A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola
Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in the model plant rice, possesses a hypersensitive response and pathogenicity (hrp), hrp-conserved (hrc), hrp-associated (hpa) cluster (hrp-hrc-hpa) that encodes a type III secretion system (T3SS) through which T3SS effecto...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
The American Phytopathological Society
2011-09-01
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| Series: | Molecular Plant-Microbe Interactions |
| Online Access: | https://apsjournals.apsnet.org/doi/10.1094/MPMI-09-10-0205 |
| _version_ | 1811291241692790784 |
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| author | Yu-Rong Li Hua-Song Zou Yi-Zhou Che Yi-Ping Cui Wei Guo Li-Fang Zou Subhadeep Chatterjee Eulandria M. Biddle Ching-Hong Yang Gong-You Chen |
| author_facet | Yu-Rong Li Hua-Song Zou Yi-Zhou Che Yi-Ping Cui Wei Guo Li-Fang Zou Subhadeep Chatterjee Eulandria M. Biddle Ching-Hong Yang Gong-You Chen |
| author_sort | Yu-Rong Li |
| collection | DOAJ |
| description | Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in the model plant rice, possesses a hypersensitive response and pathogenicity (hrp), hrp-conserved (hrc), hrp-associated (hpa) cluster (hrp-hrc-hpa) that encodes a type III secretion system (T3SS) through which T3SS effectors are injected into host cells to cause disease or trigger plant defenses. Mutations in this cluster usually abolish the bacterial ability to cause hypersensitive response in nonhost tobacco and pathogenicity in host rice. In Xanthomonas spp., these genes are generally assumed to be regulated by the key master regulators HrpG and HrpX. However, we present evidence that, apart from HrpG and HrpX, HrpD6 is also involved in regulating the expression of hrp genes. Interestingly, the expression of hpa2, hpa1, hpaB, hrcC, and hrcT is positively controlled by HrpD6. Transcriptional expression assays demonstrated that the expression of the hrcC, hrpD5, hrpE, and hpa3 genes was not completely abolished by hrpG and hrpX mutations. As observed in analysis of their corresponding mutants, HrpG and HrpX exhibit contrasting gene regulation, particularly for hpa2 and hrcT. Other two-component system regulators (Zur, LrpX, ColR/S, and Trh) did not completely inhibit the expression of hrcC, hrpD5, hrpE, and hpa3. Immunoblotting assays showed that the secretion of HrpF, which is an HpaB-independent translocator, is not affected by the mutation in hrpD6. However, the mutation in hrpD6 affects the secretion of an HpaB-dependent TAL effector, AvrXa27. These novel findings suggest that, apart from HrpG and HrpX, HrpD6 plays important roles not only in the regulation of hrp genes but also in the secretion of TAL effectors. |
| first_indexed | 2024-04-13T04:26:24Z |
| format | Article |
| id | doaj.art-03707e1d83384e9c824be1c6cb2d21bc |
| institution | Directory Open Access Journal |
| issn | 0894-0282 1943-7706 |
| language | English |
| last_indexed | 2024-04-13T04:26:24Z |
| publishDate | 2011-09-01 |
| publisher | The American Phytopathological Society |
| record_format | Article |
| series | Molecular Plant-Microbe Interactions |
| spelling | doaj.art-03707e1d83384e9c824be1c6cb2d21bc2022-12-22T03:02:29ZengThe American Phytopathological SocietyMolecular Plant-Microbe Interactions0894-02821943-77062011-09-012491086110110.1094/MPMI-09-10-0205A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicolaYu-Rong LiHua-Song ZouYi-Zhou CheYi-Ping CuiWei GuoLi-Fang ZouSubhadeep ChatterjeeEulandria M. BiddleChing-Hong YangGong-You ChenXanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in the model plant rice, possesses a hypersensitive response and pathogenicity (hrp), hrp-conserved (hrc), hrp-associated (hpa) cluster (hrp-hrc-hpa) that encodes a type III secretion system (T3SS) through which T3SS effectors are injected into host cells to cause disease or trigger plant defenses. Mutations in this cluster usually abolish the bacterial ability to cause hypersensitive response in nonhost tobacco and pathogenicity in host rice. In Xanthomonas spp., these genes are generally assumed to be regulated by the key master regulators HrpG and HrpX. However, we present evidence that, apart from HrpG and HrpX, HrpD6 is also involved in regulating the expression of hrp genes. Interestingly, the expression of hpa2, hpa1, hpaB, hrcC, and hrcT is positively controlled by HrpD6. Transcriptional expression assays demonstrated that the expression of the hrcC, hrpD5, hrpE, and hpa3 genes was not completely abolished by hrpG and hrpX mutations. As observed in analysis of their corresponding mutants, HrpG and HrpX exhibit contrasting gene regulation, particularly for hpa2 and hrcT. Other two-component system regulators (Zur, LrpX, ColR/S, and Trh) did not completely inhibit the expression of hrcC, hrpD5, hrpE, and hpa3. Immunoblotting assays showed that the secretion of HrpF, which is an HpaB-independent translocator, is not affected by the mutation in hrpD6. However, the mutation in hrpD6 affects the secretion of an HpaB-dependent TAL effector, AvrXa27. These novel findings suggest that, apart from HrpG and HrpX, HrpD6 plays important roles not only in the regulation of hrp genes but also in the secretion of TAL effectors.https://apsjournals.apsnet.org/doi/10.1094/MPMI-09-10-0205 |
| spellingShingle | Yu-Rong Li Hua-Song Zou Yi-Zhou Che Yi-Ping Cui Wei Guo Li-Fang Zou Subhadeep Chatterjee Eulandria M. Biddle Ching-Hong Yang Gong-You Chen A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola Molecular Plant-Microbe Interactions |
| title | A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola |
| title_full | A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola |
| title_fullStr | A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola |
| title_full_unstemmed | A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola |
| title_short | A Novel Regulatory Role of HrpD6 in Regulating hrp-hrc-hpa Genes in Xanthomonas oryzae pv. oryzicola |
| title_sort | novel regulatory role of hrpd6 in regulating hrp hrc hpa genes in xanthomonas oryzae pv oryzicola |
| url | https://apsjournals.apsnet.org/doi/10.1094/MPMI-09-10-0205 |
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