Identification of Novel Type III Secretion Effectors in Xanthomonas oryzae pv. oryzae
Identification of Novel Type III Secretion Effectors in Xanthomonas oryzae pv. oryzae
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DOI：
10.1094/mpmi-22-1-0096
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发表时间：
2009-01-01
影响因子：
3.5
通讯作者：
Tsuge, Seiji
中科院分区：
文献类型：
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作者：
Furutani, Ayako;Takaoka, Minako;Tsuge, Seiji
许多革兰氏阴性细菌通过III型分泌系统(T3S)分泌所谓的效应蛋白。通过对编码潜在T3S效应基因的基因组筛选，从水稻白叶枯病菌中筛选出60个候选基因。这些标准包括：i)植物病原细菌中已知的T3S效应物的同源物，ii)受HRP调节蛋白HrpX调控的基因，或iii)与紫丁香假单胞菌T3S底物相关的N末端氨基酸模式的蛋白质。在用百日咳杆菌钙调素依赖的腺苷环化酶报告转位到植物细胞的效应候选中，有16个蛋白质以T3S系统依赖的方式转位。在这16个蛋白质中，9个是其他植物病原细菌中已知的效应物的同源物，7个不是。大多数效应子在Xanthomonas spp.中广泛保守，但也有一些是X.oryzae所特有的。有趣的是，所有这些效应器都是以HrpX依赖的方式表达的，这表明效应器和T3S系统的共同调节。野油菜X.campestris pv.Vesicatoria、HpaB和HpaC(稻瘟病菌X.oryzae PV.Oryzae)在将T3S底物募集到分泌器官中起着核心作用。在HpaB(-)和HPAP(-)突变株中，除一个效应物外，其余效应物的分泌均减少，表明HpaB和HPAP广泛参与效应物的有效分泌。
Many gram-negative bacteria secrete so-called effector proteins via a type III secretion (T3S) system. Through genome screening for genes encoding potential T3S effectors, 60 candidates were selected from rice pathogen Xanthomonas oryzae pv. oryzae MAFF311018 using these criteria: i) homologs of known T3S effectors in plant-pathogenic bacteria, ii) genes with expression regulated by hrp regulatory protein HrpX, or iii) proteins with N-terminal amino acid patterns associated with T3S substrates of Pseudomonas syringae. Of effector candidates tested with the Bordetella pertussis calmodulin-dependent adenylate cyclase reporter for translocation into plant cells, 16 proteins were translocated in a T3S system-dependent manner. Of these 16 proteins, nine were homologs of known effectors in other plant-pathogenic bacteria and seven were not. Most of the effectors were widely conserved in Xanthomonas spp.; however, some were specific to X. oryzae. Interestingly, all these effectors were expressed in an HrpX-dependent manner, suggesting coregulation of effectors and the T3S system. In X. campestris pv. vesicatoria, HpaB and HpaC (HpaP in X. oryzae pv. oryzae) have a central role in recruiting T3S substrates to the secretion apparatus. Secretion of all but one effector was reduced in both HpaB(-) and HpaP(-) mutant strains, indicating that HpaB and HpaP are widely involved in efficient secretion of the effectors.