PDF(Pubmed)
Abstract：
Alder yellows (ALY) phytoplasma (16SrV-C) is associated with ALY, a disease of several Alnus (alder) species in Europe and A. rubra in North America. In all affected species, the symptoms are similar. However, latent infections are common. ALY phytoplasma includes different strains which may be occasionally transmitted to grapevines leading to some grapevine yellows diseases. In the current study, visual symptom assessment and PCR-based methods using universal and group-specific phytoplasma primers were used to update and extend knowledge on the occurrence, impact, and genetic diversity of ALY phytoplasma in declining and non-symptomatic A. glutinosa and A. cordata trees in the Basilicata and Campania regions of southern Italy. ALY phytoplasma was detected in 80% of alder trees examined. In symptomatic trees, no other cause of disease was observed. More than half of alder trees that tested phytoplasma-positive proved to be latently infected. A considerable genetic variability was observed among the newly recorded ALY phytoplasma strains in southern Italy in almost of the genes examined. These included 16S rRNA, 16S/23S rDNA spacer region, ribosomal protein rpsV (rpl22) and rpsC (rps3), map, imp, and groEL genes. Eleven new genotypes were identified at map gene sequence level. However, the genetic differences observed were not related to plant host species, geographical origin, and symptoms shown by infected alder trees. Also, this study indicates that ALY phytoplasma is more widespread than previously thought.
摘要：
Alder黄（ALY）植原体（16SrV-C）与ALY有关，欧洲的几种Alnus（al木）和北美的A.rubra的一种疾病。在所有受影响的物种中，症状相似。然而,潜伏感染很常见。ALY植物质包括不同的菌株，这些菌株可能偶尔传播给葡萄树，从而导致一些葡萄树黄色疾病。在目前的研究中,视觉症状评估和基于PCR的方法，使用通用和群体特异性的植原体引物，以更新和扩展知识的发生，影响，在意大利南部的Basilicata和Campania地区，下降且无症状的a.glutinosa和A.cordata树的ALY植物血浆的遗传多样性。在所检查的80％的al木中检测到ALY植物质。在有症状的树上，没有观察到其他疾病原因。超过一半的测试植物支原体阳性的al木被证明是潜在感染的。在意大利南部新记录的ALY植物质菌株中，几乎在所检查的基因中都观察到了相当大的遗传变异。这些包括16SrRNA，16S/23SrDNA间隔区，核糖体蛋白rpsV（rpl22）和rpsC（rps3），地图，imp,和GroEL基因。在图谱基因序列水平上鉴定出11种新的基因型。然而,观察到的遗传差异与植物宿主物种无关，地理起源,和受感染的秃木表现出的症状。此外，这项研究表明，ALY植原体比以前认为的更广泛。
