Gutarra Liliam, Herrera Juan, Fernandez Elizabeth, Kreuze Jan, Lindqvist-Kreuze Hannele
Crop and Systems Sciences Division, International Potato CenterLima, Peru.
Genetics, Genomic and Crop Improvement Division, International Potato CenterLima, Peru.
Front Plant Sci. 2017 Jul 18;8:1221. doi: 10.3389/fpls.2017.01221. eCollection 2017.
The current bacterial wilt infestation level in the potato fields in the Peruvian Andes was investigated by collecting stem samples from wilted plants and detecting . In total 39 farmers' fields located in the central and northern Peru between the altitudes 2111 and 3742 m above sea level were sampled. was detected in 19 fields, and in 153 out of the 358 samples analyzed. Phylogenetic analysis using the partial sequence of the endoglucanase gene on strains collected in Peru between 1966 and 2016 from potato, pepper, tomato, plantain or soil, divided the strains in phylotypes I, IIA, and IIB. The Phylotype IIB isolates formed seven sequevar groups including the previously identified sequevars 1, 2, 3, 4, and 25. In addition to this, three new sequevars of phylotype IIB were identified. Phylotype IIA isolates from Peru clustered together with reference strains previously assigned to sequevars 5, 39, 41, and 50, and additionally one new sequevar was identified. The Phylotype I strain was similar to the sequevar 18. Most of the Peruvian isolates were IIB-1 strains. In the old collection sampled between 1966 and 2013, 72% were IIB-1 and in the new collection at 2016 no other strains were found. The pathogenicity of 25 isolates representing the IIA and IIB sequevar groups was tested on potato, tomato, eggplant and tobacco. All were highly aggressive on potato, but differed in pathogenicity on the other hosts, especially on tobacco. All IIA strains caused latent infection on tobacco and some strains also caused wilting, while IIB strains caused only few latent infections on this species. In conclusion, high molecular diversity was found among the strains in Peru. Most of the variability was found in areas that are no longer used for potato cultivation and thus these strains do not pose a real threat for potato production in the country. Compared to the previous data from the 1990s, the incidence of bacterial wilt has decreased in Peru. The epidemics are likely caused by infected seed tubers carrying the clonal brown rot strain IIB-1.
通过采集枯萎植株的茎样本并进行检测，对秘鲁安第斯山脉马铃薯田当前的青枯病侵染水平展开了调查。总共对位于秘鲁中部和北部、海拔在海平面2111米至3742米之间的39个农户田地进行了采样。在19个田地以及所分析的358个样本中的153个样本中检测到了[相关病菌]。利用1966年至2016年间从秘鲁的马铃薯、辣椒、番茄、大蕉或土壤中采集的菌株的内切葡聚糖酶基因部分序列进行系统发育分析，将这些菌株分为I型、IIA和IIB型。IIB型分离株形成了七个序列变种组，包括先前鉴定出的序列变种1、2、3、4和25。除此之外，还鉴定出了IIB型的三个新序列变种。来自秘鲁的IIA型分离株与先前归为序列变种5、39、41和50的参考菌株聚集在一起，另外还鉴定出一个新的序列变种。I型菌株与序列变种18相似。秘鲁的大多数[相关病菌]分离株为IIB - 1菌株。在1966年至2013年间采集的旧样本中，72%为IIB - 1，而在2016年的新样本中未发现其他菌株。对代表IIA和IIB序列变种组的25个分离株在马铃薯、番茄、茄子和烟草上进行了致病性测试。所有分离株对马铃薯都具有高度侵袭性，但对其他寄主的致病性存在差异，尤其是对烟草。所有IIA菌株在烟草上引起潜伏感染，一些菌株还导致萎蔫，而IIB菌株在该物种上仅引起少量潜伏感染。总之，在秘鲁的[相关病菌]菌株中发现了高度的分子多样性。大多数变异性存在于不再用于马铃薯种植的地区，因此这些菌株对该国的马铃薯生产并未构成真正威胁。与20世纪90年代的先前数据相比，秘鲁青枯病的发病率有所下降。疫情很可能是由携带克隆性褐腐病菌株IIB - 1的受感染种薯引起的。
