Min-Jung Seo

Inheritance and Quantitative Trait Loci Analysis of Resistance Genes to Bruchid and Bean Bug in Mungbean ( Vigna radiata L. Wilczek)

Bruchid (Callosobruchus chinenesis L.) and pod sucking bug (Riptortus clavatus Thunberg) are serious insect pests during the reproduction stage and seed storage period of legume crops worldwide. However, few sources of resistance to each of these insects have been identified and characterized, and no genetic studies have been carried out with simultaneous tests of these two insects. In this study, the inheritance of seed resistance to Callosobruchus chinenesis L. and Riptortus clavatus Thunberg was examined in a mungbean cultivar, Jangan mungbean, which was developed by backcrossing with the V2709 resistant donor. The F1, F2, and F3 seed generations were developed from the cross between susceptible and resistant parents, and evaluated for resistance to the two insects. It was found that resistance to bruchid and bean bug was controlled by a single dominant gene in the F1 and F2 seeds. However, the segregation pattern of reciprocal reaction to each insect in F2 seeds showed seeds were susceptible to each insect. These results suggest that the resistance genes in Jangan mungbean to bug and weevil are either different or closely linked with each other. A genetic linkage map 13.7 cM in length with 6 markers was successfully constructed. Two QTLs were identified for bruchid resistance, and a QTL for bean bug resistance was detected. One of the QTLs for resistance to bruchid was shared with the QTL for bean bug. These newly developed closely linked markers will be used for cloning of the resistance genes to bruchid and bean bug in the future.

Genetic diversity and population structure of wild soybean ( Glycine soja Sieb. and Zucc.) accessions in Korea

Genetic variation in wild soybean ( Glycine soja Sieb. and Zucc.) is a valuable resource for crop improvement efforts. Soybean is believed to have originated from China, Korea, and Japan, but little is known about the diversity or evolution of Korean wild soybean. Therefore, in this study, we evaluated the genetic diversity and population structure of 733 G. soja accessions collected in Korea using 21 simple sequence repeat (SSR) markers. The SSR loci produced 539 alleles (25.7 per locus) with a mean genetic diversity of 0.882 in these accessions. Rare alleles, those with a frequency of less than 5%, represented 75% of the total number. This collection was divided into two populations based on the principal coordinate analysis. Accessions from population 1 were distributed throughout the country, whereas most of the accessions from population 2 were distributed on the western side of the Taebaek and Sobaek mountains. The Korean G. soja collection evaluated in this study should provide useful background information for allele mining approach and breeding programmes to introgress alleles into the cultivated soybean ( G. max (L). Merr.) from wild soybean.

Optimization of a Virus-Induced Gene Silencing System with Soybean yellow common mosaic virus for Gene Function Studies in Soybeans

Virus-induced gene silencing (VIGS) is an effective tool for the study of soybean gene function. Successful VIGS depends on the interaction between virus spread and plant growth, which can be influenced by environmental conditions. Recently, we developed a new VIGS system derived from the Soybean yellow common mosaic virus (SYCMV). Here, we investigated several environmental and developmental factors to improve the efficiency of a SYCMV-based VIGS system to optimize the functional analysis of the soybean. Following SYCMV: Glycine max-phytoene desaturase (GmPDS) infiltration, we investigated the effect of photoperiod, inoculation time, concentration of Agrobacterium inoculm, and growth temperature on VIGS efficiency. In addition, the relative expression of GmPDS between non-silenced and silenced plants was measured by qRT-PCR. We found that gene silencing efficiency was highest at a photoperiod of 16/8 h (light/dark) at a growth temperature of approximately 27°C following syringe infiltration to unrolled unifoliolate leaves in cotyledon stage with a final SYCMV:GmPDS optimal density (OD)600 of 2.0. Using this optimized protocol, we achieved high efficiency of GmPDS-silencing in various soybean germplasms including cultivated and wild soybeans. We also confirmed that VIGS occurred in the entire plant, including the root, stem, leaves, and flowers, and could transmit GmPDS to other soybean germplasms via mechanical inoculation. This optimized protocol using a SYCMV-based VIGS system in the soybean should provide a fast and effective method to elucidate gene functions and for use in large-scale screening experiments.

Development of Low Gly m Bd 30K (P34) Allergen Breeding Lines Using Molecular Marker in Soybean [ Glycine max (L.) Merr.]

An increasing production of soybean (Glycine max (L.) Merr.)-based food products may limit dietary choices for soy-allergic individuals. Gly m Bd 30K (P34) is the main seed allergen causing implications in soybean-sensitive patients. The objective of this research was to develop low allergenic soybean lines with molecular marker. The soybean genome assembly specifies that three copy genes of P34 exist in soybean genome. These are Glyma08g12270, which is expressed at significantly higher level over the other two, Glyma08g12280 and Glyma05g29130. Glyma08g12270 was found inactive and was not expressed in low P34 germplasm accessions. Using a co-dominant marker and a polyclonal antibody, polymorphisms and the quantity of protein produced by Glyma08g12270 were analyzed in the F2 and F3 generations obtained by crossing PI567476 and the Korean cultivar Hwanggum. The molecular marker and polyclonal antibody developed in this study could therefore be effectively used for selecting lines that express P34 at low levels. Selected lines could further be used to cross with other null allergenic soybean accessions to breed low allergenic soybean variety.

Genetic analysis of new short petiole gene in soybean

The short petiole trait is valuable for the development of plant ideotype with high yield. Soybean breeding line, SS98206SP, showed extremely short petioles in greenhouse and field. In this study, the short petiole of two mutant lines, SS98206SP and D76-1609, were investigated to determine the genetic segregations. These two mutants were crossed with each other and with two normal petiole genotypes. Genetic analysis indicated that the short petioles in D76-1609 and SS98206SP were controlled by a single recessive gene, respectively. The short petiole gene in SS98206SP was non-allelic with lps, conferring short petiole in D76-1609. Two recessive genes showed complementary relationship having short petioles with recessive homozygote (LPS1-lps?lps?, lps1lps1LPS?-, lps1lps1lps?lps?). Our data indicated that the short petioles in SS98206SP were controlled by a single recessive gene designated as lps3.

A New Soy-paste Soybean Cultivar, ‘Daeha 1’ with Disease Resistance, Lodging Tolerance and High Yielding

A new soybean cultivar for soy-paste, ‘Daeha 1’, was developed by soybean breeding team in the Yeongnam Agricultural Research Institute (YARI) in 2008. A promising line, SS97214-S-S-S-15, was selected from the combination between ‘Suwon192’ and a pedigree came from cross combination between ‘Jangyeobkong’ and ‘Hwaeomputkong’. It was designated as the name of ‘Milyang 164’. It had good result from regional adaptation yield trial (RYT) for three years from 2006 to 2008 and released as the name of ‘Daeha 1’. It has a determinate growth habit, white flower, grey pubescence, yellow seed coat, yellow hilum, large spherical seed (25.4 grams per 100 seeds). ‘Daeha 1’ is tolerant to soybean mosaic virus and bacterial pustule, the major soybean disease in Korea. The average yield of ‘Daeha 1’ was 2.62 ton per hectare in the regional yield trial (RYT) carried out for three years from 2006 to 2008, which was 5 percent higher than that of check cultivar, ‘Taekwangkong’.

An assessment of the interactions between climatic conditions and genetic characteristic on the agricultural performance of soybeans grown in Northeast Asia

Glycine max, commonly known as soybean or soya bean, is a species of legume native to East Asia. The interactions between climatic conditions and genetic characteristic affect the agricultural performance of soybean. Therefore, an investigation to identify the main elements affecting the agricultural performances of 11 soybeans was conducted in Northeast Asia, China [Harbin (45°12′N) Yanji (42°53′N) Dalian (39°30′N) Qingdao (36°26′N)] Republic of Korea [Suwon (37°16′N) and Jeonju (35°49′N)]. The days to flowering (DTF) of soybeans with the e1-nf and e1-as alleles and the E1e2e3e4 genotype, except Keumgangkong, Tawonkong, and Duyoukong, was relatively short compared to soybeans with other alleles. Although DTF of the soybeans was highly correlated to all climatic conditions, days to maturity (DTM) and 100-seed weight (HSW) of the soybeans showed no significant correlation with any climatic conditions. The soybeans with a dominant Dt1 allele, except Tawonkong, had the longest stem length (STL). Moreover, the STL of the soybeans grown at the test fields showed a positive correlation with only day length (DL) although the results of our chamber test showed that STL of soybean was positively affected by average temperature (AVT) and DL. Soybean yield (YLD) showed positive correlations with latitude and DL (except L62-667, OT89-5, and OT89-6) although the response of YLD to the climatic conditions was cultivar-specific. Our results show that DTF and STL of soybeans grown in Northeast Asia are highly affected by DL although AVT and genetic characteristic also affect DTF and STL. Along with these results, we confirmed that the DTM, HSW, and YLD of the soybeans vary in relation to their genetic characteristic.