Wheat Blast and Fusarium Head Blight Display Contrasting Interaction Patterns on Ears of Wheat Genotypes Differing in Resistance
Wheat Blast and Fusarium Head Blight Display Contrasting Interaction Patterns on Ears of Wheat Genotypes Differing in Resistance
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DOI：
10.1094/phyto-09-15-0202-r
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发表时间：
2016-03-01
期刊：
影响因子：
3.2
通讯作者：
von Tiedemann, Andreas
中科院分区：
文献类型：
--
作者：
Ha, Xia;Koopmann, Birger;von Tiedemann, Andreas
从表型、组织学和基因表达水平上研究了小麦与两种穗部病原菌--小麦稻瘟病和小麦赤霉病的相互作用。接种MWB和F.graminearum的27个小麦品种中，大多数品种对稻瘟病和赤霉病表现出相反的病害反应。选择了表现BLAST(米兰，R)/(苏麦3号，S)和FHB(米兰，S)/(苏麦3，R)的两个品种米兰和苏麦3号。激光共聚焦扫描显微镜观察到MWB在两个品种上较早(接种后12h)侵染小穗，而禾谷镰刀菌较早侵染感病品种的花药。两种病原菌在感病品种小穗轴上的生长速度均明显快于抗病品种，说明抗性主要表现在小穗与轴相连的部位。总体而言，在所研究的四个相互作用中，O-2(-)和H_2O_2水平与疾病表达无关。不同的基因表达模式证实了不同的病害表型、真菌在轴上的传播和在小穗上的定殖模式。在分析的8个基因中，有7个基因受FHB的诱导作用强于BLAST。几丁质酶(Chi2)、β-1，3-葡聚糖酶(PR2)、植物防御素同源物(PRP1)和过氧化物酶(POX2)基因在米兰对这两种病原菌都有强烈的响应上调，而PR2和PR5(类似于thaumatin的蛋白)在两个品种上都被MWB瞬时触发。感染禾谷镰刀菌的小麦穗中肉桂酰辅酶A还原酶(CCR)、细胞色素P450(CYP709C1)和UDP-糖基转移酶(UGT)的表达上调较明显，而苏麦3号的UGT表达上调较高。小麦品种对赤霉病的抗性表现为UGT和CYP709C1在苏麦3号中的高表达。由于小麦对这两种穗部病原菌的反应不同，不可能存在共同的控制赤霉病和稻瘟病的抗性基因，这表明在多重抗性育种计划中需要叠加许多与抗性相关的基因。
The interaction of wheat with two ear pathogens, Magnaporthe wheat blast (MWB) and Fusarium graminearum (Fusarium head blight, FHB), was studied on the phenotypic, histological, and gene expression level. Most of the 27 wheat cultivars inoculated with MWB and F. graminearum displayed inverse disease responses to blast and FHB infection. Two cultivars, Milan and Sumai 3, were selected expressing converse disease phenotypes to blast (Milan, R)/(Sumai 3, S) and FHB (Milan, S)/(Sumai 3, R). Confocal laser scanning microscopy revealed early (12 h postinoculation) colonization of the spikelets by MWB similarly on both cultivars, while F. graminearum infected anthers of the susceptible cultivar earlier. Both pathogens grew much faster in the rachilla of susceptible than resistant cultivars, indicating that resistance is mainly expressed in this part connecting the spikelet with the rachis. In general, O-2(-) and H2O2 levels were unrelated to disease expression in the four studied interactions. The differential disease phenotypes, fungal spread in the rachis, and colonization patterns in the spikelets were confirmed by distinct gene expression patterns. Among the eight genes analyzed, seven were more strongly induced by FHB than by blast. Genes for chitinase (Chi2), beta-1,3-glucanase (PR2), a plant defensin homolog (PRP1), and peroxidase (Pox2) were strongly upregulated in Milan in response to both pathogens, while PR2 and PR5 (thaumatin-like protein) were transiently triggered by MWB on both cultivars. Upregulation of cinnamoyl-CoA reductase (CCR), cytochrome P450 (CYP709C1), and UDP-glycosyl transferase (UGT) were more prominent in ears infected with F. graminearum, while upregulation of UGT was higher in Sumai 3 when infected with either pathogen. Cultivar resistance to FHB was reflected by clearly higher expression levels of UGT and CYP709C1 in Sumai 3. The differential responses of wheat to the two ear pathogens demonstrated in this study makes it unlikely that common resistance genes exist for control of FHB and blast, suggesting the need to stack many genes associated with resistance in breeding programs for multiple resistance.