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Frank F White - One of the best experts on this subject based on the ideXlab platform.

  • code assisted discovery of tal effector targets in Bacterial leaf streak of rice reveals contrast with Bacterial Blight and a novel susceptibility gene
    PLOS Pathogens, 2014
    Co-Authors: Raul A Cernadas, Bing Yang, Clarice Schmidt, Erin L Doyle, Li Wang, David O Ninoliu, Katherine Wilkins, Timothy J Bancroft, Rico A Caldo, Frank F White
    Abstract:

    Bacterial leaf streak of rice, caused by Xanthomonas oryzae pv. oryzicola (Xoc) is an increasingly important yield constraint in this staple crop. A mesophyll colonizer, Xoc differs from X. oryzae pv. oryzae (Xoo), which invades xylem to cause Bacterial Blight of rice. Both produce multiple distinct TAL effectors, type III-delivered proteins that transactivate effector-specific host genes. A TAL effector finds its target(s) via a partially degenerate code whereby the modular effector amino acid sequence identifies nucleotide sequences to which the protein binds. Virulence contributions of some Xoo TAL effectors have been shown, and their relevant targets, susceptibility (S) genes, identified, but the role of TAL effectors in leaf streak is uncharacterized. We used host transcript profiling to compare leaf streak to Blight and to probe functions of Xoc TAL effectors. We found that Xoc and Xoo induce almost completely different host transcriptional changes. Roughly one in three genes upregulated by the pathogens is preceded by a candidate TAL effector binding element. Experimental analysis of the 44 such genes predicted to be Xoc TAL effector targets verified nearly half, and identified most others as false predictions. None of the Xoc targets is a known Bacterial Blight S gene. Mutational analysis revealed that Tal2g, which activates two genes, contributes to lesion expansion and Bacterial exudation. Use of designer TAL effectors discriminated a sulfate transporter gene as the S gene. Across all targets, basal expression tended to be higher than genome-average, and induction moderate. Finally, machine learning applied to real vs. falsely predicted targets yielded a classifier that recalled 92% of the real targets with 88% precision, providing a tool for better target prediction in the future. Our study expands the number of known TAL effector targets, identifies a new class of S gene, and improves our ability to predict functional targeting.

  • rice xa13 recessive resistance to Bacterial Blight is defeated by induction of the disease susceptibility gene os 11n3
    The Plant Cell, 2010
    Co-Authors: Ginny Antony, Junhui Zhou, Frank F White, Ting Li, Sheng Huang, Bing Yang
    Abstract:

    The rice (Oryza sativa) gene xa13 is a recessive resistance allele of Os-8N3, a member of the NODULIN3 (N3) gene family, located on rice chromosome 8. Os-8N3 is a susceptibility (S) gene for Xanthomonas oryzae pv oryzae, the causal agent of Bacterial Blight, and the recessive allele is defeated by strains of the pathogen producing any one of the type III effectors AvrXa7, PthXo2, or PthXo3, which are all members of the transcription activator-like (TAL) effector family. Both AvrXa7 and PthXo3 induce the expression of a second member of the N3 gene family, here named Os-11N3. Insertional mutagenesis or RNA-mediated silencing of Os-11N3 resulted in plants with loss of susceptibility specifically to strains of X. oryzae pv oryzae dependent on AvrXa7 or PthXo3 for virulence. We further show that AvrXa7 drives expression of Os-11N3 and that AvrXa7 interacts and binds specifically to an effector binding element within the Os-11N3 promoter, lending support to the predictive models for TAL effector binding specificity. The result indicates that variations in the TAL effector repetitive domains are driven by selection to overcome both dominant and recessive forms of resistance to Bacterial Blight in rice. The finding that Os-8N3 and Os-11N3 encode closely related proteins also provides evidence that N3 proteins have a specific function in facilitating Bacterial Blight disease.

  • os8n3 is a host disease susceptibility gene for Bacterial Blight of rice
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Bing Yang, Akiko Sugio, Frank F White
    Abstract:

    Many Bacterial diseases of plants depend on the interaction of type III effector genes of the pathogen and disease-susceptibility genes of the host. The host susceptibility genes are largely unknown. Here, we show that expression of the rice gene Os8N3, a member of the MtN3 gene family from plants and animals, is elevated upon infection by Xanthomonas oryzae pv. oryzae strain PXO99A and depends on the type III effector gene pthXo1. Os8N3 resides near xa13, and PXO99A failed to induce Os8N3 in rice lines with xa13. Silencing of Os8N3 by inhibitory RNA produced plants that were resistant to infection by strain PXO99A yet remained susceptible to other strains of the pathogen. The effector gene avrXa7 from strain PXO86 enabled PXO99A compatibility on either xa13- or Os8N3-silenced plants. The findings indicate that Os8N3 is a host susceptibility gene for Bacterial Blight targeted by the type III effector PthXo1. The results support the hypothesis that X. oryzae pv. oryzae commandeers the regulation of otherwise developmentally regulated host genes to induce a state of disease susceptibility. Furthermore, the results support a model in which the pathogen induces disease susceptibility in a gene-for-gene manner.

  • diverse members of the avrbs3 ptha family of type iii effectors are major virulence determinants in Bacterial Blight disease of rice
    Molecular Plant-microbe Interactions, 2004
    Co-Authors: Bing Yang, Frank F White
    Abstract:

    AvrXa7 is a member of the avBs3/pthA gene family and the only known type III secretion system effector gene from Xanthomonas oryzae pv. oryzae with a major contribution to Bacterial growth and lesion formation in Bacterial Blight disease of rice. We examined the general requirement for effectors of the AvrBs3/PthA family in Bacterial Blight of rice by identifying effectors from diverse strains of the pathogen. Inactivation of single effector genes in representative strains from Japan, Korea, and the Philippines resulted in severely limited growth in plants. Five strains harbored one gene of the avrBs3/pthA family, while one strain had two genes with the equivalent virulence activity of avrXa7. Sequence analysis revealed three genes with unique repeat arrangements in comparison to avrXa7. Comparison of the repetitive regions revealed a potential motif for the group that was also present in the repetitive region of avrBs3. However, the repetitive region of avrBs3 could not support virulence activity but, in combination with the C-terminal coding region of avrXa7, triggered a Xa7-dependent avirulence reaction. The results revealed diverse members of the avrBs3/pthA gene family with virulence activity in X. oryzae pv. oryzae and supported the hypothesis that Bacterial Blight disease of rice is highly dependent on a single class of type III effectors. The results also indicated that avrXa7 avirulence specificity is separable from virulence activity.

  • diverse members of the avrbs3 ptha family of type iii effectors are major virulence determinants in Bacterial Blight disease of rice
    Molecular Plant-microbe Interactions, 2004
    Co-Authors: Bing Yang, Frank F White
    Abstract:

    AvrXa7 is a member of the avBs3/pthA gene family and the only known type III secretion system effector gene from Xanthomonas oryzae pv. oryzae with a major contribution to Bacterial growth and lesion formation in Bacterial Blight disease of rice. We examined the general requirement for effectors of the AvrBs3/PthA family in Bacterial Blight of rice by identifying effectors from diverse strains of the pathogen. Inactivation of single effector genes in representative strains from Japan, Korea, and the Philippines resulted in severely limited growth in plants. Five strains harbored one gene of the avrBs3/pthA family, while one strain had two genes with the equivalent virulence activity of avrXa7. Sequence analysis revealed three genes with unique repeat arrangements in comparison to avrXa7. Comparison of the repetitive regions revealed a potential motif for the group that was also present in the repetitive region of avrBs3. However, the repetitive region of avrBs3 could not support virulence activity but, in...

Nagendra K Singh - One of the best experts on this subject based on the ideXlab platform.

  • an xa5 resistance gene breaking indian strain of the rice Bacterial Blight pathogen xanthomonas oryzae pv oryzae is nearly identical to a thai strain
    Frontiers in Microbiology, 2020
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) constrains production in major rice growing countries of Asia. Xoo injects transcription activator-like effectors (TALEs) that bind to and activate host "susceptibility" (S) genes that are important for disease. The Bacterial Blight resistance gene xa5, which reduces TALE activity generally, has been widely deployed. However, strains defeating xa5 have been reported in India and recently also in Thailand. We completely sequenced and compared the genomes of one such strain from each country and examined the encoded TALEs. The two genomes are nearly identical, including the TALE genes, and belong to a previously identified, highly clonal lineage. Each strain harbors a TALE known to activate the major S gene SWEET11 strongly enough to be effective even when diminished by xa5. The findings suggest international migration of the xa5-compatible pathotype and highlight the utility of whole genome sequencing and TALE analysis for understanding and responding to breakdown of resistance.

  • a strain of an emerging indian xanthomonas oryzae pv oryzae pathotype defeats the rice Bacterial Blight resistance gene xa13 without inducing a clade iii sweet gene and is nearly identical to a recent thai isolate
    Frontiers in Microbiology, 2018
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host "susceptibility" (S) genes important for disease. Clade III SWEET genes are major S genes for Bacterial Blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harboring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

  • a strain of an emerging indian pathotype of xanthomonas oryzae pv oryzae defeats the rice Bacterial Blight resistance gene xa13 without inducing a clade iii sweet gene and is nearly identical to a recent thai isolate
    bioRxiv, 2018
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host susceptibility (S) genes important for disease. Clade III SWEET genes are major S genes for Bacterial Blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harbouring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

Sara C D Carpenter - One of the best experts on this subject based on the ideXlab platform.

  • an xa5 resistance gene breaking indian strain of the rice Bacterial Blight pathogen xanthomonas oryzae pv oryzae is nearly identical to a thai strain
    Frontiers in Microbiology, 2020
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) constrains production in major rice growing countries of Asia. Xoo injects transcription activator-like effectors (TALEs) that bind to and activate host "susceptibility" (S) genes that are important for disease. The Bacterial Blight resistance gene xa5, which reduces TALE activity generally, has been widely deployed. However, strains defeating xa5 have been reported in India and recently also in Thailand. We completely sequenced and compared the genomes of one such strain from each country and examined the encoded TALEs. The two genomes are nearly identical, including the TALE genes, and belong to a previously identified, highly clonal lineage. Each strain harbors a TALE known to activate the major S gene SWEET11 strongly enough to be effective even when diminished by xa5. The findings suggest international migration of the xa5-compatible pathotype and highlight the utility of whole genome sequencing and TALE analysis for understanding and responding to breakdown of resistance.

  • a strain of an emerging indian xanthomonas oryzae pv oryzae pathotype defeats the rice Bacterial Blight resistance gene xa13 without inducing a clade iii sweet gene and is nearly identical to a recent thai isolate
    Frontiers in Microbiology, 2018
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host "susceptibility" (S) genes important for disease. Clade III SWEET genes are major S genes for Bacterial Blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harboring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

  • a strain of an emerging indian pathotype of xanthomonas oryzae pv oryzae defeats the rice Bacterial Blight resistance gene xa13 without inducing a clade iii sweet gene and is nearly identical to a recent thai isolate
    bioRxiv, 2018
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host susceptibility (S) genes important for disease. Clade III SWEET genes are major S genes for Bacterial Blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harbouring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

  • TAL effector driven induction of a SWEET gene confers susceptibility to Bacterial Blight of cotton.
    Nature communications, 2017
    Co-Authors: Kevin L. Cox, Nicholas J Booher, Sara C D Carpenter, Katherine Wilkins, Fanhong Meng, Ping Wang, Li Qing Chen, Hui Zheng, Xiquan Gao
    Abstract:

    Transcription activator-like (TAL) effectors from Xanthomonas citri subsp. malvacearum (Xcm) are essential for Bacterial Blight of cotton (BBC). Here, by combining transcriptome profiling with TAL effector-binding element (EBE) prediction, we show that GhSWEET10, encoding a functional sucrose transporter, is induced by Avrb6, a TAL effector determining Xcm pathogenicity. Activation of GhSWEET10 by designer TAL effectors (dTALEs) restores virulence of Xcm avrb6 deletion strains, whereas silencing of GhSWEET10 compromises cotton susceptibility to infections. A BBC-resistant line carrying an unknown recessive b6 gene bears the same EBE as the susceptible line, but Avrb6-mediated induction of GhSWEET10 is reduced, suggesting a unique mechanism underlying b6-mediated resistance. We show via an extensive survey of GhSWEET transcriptional responsiveness to different Xcm field isolates that additional GhSWEETs may also be involved in BBC. These findings advance our understanding of the disease and resistance in cotton and may facilitate the development cotton with improved resistance to BBC.

  • tal effector driven induction of a sweet gene confers susceptibility to Bacterial Blight of cotton
    Nature Communications, 2017
    Co-Authors: Fanhong Meng, Nicholas J Booher, Sara C D Carpenter, Katherine Wilkins, Ping Wang, Li Qing Chen, Hui Zheng, Fangjun Li, Yi Zheng, John Z Yu
    Abstract:

    Transcription activator-like (TAL) effectors from Xanthomonas citri subsp. malvacearum (Xcm) are essential for Bacterial Blight of cotton (BBC). Here, by combining transcriptome profiling with TAL effector-binding element (EBE) prediction, we show that GhSWEET10, encoding a functional sucrose transporter, is induced by Avrb6, a TAL effector determining Xcm pathogenicity. Activation of GhSWEET10 by designer TAL effectors (dTALEs) restores virulence of Xcm avrb6 deletion strains, whereas silencing of GhSWEET10 compromises cotton susceptibility to infections. A BBC-resistant line carrying an unknown recessive b6 gene bears the same EBE as the susceptible line, but Avrb6-mediated induction of GhSWEET10 is reduced, suggesting a unique mechanism underlying b6-mediated resistance. We show via an extensive survey of GhSWEET transcriptional responsiveness to different Xcm field isolates that additional GhSWEETs may also be involved in BBC. These findings advance our understanding of the disease and resistance in cotton and may facilitate the development cotton with improved resistance to BBC. Transcription activator-like effectors contribute to virulence of theXanthomonas strain responsible for Bacterial Blight in cotton. Here Cox et al. show that the XanthomonasAvrb6 effector induces expression of the cotton SWEET10 sugar transporter and that this induction promotes disease.

Bing Yang - One of the best experts on this subject based on the ideXlab platform.

  • code assisted discovery of tal effector targets in Bacterial leaf streak of rice reveals contrast with Bacterial Blight and a novel susceptibility gene
    PLOS Pathogens, 2014
    Co-Authors: Raul A Cernadas, Bing Yang, Clarice Schmidt, Erin L Doyle, Li Wang, David O Ninoliu, Katherine Wilkins, Timothy J Bancroft, Rico A Caldo, Frank F White
    Abstract:

    Bacterial leaf streak of rice, caused by Xanthomonas oryzae pv. oryzicola (Xoc) is an increasingly important yield constraint in this staple crop. A mesophyll colonizer, Xoc differs from X. oryzae pv. oryzae (Xoo), which invades xylem to cause Bacterial Blight of rice. Both produce multiple distinct TAL effectors, type III-delivered proteins that transactivate effector-specific host genes. A TAL effector finds its target(s) via a partially degenerate code whereby the modular effector amino acid sequence identifies nucleotide sequences to which the protein binds. Virulence contributions of some Xoo TAL effectors have been shown, and their relevant targets, susceptibility (S) genes, identified, but the role of TAL effectors in leaf streak is uncharacterized. We used host transcript profiling to compare leaf streak to Blight and to probe functions of Xoc TAL effectors. We found that Xoc and Xoo induce almost completely different host transcriptional changes. Roughly one in three genes upregulated by the pathogens is preceded by a candidate TAL effector binding element. Experimental analysis of the 44 such genes predicted to be Xoc TAL effector targets verified nearly half, and identified most others as false predictions. None of the Xoc targets is a known Bacterial Blight S gene. Mutational analysis revealed that Tal2g, which activates two genes, contributes to lesion expansion and Bacterial exudation. Use of designer TAL effectors discriminated a sulfate transporter gene as the S gene. Across all targets, basal expression tended to be higher than genome-average, and induction moderate. Finally, machine learning applied to real vs. falsely predicted targets yielded a classifier that recalled 92% of the real targets with 88% precision, providing a tool for better target prediction in the future. Our study expands the number of known TAL effector targets, identifies a new class of S gene, and improves our ability to predict functional targeting.

  • inoculation and virulence assay for Bacterial Blight and Bacterial leaf streak of rice
    Methods of Molecular Biology, 2013
    Co-Authors: Bing Yang, Adam J Bogdanove
    Abstract:

    Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) cause Bacterial Blight and Bacterial leaf streak in rice, respectively. Despite being very closely related, the pathogens colonize different tissues and cause distinct diseases. The diseases are economically important and also serve as model systems for studying plant-Bacterial interactions. Here we describe protocols for Xoo and Xoc inoculation and disease scoring methods that are appropriate to their different modes of infection. These methods are routinely used to evaluate pathogen virulence or host responses under controlled environmental conditions.

  • rice xa13 recessive resistance to Bacterial Blight is defeated by induction of the disease susceptibility gene os 11n3
    The Plant Cell, 2010
    Co-Authors: Ginny Antony, Junhui Zhou, Frank F White, Ting Li, Sheng Huang, Bing Yang
    Abstract:

    The rice (Oryza sativa) gene xa13 is a recessive resistance allele of Os-8N3, a member of the NODULIN3 (N3) gene family, located on rice chromosome 8. Os-8N3 is a susceptibility (S) gene for Xanthomonas oryzae pv oryzae, the causal agent of Bacterial Blight, and the recessive allele is defeated by strains of the pathogen producing any one of the type III effectors AvrXa7, PthXo2, or PthXo3, which are all members of the transcription activator-like (TAL) effector family. Both AvrXa7 and PthXo3 induce the expression of a second member of the N3 gene family, here named Os-11N3. Insertional mutagenesis or RNA-mediated silencing of Os-11N3 resulted in plants with loss of susceptibility specifically to strains of X. oryzae pv oryzae dependent on AvrXa7 or PthXo3 for virulence. We further show that AvrXa7 drives expression of Os-11N3 and that AvrXa7 interacts and binds specifically to an effector binding element within the Os-11N3 promoter, lending support to the predictive models for TAL effector binding specificity. The result indicates that variations in the TAL effector repetitive domains are driven by selection to overcome both dominant and recessive forms of resistance to Bacterial Blight in rice. The finding that Os-8N3 and Os-11N3 encode closely related proteins also provides evidence that N3 proteins have a specific function in facilitating Bacterial Blight disease.

  • os8n3 is a host disease susceptibility gene for Bacterial Blight of rice
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Bing Yang, Akiko Sugio, Frank F White
    Abstract:

    Many Bacterial diseases of plants depend on the interaction of type III effector genes of the pathogen and disease-susceptibility genes of the host. The host susceptibility genes are largely unknown. Here, we show that expression of the rice gene Os8N3, a member of the MtN3 gene family from plants and animals, is elevated upon infection by Xanthomonas oryzae pv. oryzae strain PXO99A and depends on the type III effector gene pthXo1. Os8N3 resides near xa13, and PXO99A failed to induce Os8N3 in rice lines with xa13. Silencing of Os8N3 by inhibitory RNA produced plants that were resistant to infection by strain PXO99A yet remained susceptible to other strains of the pathogen. The effector gene avrXa7 from strain PXO86 enabled PXO99A compatibility on either xa13- or Os8N3-silenced plants. The findings indicate that Os8N3 is a host susceptibility gene for Bacterial Blight targeted by the type III effector PthXo1. The results support the hypothesis that X. oryzae pv. oryzae commandeers the regulation of otherwise developmentally regulated host genes to induce a state of disease susceptibility. Furthermore, the results support a model in which the pathogen induces disease susceptibility in a gene-for-gene manner.

  • diverse members of the avrbs3 ptha family of type iii effectors are major virulence determinants in Bacterial Blight disease of rice
    Molecular Plant-microbe Interactions, 2004
    Co-Authors: Bing Yang, Frank F White
    Abstract:

    AvrXa7 is a member of the avBs3/pthA gene family and the only known type III secretion system effector gene from Xanthomonas oryzae pv. oryzae with a major contribution to Bacterial growth and lesion formation in Bacterial Blight disease of rice. We examined the general requirement for effectors of the AvrBs3/PthA family in Bacterial Blight of rice by identifying effectors from diverse strains of the pathogen. Inactivation of single effector genes in representative strains from Japan, Korea, and the Philippines resulted in severely limited growth in plants. Five strains harbored one gene of the avrBs3/pthA family, while one strain had two genes with the equivalent virulence activity of avrXa7. Sequence analysis revealed three genes with unique repeat arrangements in comparison to avrXa7. Comparison of the repetitive regions revealed a potential motif for the group that was also present in the repetitive region of avrBs3. However, the repetitive region of avrBs3 could not support virulence activity but, in combination with the C-terminal coding region of avrXa7, triggered a Xa7-dependent avirulence reaction. The results revealed diverse members of the avrBs3/pthA gene family with virulence activity in X. oryzae pv. oryzae and supported the hypothesis that Bacterial Blight disease of rice is highly dependent on a single class of type III effectors. The results also indicated that avrXa7 avirulence specificity is separable from virulence activity.

J S Lore - One of the best experts on this subject based on the ideXlab platform.

  • an xa5 resistance gene breaking indian strain of the rice Bacterial Blight pathogen xanthomonas oryzae pv oryzae is nearly identical to a thai strain
    Frontiers in Microbiology, 2020
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) constrains production in major rice growing countries of Asia. Xoo injects transcription activator-like effectors (TALEs) that bind to and activate host "susceptibility" (S) genes that are important for disease. The Bacterial Blight resistance gene xa5, which reduces TALE activity generally, has been widely deployed. However, strains defeating xa5 have been reported in India and recently also in Thailand. We completely sequenced and compared the genomes of one such strain from each country and examined the encoded TALEs. The two genomes are nearly identical, including the TALE genes, and belong to a previously identified, highly clonal lineage. Each strain harbors a TALE known to activate the major S gene SWEET11 strongly enough to be effective even when diminished by xa5. The findings suggest international migration of the xa5-compatible pathotype and highlight the utility of whole genome sequencing and TALE analysis for understanding and responding to breakdown of resistance.

  • a strain of an emerging indian xanthomonas oryzae pv oryzae pathotype defeats the rice Bacterial Blight resistance gene xa13 without inducing a clade iii sweet gene and is nearly identical to a recent thai isolate
    Frontiers in Microbiology, 2018
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host "susceptibility" (S) genes important for disease. Clade III SWEET genes are major S genes for Bacterial Blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harboring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

  • a strain of an emerging indian pathotype of xanthomonas oryzae pv oryzae defeats the rice Bacterial Blight resistance gene xa13 without inducing a clade iii sweet gene and is nearly identical to a recent thai isolate
    bioRxiv, 2018
    Co-Authors: Sara C D Carpenter, Li Wang, J S Lore, P K Mishra, Chandrika Ghoshal, Prasanta K Dash, Samriti Midha, G S Laha, Wichai Kositratana, Nagendra K Singh
    Abstract:

    The rice Bacterial Blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host susceptibility (S) genes important for disease. Clade III SWEET genes are major S genes for Bacterial Blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harbouring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

  • new pcr based sequence tagged site marker for Bacterial Blight resistance gene xa38 of rice
    Molecular Breeding, 2012
    Co-Authors: Hemal Bhasin, Dharminder Bhatia, Saurabh Raghuvanshi, J S Lore, Gurpreet K Sahi, Baljit Kaur, Yogesh Vikal, Kuldeep Singh
    Abstract:

    Bacterial Blight (BB), caused by Xanthomonas oryzae pv. oryzae, is a major disease of rice managed largely through the deployment of resistance genes. Xa38, a BB resistance gene identified from Oryza nivara acc. IRGC 81825, was mapped on chromosome 4L in a 38.4-kb region. The closely linked markers for this gene, identified earlier, were simple sequence repeat marker RM17499 and sequence-tagged site markers developed from loci Os04g53060 and Os04g53120. Marker Os04g53060 is dominant while the other two markers show smaller size differences difficult to resolve accurately on agarose gel. Based on gene annotation, three nucleotide binding site–leucine-rich repeat genes present in the target region were cloned from O. nivara and sequenced. One of the loci, LOC_Os04g53050, had a 48-base-pair deletion in O. nivara acc. IRGC 81825 compared to the cultivated rice. Primers were designed around the deletion and the resulting marker is codominant and easy to score in agarose gel. The newly designed marker co-segregated with Xa38, amplifying products of 269 bp in O. nivara and 317 bp in cultivated rice. This marker could be more useful for marker-assisted selection than ones reported earlier.