Perilla Crop Research Articles

Association mapping analysis (AMA) for morpho-agronomic traits and leaf aromatic compounds using SSR markers in three types of Perilla crop collected from South Korea.

Perilla is a representative leafy vegetable in South Korea. As K-Food (Korean food) is in the spotlight around the world, there is also increasing interest in Western countries in Perilla crop, an annual plant belonging to the Lamiaceae family. To discover comprehensive information, including genetic and phylogenetic relationships among the 80 native Perilla accessions, using three types of data: simple sequence repeat (SSR) marker data, volatiles profile data, and morpho-agronomic data. This study conducted genotypic and phenotypic analyses on 80 Perilla accessions of three types (cultivated var. frutescens, weedy var. frutescens, weedy var. crispa) from South Korea. Five groups (G1-G5) of the 80 Perilla accessions of the three types were differentiated into two different clusters [genotype-based clustering (GTC) and phenotype-based clustering (PTC)] based on an aroma sensory phenotypic test. A total of 314 alleles were confirmed using 55 Perilla SSR primer sets, and genetic variation in the 80 Perilla accessions was evaluated. Among the three statistical analysis methods, principal coordinate analysis (PCoA) and GTC using data of the 55 Perilla SSR markers revealed perfectly consistent results, whereas PTC produced a total of six clusters. The 10 Perilla SSR markers associated with and significantly correlated with both biochemical and morphological characteristics were selected. These findings are expected to provide valuable information for developing global South Korean Perilla cultivars for further studies in Perilla crop breeding programs.

Association analysis of leaf aromatic substances in cultivated and weedy types of Perilla crop using SSR markers

In East Asia, particularly South Korea, the two cultivated varieties of Perilla are commonly grown. They are clearly distinguished by their aromatic substances and have different uses as leafy vegetables or oil crop. This study was performed for the development of simple sequence repeat (SSR) markers linked to volatile compounds in Perilla leaves that show differences between cultivated var. frutescens (CF), weedy var. frutescens (WF), and weedy var. crispa (WC) of Perilla. Fifty Perilla SSR primer sets were used to analyze genetic diversity for the 80 Perilla accessions of the three types. A total of 276 alleles were detected, with an average of 5.5 alleles per locus. The average genetic diversity values for CF, WF, and WC accessions were 0.402, 0.583, and 0.437, respectively. WF accessions exhibited the highest genetic diversity among the three types of the Perilla crop. Phylogenetic tree analysis classified 80 Perilla accessions of the three types into four groups, showing 37.2 % genetic similarity. Three types of the Perilla crop were clearly distinguished except for outstanding accessions. Through the application of an association analysis involving 50 Perilla SSR primer sets and five volatile compounds (perilla aldehyde, perilla ketone, myristicin, dill apiol, (Z,E)-α-farnesene) in the three types of the Perilla accessions, we detected 11 significant marker-trait associations duplicated in both Q GLM and Q + K MLM methods. These findings serve as valuable insights for identifying the aromatic substances in Perilla plants originating from various regions of South Korea.

Association mapping analysis for cultivated and weedy types of Perilla crop collected from South Korea using morphological characteristics and SSR markers

There are two cultivated and weedy types of Perilla crop (TCWTPC), and they are widely distributed and cultivated in East Asia, especially in South Korea and Japan. The objective of this study is to create simple sequence repeat (SSR) markers linked to morphological traits that show differences between accessions of the TCWTPC using recently designed SSR primer sets in Perilla crop. Genetic diversity within 52 accessions of the TCWTPC, gathered from South Korea, was assessed using 28 novel Perilla SSR primer sets. Based on the assessment, a collection of 28 Perilla SSR primer sets were shown to exhibit polymorphism and yielded a total of 142 alleles across the 52 accessions of the TCWTPC. Through inspection of a phylogenetic tree and population structure, the 52 accessions of the TCWTPC were classified into three major groups. Although most accessions of the TCWTPC were relatively clearly distinguished, SSR markers failed to distinguish several accessions belonging to the two weedy types of the Perilla crop. By using an association mapping analysis (AMA) of the 28 Perilla SSR markers and seven morphological characteristics in the 52 TCWTPC accessions, we detected that three of the Perilla SSR markers (KNUPF134, KNUPF137, KNUPF149) were associated with plant and seed characteristics. The novel SSR primer sets developed in Perilla crop should be useful in AMA for assessing genetic diversity and relationships between and within TCWTPC accessions, and this information will be helpful for genetic mapping in breeding programs for Perilla crop.

Characterization of volatile compounds of Perilla crop (Perilla frutescens L.) in South Korea

This study was performed to identify and profile the volatile compounds present in three different types of Perilla leaves collected from South Korea. Volatile compounds were analyzed by gas-chromatograph-mass spectrometry. In total, 41 volatile compounds were identified belonging to nine chemical classes (six alcohols, seven aldehydes, two benzodioxoles, two esters, three ethers, four ketones, five monoterpenes, one phenylpropanoid, and eleven sesquiterpenes). In cultivated type of var. frutescens (CF), weedy type of var. frutescens (WF), and weedy type of var. crispa (WC), a total of 34, 39, and 41 volatile compounds, respectively, were identified. The predominant compound in CF and WF was perilla ketone (PK; 87.2% and 64.5%, respectively) and in WC was perilla aldehyde (PA; 26.4%). There were 29 and 27 volatile compounds that showed significant differences of content between WC and CF or WF, respectively. In terms of chemotype based on the volatile compounds, CF and WC were PK type and PA or phenylpropanoid (PP) types, respectively. WF accessions, which were PK and PP types in chemical composition, showed intermediate characteristics in the composition of volatile compounds compared with CF and WC. The results obtained in this study identified successfully the composition and content of volatile compounds in Perilla crop in South Korea. These results will provide useful information for industries and research related to Perilla crop.

Morphological Variation of Cultivated and Weedy Types in Perilla Crop Collected from South Korea

Background: Perilla (Perilla frutescens L.) has been widely cultivated and used for medicinal use, aromatic, functional food, and ornamental plant in South Korea. To understand the morphological variation in the cultivated and weedy types of Perilla (CWTP) collected from South Korea, 52 accessions collected from different areas were evlauated using one quantitative and 10 qualitative characteristics.BRMethods and Results: Principal component analysis (PCA) was performed using the NTSYS-pc V2.1 program to detect the differences among the accessions of the CWTP. Multivariate analysis was performed using Microsoft Excel Statistical Analysis System. The cultivated P. frutescens var. frutescens and two weedy types of Perilla crop were accurately distinguished based on he 11 morphological characteristics, paricularly seed related traits, used in the study. PCA results showed that, most morphological characteristics such as weight per 100 seeds (QN1), color of leaf adaxial side (QL1), color of leaf abaxial side (QL2), stem color (QL4), flower color (QL5), seed size (QL9), and seed hardness (QL10) provided a significant contribution in the positive or negative direction on the first axis. These characteristics are considered useful for distinguishing between accessions of the CWTP collected from South Korea.BRConclusions: The accessions of weedy P. frutescens var. frutescens are located between the accessions of cultivated P. frutescens var. frutescens and the those of weedy P. frutescens var. crispa on the first axis. Although the cultivated and weedy types of P. frutescens var. frutescens and the two weedy types of P. frutescens var. frutescens and P. frutescens var. crispa cannot be completely distinguished, the results provide useful information for future studies on the identification and classification of CWTP germplasm accessions collected from different areas in South Korea.

Utilization of Novel Perilla SSR Markers to Assess the Genetic Diversity of Native Perilla Germplasm Accessions Collected from South Korea.

The Perilla crop is highly regarded in South Korea, both as a health food and traditional food. However, there is still a lack of Perilla SSR primer sets (PSPSs) for studying genetic variation among accessions of cultivated and weedy types of Perilla crop (CWTPC) from South Korea. In this study, 30 PSPSs were newly developed based on transcriptome contigs in P. frutescens, and 17 of these PSPSs were used to study the genetic diversity, phylogenetic relationships and structure population among 90 accessions of the CWTPC collected from South Korea. A total of 100 alleles were detected from selected 17 PSPSs, with an average of 5.9 alleles per locus. The gene diversity (GD) ranged from 0.164 to 0.831, with an average of 0.549. The average GD values from the cultivated var. frutescens, weedy var. frutescens, and weedy var. crispa, were 0.331, 0.588, and 0.389 respectively. In addition, most variance shown by Perilla SSR markers was within a population (73%). An analysis of the population structure and phylogenetic relationships showed that the genetic relationship among accessions of the weedy var. frutescens and weedy var. crispa is closer than that for the accessions of the cultivated var. frutescens. Based on association analysis between 17 PSPSs and three seed traits in 90 Perilla accessions, we detected 11 PSPSs that together were associated with the seed size and seed hardness traits. Therefore, the newly developed PSPSs will be useful for analyzing genetic variation among accessions of the CWTPC, association mapping, and selection of important morphological traits in Perilla crop breeding programs.

Genetic variation of seed oil characteristics in native Korean germplasm of Perilla crop (Perilla frutescens L.) using SSR markers.

In order to maximize the use of valuable native Perilla germplasm in South Korea, knowledge of the Perilla seed oil content and genetic variation among native Perilla germplasm resources is very important for the conservation and development of new Perilla seed oil varieties using the native Perilla germplasm accessions preserved from the Rural Development Administration Genebank (RDA-Genebank) collection from South Korea. In this study, we studied population structure and association mapping to identify Perilla SSR markers (PSMs) associated with the five fatty acid contents and two seed characteristics of the native Korean Perilla germplasm accessions of cultivated var. frutescens of the RDA-Genebank collected in South Korea. For an association mapping analysis to find PSMs associated with the five fatty acid contents and two seed characteristics of the Perilla germplasm accessions of cultivated var. frutescens, we evaluated the content of five fatty acids of 280 native Korean Perilla germplasm accessions and used 29 Perilla SSR primer sets to measure the genetic diversity and relationships, population structure, and association mapping of the native Korean Perilla germplasm accessions of the RDA-Genebank collected in South Korea. Five fatty acids of 280 native Korean Perilla accessions were identified as follows: palmitic acid (PA) (5.30-8.66%), stearic acid (SA) (1.60-4.19%), oleic acid (OA) (9.60-22.5%), linoleic acid (LA) (8.38-25.4%), and linolenic acid (LNA) (52.7-76.4%). In a correlation analysis among the five fatty acids and two seed characteristics of the 280 Perilla accessions, the combinations of PA and SA (0.794**) and SA and OA (0.724**) showed a particularly high positive correlation coefficients compare to other combinations. By using an association analysis of the 29 PSMs and the five fatty acids in the 280 Perilla accessions, we found 17 PSMs (KNUPF1, KNUPF2, KNUPF4, KNUPF10, KNUPF16, KNUPF25, KNUPF26, KNUPF28, KNUPF37, KNUPF55, KNUPF62, KNUPF71, KNUPF74, KNUPF77, KNUPF85, KNUPF89, and KNUPF118) associated with the content of the five fatty acid components and two seed characteristics. These PSMs are considered to be useful molecular markers related to five fatty acid components and two seed characteristics for selecting accessions from the germplasm accessions of the Perilla crop and their related weedy types through association mapping analysis and marker-assisted selection (MAS) breeding programs.

Feeding behavior and development response of the perilla seed bugs (Nysius sp.) (Heteroptera: Lygaeidae) on multiple crop seeds combinations

• Effects of oilseed and cereal crops were studied on Nysius sp. • Multiple (MC)-and double (DC) seed combinations affected oviposition. • Higher number of eggs were laid on MC, with minimal nymph mortality. • The MC was ideal for normal development and positive adult performance. • Field distance maintain among crop fields is crucial for minimizing damages of Nysius sp. The perilla seed bugs, Nysius plebeius Distant and Nysius hidakai Nakatani, are emerging pests of several field crop species including perilla crop in Korea. Here, we investigated the oviposition, nymphal mortality, development, adult emergence, adult longevity, adult weight and female ratio of N. plebeius and N. hidakai on multiple (MC) and double (DC) combinations of five crop seed species: perilla [ Perilla frutescens (L.) Britton.], sesame ( Sesamum indicum L.), sorghum [ Sorghum bicolor (L.)], proso millet ( Panicum miliaceum L.), and foxtail millet ( Setaria italic L.) in no-choice test. The life-history variables of N. plebeius and N. hidakai were significantly influenced by the crop seed combinations. The most preferred crop seed combinations for oviposition were MC (perilla + sorghum + sesame + proso millet + foxtail millet), followed by DC (perilla + foxtail millet and perilla + sorghum), whereas the least preferred seed combination was DC (proso millet + foxtail millet). Both Nysius sp. were developed faster in MC (perilla + sorghum + sesame + proso millet + foxtail millet), with minimal nymphal mortality, higher adult emergence, longer adult longevity and heavier adult weight. The positive adult bug’s performance on the MC (perilla + sorghum + sesame + proso millet + foxtail millet) may be due to the nutrient contents and physicochemical components associated with the crop seeds. Further, the findings of this study are discussed in terms of bug's behavioral response to crop seed species combinations and management strategies of Nysius sp. as an alternative to chemical management.

Construction of a core collection of native Perilla germplasm collected from South Korea based on SSR markers and morphological characteristics

The leaves and seed oil of Perilla crop (Perilla frutescens L.) have attracted interest as health foods in East Asia. This crop has been traditionally cultivated and used for a long time as a folk plant, especially in Korea. In our study, the 22 SSR markers and eight morphological traits were used to assess the genetic diversity and population structure, to select a core collection of 400 Perilla accessions conserved in the RDA-Genebank of South Korea. A total of 173 alleles were detected and the number of alleles per locus ranged from 4 to 15 (average = 7.9). Gene diversity and polymorphic information content ranged from 0.138 to 0.868 (average = 0.567) and 0.134 to 0.853 (average = 0.522), respectively. The 400 accessions were not clearly distinguished geographically by STRUCTURE and UPGMA analyses. A core collection (44 accessions) was selected from the entire collection by using PowerCore. The core collection accounted for 11.0% of the entire Perilla collection, including 100% of the number of alleles maintained in the whole collection and with similar or greater Shannon–Weaver and Nei diversity indices than the whole collection. The core collection selected by SSR markers was evenly distributed in three clusters on a scatter plot by eight morphological traits. The first core collection of Perilla accessions was constructed, and it maintained allelic richness. Further modification of the core collection is expected with the continuous addition of new accessions of the two cultivated types of Perilla crop and their weedy types.

Species Composition, Abundance, and Seasonal Dynamics of Perilla Seed Bugs (Heteroptera: Lygaeidae) in Weeds and Perilla Fields in Korea.

Perilla seed bugs (Nysius sp.) are considered to be the emerging pests causing nutritional and yield losses in perilla and cereal crops. A survey of perilla seed bugs on weeds and perilla crops was conducted over the course of 2 yr in Korea to determine the species composition, abundance, and seasonal dynamics of perilla seed bugs. Three species of Heteroptera (Nysius plebeius, Nysius hidakai, and Nysius inconspicuus), nymphs of Nysius species, and several parasitoid species were collected from weeds and perilla crops. Nysius hidakai was the most abundant perilla seed bugs. In 2019, adult perilla seed bugs, nymphs of perilla seed bugs, and parasitoid species were more abundant in weed species than in perilla crops. An early peak with a greater number of adult perilla seed bug (N. hidakai) was observed in weeds in 2020. However, an identical peak with a similar number of perilla seed bug (N. hidakai) was found in perilla crops in both years. Peak perilla seed bugs densities were observed in the 4th week of June, 2020 in weeds. Parasitoid species from Aphidiidae (1), Braconidae (11), Eulophidae (7), Figitidae (5), Ichneumonidae (7), Platygastridae (1), and Pteromalidae (5) subfamilies were collected. Perilla seed bugs seem to be a serious and increasingly important pest in several field crop species including perilla crops grown on the southern Korean peninsula. Monitoring and early detection of insect species are vital to predicting seasonal colonization and population build-up of perilla seed bugs on perilla crops from a climate change perspective, and essential for developing appropriate management techniques. Thus, continuous monitoring of perilla seed bugs in alternative weed hosts is needed to protect perilla crops from perilla seed bug infestation.

Identifying SSR Markers Related to Seed Fatty Acid Content in Perilla Crop (Perilla frutescens L.).

Perilla seed oil has been attracting attention in South Korea as a health food. Five fatty acids of 100 Perilla accessions were identified as follows: palmitic acid (PA) (5.10–9.13%), stearic acid (SA) (1.70–3.99%), oleic acid (OA) (11.1–21.9%), linoleic acid (LA) (10.2–23.4%), and linolenic acid (LNA) (54.3–75.4%). Additionally, the 100 Perilla accessions were divided into two groups (high or low) based on the total fatty acid content (TFAC). By using an association analysis of 40 simple sequence repeat (SSR) markers and the six Perilla seed oil traits in the 100 Perilla accessions, we detected four SSR markers associated with TFAC, five SSR markers associated with LNA, one SSR marker associated with LA, two SSR markers each associated with OA and PA, and four SSR markers associated with SA. Among these SSR markers, four SSR markers (KNUPF14, KNUPF62, KNUPF72, KNUPF85) were all associated with TFAC and LNA. Moreover, two SSR markers (KNUPF62, KNUPF85) were both associated with TFAC, LNA, and OA. Therefore, these SSR markers are considered to be useful molecular markers for selecting useful accessions related to fatty acid contents in Perilla germplasm and for improving the seed oil quality of Perilla crop through marker-assisted selection (MAS) breeding programs.

Genetic variation and association mapping in the F2 population of the Perilla crop (Perilla frutescens L.) using new developed Perilla SSR markers

The transcriptome sequencing approach RNA-seq represents a powerful tool for transcriptional analysis and development of simple sequence repeat (SSR) markers for nonmodel crop. In the Perilla crop, analysis of the distribution of different repeat motifs showed that the most abundant type was dinucleotide repeats (62.0%), followed by trinucleotide repeats (35.3%), with the two together comprising 97.3% of the eSSR repeats. In this study, we developed 39 new SSR primer sets by the transcriptome sequencing approach RNA-sEq. In total, 130 alleles were detected segregating in nine Perilla accessions with an average of 3.3 alleles per locus, ranging from 125 to 360 bp. The number of alleles per locus ranged from two to six. To detect SSR markers associated with morphological characteristics of Perilla crop, 40 individuals from an F2 population of Perilla were selected for association analysis based on their leaf- and plant-related characteristics. An association analysis of 37 SSR markers and 9 leaf- and plant-related traits in the 40 individuals of the F2 population was conducted. From the analysis, we identified 12 SSR markers associated with leaf-related traits and 11 SSR markers associated with plant-related traits. Therefore, the new Perilla SSR primers described in this study could be helpful in identifying genetic diversity and genetic mapping, designating important genes/QTLs for Perilla crop breeding programs, and allowing Perilla breeders to improve leaf and plant quality through marker-assisted selection (MAS) breeding programs.

Nysius Plebeius distant (Heteroptera: Lygaeidae; Orsillinae) feeding impacts on seed weight and germination of perilla crop

Nysius species are one of the emerging pests of perilla crop in Korea. Seed weight loss and germination of perilla seeds caused by Nysius plebeius were studied by exposing perilla seeds cv. Deulsaem to six insect infestation levels (0, 5, 10, 15, 20, and 25 individual) for 3 and 5 days in the laboratory. The seed weight loss and germination rate were significantly affected by infestation levels and feeding durations. The feeding impacts on seeds increased with increasing in bug density and duration. The higher seed weight loss, and weak germination were recorded at higher bug density (25 individuals) for longer (5 days) feeding duration. The triphenyl tetrazolium chloride, TTC, showed lower seed viability for damaged seeds than undamaged seeds. The outcomes of the study are discussed in terms of impacts of perilla seed bugs infestation, and suggest longer field exposure of perilla seeds to seed bugs may bring lower yield with poor quality of seeds and low germination potential of seeds. Future studies should examine the changes in nutrient contents of seeds after exposed to perilla seed bugs.

Morphological Variation of Accessions of Perilla Crop (Perilla frutescens L.) and Related Weedy Types Collected from South Korea

Morphological Variation of Accessions of <i>Perilla Crop</i> (<i>Perilla frutescens</i> L.) and Related Weedy Types Collected from South Korea

Bulk segregant analysis identifies SSR markers associated with leaf- and seed-related traits in Perilla crop (Perilla frutescens L.)

Bulk segregant analysis (BSA) is another method of identifying significant molecular markers linked to the target gene or region for specific traits. BSA is easier and less expensive than other methods; it does not require genetic map construction and needs fewer markers than the number needed to construct a genetic map for QTL mapping. The purpose of our study was to identify simple sequence repeat (SSR) markers linked with leaf- and seed-related traits in Perilla crop, and to allow the selection of better accessions in Perilla breeding programs with marker-assisted selection (MAS). The genotypes of the 25 SSR markers and phenotypic data for the eight qualitative traits were used to confirm significant marker-trait associations (SMTAs) using TASSEL software. To detect SSR markers associated with leaf color, the 16 individuals of the F3 population were divided into three bulk groups based on the colors of the surface and reverse sides of the leaf, respectively: six in the green/green group, five in the green/purple group and five in the purple/purple group. This study detected 18 significant marker-trait associations (SMTAs) involving 12 SSR markers associated with six agronomic traits. The SSR markers KNUPF15, KNUPF21, KNUPF29, and KNUPF60 were associated with leaf surface color, and KNUPF11, KNUPF15, KNUPF21, and KNUPF60 were associated with leaf reverse side color. In addition, five SSR markers were associated with seed-related traits. KNUPF11 and KNUPF29 were associated with seed coat color, while KNUPF29 was associated with seed size. KNUPF12, KNUPF16, and KNUPF42 were associated with seed hardness. To verify the selected significant SSR markers associated with leaf color and seed-related traits, a UPGMA dendrogram for 11 individuals in the F3 population, which formed two bulk groups consisting of 6 green/green and 5 purple/purple individuals, was constructed using six SSR marker-related LC and RLC traits. These results are very important for understanding the characteristics of Perilla leaves and seeds; they may also support opportunities to effectively preserve and utilize existing accessions and to allow Perilla breeders to improve crop quality by mean of MAS.

Identifying SSR markers associated with seed characteristics in Perilla (Perilla frutescens L.).

The online version of this article (10.1007/s12298-021-00933-3) contains supplementary material, which is available to authorized users.

Assessment of genetic diversity and population structure among a collection of Korean Perilla germplasms based on SSR markers.

Information on the genetic variation of genetic resource collections is very important for both the conservation and utilization of crop germplasms in genebanks. Var. frutescens of Perilla crop is extensively cultivated in South Korea as both an oil crop and a vegetable crop. We used SSR markers to evaluate the genetic diversity, genetic relationships, and population structure of 155 accessions of var. frutescens that have been selected as genetic resources for the development of leaf vegetable cultivars and preserved in the RDA-Genebank collection from South Korea. A total of 155 accessions of var. frutescens of Perilla crop collected in South Korea were obtained from the RDA-Genebank of the Republic of Korea. We selected 20 SSR markers representing the polymorphism of and adequately amplifying all the Perilla accessions. The average GD and PIC values were 0.642 and 0.592, respectively, with ranges of 0.244-0.935 and 0.232- 0.931. The genetic variability in the southern region of South Korea was higher than that in the central region. The clustering patterns were not clearly distinguished between the accessions of var. frutescens from the central and southern regions of South Korea. These results regarding the genetic diversity and population structure of the 155 accessions of var. frutescens of South Korea provide useful information for understanding the genetic variability of this crop and selecting and managing core germplasm sets in the RDA-Genebank of the Republic of Korea.

Geographic Variation of Morphological Characters among Cultivated Types ofPerillaCrop and Their Weedy Types in Korea and China

In this study, we detected the morphological variation of 83 Perilla accessions from Korea and China by observing the measurements of seven quantitative and eight qualitative characters. Most accessions of cultivated var. frutescens from Southern China showed higher plant height than accessions from Korea and Northern China. The accessions of cultivated var. frutescens from Southern China have a relatively late flowering time, while there were three types of accessions for cultivated var. frutescens from Korea and Northern China: early-maturity, middle-maturity, and late-maturity. These results indicate that latitude with geographical distribution may be an essential factor affecting the flowering time in Perilla species in East Asia. In principal components analyses (PCAs), four quantitative traits and five qualitative characters contributed in the positive direction on the first axis. The accessions of cultivated var. frutescens were clearly separated from accessions of cultivated and weedy types of var. crispa in the PCAs, while the accessions of cultivated and weedy types of var. crispa revealed no separation. In addition, most accessions of weedy type of var. frutescens were not clearly separated with the accessions of cultivated and weedy types of var. crispa. In this study, we have provided the information regarding the morphological variation of accessions of two cultivated types of Perilla crop and their weedy types from Korea and China. The findings provide further insight into the morphological variations and differentiation of Perilla accessions with different geographical distributions in Korea and China.

Genetic diversity and population structure of Perilla frutescens collected from Korea and China based on simple sequence repeats (SSRs).

Perilla frutescens (L.) Britt. is divided into two varieties based on morphology and use. One is P. frutescens var. frutescens, which is used both as a leafy vegetable and as an oil obtained from the seeds. The other variety is P. frutescens var. crispa, a Chinese medicine or spice vegetable crop. In addition, weedy types of var. frutescens and var. crispa are occasionally grown as relict forms and are easy to find on roadsides, in waste areas and around farmers' fields or farmhouses. SSR markers have been successfully used to examine the genetic diversity and relationships of cultivated and weedy types of Perilla in many regions. In this study, we used 25 simple sequence repeat (SSR) markers were used to assess the genetic diversity and population structure of 90 Perilla accessions from Korea and China. A total of 90 accessions of Perilla were collected in Korea and China included 45 accessions from each of Korea and China. We selected 25 SSR markers representing the polymorphism of and adequately amplifying all the Perilla accessions. A total of 153 alleles were identified, with an average of 6.12 alleles per locus. The GD level and PIC value for cultivated and weedy types of P. frutescens from China were higher than those for accessions from Korea. Weedy accessions had higher GD and PIC values than cultivated accessions. In the population structure analysis using the model-based method, the 90 Perilla accessions were divided into two main group and an admixed group based on a membership probability threshold of 0.8. Based on the distance-based unweighted pair group method with the arithmetic mean (UPGMA), all accessions were classified into four major groups with a genetic similarity of 32.8%. Finally, the findings of this study will provide useful theoretical knowledge for further study of the population structure and genetic diversity of Perilla species and benefit Perilla crop breeding and germplasm conservation in Korea and China.

Fatty acid composition and oil content of seeds from perilla (Perilla frutescens (L.) var. frutescens) germplasm of Republic of Korea

Perilla (Perilla frutescens (L.) var. frutescens) is an oilseed crop that produces a large amount of α-linolenic acid (ALA, 18:3), an ω-3 fatty acid in seeds. Perilla is also a fragrant leafy herb with great health benefits. To develop value-added perilla crop, we surveyed the fatty acid composition and oil content of 87 germplasms accessions maintained at Republic of Korea. Our results show that ALA is the major fatty acid, ranging from 47 to 64%, followed by linoleic acid (LA, 18:2, an ω-6 fatty acid) from 10 to 24% and the oleic acid (OA, 18:1, an ω-9 fatty acid) from 9 to 20%. The seed oil content among accessions ranges from 17 to 42.7%. To access if the different fatty acid profile and oil content among germplasms are associated with changes in key genes, we compare the sequences encoding fatty acid desaturase 2 (FAD2) and fatty acid desaturase 3 (FAD3) responsible for LA and ALA synthesis, respectively. Besides, we examine the sequence of diacylglycerol acyltransferase 1 (DGAT1), a key enzyme in determining oil content. We do not find major changes in FAD2 or FAD3 associated with different fatty acid profiles. We discover a change in DGAT1 that might associate a low oil content in seeds.