In field conditions, the zebra2 (z2) mutant in rice (Oryza sativa) produces leaves with transverse pale-green/yellow stripes. It was recently reported that ZEBRA2 encodes carotenoid isomerase (CRTISO) and that low levels of lutein, an essential carotenoid for non-photochemical quenching, cause leaf variegation in z2 mutants. However, we found that the z2 mutant phenotype was completely suppressed by growth under continuous light (CL; permissive) conditions, with concentrations of chlorophyll, carotenoids and chloroplast proteins at normal levels in z2 mutants under CL. In addition, three types of reactive oxygen species (ROS; superoxide [O2-], hydrogen peroxide [H2O2], and singlet oxygen [1O2]) accumulated to high levels in z2 mutants grown under short-day conditions (SD; alternate 10-h light/14-h dark; restrictive), but do not accumulate under CL conditions. However, the levels of lutein and zeaxanthin in z2 leaves were much lower than normal in both permissive CL and restrictive SD growth conditions, indicating that deficiency of these two carotenoids is not responsible for the leaf variegation phenotype. We found that the CRTISO substrate tetra-cis-lycopene accumulated during the dark periods under SD, but not under CL conditions. Its accumulation was also positively correlated with 1O2 levels generated during the light period, which consequently altered the expression of 1O2-responsive and cell death-related genes in the variegated z2 leaves. Taking these results together, we propose that the z2 leaf variegation can be largely attributed to photoperiodic accumulation of tetra-cis-lycopene and generation of excessive 1O2 under natural day-night conditions.

Pollen development in flowering plants is regulated by a comprehensive pattern of genes. One way to produce hybrid rice based on nuclear male sterility is to find out firstly the potential promoters that function specifically in anthers since it is a specific site for transcription initiation and play key roles for the spatial and temporal expression of the genes. To implement this objective, we were selected promoter region of 16 genes based on the expression pattern of microarray and then those were introduced into the promoterless final destination vector which containing the GFP and GUS reporters genes. The resulting twelve vectors were transformed into monocotyledonous rice (Oryza sativa L) and a dicotyledonous Arabidopsis as heterologous system. Minimum 20 plants for each vector were analyzed by histochemical GUS assay at the flowering stage in Arabidopsis. 9 vectors out of 12 vectors constructed were expressed exclusively at the anther, especially in pollen, however one vector exhibited expression in stigma. For rice, T-DNA insertion were confirmed with specific primers in each promoter and GFP region. All T0 transgenic plants contained T-DNA insertion in their genome. This study would provide valuable information for biotechnological application for the induction of male sterility in plants.

Calcium-binding proteins, like calcineurin B-like (CBL) proteins, represent important roles in plant calcium signaling. Calcium signals mediate a multitude of plant responses to external stimuli and regulate a wide range of physiological processes including pathogens, abiotic stresses and hormones. These proteins form a complex network with their target kinases being the CBL-interacting protein kinases (CIPKs). CBL genes play vital roles in multiple abiotic stress response pathways whereas some of these are more specifically involved in mediating ABA signaling. In this study, we collected 17 CBL genes designated as B. rapa CBL (BrCBL) from the Brassica database and analyzed the sequences. In comparison analysis, these genes showed high homology with published CBL genes of other species. An organ specific expression of these genes was observed in different organs of chinese cabbage plants. In addition, six BrCBL genes showed responsive expression after cold and drought stress treatments at certain time courses. All these data revealed that these CBL genes might be useful resources in developing abiotic stresses resistance Brassica.

Arabidopsis atDjC53 and atDjC32 gene DnaJ-like protein homologous to DnaJ-like protein was characterized for the functional analysis of DnaJ-like protein. It was shown that atDjC53 and atDjC32 RNA expression is induced by heat shock stress and atDjC53- and atDjC32-GFP was targeted to the nucleus of protoplasts. The atDjC53 and atDjC32 promoter (1 kb) was isolated and fused to the GUS reporter gene to investigate gene regulation of atDjC53 and atDjC32 specific to heat shock stress or to developmental organ in the transgenic lines. RNAi and overexpression construct was employed to generate atDjC53 and atDjC32 knock-out plants for the study of their function. Molecular function of atDjC53 and atDjC32 is discussed in relation to heat shock and also developmental stages in Arabidopsis.

The timing of flowering, which is of crucial importance for plant growth and survival, is controlled by intricate pathways. To identify heading date-QTL, we constructed high resolution map on chromosome 3 using heterogeneous inbred family-near isogenic lines (H-NILs) derived from F7 RILs generated by the cross of early-heading japonica rice ‘H143’ and middle-late-heading indica-japonica hybrid cultivar ‘Milyang23’. QTL and subsequent sequence analysis using H-NILs revealed that the gene underlining QTL EH3, which is detected in the region of Hd16, is EL1 encoding casein kinase I (CKI). Two types of single amino acid substitutions in Ser/Thr kinase domain of EL1 were found in various cultivars, among which H-NIL(eh3) caused loss of function in EL1 demonstrated by altered heading date and GA response. Moreover, the phosphorylation of EL1 appears to involve in EL1 activity to regulate heading date. Transcriptional analysis clearly indicated that H-NIL(EH3) suppresses heading under LD conditions by down-regulating Ehd1, there by Hd3a and RFT1 expressions were not induced, suggesting that EL1 is photoperiod-sensitive and functions as a LD-specific suppressor of heading. Further characterization suggested that EL1 is likely to involve in anther development and seed settings by regulating GAMYB expression. Our study demonstrated that the genetic basis of natural variation occurred in ‘H143’ was revealed by QTL analysis using H-NILs, and EH3/EL1 function is crucial for heading and development in rice. The genetic natural variation of H-NIL(eh3) may have contributed to adaptation of rice cultivation to the higher regions by regulating the expression of rice flowering activator genes and GA signaling.

The molecular processing of upstream regulation of Pi response genes during Pi starvation remains inadequately understood. several transcription factor have been studied that appear to regulate subsets of the responses to Pi stress either positively or negatively. MYB gene is responsive to one or multiple type of hormone and stress treatments. In this study, cDNA of the MYB have been cloned, and we generated Rice overexpressing plants for characterization of these genes .OsMYB gene’s functions focused on phosphate conditions with rice and Arabidopsis transgenic plants. We selected 30 - T1 transgenic lines from T0 transgenic rices. those are shown high Pi content. The Pi contents of shoots part of transgenic plants were shown 10~20% increased Pi contents than WT, whereas roots have 30% increased Pi contents. As a result, OsMYB genes affect Pi uptake in plants. To investigate interactions between MYB proteins and phosphate signaling related genes.

Composition of nutrient media, flower bud size, cold pretreatment, heat shock stress, and ethylene inhibitor could have marked effects on microspore embryogenesis. No microspore-derived embryos (MDE) were formed when microspores were isolated from radish (Raphanus sativus L.) flower buds of 1.0-2.5 mm in size, whereas MDE were formed with microspores isolated from 2.5-4.5 and 4.5-6.5 mm flower buds. The microspores isolated from 2.5-4.5 mm flower buds showed high embryo yields. When the isolated microspores were washed with Nitsch & Nitsch (NLN) liquid medium containing 130 g‧L-1 sucrose (NLN-13), the yield of MDE increased significantly when comparing with washing using B-5 liquid medium containing 130 g‧L-1 sucrose.Microspores cultured on half strength NLN liquid medium containing 0.05 mgL-1 silver nitrate (AgNO3) produced the most MDE, showing a more than two-fold increase in yield compared to those cultured on medium without AgNO3. A heat shock pretreatment of microspores at 32°C for 24 h gave high-frequency production of MDE when compare to higher or lower temperatures; no MDE were formed at 42.5°C. Microspore viability is known to decrease rapidly with storage; however, in this experiment, microspore viability was maintained for 24 h at 4°C without media. A polyploidy test indicated that 19.7% of the microspore-derived plants were double haploid, other plants were haploid, and chimeras were haploid and diploid. This protocol is thought to be very useful for efficient production of homozygous lines that is critical for the production of radish F1 hybrids

Grain yield, one of the most important agronomic traits, is greatly affected by architecture in rice. Here, we show that an OsPrMC3, a rice PrMC3 orthologue with a lipase or esterase domain, involves in yielding by tillering. Phenotypic analysis of T-DNA insertion mutant revealed that it has high number of tillers than wild type although height and leaf width are shorter and narrower than wild type. Size and branch number of panicle were greatly reduced in the mutant, which resulted in significant decrease of seed number per panicle and dry weight of the seeds. OsPrMC3 is highly expressed in the leaf during the early stage of development. However, it is mainly expressed in mature seed and root after flowering although its expression is detected in all of the tissues. Our result indicates that OsPrMC3 involves in leaf growth and tillering during vegetative growth and also seed development after flowering, suggesting its crucial regulatory role in yielding

The use of functional markers, it is expected to make direct identification about genetic diversity at DNA level and overcome the problem of recombination /linkage. These markers can be used to identify interesting alleles in a breeding program and indirectly select for the trait, saving money, time and labor. Bacterial blight of rice caused by Xanthomonas oryzaepv. Oryzae is a destructive disease in rice production worldwide. No bactericide is effective to control the bacterial blight disease yet. Xa3, which is a gene conferring resistance to BB of the rice plant has been previously characterized by map-based cloning. We have cloned and sequenced the Xa3/xa3 gene in Korean cultivar, Hwayoung, Ilmi and Goun with gene specific primers. Our work detected polymorphisms and PCR-based allele specific SNP markers were developed. Susceptible or resistant individuals from an F2 population developed from across between Milyang244 and Ilmi, Korean germplasms and near isogenic lines carrying BB resistance genes were screened with allele specific markers. We found that the genotype completely matched their phenotype to BB using ASP-primers. These markers could be effective to marker-assisted selection for the Xa3 gene in rice breeding programs.

Tocopherols (α-, β-, γ- and δ-tocopherols) represent a group of lipophilic antioxidants which are synthesized only by photosynthetic organisms. It is widely believed that protection of pigments and proteins of photosynthetic system and polyunsaturated fatty acids from oxidative damage caused by reactive oxygen species (ROS) is the main function of tocopherols. In the present study, NtTC, which encodes a tobacco tocopherol cyclase ortholog, was cloned and characterized. Compared with control plants, NtTC transgenic rice showed higher tolerance to drought stress, and total tocopherol content increased by 52 % in leaf. Additionally, total antioxitant activity of NtTC transgenic lines was increased significantly by 19%. These results demonstrate that over-expressing NtTC could improve the tolerance to abiotic stress in rice, and tocopherols play a crucial role in the protection of oxidative stress.

Farmers have use phosphate fertilizer to provide sufficient yields. However, overuse of phosphorus accumulate in soil and causes soil and water pollution. We evaluated the phosphate acquisition and growth characteristics of OsPT1 transgenic rice (OsPT1-OX, over-expressing the high affinity phosphate transporter 1) in high phosphate soils with different level of nitrogen fertilizer treatment to investigate removing ability of excessive phosphate from soil. OsPT1-OX had shorter culm length but more tillers than those of wild-type plants in each soil conditions. Phosphate content per dry weight of OsPT1-OX was 1.8 times higher than that of wild-type under control fertilizer treated conditions. Although the dry weight of OsPT1-OX was not different from that of wild-type plants, whole plant phosphate content was 1.7 times higher than that of wild-type plants under control fertilizer conditions. Tiller number and phosphate content per dry weight of wild-type plants increased following high levels of phosphate application but did not change by following additional nitrogen application. Tiller number and phosphate content per dry weight of OsPT1-OX did not change under the high phosphate condition, but increased following nitrogen application under similar conditions. Whole plant phosphate content was highest under high nitrogen and high phosphate application conditions. These results suggest that OsPT1-OX may reduce phosphate content in soils containing excess phosphate and may be further effective under high nitrogen condition.

Understanding the host defense mechanisms in response to brown leaf spot disease caused by Cochliobolus miyabeanus is very important for production of resistant plant. In this study, two-dimensional gel electrophoresis (2-DGE) in conjunction with mass spectrometry was utilized to unravel changes of stress inducible proteins in rice leaves infected with C. miyabeanus. For this purpose, we firstly observed disease developmental process of C. miyabeanus in rice using trypan blue, anilin blue, acid fuchsin staining, and DAB staining for ROS detection and expressional abundance of ROS related proteins in rice leaves inoculated was confirmed by Western blotting. Proteins were extracted by PEG fractionation and their expression patterns were analyzed by 2-DGE and subjected to image analysis using the ImageMaster 6.0 2D Platinum software, resulting in the identification of 86 differentially expressed protein spots with significantly changes (p<0.05) compared with control. MALDI-TOFTOF-MS analysis revealed that 69 proteins including 42 and 27 significantly up- and down-regulated proteins, respectively, were identified. Based on gene ontology analysis, identified proteins were classified according to their functional groups: metabolism (20%), oxygen-detoxifying (13%), protein stress/defense (24%). Thus, these results for the first time suggest that differentially induced proteins may play a key role for understanding host defense mechanisms during rice -C. miyabeanus interaction.

Protein disulfide isomerase (PDI) is a chaperone protein that involves in oxidative protein folding by acting as catalysts and folding assistants in the endoplasmic reticulum (ER). Genome database showed that rice contains three PDI-like genes. But, their functions and subcellullar localization are not clearly identified. Here, we show possible functions of rice PDI (OsPDI) during seed development. Seeds of OsPDI T-DNA insertion mutants which were identified by genomic DNA PCR and western blot display chalky phenotype. Electron microscope analysis revealed that endosperms of the OsPDIL1-1Δ mutant show imperfect packing of round starch granules, causing floury-white color. Abnormal form of protein body I (PB-I) containing prolamin and thick aleurone layer were also observed in the OsPDIL1-1Δ mutants. Protein content per seed was significantly low in the OsPDIL1-1Δ mutant. However, free sugar content was high in the OsPDIL1-1Δ mutant seed. Northern and western blot analyses showed that during seed development, OsPDI protein is steadily accumulated in the seed until maturation while its transcript level was highest at 10 days after flowering and rapidly decreased to basal level. In addition, OsPDI strongly interacts with cysteine protease OsCP1 and chaperone BiP protein accumulates in OsPDIL1-1Δ mutant. Besides, proteomic analysis of the OsPDIL1-1Δ mutant seed showed that OsPDI is post-translationally regulated and its loss causes accumulation of many types of seed proteins. Our results indicate that OsPDI plays a critical role in seed development through its regulatory activity for various proteins.

Heterosis describes the increased performance of F1 hybrid plants in terms of increased biomass, yield, vegetative growth rate, and tolerance against biotic and abiotic stresses as compared with their inbred parents. Two sets of rice materials, 166 RILs derived from a cross between Milyang 23 (Korean indica-type rice) and Tong 88-7 (japonica Rice), and BC1F1 hybrids derived from crosses between the RILs and the female parent, Milyang 23, were produced to identify QTLs for heterosis of yield and yield-related traits. The QTLs were detected from three different phenotype data sets including the RILs, BC1F1 hybrids, and mid-parental heterosis data set. A total of 57 QTLs were identified for nine traits. Of eight QTLs detected for yield heterosis, five overlapped with other heterosis QTLs for yield-related traits such as spikelet number per panicle, days to heading, and spikelet fertility. Four QTLs for yield heterosis, gy1.1, py6, gy10, and py11, were newly identified in this study. We identified a total of 17 EpQTLs for yield heterosis that explain 21.4 ~ 59.0 % of total phenotypic variation, indicating that epistatic interactions may play an important role in heterosis.

The HWC-line of rice showed wide compatibility with both indica and japonica cultivars, tall culm length, long and slender grain shape. For QTL analysis, two F2 populations were derived from the crosses between the HWC-line and each of two Korean variety, Dasanbyeo (Korean Tongil-type cultivar) and Hwacheongbyeo (temperate japonica cultivar), respectively. A total of 190 F2 plants were evaluated in each of two F2 populations. Eight agronomic characters were measured for QTL analysis in F2 populations and parents. Two molecular linkage maps were constructed. In the F2 population from cross between HWC-line / Dasanbyeo (HD) cross, 93 STS markers and 13 SSR markers were mapped on 12 chromosomes, covering a total length of 1942.6 cM, with an average distance of 18.33cM between adjacent markers. In the F2 population from HWC-line / Hwacheongbyeo (HH) cross, 28 STS markers, 29 SSR markers and 1 FNP marker were mapped on 11 chromosomes, spanning a total length of 925.53cM, with an average distance of 15.96cM between adjacent markers. In the F2 population from HD cross, 16 M-QTLs and 1 E-QTL were detected for culm length, spikelets per panicle, spikelet fertility, grain length, grain width, grain shape and 100 grains weight. 7 QTLs of spikelet fertility, grain length, grain width and grain shape were newly identified in this study. In the F2 population from HH cross, 15 M-QTLs were detected for culm length, panicle length, spikelet fertility, grain length, grain width, grain shape and 100 grains weight. 6 QTLs of culm length, grain length, grain width and grain shape were newly identified in this study. The QTLs identified in this study would provide basic information on putative functional genes related agronomic characters and facilitate breed new rice cultivar.

Hybrid sterility is one of the major barrier to the application of wide crosses in plant breeding and is commonly encountered in crosses between indica and japonica rice varieties. Ten mapping populations comprised of two reciprocal F2 and eight BC1F1 populations generated from the cross between Ilpumbyeo (japonica) and Dasanbyeo (indica) were used to identify QTLs and to interpret the gametophytic factors involved in hybrid fertility or sterility between two subspecies. Frame maps were constructed using a total of 107 and 144 STS markers covering 12 rice chromosomes in two reciprocal F2 and eight BC1F1 populations, respectively. A total of 15 main-effect QTLs and 17 significant digenic- epistatic interactions controlling spikelet fertility (SF) were resolved in the the entire genome map of F2 BC1F1 populations . Among detected QTLs responsible for hybrid ferility, four QTLs, qSF5.1 and and qS F5.2 on chromosome 5, qSF6.2 on chromosome 6, and qSF12.2 on chromosome 12 were identified as major QTLs since they were located at corresponding position in at least three mapping populations. Loci qSF5.1, qSF6.1 and qSF6.2 were responsible for both female and male sterility, whereas qSF3.1, qSF7 and qSF 12.2 affected the spikelet fertility only through embryosac factors, and qSF9.1 did through pollen factors. Five new QTLs identified in this study will be helpful for understanding the hybrid sterility and for breeding programs via inter-subspecific hybridization.

Hybrid sterility is one of the major barrier to the application of wide crosses in plant breeding and is commonly encountered in crosses between indica and japonica rice varieties. Ten mapping populations comprised of two reciprocal F2 and eight BC1F1 populations generated from the cross between Ilpumbyeo (japonica) and Dasanbyeo (indica) were used to identify QTLs and to interpret the gametophytic factors involved in hybrid fertility or sterility between two subspecies. Frame maps were constructed using a total of 107 and 144 STS markers covering 12 rice chromosomes in two reciprocal F2 and eight BC1F1 populations, respectively. A total of 15 main-effect QTLs and 17 significant digenic- epistatic interactions controlling spikelet fertility (SF) were resolved in the the entire genome map of F2 BC1F1 populations . Among detected QTLs responsible for hybrid ferility, four QTLs, qSF5.1 and and qS F5.2 on chromosome 5, qSF6.2 on chromosome 6, and qSF12.2 on chromosome 12 were identified as major QTLs since they were located at corresponding position in at least three mapping populations. Loci qSF5.1, qSF6.1 and qSF6.2 were responsible for both female and male sterility, whereas qSF3.1, qSF7 and qSF 12.2 affected the spikelet fertility only through embryosac factors, and qSF9.1 did through pollen factors. Five new QTLs identified in this study will be helpful for understanding the hybrid sterility and for breeding programs via inter-subspecific hybridization.

최근 옥수수는 식량작물의 역할과 더불어 간식용, 사료용, 공업원료 등의 다양한 용도로 이용되고 있다. 현재 강원도 농업기술원 옥수수시험장에서는 천연색소 원료로 이용될 수 있고, 항암, 항산화, 항당뇨에 효과가 있다고 알려진 안토시아닌 색소를 함유한 기능성 색소옥수수자식계통들을 육성하고 있다. 따라서 본 연구는 강원도 농업기술원 옥수수시험장에서 육성한 색소옥수수 24계통(색소포엽 옥수수 9계통, 색소종실 옥수수 3계통, 색소찰 옥수수 12계통)들과 종실옥수수 2 계통, 찰옥수수 5 계통들에 대하여 분자생물학적 분석법인 SSR 분자마커를 이용하여 색소옥수수 자식계통들에서 특이적으로 나타나는 분자마커를 찾기 위하여 유전적 다양성, 계통유연관계 및 집단구조를 분석하였다. 그 결과 분석에 이용된 50개의 SSR primer들은 31개의 옥수수 자식계통들에서 총 282개의 대립단편을 나타내었으며, 각 SSR primer 당 증폭된 대립단편의 수는 2개(umc2338)에서 11개(bnlg279)의 범위로 나타나, 평균 대립단편 수는 5.64개였다. 이들 집단들에서 측정된 Gene diversity 값은 전체 50개의 SSR 마커들에서 0.17(umc2338)∼0.86(bnlg279)의 범위로 나타나 평균 0.67의 값을 보였으며, PIC 값은 0.16(umc2338)∼0.84(bnlg279)의 범위로 나타나 평균 0.62의 값을 보였다. 본 연구에서 색소옥수수 계통 중 색소포엽 옥수수와 색소알곡 옥수수에 특이적으로 나타나는 대립단편을 분석한 결과, 총 100개의 특이적 대립단편을 확인하였다. 이들 100개 대립단편 중에서, 색소포엽 옥수수 자식계통들에서 특이적으로 나타나는 대립단편은 55개로 확인되었고, 색소알곡 옥수수 자식계통들에서 특이적으로 나타나는 대립단편은 45개로 확인되었다. 집단구조 분석 결과에 의하면, 31개의 옥수수 자식계통들은 membership probability threshold 0.8을 기준으로, Groups I, II, III, IV, V 그리고 admixed group으로 나누어 졌다. 그리고 UPGMA 법에 의한 계통유연관계 분석에서 31개의 옥수수 자식계통들은 유전적 유사성 27.4% 수준에서 크게 3개의 그룹으로 분리되었다. 첫 번째 그룹은 10개의 옥수수 자식계통(종실옥수수 2 계통, 찰옥수수 2 계통, 색소옥수수 6계통)들로 구성되었고, 두 번째 그룹은 20개의 계통(찰옥수수 3 계통, 색소옥수수 5계통, 색소찰옥수수 12계통)들로 구성되어 있었으며, 세 번째 그룹은 색소옥수수 1 계통으로 구성되어 있었다. 본 연구의 결과는 색소 옥수수 자식계통들에 대한 유전적 변이성 및 계통유연관계 그리고 집단구조를 밝힘으로써 앞으로 색소용 종실 및 찰옥수수 그리고 색소용 포엽 옥수수의 신품종을 개발하기 위한 육종연구에 유용한 정보를 제공할 것으로 기대된다.

The ureide pathway has recently been identified as the metabolic route of purine catabolism in plants and some bacteria. In this pathway, uric acid, which is a major product of the early stage of purine catabolism, is degraded into glyoxylate and ammonia via stepwise reactions of seven different enzymes. Therefore, the pathway has a possible physiological role in mobilization of purine ring nitrogen for further assimilation. (S)-Ureidoglycine aminohydrolase enzyme converts (S)-ureidoglycine into (S)-ureidoglycolate and ammonia, providing the final substrate to the pathway. Here, we report a structural and functional analysis of this enzyme from Arabidopsis thaliana (AtUGlyAH). The crystal structure of AtUGlyAH in the apo-form shows a monomer structure in the bi-cupin fold of the β-barrel and an octameric functional unit, as well as an Mn2+ ion binding site. The structure of AtUGlyAH in complex with (S)-ureidoglycine revealed that the Mn2+ ion acts as a molecular anchor to bind (S)-ureidoglycine and its binding mode dictates the enantioselectivity of the reaction. Further kinetic analysis characterized the functional roles of the active site residues, including the Mn2+ ion binding site and residues in the vicinity of (S)-ureidoglycine. These analyses provide molecular insights into the structure of the enzyme and its possible catalytic mechanism.

In higher plants, formate dehydrogenase (FDH; EC 1.2.1.2) is a NAD-dependent enzyme that catalyzes the oxidation of formate into carbon dioxide. Although FDHs have been reported to be induced by various abiotic stresses, the function of FDHs in biotic stress is rarely known. In this work, we describe the identification of pepper mitochondrial FORMATE DEHYDROGENASE1 (CaFDH1) as a positive regulator of cell death and disease resistance. Transient expression of CaFDH1 in Nicotiana benthamiana leaves caused hypersensitive response (HR)-like cell death, where D-isomer specific 2-hydroxyacid dehydrogenase signature was crucial for the induction of the cell death. Localization analysis using green fluorescence protein showed that CaFDH1 targeted to the mitochondria with the mitochondria targeting sequence at N-terminal region. However, the mitochondrial localization of CaFDH1 is not essential for the induction of HR-like cell death, because the cytosolic CaFDH1 could elicit cell death response. Silencing of CaFDH1 in pepper significantly compromised the cell death response and salicylic acid (SA) levels, but enhanced growth of Xanthomonas campestris pv. vesicatoria. In contrast, transgenic Arabidopsis overexpressing FDH1 exhibited enhanced resistance to Pseudomonas syringae pv. tomato. Taken together, these data suggest that CaFDH1 has a role in HR cell death and defense response to microbial pathogens.