Sequence Variation and Recognition Specificity of the Avirulence Gene AvrPiz-T in Magnaporthe Oryzae Field Populations

Chen, Chenxi Chen Meilian

doi:10.4172/2165-8056.1000113

Cited by 5 publications

(17 citation statements)

References 42 publications

(52 reference statements)

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“…The insertion of solo-LTR of retrotransposons Inago2 in promoter regions is predicted to change the avirulent function of the isolate 07-231-2a. Inago2 was founded at 41 bp upstream ORF in Chinese isolates without pathogenicity results (Chen et al, 2014). So, the inserting location and element of inago2 in this study are different from the previous study.…”

Section: Avrpiz-t Haplotypes Variance and Distributioncontrasting

confidence: 62%

“…A strong positive selection is detected at the locus. M. oryzae evades recognition of Piz-t gene in rice through diversification of its coding sequence and TEs in the promoter region of AvrPiz-t (Chen et al, 2014). In this study, at least nine haplotypes were identified based on AvrPiz-t gene (non-CDS and CDS, 2507 bp) from 312 M. oryzae isolates in Yunnan.…”

Section: Discussionmentioning

confidence: 88%

“…As a result, the frameshift mutation is predicted to produce truncated proteins and lead the isolate 08-39-2d to be virulent to Piz-t. The insertion in H7 is the same as the VII haplotype based on AvrPiz-t ORF sequence (Chen et al, 2014). The VII haplotype is determined only by variable sites of ORF sequence; however, haplotypes were determined by variable sites of coding and noncoding region sequences of AvrPiz-t gene in this study.…”

Section: Avrpiz-t Haplotypes Variance and Distributionmentioning

confidence: 82%

“…Higher variance levels of Piz-t gene suggested that AvrPiz-t gene experienced some degree of selection pressure. Four haplotypes (I, II, VII, and VIII) in rice isolates, three haplotypes (III, IV, and V) in nonrice isolates, and one haplotype (VI) shared by distant isolates in the phylogeny were identified in ORFs (327 bp) among 711 isolates of M. oryzae collected from 38 countries and regions (Chen et al, 2014). Four TE insertions on promoter regions were identified in these isolates.…”

Section: Discussionmentioning

confidence: 97%

“…Lower virulent frequency of AvrPiz-t and higher resistant frequency of Piz-t suggests that AvrPiz-t and Piz-t are a pair of valuable genes in the Rice-Magnaporthe pathosystem in some provinces of China. Sequence variance on open reading frames (ORFs) and size variance on promoter regions of AvrPiz-t have been detected from 38 countries and regions (Chen et al, 2014). Yunnan Province of China holds abundant resources of both rice and blast fungus (Jiang, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Novel Variation and Evolution of AvrPiz-t of Magnaporthe oryzae in Field Isolates

Wang

Lü

et al. 2020

Front. Genet.

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The product of the avirulence (Avr) gene of Magnaporthe oryzae can be detected by the product of the corresponding resistance (R) gene of rice and activates immunity to rice mediated by the R gene. The high degree of variability of M. oryzae isolates in pathogenicity makes the control of rice blast difficult. That resistance of the R gene in rice has been lost has been ascribed to the instability of the Avr gene in M. oryzae. Further study on the variation of the Avr genes in M. oryze field isolates may yield valuable information on the durable and effective deployment of R genes in rice production areas. AvrPiz-t and Piz-t are a pair of valuable genes in the Rice-Magnaporthe pathosystem. AvrPiz-t is detectable by Piz-t and determines the effectiveness of Piz-t. To effectively deploy the R gene Piz-t, the distribution, variation, and evolution of the corresponding Avr gene AvrPiz-t were found among 312 M. oryzae isolates collected from Yunnan rice production areas of China. PCR amplification and pathogenicity assays of AvrPiz-t showed that 202 isolates (64.7%) held AvrPiz-t alleles and were avirulent to IRBLzt-T (holding Piz-t). There were 42.3-83.3% avirulent isolates containing AvrPiz-t among seven regions in Yunnan Province. Meanwhile, 11 haplotypes of AvrPiz-t encoding three novel AvrPiz-t variants were identified among 100 isolates. A 198 bps insertion homologous to solo-LTR of the retrotransposon inago2 in the promoter region of AvrPizt in one isolate and a frameshift mutation of CDS in another isolate were identified among 100 isolates, and those two isolates had evolved to virulent from avirulent. Synonymous mutation and non-AUG-initiated N-terminal extensions keeps the AvrPizt gene avirulence function in M. oryzae field isolates in Yunnan. A haplotype network showed that H3 was an ancestral haplotype. Structure variance for absence (28.2%) or partial fragment loss (71.8%) of AvrPiz-t was found among 39 virulent isolates and may cause the AvrPiz-t avirulence function to be lost. Overall, AvrPiz-t evolved to virulent from avirulent forms via point mutation, retrotransposon, shift mutation, and structure variance under field conditions.

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Section: Avrpiz-t Haplotypes Variance and Distributioncontrasting

confidence: 62%

Section: Discussionmentioning

confidence: 88%

Section: Avrpiz-t Haplotypes Variance and Distributionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Novel Variation and Evolution of AvrPiz-t of Magnaporthe oryzae in Field Isolates

Wang

Lü

et al. 2020

Front. Genet.

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Transposable elements impact the population divergence of rice blast fungusMagnaporthe oryzae

Zheng¹,

Lin²,

Sun

et al. 2023

Preprint

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Dynamic transposition of transposable elements (TEs) in fungal pathogens have been shown to have a significant impact on genome stability, gene expression, and virulence to the host. InMagnaporthe oryzae, genome plasticity resulting from TE insertion polymorphisms is a major driving force leading to the rapid evolution and diversification of this rice blast fungus. Despite their importance inM. oryzaepopulation evolution and divergence, our understanding of TEs in this context remains limited. Here we conducted a genome-wide analysis of TE transposition dynamics in the eleven most abundant TE families and transcriptomic analysis in differentM. oryzaepopulations. Our results show that these TEs have specifically expanded in recently isolatedM. oryzaerice populations, with the presence/absence polymorphism of TE insertions highly concordant with population divergence on Geng/Japonicaand Xian/Indicarice cultivars. Among the TE families, POT2 and Mg-SINE were shown to be overrepresented in clade-specific TE insertion events, indicating their essential roles in population divergence. Notably, the genes targeted by clade-specific TEs showed clade-specific expression patterns, suggesting a transcriptional regulation of TEs on targeted genes. Furthermore, population transcriptomic analysis revealed that genes disrupted by POT2 and Mg-SINE insertions exhibited significantly lower expression, implying a silencing function of these TEs on the targeted genes. Our study provides a comprehensive analysis of TEs inM. oryzaepopulations and demonstrates a crucial role of recent TE bursts in adaptive evolution and diversification of theM. oryzaerice-infecting lineage.

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The Lesson Learned from the Unique Evolutionary Story of Avirulence Gene <i>AvrPii </i>of <i>Magnaporthe oryzae</i>

Wang¹,

Wu²,

Zhang³

et al. 2023

Preprint

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Blast, caused by Magnaporthe oryzae, is one of the most destructive diseases affecting rice production. Understanding population dynamics of the pathogen avirulence genes is pre-required for breeding and then deploying new cultivars carrying promising resistance genes. The divergence and population structure of AvrPii was dissected in the populations of southern (Guangdong, Hunan, and Guizhou) and northern (Jilin, Liaoning, and Heilongjiang) China, via population genetic and evolutionary approaches. The evolutionary divergence between a known haplotype AvrPii-J and a novel one AvrPii-C was demonstrated by haplotype-specific amplicon-based sequencing and genetic transformation. The different avirulent performances of a set of seven haplotype-chimeric mutants suggested that the integrity of the full-length gene structures is crucial to express functionality of individual haplotypes. The population structure of the AvrPii family was shaped by balancing, purifying, and positive selection pressures in the Chinese populations. The AvrPii-J was recognized as the wild type that emerged before rice domestication. Considering higher frequencies of avirulent isolates were detected in Hunan, Guizhou, and Liaoning, the cognate resistance gene Pii could be continuously served as a basic and critical resistance resource in such regions. The unique population structures of the AvrPii family found in China have significant implications for understanding how the AvrPii family has kept an artful balance and purify among its members (haplotypes) those keenly interact with the cognate resistance gene under gene-for-gene relationships.

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Sequence Variation and Recognition Specificity of the Avirulence Gene AvrPiz-T in Magnaporthe Oryzae Field Populations

Cited by 5 publications

References 42 publications

Novel Variation and Evolution of AvrPiz-t of Magnaporthe oryzae in Field Isolates

Novel Variation and Evolution of AvrPiz-t of Magnaporthe oryzae in Field Isolates

Transposable elements impact the population divergence of rice blast fungusMagnaporthe oryzae

The Lesson Learned from the Unique Evolutionary Story of Avirulence Gene <i>AvrPii </i>of <i>Magnaporthe oryzae</i>

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