cp genome of E. japonicum has 153,851 bp with a typical quadripartite structure, including 37 tRNA genes, 8 rRNA genes, and 87 protein-coding genes. It contains 290 simple sequence repeats and prefers to end their codons with an A or T, which is the same as other Brassicaceae species. Moreover, the cp genomes of the Eutrema species had a high degree of collinearity and conservation during the evolution process. Nucleotide diversity analysis revealed that genes in the IR regions had higher Pi values than those in LSC (Large single copy) and SSC (Small single copy) regions, making them potential molecular markers for wasabi diversity studies. The analysis of genetic distance between Eutrema plants and other Brassicacea plants showed that intraspecies variation was found to be low, while large differences were found between genera and species. Phylogenetic analysis based on 29 cp genomes revealed the existence of a close relationship amongst the Eutrema species. Overall, this study provides baseline information for cp genome-based molecular breeding and genetic transformation studies of Eutrema plants. [ABSTRACT FROM AUTHOR]