Pi5 and Pii Paired NLRs Are Functionally Exchangeable and Confer Similar Disease Resistance Specificity

VO THI XUAN KIEU,이상규,Morgan K. Halane,송민영,Trung Viet Hoang,김치열,박숙영,전준현,김선태,손기훈,전종성 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.9

Effector-triggered immunity (ETI) is an effective layer of plant defense initiated upon recognition of avirulence (Avr) effectors from pathogens by cognate plant disease resistance (R) proteins. In rice, a large number of R genes have been characterized from various cultivars and have greatly contributed to breeding programs to improve resistance against the rice blast pathogen Magnaporthe oryzae. The extreme diversity of R gene repertoires is thought to be a result of co-evolutionary history between rice and its pathogens including M. oryzae. Here we show that Pii is an allele of Pi5 by DNA sequence characterization and complementation analysis. Pii-1 and Pii-2 cDNAs were cloned by reverse transcription polymerase chain reaction from the Pii-carrying cultivar Fujisaka5. The complementation test in susceptible rice cultivar Dongjin demonstrated that the rice blast resistance mediated by Pii, similar to Pi5, requires the presence of two nucleotide-binding leucine-rich repeat genes, Pii-1 and Pii-2. Consistent with our hypothesis that Pi5 and Pii are functionally indistinguishable, the replacement of Pii-1 by Pi5-1 and Pii-2 by Pi5-2, respectively, does not change the level of disease resistance to M. oryzae carrying AVR-Pii. Surprisingly, Exo70F3, required for Pii-mediated resistance, is dispensable for Pi5-mediated resistance. Based on our results, despite similarities observed between Pi5 and Pii, we hypothesize that Pi5 and Pii pairs require partially distinct mechanisms to function.

Pi5 and Pii Paired NLRs Are Functionally Exchangeable and Confer Similar Disease Resistance Specificity

Vo, Kieu Thi Xuan,Lee, Sang-Kyu,Halane, Morgan K.,Song, Min-Young,Hoang, Trung Viet,Kim, Chi-Yeol,Park, Sook-Young,Jeon, Junhyun,Kim, Sun Tae,Sohn, Kee Hoon,Jeon, Jong-Seong Korean Society for Molecular and Cellular Biology 2019 Molecules and cells Vol.42 No.9

Effector-triggered immunity (ETI) is an effective layer of plant defense initiated upon recognition of avirulence (Avr) effectors from pathogens by cognate plant disease resistance (R) proteins. In rice, a large number of R genes have been characterized from various cultivars and have greatly contributed to breeding programs to improve resistance against the rice blast pathogen Magnaporthe oryzae. The extreme diversity of R gene repertoires is thought to be a result of co-evolutionary history between rice and its pathogens including M. oryzae. Here we show that Pii is an allele of Pi5 by DNA sequence characterization and complementation analysis. Pii-1 and Pii-2 cDNAs were cloned by reverse transcription polymerase chain reaction from the Pii-carrying cultivar Fujisaka5. The complementation test in susceptible rice cultivar Dongjin demonstrated that the rice blast resistance mediated by Pii, similar to Pi5, requires the presence of two nucleotide-binding leucine-rich repeat genes, Pii-1 and Pii-2. Consistent with our hypothesis that Pi5 and Pii are functionally indistinguishable, the replacement of Pii-1 by Pi5-1 and Pii-2 by Pi5-2, respectively, does not change the level of disease resistance to M. oryzae carrying AVR-Pii. Surprisingly, Exo70F3, required for Pii-mediated resistance, is dispensable for Pi5-mediated resistance. Based on our results, despite similarities observed between Pi5 and Pii, we hypothesize that Pi5 and Pii pairs require partially distinct mechanisms to function.

A rice sucrose non-fermenting-1 related protein kinase 1, OSK35, plays an important role in fungal and bacterial disease resistance

김치열,Kieu Thi Xuan Vo,안진흥,전종성 한국응용생명화학회 2015 Applied Biological Chemistry (Appl Biol Chem) Vol.58 No.5

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, and bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), impose serious limitations on rice productivity worldwide. Sucrose nonfermenting- 1 related protein kinases (SnRKs) have been suggested to play a role in global gene expression reprogramming in response to biotic stress. However, little is known in rice about the role of SnRKs in modulating disease resistance. Here, we characterized the function of OSK35, a rice SnRK1b gene, in disease resistance by analyzing two T-DNA mutants, OSK35-D, an activation line, and osk35, a knockout line. Both mutants and their respective wild-type controls were challenged with two different rice pathogens, M. oryzae and Xoo. The OSK35- D activation mutant showed enhanced resistance against both rice pathogens. Conversely, the osk35 null mutant was more susceptible to these pathogens, compared with wildtype controls. These results clearly indicate that OSK35 is a positive regulator of rice disease resistance upon fungal and bacterial pathogen invasion.

A rice sucrose non-fermenting-1 related protein kinase 1, OSK35, plays an important role in fungal and bacterial disease resistance

Kim, Chi-Yeol,Vo, Kieu Thi Xuan,An, Gynheung,Jeon, Jong-Seong The Korean Society for Applied Biological Chemistr 2015 Applied Biological Chemistry (Appl Biol Chem) Vol.58 No.5

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, and bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), impose serious limitations on rice productivity worldwide. Sucrose non-fermenting-1 related protein kinases (SnRKs) have been suggested to play a role in global gene expression reprogramming in response to biotic stress. However, little is known in rice about the role of SnRKs in modulating disease resistance. Here, we characterized the function of OSK35, a rice SnRK1b gene, in disease resistance by analyzing two T-DNA mutants, OSK35-D, an activation line, and osk35, a knockout line. Both mutants and their respective wild-type controls were challenged with two different rice pathogens, M. oryzae and Xoo. The OSK35-D activation mutant showed enhanced resistance against both rice pathogens. Conversely, the osk35 null mutant was more susceptible to these pathogens, compared with wild-type controls. These results clearly indicate that OSK35 is a positive regulator of rice disease resistance upon fungal and bacterial pathogen invasion.

Defense Response to Pathogens Through Epigenetic Regulation in Rice

Hoang, Trung Viet,Vo, Kieu Thi Xuan,Hong, Woo-Jong,Jung, Ki-Hong,Jeon, Jong-Seong Botanical Society of Korea 2018 Journal of plant biology Vol.61 No.1

Epigenetic factors have recently emerged as key regulators of the defense response to pathogens in plants. The epigenetic mechanisms underlying defense regulation have been investigated mostly in Arabidopsis, while our understanding of the epigenetic regulation of defense in rice is limited. In this review, we summarize recent findings surrounding epigenetic mechanisms for defense in rice, primarily focusing on DNA methylation, histone modification, and small RNA regulation. In particular, we focused on RNA-directed DNA methylation (RdDM) and other epigenetic regulatory mechanisms that are involved in disease resistance. Finally, we explored potential epigenetic factors that might regulate the defense response in rice by analyzing available microarray data that can be used to uncover details of epigenetics regulation.

Functional analysis of a cold-responsive rice WRKY gene, OsWRKY71

김치열,김성룡,정동훈,이상규,VO THI XUAN KIEU,Cong Danh Nguyen,Manu Kumar,박수현,전종성,김주곤 한국식물생명공학회 2016 Plant biotechnology reports Vol.10 No.1

Publicly available microarray data and RNA gel blot analysis identified a rice WRKY transcription factor, OsWRKY71, that is highly upregulated in response to cold stress. Experiments with OsWRKY71 promoter: GFP transgenic rice confirmed its cold-inducible expression. Transient expression of OsWRKY71-GFP in maize mesophyll protoplasts indicated that it is localized predominantly in the nucleus and to a lesser extent in the cytosol. Transcriptional activation assays revealed that OsWRKY71 suppresses luciferase reporter activity in maize protoplasts, suggesting that it functions as a transcriptional repressor in rice. To characterize the function of OsWRKY71 in rice, we generated transgenic rice plants carrying CaMV35S promoter:OsWRKY71. Upon cold (4℃) treatment, two selected OsWRKY71 transgenic lines, OX12 and OX21, recovered much better with respect to survival rate, photosynthetic ability, fresh weight, and dry weight than the control lines. RT-PCR analysis of known cold-responsive genes found that expression of OsTGFR and WSI76 was increased in OsWRKY71 transgenic lines in response to cold stress. Our results suggest that OsWRKY71 has a positive function in cold tolerance by regulating downstream target genes.

Enhanced resistance of PsbS-deficient rice (Oryza sativa L.) to fungal and bacterial pathogens

Ismayil S. Zulfugarov,Altanzaya Tovuu,김치열,Kieu Thi Xuan Vo,고수연,Michael Hall,석혜연,김연기,Oscar Skogstrom,문용환,Stefan Jansson,전종성,이춘환 한국식물학회 2016 Journal of Plant Biology Vol.59 No.6

The 22-kDa PsbS protein of Photosystem II is involved in nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Genome-wide analysis of the expression pattern in PsbS knockout (KO) rice plants showed that a lack of this protein led to changes in the transcript levels of 406 genes, presumably a result of superoxide produced in the chloroplasts. The top Gene Ontology categories, in which expression was the most differential, included ‘Immune response’, ‘Response to jasmonic acid’, and ‘MAPK cascade’. From those genes, we randomly selected nine that were up-regulated. Our microarray results were confirmed by quantitative RT-PCR analysis. The KO and PsbS RNAi (knockdown) plants were more resistant to pathogens Magnaporthe oryzae PO6-6 and Xanthomonas oryzae pv. oryzae than either the wild-type plants or PsbS-overexpressing transgenic line. These findings suggest that superoxide production might be the reason that these plants have greater pathogen resistance to fungal and bacterial pathogens in the absence of energy-dependent NPQ. For example, a high level of cell wall lignification in the KO mutants was possibly due to enhanced superoxide production. Our data indicate that certain abiotic stress-induced reactive oxygen species can promote specific signaling pathways, which then activate a defense mechanism against biotic stress in PsbS-KO rice plants.

Defense Response to Pathogens Through Epigenetic Regulation in Rice

전종성,정기홍,Trung Viet Hoang,VO THI XUAN KIEU,홍우종 한국식물학회 2018 Journal of Plant Biology Vol.61 No.1

Epigenetic factors have recently emerged as key regulators of the defense response to pathogens in plants. The epigenetic mechanisms underlying defense regulation have been investigated mostly in Arabidopsis, while our understanding of the epigenetic regulation of defense in rice is limited. In this review, we summarize recent findings surrounding epigenetic mechanisms for defense in rice, primarily focusing on DNA methylation, histone modification, and small RNA regulation. In particular, we focused on RNA-directed DNA methylation (RdDM) and other epigenetic regulatory mechanisms that are involved in disease resistance. Finally, we explored potential epigenetic factors that might regulate the defense response in rice by analyzing available microarray data that can be used to uncover details of epigenetics regulation.