scholarly journals Overexpression of Magnaporthe Oryzae Systemic Defense Trigger 1 (MoSDT1) Confers Improved Rice Blast Resistance in Rice

2019 ◽  
Vol 20 (19) ◽  
pp. 4762 ◽  
Author(s):  
Wang ◽  
Li ◽  
Duan ◽  
Wang ◽  
Zhang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Blast Resistance ◽  
Plant Defense Response ◽  
Callose Deposition ◽  
Primary Metabolites ◽  
Rice Blast Resistance ◽  
Ros Accumulation ◽  
Transgenic Lines

The effector proteins secreted by a pathogen not only promote virulence and infection of the pathogen, but also trigger plant defense response. Therefore, these proteins could be used as important genetic resources for transgenic improvement of plant disease resistance. Magnaporthe oryzae systemic defense trigger 1 (MoSDT1) is an effector protein. In this study, we compared the agronomic traits and blast disease resistance between wild type (WT) and MoSDT1 overexpressing lines in rice. Under control conditions, MoSDT1 transgenic lines increased the number of tillers without affecting kernel morphology. In addition, MoSDT1 transgenic lines conferred improved blast resistance, with significant effects on the activation of callose deposition, reactive oxygen species (ROS) accumulation and cell death. On the one hand, overexpression of MoSDT1 could delay biotrophy–necrotrophy switch through regulating the expression of biotrophy-associated secreted protein 4 (BAS4) and Magnaporthe oryzaecell death inducing protein 1 (MoCDIP1), and activate plant defense response by regulating the expression of Bsr-d1, MYBS1, WRKY45, peroxidase (POD), heat shock protein 90 (HSP90), allenoxide synthase 2 (AOS2), phenylalanine ammonia lyase (PAL), pathogenesis-related protein 1a (PR1a) in rice. On the other hand, overexpression of MoSDT1 could increase the accumulation of some defense-related primary metabolites such as two aromatic amino acids (L-tyrosine and L-tryptohan), 1-aminocyclopropane carboxylic acid, which could be converted to ethylene, vanillic acid and L-saccharopine. Taken together, overexpression of MoSDT1 confers improved rice blast resistance in rice, through modulation of callose deposition, ROS accumulation, the expression of defense-related genes, and the accumulation of some primary metabolites.

scholarly journals Osa-miR162a balances rice yield and resistance to Magnaporthe oryzae

2020 ◽  
Author(s):  
Xu-Pu Li ◽  
Xiao-Chun Ma ◽  
He Wang ◽  
Yong Zhu ◽  
Xin-Xian Liu ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Yield ◽  
Blast Resistance ◽  
Blast Disease ◽  
Mirna Biogenesis ◽  
Trade Off ◽  
Rice Blast Resistance ◽  
Defense Related Gene ◽  
Transgenic Lines

Abstract MicroRNAs (miRNAs) play essential roles in rice immunity against Magnaporthe oryzae, the causative agent of rice blast disease. Osa-miR162a targets Dicer-like 1 (DCL1) genes, which play vital roles in miRNA biogenesis and act as negative regulators in rice immunity. Here we demonstrate that Osa-miR162a improves rice immunity against M. oryzae and balances the trade-off between rice yield and resistance. Overexpression of Osa-miR162a compromises rice susceptibility to M. oryzae accompanying enhanced induction of defense-related genes and accumulation of hydrogen peroxide (H2O2). In contrast, blocking miR162 by overexpressing a target mimic of miR162 enhances susceptibility to blast fungus associating with compromised induction of defense-related gene expression and H2O2 accumulation. Moreover, the transgenic lines overexpressing Osa-miR162a display decreased seed setting rate resulting in reduced yield per plant, whereas blocking miR162 leads to an increased number of grains per panicle, resulting in increased yield per plant. Altered accumulation of miR162 had limited impact on the expression of OsDCL1. Together, our results indicate that Osa-miR162a improves rice blast resistance and plays a role in the balance of trade-off between resistance and yield.

scholarly journals Every Coin Has Two Sides: Reactive Oxygen Species during Rice–Magnaporthe oryzae Interaction

2019 ◽  
Vol 20 (5) ◽  
pp. 1191 ◽  
Author(s):  
Yanjun Kou ◽  
Jiehua Qiu ◽  
Zeng Tao
Keyword(s):  
Reactive Oxygen Species ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Blast Resistance ◽  
Reactive Oxygen ◽  
Redox Balance ◽  
Ros Generation ◽  
Oxygen Species ◽  
Rice Blast Resistance ◽  
Ros Accumulation

Reactive oxygen species (ROS) are involved in many important processes, including the growth, development, and responses to the environments, in rice (Oryza sativa) and Magnaporthe oryzae. Although ROS are known to be critical components in rice–M. oryzae interactions, their regulations and pathways have not yet been completely revealed. Recent studies have provided fascinating insights into the intricate physiological redox balance in rice–M. oryzae interactions. In M. oryzae, ROS accumulation is required for the appressorium formation and penetration. However, once inside the rice cells, M. oryzae must scavenge the host-derived ROS to spread invasive hyphae. On the other side, ROS play key roles in rice against M. oryzae. It has been known that, upon perception of M. oryzae, rice plants modulate their activities of ROS generating and scavenging enzymes, mainly on NADPH oxidase OsRbohB, by different signaling pathways to accumulate ROS against rice blast. By contrast, the M. oryzae virulent strains are capable of suppressing ROS accumulation and attenuating rice blast resistance by the secretion of effectors, such as AvrPii and AvrPiz-t. These results suggest that ROS generation and scavenging of ROS are tightly controlled by different pathways in both M. oryzae and rice during rice blast. In this review, the most recent advances in the understanding of the regulatory mechanisms of ROS accumulation and signaling during rice–M. oryzae interaction are summarized.

Effector genes in Magnaporthe oryzae Triticum as Potential Targets for Incorporating Blast Resistance in Wheat

Plant Disease ◽  
2021 ◽  
Author(s):  
Monica Navia-Urrutia ◽  
Gloria Mosquera ◽  
Rebekah Ellsworth ◽  
Mark Farman ◽  
Harold N. Trick ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Blast Resistance ◽  
Genetic Resistance ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Rice Blast Resistance ◽  
Effector Genes ◽  
Transgenic Lines

Wheat blast (WB), caused by Magnaporthe oryzae Triticum pathotype, recently emerged as a destructive disease that threatens global wheat production. Since few sources of genetic resistance have been identified in wheat, genetic transformation of wheat with rice blast resistance genes could expand resistance to WB. We evaluated the presence/absence of homologs of rice blast effector genes in Triticum isolates with the aim of identifying avirulence genes in field populations whose cognate rice resistance genes could potentially confer resistance to WB. We also assessed presence of the wheat pathogen AVR-Rmg8 gene, and identified new alleles. A total of 102 isolates collected in Brazil, Bolivia and Paraguay from 1986 to 2018 were evaluated by PCR using 21 pairs of gene-specific primers. Effector gene composition was highly variable, with homologs to AvrPiz-t, AVR-Pi9, AVR-Pi54 and ACE1 showing the highest amplification frequencies (>94%). We identified Triticum isolates with a functional AvrPiz-t homolog that triggers Piz-t-mediated resistance in the rice pathosystem, and produced transgenic wheat plants expressing the rice Piz-t gene. Seedlings and heads of the transgenic lines were challenged with isolate T25 carrying functional AvrPiz-t. Although slight decreases in the percentage of diseased spikelets and leaf area infected were observed in two transgenic lines, our results indicated that Piz-t did not confer useful WB resistance. Monitoring of avirulence genes in populations is fundamental to identifying effective resistance genes for incorporation into wheat by conventional breeding or transgenesis. Based on avirulence gene distributions, rice resistance genes Pi9 and Pi54 might be candidates for future studies.

scholarly journals Fine-Tuning Roles of Osa-miR159a in Rice Immunity Against Magnaporthe oryzae and Development

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jin-Feng Chen ◽  
Zhi-Xue Zhao ◽  
Yan Li ◽  
Ting-Ting Li ◽  
Yong Zhu ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Target Genes ◽  
Blast Resistance ◽  
Fine Tuning ◽  
Post Inoculation ◽  
Grain Development ◽  
Positive Role ◽  
Rice Blast Resistance ◽  
Transgenic Lines

Abstract Background Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice. An increasing number of microRNAs (miRNAs) have been reported to fine-tune rice immunity against M. oryzae and coordinate with growth and development. Results Here, we showed that rice microRNA159a (Osa-miR159a) played a positive role in rice resistance to M. oryzae. The expression of Osa-miR159a was suppressed in a susceptible accession at 12, 24, and 48 h post-inoculation (hpi); it was upregulated in a resistant accession of M. oryzae at 24 hpi. The transgenic rice lines overexpressing Osa-miR159a were highly resistant to M. oryzae. In contrast, the transgenic lines expressing a short tandem target mimic (STTM) to block Osa-miR159a showed enhanced susceptibility. Knockout mutations of the target genes of Osa-miR159a, including OsGAMYB, OsGAMYBL, and OsZF, led to resistance to M. oryzae. Alteration of the expression of Osa-miR159a impacted yield traits including pollen and grain development. Conclusions Our results indicated that Osa-miR159a positively regulated rice immunity against M. oryzae by downregulating its target genes. Proper expression of Osa-miR159a was critical for coordinating rice blast resistance with grain development.

scholarly journals Fine-tuning roles of Osa-miR159a in rice immunity against Magnaporthe oryzae and development

2020 ◽  
Author(s):  
Jin-Feng Chen ◽  
Zhi-Xue Zhao ◽  
Yan Li ◽  
Ting-Ting Li ◽  
Yong Zhu ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Target Genes ◽  
Blast Resistance ◽  
Fine Tuning ◽  
Post Inoculation ◽  
Grain Development ◽  
Positive Role ◽  
Rice Blast Resistance ◽  
Transgenic Lines

Abstract Background Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice. An increasing number of microRNAs (miRNAs) have been reported to fine-tune rice immunity against M. oryzae and coordinate with growth and development. Results Here, we showed that rice microRNA159a (Osa-miR159a) played a positive role in rice resistance to M. oryzae. The expression of Osa-miR159a was suppressed in a susceptible accession at 12, 24, and 48 hours post-inoculation (hpi); it was upregulated in a resistant accession of M. oryzae at 24 hpi. The transgenic rice lines overexpressing Osa-miR159a were highly resistant to M. oryzae. In contrast, the transgenic lines expressing a short tandem target mimic (STTM) to block Osa-miR159 showed enhanced susceptibility. Knockout mutations of the target genes of Osa-miR159, including OsGAMYB, OsGAMYBL, and OsZF, led to resistance to M. oryzae. Alteration of the expression of Osa-miR159a impacted yield traits including pollen and grain development. Conclusions Our results indicated that Osa-miR159a positively regulated rice immunity against M. oryzae by downregulating its target genes. Proper expression of Osa-miR159a was critical for coordinating rice blast resistance with grain development.

scholarly journals Fine-tuning roles of Osa-miR159a in rice immunity against Magnaporthe oryzae and development

2020 ◽  
Author(s):  
Jin-Feng Chen ◽  
Zhi-Xue Zhao ◽  
Yan Li ◽  
Ting-Ting Li ◽  
Yong Zhu ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Target Genes ◽  
Blast Resistance ◽  
Fine Tuning ◽  
Post Inoculation ◽  
Grain Development ◽  
Positive Role ◽  
Rice Blast Resistance ◽  
Transgenic Lines

Abstract Background: Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice. An increasing number of microRNAs (miRNAs) have been reported to fine-tune rice immunity against M. oryzae and coordinate with growth and development.Results: Here, we showed that rice microRNA159a (Osa-miR159a) played a positive role in rice resistance to M. oryzae. The expression of Osa-miR159a was suppressed in a susceptible accession at 12, 24, and 48 hours post-inoculation (hpi); it was upregulated in a resistant accession of M. oryzae at 24 hpi. The transgenic rice lines overexpressing Osa-miR159a were highly resistant to M. oryzae. In contrast, the transgenic lines expressing a short tandem target mimic (STTM) to block Osa-miR159a showed enhanced susceptibility. Knockout mutations of the target genes of Osa-miR159a, including OsGAMYB, OsGAMYBL, and OsZF, led to resistance to M. oryzae. Alteration of the expression of Osa-miR159a impacted yield traits including pollen and grain development.Conclusions: Our results indicated that Osa-miR159a positively regulated rice immunity against M. oryzae by downregulating its target genes. Proper expression of Osa-miR159a was critical for coordinating rice blast resistance with grain development.

Transgenic Rice Expressing Isoflavone Synthase Gene from Soybean Shows Resistance against Blast Fungus (Magnaporthe oryzae)

Plant Disease ◽  
2021 ◽  
Author(s):  
Suresh Pokhrel ◽  
Sathish K Ponniah ◽  
Yulin Jia ◽  
Oliver Yu ◽  
Muthusamy Manoharan
Keyword(s):  
Disease Resistance ◽  
Transgenic Rice ◽  
Magnaporthe Oryzae ◽  
Plant Disease Resistance ◽  
Rice Blast ◽  
Plant Disease ◽  
Plant Secondary Metabolites ◽  
Single Copy ◽  
Transgenic Lines ◽  
Isoflavone Synthase

The isoflavones are a group of plant secondary metabolites primarily synthesized in legumes and are known for their role in improving human health and plant disease resistance. The isoflavones, especially genistein, act as precursors for the production of phytoalexins, which may induce broad-spectrum disease resistance in plants. In the present study, we screened transgenic rice lines expressing the isoflavone synthase (GmIFS1) gene from soybean for rice blast (Magnaporthe oryzae) resistance. Two homozygous transgenic lines (I2 and I10), based on single copy gene integration, were identified. The expression of GmIFS1 in transgenic lines was confirmed by qRT-PCR. Genistein was detected in the transgenic lines using LC-MS/MS. Subsequently, the transgenic lines were evaluated against the rice blast pathogen, isolate YJ54 (race IB-54). The results indicated that more than 60% of the plants in both the lines (I2 and I10) showed resistance against the blast pathogen. The progenies of one of the resistant transgenic lines (I10) also showed more than 65% resistance against rice blast. The resistance of these transgenic lines against rice blast may be attributed to the synthesis of isoflavone (genistein) in rice.

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