Incidence of endophyte Neotyphodium occultans in Lolium rigidum from Australia
Incidence of endophyte Neotyphodium occultans in Lolium rigidum from Australia
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DOI：
10.1111/j.1365-3180.2011.00846.x
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发表时间：
2011-06-01
期刊：
影响因子：
1.7
通讯作者：
Wu, H.
中科院分区：
文献类型：
--
作者：
Kirkby, K. A.;Pratley, J. E.;Wu, H.
P>黑麦草（一年生黑麦草）是澳大利亚南部谷类作物中广泛分布的杂草，经常进化出对除草剂的抗性。它通常与共生内生真菌Neotyphodium ocultans 相关。本研究的目的如下：(i) 确定澳大利亚南部刚性乳杆菌种群中隐藏隐孢子菌的发生情况，(ii) 评估感染频率与除草剂抗性、气候和地形变量之间的潜在关联，以及 (iii) 使用简单的序列重复标记检查来自该国家刚性乳杆菌收藏的隐匿假单胞菌的遗传多样性。通过对种子进行显微镜评估，我们发现所有种子批次都感染了隐匿球菌，感染频率差异很大，从 4% 到 98% 不等。新南威尔士州、南澳大利亚州和维多利亚州的频率（54-62%）高于西澳大利亚州（43%）或塔斯马尼亚州（17%）。海拔和平均降雨量以及感染频率之间存在负相关关系。显着的相互作用如下：平均降雨量（生长季节）和州以及平均降雨量（生长季节）和海拔。研究发现感染频率与除草剂作用方式之间存在显着相关性。对 B 组（磺酰脲类和咪唑啉酮）具有抗性的种子批次中感染率较低，对 D 组（二硝基苯胺）除草剂具有抗性的种子批次中感染率较高。早年的种子批次中观察到感染频率较高，最近收集的种子批次中感染频率最低。未发现与长期平均气温或降雨量存在显着关联。在澳大利亚植物中，几乎没有观察到隐球菌内生菌的遗传多样性。这些结果为 N. ocultans 与 L.rigidum 的关系提供了基准，并建议进一步研究这种内生菌在确定 L.rigidum 在不同除草剂抗性、降雨量和海拔条件下的适应性方面所起的作用，这可能有助于这种草的管理。
P>Lolium rigidum (annual ryegrass), a widespread weed of southern Australian cereal crops, has frequently evolved herbicide resistance. It is commonly found associated with the mutualistic, endophytic fungus, Neotyphodium occultans. The objectives of this study were as follows: (i) determine the occurrence of N. occultans in L. rigidum populations across southern Australia, (ii) evaluate potential associations between infection frequency and herbicide resistance, climatic and topographic variables and (iii) examine genetic diversity of N. occultans from this national collection of L. rigidum using simple sequence repeat markers. By microscopic assessment of seed, we found all seed lots were infected with N. occultans, with highly variable frequencies, ranging from 4% to 98%. Frequencies were higher in New South Wales, South Australia and Victoria (54-62%) than in Western Australia (43%) or Tasmania (17%). A negative association existed between elevation and mean rainfall, and infection frequency. Significant interactions were as follows: mean rainfall (growing season) and state and mean rainfall (growing season) and elevation. Significant associations were found between infection frequency and herbicide mode of action. Infection was lower in seed lots resistant to group B (sulfonylurea and imidazolinone) and higher in seed lots resistant to group D (dinitroaniline) herbicides. Higher infection frequencies were observed in seed lots from earlier years, with the lowest in seed lots recently collected. No significant associations were found with long-term mean temperature or rainfall. Little genetic diversity was observed for N. occultans endophyte in Australian plants. These results provide a benchmark of the relationship of N. occultans with L. rigidum and suggest further research on the role this endophyte has in determining the fitness of L. rigidum under varying conditions of herbicide resistance, rainfall and elevation that may aid in the management of this grass.