Phenotypic and Genotypic Characterization of Race TKTTF of Puccinia graminis f. sp tritici that Caused a Wheat Stem Rust Epidemic in Southern Ethiopia in 2013-14
Phenotypic and Genotypic Characterization of Race TKTTF of Puccinia graminis f. sp tritici that Caused a Wheat Stem Rust Epidemic in Southern Ethiopia in 2013-14
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DOI：
10.1094/phyto-11-14-0302-fi
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发表时间：
2015-07-01
期刊：
影响因子：
3.2
通讯作者：
Jin, Yue
中科院分区：
文献类型：
--
作者：
Olivera, Pablo;Newcomb, Maria;Jin, Yue
2013年11月至2014年1月期间，埃塞俄比亚南部发生了严重的秆锈病流行，种植最广泛的小麦品种“Digulu”的产量损失接近100%。从这些地区收集的64个茎锈病样品进行了分析。空气中孢子传播的气象模型被用来确定哪些地区最有可能从假设的初始感染地点被感染。通过对106个单脓疱菌株的分析，初步确定了禾柄锈菌的4个生理小种。鉴定出了四种常见的三疣梭子蟹sp.：TKTTF、TTKSK、RRTTF和JRCQC。TKTTF种族被认为是东南部Bale和Arsi地区流行病的主要原因。在2013年10月初从West Arsi采集的样本中首次鉴定出TKTTF小种分离株。在Bale和Arsi地区采集的31份样品中，该小种是唯一或优势小种。从Bale和Arsi区的15个样品中回收了低频率的TTKSK小种。基因分型表明，种族TKTTF的菌株属于一个遗传谱系，是从Ug99种族组不同，是由两个不同的遗传类型。从所选种质的评价结果表明，一些品种和育种系抗Ug99小种组感小种TKTTF。TKTTF小种的出现和随后的流行突出表明，茎锈病不仅在东非，而且对更大规模的小麦生产构成持续的威胁和挑战。
A severe stem rust epidemic occurred in southern Ethiopia during November 2013 to January 2014, with yield losses close to 100% on the most widely grown wheat cultivar, 'Digalu'. Sixty-four stem rust samples collected from the regions were analyzed. A meteorological model for airborne spore dispersal was used to identify which regions were most likely to have been infected from postulated sites of initial infection. Based on the analyses of 106 single-pustule isolates derived from these samples, four races of Puccinia graminis f. sp. tritici were identified: TKTTF, TTKSK, RRTTF, and JRCQC. Race TKTTF was found to be the primary cause of the epidemic in the southeastern zones of Bale and Arsi. Isolates of race TKTTF were first identified in samples collected in early October 2013 from West Arsi. It was the sole or predominant race in 31 samples collected from Bale and Arsi zones after the stem rust epidemic was established. Race TTKSK was recovered from 15 samples from Bale and Arsi zones at low frequencies. Genotyping indicated that isolates of race TKTTF belongs to a genetic lineage that is different from the Ug99 race group and is composed of two distinct genetic types. Results from evaluation of selected germplasm indicated that some cultivars and breeding lines resistant to the Ug99 race group are susceptible to race TKTTF. Appearance of race TKTTF and the ensuing epidemic underlines the continuing threats and challenges posed by stem rust not only in East Africa but also to wider-scale wheat production.