scholarly journals Suppression of the Rice Fatty-Acid Desaturase Gene OsSSI2 Enhances Resistance to Blast and Leaf Blight Diseases in Rice

2009 ◽  
Vol 22 (7) ◽  
pp. 820-829 ◽  
Author(s):  
Chang-Jie Jiang ◽  
Masaki Shimono ◽  
Satoru Maeda ◽  
Haruhiko Inoue ◽  
Masaki Mori ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Fatty Acid ◽  
Magnaporthe Grisea ◽  
Acyl Carrier Protein ◽  
Fatty Acid Desaturase ◽  
Defense Responses ◽  
Leaf Blight ◽  
Insertion Mutation ◽  
Rice Plants ◽  
Transposon Insertion

Fatty acids and their derivatives play important signaling roles in plant defense responses. It has been shown that suppressing a gene for stearoyl acyl carrier protein fatty-acid desaturase (SACPD) enhances the resistance of Arabidopsis (SSI2) and soybean to multiple pathogens. In this study, we present functional analyses of a rice homolog of SSI2 (OsSSI2) in disease resistance of rice plants. A transposon insertion mutation (Osssi2-Tos17) and RNAi-mediated knockdown of OsSSI2 (OsSSI2-kd) reduced the oleic acid (18:1) level and increased that of stearic acid (18:0), indicating that OsSSI2 is responsible for fatty-acid desaturase activity. These plants displayed spontaneous lesion formation in leaf blades, retarded growth, slight increase in endogenous free salicylic acid (SA) levels, and SA/benzothiadiazole (BTH)-specific inducible genes, including WRKY45, a key regulator of SA/BTH-induced resistance, in rice. Moreover, the OsSSI2-kd plants showed markedly enhanced resistance to the blast fungus Magnaporthe grisea and leaf-blight bacteria Xanthomonas oryzae pv. oryzae. These results suggest that OsSSI2 is involved in the negative regulation of defense responses in rice, as are its Arabidopsis and soybean counterparts. Microarray analyses identified 406 genes that were differentially expressed (≥2-fold) in OsSSI2-kd rice plants compared with wild-type rice and, of these, approximately 39% were BTH responsive. Taken together, our results suggest that induction of SA-responsive genes, including WRKY45, is likely responsible for enhanced disease resistance in OsSSI2-kd rice plants.

scholarly journals Disease Resistance against Magnaporthe grisea is Enhanced in Transgenic Rice with Suppression of  -3 Fatty Acid Desaturases

2007 ◽  
Vol 48 (9) ◽  
pp. 1263-1274 ◽  
Author(s):  
A. Yara ◽  
T. Yaeno ◽  
M. Hasegawa ◽  
H. Seto ◽  
J.-L. Montillet ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Fatty Acid ◽  
Transgenic Rice ◽  
Magnaporthe Grisea ◽  
Fatty Acid Desaturases

scholarly journals Preferential synthesis of very long chain polyunsaturated fatty acids in eutreptiella sp. (eugelnozoa) revealed by chromatographic and transcriptomic analyses

2020 ◽  
Author(s):  
Rita C. Kuo ◽  
Huan Zhang ◽  
James D. Stuart ◽  
Anthony A. Provatas ◽  
Linda Hannick ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Carbon Fixation ◽  
Acyl Carrier Protein ◽  
Lipid Production ◽  
Fatty Acid Desaturase ◽  
Biofuel Production ◽  
Type I ◽  
Long Chain

AbstractAlgal lipids are important fuel storage molecules in algae and a currency for energy transfer in the marine food chain as well as materials for biofuel production, but their production and regulation are not well understood in many species including the common coastal phytoplankton Eutreptiella spp. Here, using gas chromatography-tandem mass spectrometry (GC/MS/MS), we discovered 24 types of fatty acids (FAs) in Eutreptiella sp. with a relatively high proportion of long chain unsaturated FAs. The abundances of C16, C18 and saturated FAs decreased when phosphate in the culture medium was depleted. Among the 24 FAs, docosahexaenoic acid (22:6) and eicosapentaenoic acid (20:5) were the most abundant, suggesting that Eutreptiella sp. preferentially invests in the synthesis of very long chain polyunsaturated fatty acids (VLCPFA). Further transcriptomic analysis revealed that Eutreptiella sp. likely synthesizes VLCPFA via Δ8 pathway and uses type I and II fatty acid synthases. Using RT-qPCR, we found that some of the lipid production genes, such as β-ketoacyl-ACP reductase, fatty acid desaturase, acetyl-CoA carboxylase, acyl carrier protein, Δ8 desaturase, and Acyl-ACP thioesterase, were more actively expressed during light period. Besides, two carbon-fixation genes were more highly expressed in the high lipid illuminated cultures, suggesting a linkage between photosynthesis and lipid production.

scholarly journals Silencing Genes Encoding Omega-3 Fatty Acid Desaturase Alters Seed Size and Accumulation of Bean pod mottle virus in Soybean

2011 ◽  
Vol 24 (4) ◽  
pp. 506-515 ◽  
Author(s):  
Ajay Kumar Singh ◽  
Da-Qi Fu ◽  
Mohamed El-Habbak ◽  
Duroy Navarre ◽  
Said Ghabrial ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Pseudomonas Syringae ◽  
Fatty Acid Desaturase ◽  
Defense Responses ◽  
Mottle Virus ◽  
Omega 3 ◽  
Bean Pod Mottle Virus ◽  
Omega 3 Fatty Acid ◽  
Pathogenesis Related ◽  
Genes Encoding

Omega-3 fatty acid desaturase (FAD3)-catalyzed conversion of linoleic acid to linolenic acid (18:3) is an important step for the biosynthesis of fatty acids as well as the phytohormone jasmonic acid (JA) in plants. We report that silencing three microsomal isoforms of GmFAD3 enhanced the accumulation of Bean pod mottle virus (BPMV) in soybean. The GmFAD3-silenced plants also accumulated higher levels of JA, even though they contained slightly reduced levels of 18:3. Consequently, the GmFAD3-silenced plants expressed JA-responsive pathogenesis-related genes constitutively and exhibited enhanced susceptibility to virulent Pseudomonas syringae. Increased accumulation of BPMV in GmFAD3-silenced plants was likely associated with their JA levels, because exogenous JA application also increased BPMV accumulation. The JA-derived increase in BPMV levels was likely not due to repression of salicylic acid (SA)-derived signaling because the GmFAD3-silenced plants were enhanced in SA-dependent defenses. Furthermore, neither exogenous SA application nor silencing the SA-synthesizing phenylalanine ammonia lyase gene altered BPMV levels in soybean. In addition to the altered defense responses, the GmFAD3-silenced plants also produced significantly larger and heavier seed. Our results indicate that loss of GmFAD3 enhances JA accumulation and, thereby, susceptibility to BPMV in soybean.

scholarly journals Identification of Specific Fragments of HpaGXooc, a Harpin from Xanthomonas oryzae pv. oryzicola, that Induce Disease Resistance and Enhance Growth in Plants

2008 ◽  
Vol 98 (7) ◽  
pp. 781-791 ◽  
Author(s):  
Lei Chen ◽  
Jun Qian ◽  
Shuping Qu ◽  
Juying Long ◽  
Qian Yin ◽  
...  
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Amino Acid ◽  
Pathogenic Bacteria ◽  
Magnaporthe Grisea ◽  
Defense Responses ◽  
Xanthomonas Oryzae ◽  
Hypersensitive Cell Death ◽  
Beneficial Effects ◽  
Parent Protein

Harpin proteins from gram-negative plant-pathogenic bacteria can stimulate hypersensitive cell death (HCD) and pathogen defense as well as enhance growth in plants. Two of these diverse activities clearly are beneficial and may depend on particular functional regions of the proteins. Identification of beneficial and deleterious regions might facilitate the beneficial use of harpin-related proteins on crops without causing negative effects like cell death. Here, we report the identification and testing of nine functional fragments of HpaGXooc, a 137-amino-acid harpin protein from Xanthomonas oryzae pv. oryzicola, the pathogen that causes bacterial leaf streak of rice. Polymerase chain reaction-based mutagenesis generated nine proteinaceous fragments of HpaGXooc; these caused different responses following their application to Nicotiana tabacum (tobacco) and Oryza sativa (rice). Fragment HpaG62-137, which spans the indicated amino acid residues of the HpaG, induced more intense HCD; in contrast, HpaG10-42 did not cause evident cell death in tobacco. However, both fragments stimulated stronger defense responses and enhanced more growth in rice than the full-length parent protein, HpaGXooc. Of the nine fragments, the parent protein and one deletion mutant of HpaGXooc tested, HpaG10-42, stimulated higher levels of rice growth and resulted in greater levels of resistance to X. oryzae pv. oryzae and Magnaporthe grisea. These pathogens cause bacterial leaf blight and rice blast, respectively, the two most important diseases of rice world-wide. HpaG10-42 was more active than HpaGXooc in inducing expression of several genes that regulate rice defense and growth processes and activating certain signaling pathways, which may explain the greater beneficial effects observed from treatment with that fragment. Overall, our results suggest that HpaG10-42 holds promise for practical agricultural use to induce disease resistance and enhance growth of rice.

scholarly journals Protein Elicitor PemG1 from Magnaporthe grisea Induces Systemic Acquired Resistance (SAR) in Plants

2011 ◽  
Vol 24 (10) ◽  
pp. 1239-1246 ◽  
Author(s):  
Dong-Hai Peng ◽  
De-Wen Qiu ◽  
Li-Fang Ruan ◽  
Chen-Fei Zhou ◽  
Ming Sun
Keyword(s):  
Disease Resistance ◽  
Bacterial Infection ◽  
Plant Disease Resistance ◽  
Plant Disease ◽  
Magnaporthe Grisea ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Defense Responses ◽  
Channel Blockers ◽  
Protein Elicitor

Elicitors can stimulate defense responses in plants and have become a popular strategy in plant disease control. Previously, we isolated a novel protein elicitor, PemG1, from Magnaporthe grisea. In the present study, PemG1 protein expressed in and purified from Escherichia coli improved resistance of rice and Arabidopsis to bacterial infection, induced transient expression of pathogenesis-related (PR) genes, and increased accumulation of hydrogen peroxide in rice. The effects of PemG1 on disease resistance and PR gene expression were mobilized systemically throughout the rice plant and persisted for more than 28 days. PemG1-induced accumulation of OsPR-1a in rice was prevented by the calcium channel blockers LaCl3, BAPTA, EGTA, W7, and TFP. Arabidopsis mutants that are insensitive to jasmonic acid (JA) and ethylene showed increased resistance to bacterial infection after PemG1 treatment but PemG1 did not affect resistance of mutants with an impaired salicylic acid (SA) transduction pathway. In rice, PemG1 induced overexpressions of the SA signal-related genes (OsEDS1, OsPAL1, and OsNH1) but not the JA pathway-related genes (OsLOX2 and OsAOS2). Our findings reveal that PemG1 protein can function as an activator of plant disease resistance, and the PemG1-mediated systemic acquired resistance is modulated by SA- and Ca2+-related signaling pathways.

scholarly journals Iron treatment induces defense responses and disease resistance against Magnaporthe oryzae in rice

2021 ◽  
Author(s):  
Ferran Sanchez-Sanuy ◽  
Roberto Mateluna Cuadra ◽  
Kazunori Okada ◽  
Gian Attilio Sacchi ◽  
Sonia Campo ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Iron Homeostasis ◽  
Molecular Mechanisms ◽  
Iron Status ◽  
Defense Responses ◽  
Histochemical Staining ◽  
Pathogen Infection ◽  
High Iron ◽  
Rice Plants ◽  
The Impact

Background: Iron is an essential micronutrient required for plant growth and development. The impact of iron in plant-pathogen interactions is also well recognized. However, the molecular basis underlying the effect of plant iron status and immune function in plants is poorly understood. Here, we investigated the impact of treatment with high iron in rice immunity at the cellular and molecular level. Results: We show that treatment with high iron confers resistance to infection by the blast fungus M. oryzae in rice. Histochemical staining of M. oryzae-infected leaves revealed that iron and Reactive Oxygen Species (ROS) accumulate at high levels in cells in the vicinity of the infection site. During pathogen infection, a stronger induction of defense-related genes occurs in leaves of iron-treated plants. Notably, a superinduction of phytoalexin biosynthetic genes, both diterpene phytoalexins and sakuranetin, is observed in iron-treated plants during pathogen infection. As a consequence, phytoalexin accumulation was higher in iron-treated plants compared with control plants. Transcriptional alterations of iron homeostasis-related genes and a reduction in apoplastic iron content were observed in leaves of Fe-treated rice plants. Conclusions: These results illustrate that the iron status plays a key role in the response of rice plants to pathogen infection, while reinforcing the notion that iron signaling and defense signaling must operate in a coordinated manner in controlling disease resistance in plants. This information provides a basis to better understand the molecular mechanisms involved in rice immunity.

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