During pathogen attack, the host plant induces genes to ward off the pathogen while the pathogen often induces host genes that increase susceptibility to the pathogen. Gene expression studies identified many soybean genes altered in expression in resistant and susceptible plant roots over time during infection by soybean cyst nematode (Heterodera glycines; SCN). However, it is difficult to assess the role and impact of these genes on resistance and susceptibility by using gene expression patterns alone, because the nematode injects proteins into the host. These nematode effector proteins interfere with and subvert the normal molecular mechanisms of the host cell. Therefore, we cloned >110 soybean genes from gene expression experiments using microarrays and RNA-Seq deep sequencing. The genes were overexpressed in soybean roots of composite plants to determine their impact on SCN development. Several overexpressed genes decreased the number of mature SCN females more than 50% at 32-35 days after inoculation; numerous other genes increased the number of mature females by more than 150%. Genes that reduced the number of mature females per plant by more than 50% when overexpressed, included genes encoding a β-glucanase, two lipases, calmodulin, a possible transcription factor, as well as proteins of unknown function. Four genes increased the number of mature SCN females more than 200%, while eleven more genes increased the number of mature SCN females more than 150%. Genes enhancing susceptibility included several transporters, pectate lyase, a Ca-dependent kinase and ACC oxidase. Our data support a role for auxin and ethylene in susceptibility of soybean to SCN. These studies highlight the contrasting gene sets induced by host and nematode during infection and provide new insights into the interactions between host and pathogen at the molecular level. Some genes that conferred resistance to SCN were also tested against the root-knot nematode (RKN), Meloidogyne incognita. Many of the genes that conferred resistance to SCN also conferred resistance to RKN. This demonstrated that the genes conferred resistance across genera and provides new strategies for developing broad resistance in plants to parasitic nematodes.

Soybean cyst nematode (Heterodera glycines Ichinohe) is one of the serious soybean [Glycine max (L.) Merr.] pests in major soybean producing countries. The objective of this study was to investigate of Heterodera glycines type using the five SCN infested soybean field soils and was to evaluate resistance to the soybean cyst nematode HG 2.5.7 type on soybean varieties and germplasms. The five SCN contaminated soil samples were collected from the three provinces on November 2011 in Korea, and eggs were cultured on early spring season in 2012. For the second study, a total fifty nine soybean varieties and germplasms were tested by infestation of HG type 2.5.7 in the greenhouse. Soybean cyst nematode HG types were investigated from five locations, HG 2 (race 1) type at Donghae, HG 2.5 (race 1) type at Jeongseon and Hapcheon, HG type 2.5.7 (race 1 or 5) at Yeongwol, and HG 1.2.7 (race 5) type at Haenam locations in present study. No Korean soybean varieties and germplasms were observed with SCN resistant trait to the HG type 2.5.7. Average SCN female index were calculated with 82.7% in 59 plant materials. Our results could be provided useful information to develop a SCN resistant cultivar in Korea.

Two important loci, designated Rhg1 and Rhg4, are responsible for most resistance to soybean cyst nematode (SCN). The objective of this study was to survey single nucleotide polymorphism (SNP) and to map the SCN-resistant gene, Rhg4, on soybean genetic ma

Soybean cyst nematode (Heterodera glycines Ichinohe, SCN) is an important soybean pest and the use of resistant cul-tivars is an effective method to reduce or eliminate SCN damage. SCN resistance loci, rhg1 and Rhg4 are generally accepted as anecesity for

Soybean cyst nematode (Heterodera glycines Ichinohe; SCN) is an important soybean pest and the use of resistant cultivars is the effective method to reduce or eliminate SCN damage. However, breeding for SCN resistance is difficult and expensive by the oligogenic nature of the resistance and genetic variability in the pathogen. Fortunately, SCN resistance loci, rhg1 and Rhg4 are generally accepted as a necessity for the development of resistant genotypes using any source of resistance. In this study, resistance of 44 Korean soybean cultivars to SCN was tested using two molecular markers. Seonheukkong and Pokwangkong were the homozygous to rhg1 locus. Seven cultivars were susceptible to SCN based on Satt309 marker linked rhg1 locus. All Korean cultivars estimated in this study were recessive homozygous to Rhg4 locus and were susceptible in the PCR reaction using primer 548/563 linked to the Rhg4 locus conferring resistance to SCN race 3. Among 44 cultivars estimated, seven cultivars were susceptible to SCN in both Satt309 and primer 548/563 markers. Based on both Satt309 and primer 548/563 markers, there is no resistant cultivar to SCN in Korea. Therefore, SCN resistant cultivars need to be developed in the future. These two markers can be used for improving SCN resistant cultivars.

콩 품종 Essex와 PI 437654간 교잡 후 F2 유래 F3 계통들을 재료로 하여 작성된 RAPD 유전자지도상에 cyst 선충 race 5에 대한 저항성 QTLs 분석을 실시한 바 결과를 요약하면 다음과 같다. 1. 회귀분석 결과 26개의 marker들(22 RAPD, 4 RFLP)에서 cyst 선충 race 5 저항성 반응에 대한 유의성이 인정되었다. 2. MAPMAKER /QTL 분석 결과2개의 저항성 QTL들이 탐색되었는데, 이 QTL들은 2개의 linkage groups(LGC-20와 Group 2)에 위치하였다. 3. 탐색된 2개의 QTL들 중 1개는 우성유전, ？고 나머지 하나는 열성유전양상을 나타내었다. 4. 콩 cyst 선충 race 5의 저항성에 대한 유의성이 인정되는 5개의 marker들간 상호작용을 알아보기 위한 다중회귀분석 결과 총 26개의 조합들 중 4개의 marker들(E023 , G101 , W03, pK418C)로 구성된 조합에서 가장 높은 표리적 변이의 값(35.2%)을 나타내었다.

대두 씨스트 선충포에 있어서 대두 품종별 선충저항성정도를 검정하여 내선충성 대두 품종육성시 기초자료로 삼고져 본 시험을 실시하였던 바 그 결과를 요약하면 다음과 같다. 1. 지표품종에 대한 평균 종실중 감소율은 저항성 품종은 38~44%, 감수성 품종은 6972%로 차리가 뚜렷하였으며 전중 및 협수도 같은 경향이었다. 2. 공시된 품종중 저항성정도가 최강 인 품종은 5, 강 에 속하는 것이 8품종으로써 이를은 모두 중ㆍ만생종이었다. 저항성 품종으로 유망시 되는 것으로는 울산, 강림, pickett 71, Forrest, Bedford 등이었다. 3. 선충포에 있어서 종실중, 전중 및 협수의 감소율을 조생종을 62~75%, 중생종은 39~65%, 만생종은 29~36%로써 생육일수가 짧은 품종일수록 저항성이 약하게 나타났다. 이 원인으로서는 선충의 분포범위와 대두 뿌리의 발생심도 및 발생량, 가해시기와 대두의 개화기 및 회복가능기간이 밀접히 관여하고 있는 것으로 고찰되었다. 4. 내선충성 품종선파을 위한 유의 상관 형질은 전중, 협수, 100입중, 주전장이었으며 특히 전종과 협수는 모두 +0.9 이상의 고도의 상관계수를 보였다.