‘Suzhouqing’ is a unique landrace of nonheading Chinese cabbage [Brassica rapa var. chinensis (Linnaeus) Kitamura] with a long history of cultivation in Suzhou of Jiangsu Province, China. However, transitional and overlapped morphologic traits make it difficult to authenticate this accession from other nonheading Chinese cabbages. Genetic relationship between ‘Suzhouqing’ and the related 10 popular accessions in the Yangtze River Delta were analyzed using two well-studied single-copy nuclear genes—ARGONAUTES 7 (AGO7) and BcMF15; the molecular identification of ‘Suzhouqing’ was determined based on the intersimple sequence repeat–sequence-characterized amplified region (ISSR-SCAR) marker. The results indicated that ‘Suzhouqing’ could be identified specifically from the other 10 accessions based on 21 specific nucleotide variations of the AGO7 gene. Sequence variations show a strong correlation with leaf morphology, suggestive of partial causal links between the two. Genetic relationship analysis showed that five accessions with close geographic locations had a very close genetic relationship, whereas the genetic relationship of the other five accessions was related to their morphologic similarity. One exception, ‘AJH’, might undergo a special evolutionary process. Furthermore, ISSR-880 was screened as the specific primer to identify accession ‘Suzhouqing’, and a specific discrimination ISSR-SCAR marker was explored, which amplified no target band in any other accessions. The development of molecular markers for the specific identification of ‘Suzhouqing’ in 11 popular accessions in the Yangtze River Delta could provide a theoretical basis for the protective identification of other agricultural crops.
Xuelin Shen, Yanmei Zhang, Zhao Lei, Yibo Lin, Minxu Cao, Yueyu Hang and Xiaoqin Sun
Yanmei Zhang, Xuelin Shen, Xiaoqin Sun, Jia Liu, Yifeng Xia, Xin Zou and Yueyu Hang
Water chestnut (Trapa natans L.) is a group of annual, floating-leaved aquatic plants that serves as food and medical resources in many countries. However, the molecular method for distinguishing different T. natans L. resources is lacking. In this study, we detected genetic diversity of several chloroplast and nuclear genic or intergenic sequences in four varieties of T. natans and one wild type of Trapa incisa Siebold & Zuccarini to evaluate their potential as molecular markers. Our data revealed that the three chloroplast fragments (rbcL, matK, and pbsA-trnH) show no sequence difference among all tested samples. Only one nucleotide substitution is detected for the nuclear ribosomal internal transcribed spacer (ITS) in the T. natans variety Shuihongling. Four nucleotide substitutions are detected for the nuclear carotenoid isomerase (CRTISO) gene in the variety Hongxiuxie. In contrast, a total of 29 polymorphic sites are detected for a Toll and interleukin-1 receptor-nucleotide binding site–leucine rich repeat (TNL) gene in the five samples, among which six are nucleotide substitutions and the rest are insertions/deletions. The five samples could be fully distinguished from each other based on the TNL gene. To specifically authenticate ‘Heshangling’, 33 randomly amplified polymorphic DNA (RAPD) markers were adopted to amplify genomic sequences from the five samples. A pair of sequence characterized amplified region (SCAR) primers were designed based on the results of RAPD markers, which could specifically amplify one target band from all eight individuals of ‘Heshangling’, but none from any individuals of other T. natans varieties or one T. incisa. Taken together, a TNL sequence was provided in this study to distinguish four T. natans varieties and one T. incisa. Furthermore, a RAPD-SCAR marker was developed for efficient authentication of ‘Heshangling’.